Abstract: A refrigeration apparatus includes a compressor, first and second heat exchangers, first and second electric valves, a passage-switching valve, a supercooling heat exchanger, and a controller. The first and second valves are disposed in first and second refrigerant passages. The supercooling heat exchanger conducts heat exchange between refrigerant flowing through the first and second refrigerant passages. The controller transitions to a defrosting operation mode upon determining that frost has formed on the second heat exchanger during a heating operation mode. The controller executes a defrosting preparatory control and a defrosting control after the defrosting preparatory control during the defrosting operation mode. The controller switches the passage-switching valve during the defrosting control. The controller narrows the opening degree of the first electric valve and controls the opening degree of the second electric valve to a minimum opening degree during the defrosting preparatory control.

Abstract: A motor driving device includes: an inverter control unit configured to generate and output a control signal for feedback-controlling a motor using a control command value for setting driving of the motor and a feedback value including a current value of driving power supplied to the motor; an inverter configured to supply driving power to the motor in accordance with the control signal output from the inverter control unit; and an abnormality detecting unit configured to detect an abnormality of the inverter. The abnormality detecting unit determines that the inverter is abnormal when a sum of three-phase AC voltage values of the driving power supplied to the motor is greater than a predetermined voltage value and a difference between the control command value supplied to the inverter control unit and the feedback value is less than a predetermined value.

Abstract: A motor control apparatus for a vehicle includes a data detector detecting driving data and a vehicle controller controlling a drive motor according to the driving data. The vehicle controller includes an acceleration generator determining a request torque and a request speed using the driving data and generating a request acceleration using the request torque and the request speed; a driving point determinator selecting an inductance control current map or a motor efficiency control current map according to the request acceleration and determining a current driving point according to the request torque and the request speed using the selected current map; and a motor controller controlling the drive motor using the current driving point.

Abstract: An embedded controller in a vehicle electronics subsystem includes a signal processing circuit used to communicate with an electric machine. The signal processing circuit may be configured to receive an input signal from the electric machine and provide digital output signals to the embedded controller. The digital output signals may include Hall position and rotor position signals. Once the digital output signals are processed by a processor embedded within the controller, the processor may issue a control command to the electric machine. The processor may have memory containing software to make the processor execute the computation of the control command of the electric machine in accordance with a torque command.

Abstract: An electrified vehicle propulsion system uses current feedback to modify gate drive signals to suppress voltage spikes and increase switching efficiency. A DC link having a link capacitor and a link inductance is connected to first and second converters. A first converter bridge has a first phase leg with first upper and lower switching devices, each switching device having a respective gate loop. A second converter bridge has a second phase leg with second upper and lower switching devices, each switching device having a respective gate loop. A plurality of gate drivers provide gate drive signals to respective gate loops for turning the respective switching devices on and off. A plurality of gate coils are provided, wherein each gate coil is connected in series between a respective gate driver and a respective gate loop. Each gate coil is respectively inductively coupled to the link inductance.

Abstract: A method for performing a jump starting operation or a remote charging operation of a recipient vehicle. A current path from an inverter to an electric drive of the donor vehicle is disconnected. For the jump starting operation, the inverter of the donor vehicle is connected on the output side to the electric drive of the recipient vehicle and the inverter of the donor vehicle is operated in the virtual driving operation mode and the electric drive of the recipient vehicle is started. During the remote charging operation, the inverter of the donor vehicle is connected on the output side to the inverter of the recipient vehicle and is operated in the virtual driving operation mode, while the inverter of the recipient vehicle is operated in the virtual recuperation operation mode and charges the discharged battery of the recipient vehicle.

Abstract: A power management device includes a first power unit, a second power unit, and a control unit. The first power unit receives a first control signal of a first phase to generate a first current of the first phase flowing to an output node. The second power unit receives a second control signal of a second phase to generate a second current of the second phase flowing to the output node. A phase delay is the difference between the first phase and the second phase. The control unit receives a clock signal in a clock frequency to generate the first control signal and the second control signal. The control unit controls the phase delay to cancel a corresponding harmonic of the clock frequency at the output node.

