Abstract: An HVAC/R system is configured with a variable frequency drive power supply which provides power to each of a compressor, a condenser fan, and a blower. In some embodiments, the compressor has a three-phase motor and the condenser fan has a single-phase motor.

Abstract: A method and an apparatus for the failsafe monitoring of an electromotive drive without additional sensors, including a drive having a three-phase control of an electric motor, detection of the current and voltage profiles of each of the three phases, as they are forwarded to the motor by drive electronics, determination of the load speed while using the detected current and voltage values, where the determination of the load speed takes place by calculating an observer model with reference to the detected current, to the detected voltage, to the frequency preset by the control and to the characteristic data of the motor and generation of a failsafe switch signal for the motor when the calculated load speed does not correspond to a preset desired speed within the framework of preset tolerances. The load torque can also be determined and monitored with reference to the observer model.

Abstract: A sensorless induction motor control device with a function of correcting a slip frequency wherein a slip frequency estimation unit estimates the slip frequency from at least one kind of current flowing through the motor. A voltage command value calculation unit calculates a D-phase voltage command value and a Q-phase voltage command value which are used for controlling a voltage applied to the motor using a Q-phase current command value calculated based on a difference between a speed estimation value, which is calculated using an estimation value of the slip frequency, and an externally supplied speed command value. An ideal voltage command value determination unit determines an ideal voltage command value using the speed command value and the Q-phase current command value. An actual voltage command value calculation unit calculates an actual voltage command value using the D-phase voltage command value and the Q-phase voltage command value.

Abstract: A drive system has a low voltage system, a high voltage system, and a transformer. The high voltage system has drive units which correspond to power switching elements. A capacitance in the high voltage system serves as a flouting power source which supplies electric power to each of the drive units. An output voltage of a secondary side coil of the transformer is supplied to the capacitance. A comparator compares the output voltage at the secondary side coil of the transformer with a threshold value. A switching speed change part changes the switching speed of each of the power switching element based on the comparison result of the comparator.

Abstract: A power supply for an HVAC/R system is configured to provide back-up power functionality for situations when the main source of power fails. The power supply includes a DC power bus which receives power from the main source of power as well as a back up source. When the main source fails the back up source provides power to the DC power bus. Connected to the DC power bus is a variable frequency drive power supply (VFD). The VFD is configured to provide power to the components of the HVAC/R system based on power received from the DC power bus.

Abstract: A winding switching apparatus includes a winding switching device and a drive circuit. The winding switching device is configured to switch a plurality of windings of an AC motor. The drive circuit is configured to control the winding switching device. The winding switching device includes a winding switch, a diode bridge, and a capacitor. The diode bridge includes a positive-side DC output terminal, a negative-side DC output terminal, and AC input terminals. The AC input terminals corresponds to respective phases of the AC motor. The positive-side and negative-side DC output terminals are respectively connected to positive-side and negative-side DC buses provided in an inverter. The AC input terminals are respectively connected to winding-switching terminals corresponding to the respective phases of the AC motor. The AC input terminals are respectively connected to phase terminals provided in the winding switch.

Abstract: An automotive drive system and methods for making