Abstract: A control method includes initially operating a compressor at the same RPM as an operating RPM of the compressor during a previous cycle, adjusting the RPM in consideration of an operation rate of the previous cycle such that the RPM is increased when the operation rate is greater than a first set value, reduced when the operation rate is less than a second set value, and maintained when the operation rate is within a range between the first set value and the second set value, and operating the compressor at the adjusted RPM, the first set value being greater than the second set value.

Abstract: A system and/or method for controlling a dual-three-phase machine with respect to a power electronics inverter is provided. The dual-three-phase machine includes six phase windings divided into at least two windings groups configured to provide a combination of six voltages that achieve zero common-mode voltage and a significantly reduced common-mode noise current.

Abstract: A three-phase rotating machine controller includes electric power converters that output, to the winding sets of a three-phase rotating machine, alternating currents having a same amplitude and a phase difference of (30 ±60*n) degrees from each other, n being an integer, and a control unit that reduces a peak of a phase current 1st order component applied to the rotating machine by superimposing therewith a phase current 5th order component and a phase current 7th order component, which have 5 times and 7 times the frequency of the phase current 1st order component, respectively. The control unit superimposes the phase current 5th and 7th order components having an optimum combination of amplitudes such that a peak reduction amount of the phase current 1st order component exceeds 5%, the amplitudes of the phase current 5th and 7th order components being with respect to the amplitude of the phase current 1st order component.

Abstract: Provided is a motor control device controlling several motors independently. The motor control device includes a plurality of inverters supplying power to each of several motors, respectively, and a control CPU provided with a command generator generating a control command, a PI controller that generates a torque command and a speed command by performing a proportional integral operation using feedback information and the control command transmitted from the command generator, and a vector controller that generates a PWM control signal using the torque command and the speed command and supplies the generated PWM signal to the plurality of inverters, in which the command generator includes an input translator that converts the command input as a QMCL command into the control command.

Abstract: Power supply and drive device for a permanent magnet motor including a full-wave voltage rectifier stage, which can be supplied with an alternating current voltage to provide a rectified voltage, a power factor corrector stage, a smoothing capacitor to provide a direct current voltage and a motor drive stage, which is supplied with the direct current voltage and provides a signal indicating the power required by the motor. The smoothing capacitor is not of the electrolytic type and the power factor corrector stage has feedback control means to generate a reference current as a function of the direct current voltage and of the signal indicating the power required and to control an input current of the power factor corrector stage as a function of the reference current.

Abstract: A system and method for position sensorless control of an AC electric machine is disclosed. A drive system for driving an AC electric machine provides a primary current excitation to drive the AC electric machine, the primary current excitation comprising a current vector having a magnitude and angle. The drive system injects a carrier signal to the AC electric machine that is superimposed onto the current vector, with the carrier signal being selected to generate a carrier response signal that has sensitivity to magnetic alignment information of the AC electric machine at its operating point. The drive system measures at least one magnetic alignment signature of the AC electric machine from the generated carrier response signal and controls an orientation of the current vector using the measured at least one magnetic alignment signature, so as to achieve a desired magnetic operation of the AC electric machine.

Abstract: Circuits, methods, and systems for driving a load are described. An exemplary driving circuit may include a plurality of switching devices and a controller electrically connected to the switching devices. The controller may be configured to receive a reference voltage signal indicating a target voltage for the driving circuit to generate to drive the load. The reference voltage signal may correspond to a reference space vector in a reference frame. The controller may also be configured to determine that the reference space vector falls within a holding region in which the reference voltage signal is subject to over-modulation. The controller may then generate an adjusted reference voltage signal by adjusting the reference space vector to match a predetermined space vector associated with the holding region. In addition, the controller may be configured to provide the adjusted reference voltage signal to the plurality of switching devices to drive the load.

Abstract: In a method for generating with a modular multilevel power converter (M2C) having a plurality of sub-modules a frequency-variable output voltage, the sub-modules are switched on and off to generate from an input voltage discrete voltage steps approximating an approximately sinusoidal alternating output voltage having a first angular frequency located between a zero frequency and a second angular frequency, and the input voltage is controlled or regulated as a function of the first angular frequency so as to be located between a lower angular frequency, which is equal to or greater than the zero frequency, and a third angular frequency, such that the input voltage increases with increasing first angular frequency, thereby reducing capacitor complexity in the power converter.

Abstract: A variable frequency motor drive comprises a converter including a rectifier having an input for connection to an AC power source and converting the AC power to DC power. A DC bus is connected to the rectifier circuit. At least one bus capacitor is across the DC bus. An inverter receives DC power from the DC bus and converts the DC power to AC power to drive a motor. A controller is operatively connected to the converter. The controller comprises a speed control controlling the inverter responsive to a speed command to maintain a desired motor speed. A speed foldback control measures DC bus ripple voltage and regulates the speed command responsive to the measured DC bus ripple voltage.

Abstract: A method and an apparatus for decoupling output power of an inverter are provided. The method comprises: obtaining voltage amplitude instruction E* and voltage phase instruction ?* according to an output voltage and an output current of the inverter; obtaining an amplitude feedforward amount Eff and a phase feedforward amount ?ff according to an amplitude U of a grid voltage of the power grid, an amplitude E of the output voltage of the inverter, and a phase difference ? between the output voltage of the inverter[0] and the grid voltage; obtaining a reference voltage amplitude Eref according to the voltage amplitude instruction E* and the amplitude feedforward amount Eff, and obtaining a reference voltage phase ?ref according to the voltage phase instruction ?* and the phase feedforward amount ?ff; and regulating the output power of the inverter using the reference voltage amplitude Eref and the reference voltage phase ?ref.

Abstract: A method of estimating stator resistance of an induction motor is provided. The method includes applying voltage pulses through two phase paths of the motor for a plurality of electrical cycles to inject current in the motor, wherein the voltage pulses are applied until rotor flux of the motor is substantially stabilized and measuring stator voltage and stator current in response to the applied voltage pulses for each of the plurality of electrical cycles. The method also includes calculating the stator resistance based upon the measured stator voltages and the stator currents.

Abstract: A power conversion device includes a high-pass filter for extracting an AC component of voltage Vdc of a DC link section, a multiplier for multiplying output VdcAC of the high-pass filter by a first gain K1 and outputting the result, a multiplier for multiplying output of the multiplier by a second gain K2 and outputting the result as a d-axis voltage correction signal vdcmp*, and a multiplier for multiplying output of the multiplier by a third gain K3 and outputting the result as a q-axis voltage correction signal vqcmp*. The gate signal generation section generates gate signals on the basis of a signal vd1 obtained by adding the d-axis voltage correction signal vdcmp* to a d-axis voltage command value vd* and a signal vq1 obtained by adding the q-axis voltage correction signal vqcmp* to a q-axis voltage command value vq*.

Abstract: A vehicle power system includes a controller configured to issue commands to open a selected set of switches of an inverter and then to operate the selected set of switches according to a pulse width modulation signal having an increasing duty cycle such that input current to a battery is driven towards zero and a magnitude of d-axis current of the drive system is reduced in response to a fault with an electric drive system.

Abstract: Systems and methods associated with example power converter systems are disclosed. For instance, a power converter system can include a power converter couplable to an input power source and configured to generate an output power substantially at a grid frequency. The power converter can include one or more inverter bridge circuits, each associated with an output phase of the power converter. Each inverter bridge circuit can include one or more first switching modules having a pair of switching elements coupled in series with one another, and an output coupled between the pair of switching elements. At least one switching element of each first switching module includes a reverse blocking transistor. The power converter further includes one or more input bridge circuits having a plurality of second switching modules coupled in parallel, each second switching module comprising a pair of silicon carbide transistors.

Abstract: A control system to realize input power changing along with both loads and rotate speed by an inverter bridge dragging many sets of motors, is composed of a stator voltage regulating unit (1), a motor unit (2), a rotor speed control unit (3), an inverter bridge unit (4), a control drive unit (5) and a signal processing unit (6). By setting a power factor sensor, the phase voltage and phase current of the motor stator are acquired as a control signal to regulate the input power so as to make it change with loads. At the same time, by setting a voltage sensor and a current sensor, motor rotor phase voltage, rectifier output current, overvoltage protection current and chopper working current are acquired separately as a control signal to regulate the input power so as to make it change with the rotate speed, thus realizing input power changing along with both loads and rotate speed.

Abstract: A controller of an AC electric vehicle includes a first specific-frequency-current computation unit that extracts a current component corresponding to a first specific frequency set value from a main-transformer output current and outputs the current component as a first specific-frequency current, a subtractor that subtracts the first specific-frequency current from the main-transformer output current and outputs a subtraction result as a current deviation, a second specific-frequency-current computation unit that extracts a current component corresponding to a second specific frequency set value from the current deviation and outputs the current component as a second specific-frequency current, and a power-failure detection unit that compares the second specific-frequency current with a predetermined power-failure detection-current set value and outputs a power-failure detection signal when the second specific-frequency current is larger than the power-failure detection-current set value.

Abstract: A power supply device includes a battery, an inverter, a converter, an electronic control unit. The inverter includes an upper arm having a third switching element and a lower arm having a fourth switching element. The converter includes an upper arm having a first switching element and a lower arm having a second switching element. The electronic control unit is configured to, when a state where the primary-side voltage is at least equal to the specified threshold continues for a specified time or longer, i) increase the primary-side voltage by repeatedly switching the second switching element between ON and OFF state while maintaining the first switching element to be OFF state, and apply the increased voltage as the secondary-side voltage to the inverter, and ii) convert the secondary-side voltage to the AC voltage by repeatedly switching each of the third and the fourth switching element between ON and OFF state.

Abstract: A DC power-supply device that suppresses an excessive inrush current, can prevent breakage of elements and burnout of circuits, and converts alternating current from a three-phase AC power supply into direct current to supply it to a load, includes a rectifier circuit having a reactor connected to input or output side thereof and rectifying the alternating current from the three-phase AC power supply; first and second capacitors and connected in series between output terminals to the load; a charging unit selectively charges one or both of the first and second capacitors; and a control unit controlling the charging unit. When charging of the first and second capacitors is started, the control unit reduces the on-duty ratio, and then, until the on-duty ratio during a normal operation is reached, the control unit executes control such that the on-duty ratio is gradually increased as a predetermined time period is passed.

Abstract: A backlash automatic detection system comprises a control device and a machine tool. The machine tool comprises a servo driver, a lead screw, a nut seat and a platform. The method comprises: entering an initial state and outputting a control command to the servo driver through the control device; driving the lead screw by the servo driver to move the nut seat towards a first direction and changing the movement direction of the nut seat towards a reverse second direction by the servo driver; defining a backlash phenomenon period according to one time point at which the nut seat starts to move towards the second direction and another time point at which the platform is driven to move by the nut seat; defining the displacement of the nut seat corresponding to the backlash phenomenon period as a backlash value.

Abstract: A method and system for maintaining consistent output for a pump powered by an electric motor, is provided, including: sending electrical measurements regarding power applied to the motor to a controller; determining if the electrical measurements indicate a power variation; changing the parameters of output from the motor to compensate for the variation. The system uses a controller configured to receive electrical measurements regarding power input to the motor, to determine if the electrical measurements indicate a power variation; and to change the parameters of output from the motor to compensate for the variation.

Abstract: In a motor control device that can perform more appropriate motor control, a switching arm has a first upper FET, a second upper FET, and a lower FET connected in series to one another. A source electrode of the second upper FET and a drain electrode of the lower FET are connected to each other via an intermediate line. The intermediate line is connected to a U-phase motor coil of a motor via a power line. The first upper FET, the second upper FET, and the lower FET are each provided with a parasitic diode that prevents current from flowing from a battery side to a ground side. A phase opening relay FET is provided on the U-phase power line. A parasitic diode of the phase opening relay FET is provided such that a current is not applied from the U-phase motor coil to the U-phase switching arm.

Abstract: A conversion device includes: a DC bus provided between a DC power supply and an AC power supply; a first converter provided between the DC power supply and the DC bus to perform DC/DC conversion; a second converter provided between the DC bus and the AC power supply to perform DC/AC or AC/DC conversion; and a control unit configured to selectively cause the first converter and the second converter to operate within one cycle of the AC power supply, to alternately generate a part of an absolute value of an AC waveform, and a DC waveform, as voltage of the DC bus, wherein the control unit adds a compensation value in a positive direction, to a voltage target value for the DC bus, at a timing that should have corresponded to a discontinuity point where the AC waveform and the DC waveform are connected to each other.

Abstract: Provided are a solar panel (1), a first DC/DC conversion circuit (13), a DC/AC conversion circuit (21) connected via a DC bus (25), a second DC/DC conversion circuit (17) for controlling bus voltage in the case of power outage, a first control section (14) having two kinds of control modes and controlling the first DC/DC conversion circuit (13), a second control section (18) for controlling the second DC/DC conversion circuit (17), and a third control section (22) for controlling the DC/AC conversion circuit (21). The second control section (18) controls bus voltage in the case of power outage, and the first control section (14) switches the control mode based on information of the second control section (18).

Abstract: A motor structure is provided. The motor structure has: a motor; a circuit board including a driver circuit for controlling the motor; an upper shell; a base; a lower shell; an outlet, wherein wires of the circuit board is connected to the exterior of the motor structure through the outlet; a first tight chamber, formed by closing the upper shell and the base together, wherein the motor is disposed in the first tight chamber; and a second tight chamber, formed by closing the base and the lower shell together, wherein the circuit board is disposed in the second tight chamber.

Abstract: A method of operating a touch screen sensor integrated circuit includes: receiving a plurality of current signals through a plurality of pins, wherein each current signal is generated according to mutual capacitance in response to a modulation signal; sensing the current signals and generating a plurality of sensed current signals corresponding to each of the current signals; and generating a plurality of subtracted current signals, wherein each subtracted current signal is generated by performing a subtraction on sensed current signals corresponding to a pair of the pins.

Abstract: A temperature estimation module estimates each junction temperature of a corresponding semiconductor device, among a plurality of semiconductor devices, for each phase of an inverter. The temperature estimation module or the data processing system determines a hottest device with a highest junction temperature among the semiconductor devices. A thermal adjustment module or data processing system determines if the highest junction temperature parameter is less than maximum junction temperature parameter for the respective semiconductor device or deciding whether or not to adjust a duty cycle of the semiconductor devices.

Abstract: A method (29) for controlling a synchronous reluctance electric motor (2) is suggested, wherein the electric voltage (7) that is applied to the synchronous reluctance electric motor (2) is controlled, and wherein the control of said electric voltage (7) is based on the electric current (14) in the d-q-reference frame (25, 26).

Abstract: A method of monitoring an electric motor circuit of the kind comprising an electric motor having a plurality of phases delta configuration, a plurality of electrical switches arranged in a bridge, operable in response to signals from a controller to selectively connect the phases to a power supply, the motor controller being responsive to a current error signal dependent on the difference between a demanded motor current value and an actual motor current value indicative of the actual current flowing in the motor where the method comprising the steps of processing at least one signal that is present in use of the electric motor circuit to identify a frequency component of the at least one signal that meets certain predefined criteria and in the event that the component is identified and that it does meet the criteria providing an indication that there is a fault.

Abstract: Power converter modules and parallel conversion systems are presented in which the modules are provided in a rollable enclosure having AC and DC electrical connections, and an interior including a switching circuit with switching devices individually connected between a corresponding AC node and a corresponding DC node for operation as either a rectifier or an inverter and an internal filter circuit with inductors individually connected between a corresponding AC node of the switching circuit and a corresponding AC electrical connection, with a built-in blower or fan to cool the filter circuit during operation.

Abstract: The device according to the invention controls a polyphase inverter (10, 14, 17) intended for powering from a DC current source (CC) a polyphase rotating electric machine (1). The device is of the type of those generating commutation functions driving commutation elements (9, 13) of the inverter in such a way as to obtain a reduction of the losses in the commutation elements and a decrease of an effective current in a decoupling capacitor (16) of the source (CC). According to the invention, this reduction and this decrease are obtained by means of a set of control strategies (21, 24) determining the commutation functions by using additional degrees of freedom of the polyphase machine (1) with respect to a three-phase reference machine. The polyphase machine comprises first and second phase windings forming a first three-phase system (2, 3, 4) and a second three-phase system (5, 6, 7) with distinct neutral points (11, 15) offset angularly by a predetermined angle of offset (?).

Abstract: A rotary machine includes two sets of three-phase stator winding wires and two sets of inverters connected to the same direct-current power supply. Alternating-current terminals of the inverters are respectively connected to the three-phase stator winding wires. Stator winding wires are housed in a plurality of slots to form a stator. The two sets of three-phase stator winding wires and the stator winding wires in the same phase of the sets are started to be wound from the slot positions, with phases thereof being different from each other by 180 degrees, among the plurality of slots and are finished being wound in the slot positions, with phases thereof different from each other by 180 degrees. Winding end points of the three-phase stator winding wires are respectively connected in common, and alternating-current voltages having the same magnitude and opposite phases are applied to the two sets of three-phase stator winding wire.

Abstract: A protective circuit for an inverter is disclosed, the protective circuit comprising a safety element, a switching arrangement, and a control circuit, with the safety element being arranged in a feed line to the power element, and the switching device being switched to the safety element such that the switching arrangement bridges the safety element when the switching arrangement is in a conducting state. The control circuit is embodied such that it, upon receipt of one control pulse or several successive control pulses, emits a switching signal to a switching arrangement for a predetermined period of time, with the switching arrangement being switched through in case of periodic receipt of the control pulses and with the absence of the control pulse opening the switching arrangement after a predetermined period of time, and triggering a protection of the inverter by the safety element.

Abstract: A method of estimating a rotational position of a motor having saliency includes the steps of a) superimposing, on a drive voltage to rotate a rotating portion of the motor, a measuring voltage having a predetermined frequency higher than a frequency of the drive voltage to generate a plurality of voltages, and supplying the plurality of voltages to a stationary portion of the motor; b) in parallel with step a), extracting a component of the predetermined frequency in a current flowing in the stationary portion as an extracted current; c) calculating a sum of squares of the extracted current and a phase-shifted current obtained by shifting a phase of the extracted current by ?/2 to acquire a composite signal related to an amplitude of the extracted current; and d) acquiring a rotational position of the rotating portion based on the composite signal.

Abstract: A method for operating a multi-phase modular power inverter having DC input terminals and AC phase voltage output terminals connected to a load, phase modules connected between the DC input terminals, with each phase module composed of valve arms connected in series at a connection point forming an AC phase voltage output terminal which is connected to a load, each valve arm having a plurality of power inverter cells with turn-off semiconductor switches and a choke connected in series, includes controlling, with a control device, the turn-off semiconductor switches of each power inverter cell as a function of a plurality of setpoint values, wherein the setpoint values are generated such that a time-averaged energy value stored in a capacitor of a corresponding power inverter cells is predetermined by an operating point of the load and-or an operating mode of the modular multi-level power inverter.

Abstract: The invention relates to a method (60) for controlling an inverter (10) using space-vector pulse width modulation, in particular to control an electric machine (14), said inverter (10) being equipped with a plurality of controllable switches (S) and being designed to provide a polyphase electric current (IU, IV, IW), in particular to supply multiphase electric current to an electric machine (14). In said method, a reference phase angle (alpha_R) is predefined, and the inverter (10) is controlled in such a way that a plurality of different successive switching states (V0-V7) is established for the switches (S) in order to provide the electric current (IU, IV, IW) in the form of a current space vector (I*).

Abstract: Circuits and methods for driving a load are disclosed. An exemplary driving circuit may include a plurality of switching devices and a controller electrically connected to the plurality of switching devices. The controller may be configured to provide a switching signal for controlling switching operations of the switching devices. The controller may also be configured to determine whether the switching signal falls within a predetermined dead zone. When it is determined that the switching signal falls within the predetermined dead zone, the controller may be configured to modify the switching signal by moving a space vector corresponding to the switching signal to a boundary of the predetermined dead zone. In addition, the controller may be configured to provide the modified switching signal to the switching devices.

Abstract: An electric motor in a work apparatus has a power characteristic line which runs between a lower rotational speed of the electric motor and an upper rotational speed of the electric motor. The power characteristic line has a power characteristic with a pronounced maximum (M) and an operating plateau (AP) which lies in a working rotational speed range (AD) of the work apparatus. A method for operating the electric motor provides for configuring the position of the operating plateau (AP) to be variable with respect to the rotational speed of the electric motor to achieve stable operating points over a wide rotational speed range.

Abstract: A multiphase motor generator system includes a multiphase induction motor having a plurality of separate terminals, a multiphase inverter coupled to a DC link voltage source and the plurality of terminals of the multiphase induction motor, a plurality of current detectors configured to detect a plurality of currents that flow between the multiphase inverter and the plurality of terminals of the multiphase induction motor, and a controller coupled to the current detectors and the multiphase inverter, and configured to receive the detected currents and output a plurality of control voltages to the multiphase inverter. The controller includes a multiphase to direct-quadrature (dq) conversion unit, a dq equivalent unit, a dq to multiphase conversion unit, and a pulse-width-modulator (PWM) converter.

Abstract: There is provided a refrigeration cycle apparatus in which an outdoor heat source unit, an indoor unit, and a water heating unit are connected, and an air conditioning operation and a water heating operation can be performed separately, and an exhaust-heat recovery operation can be performed by simultaneously performing air cooling and water heating. The outdoor heat source unit includes a compressor for compressing refrigerant, a refrigerant air-heat exchanger that performs heat exchange between the refrigerant and outside air, a fan for cooling the refrigerant air-heat exchanger, a control device that includes an inverter device for driving the compressor, and a heat sink for dissipating heat of the inverter device, and a switching element in the inverter device is constituted by an element formed by a wide bandgap semiconductor.

Abstract: Provided is a maximum power point (MPP) tracker for a PV cell inverter, and a PV cell inverter. The MPP tracker decouples output power oscillations from the input power generation and extracts maximum available power from the PV cell. The PV cell inverter uses the MPP tracker and generates a sinusoidal output current from the MPP tracker output. The sinusoidal output current may be fed to a power distribution grid. The PV cell inverter may use a pulse width modulation technique to cancel harmonics in the sinusoidal output current. The circuits use a minimum number of components and avoid use of large electrolytic capacitors.

Abstract: A method of estimating a rotational position of a motor having saliency, the method including the steps of a) superimposing, on a drive voltage for the motor, a measuring voltage having a predetermined frequency higher than a frequency of the drive voltage to generate three-phase voltages, and supplying the three-phase voltages to a stationary portion of the motor; b) in parallel with step a), extracting components of the predetermined frequency in three-phase currents flowing in the stationary portion as first, second, and third extracted currents; c) multiplying the first and second extracted currents together to acquire a first composite signal, multiplying the second and third extracted currents together to acquire a second composite signal, and multiplying the first and third extracted currents together to acquire a third composite signal; d) subjecting the first, second, and third composite signals to low-pass filtering to acquire first, second, and third filtered signals, respectively, the low-pass fil

Abstract: The present subject matter is directed to systems and methods for controlling variable speed generators, particularly converters associated with doubly-fed induction generators (DFIG) to permit use of harmonic attenuating filters that are generally smaller and less costly than previous similar filters. The subject matter provides for controlling line-side and rotor-side converters in such a manner that the frequencies generated by the converters are interleaved in a manner that the filters see a higher switching frequency and thus may be designed based on those higher frequencies, thereby requiring smaller and less expensive components.

Abstract: A method of controlling a motor includes a) acquiring a rotational speed parameter; b) selecting either a three-phase modulation scheme and a two-phase modulation scheme based on a result of comparing a rotational speed of the motor with a predetermined reference speed; c) calculating phase voltage command values based on a target rotational speed and the rotational speed parameter; d) generating switching signals by using the selected modulation scheme based on the phase voltage command values; and e) outputting the switching signals to an inverter. In step b), the two-phase modulation scheme is selected when the rotational speed of the motor is higher than the reference speed to reduce switching loss is reduced and improve power efficiency without deteriorating starting characteristics and motor drive characteristics when the rotational speed is low.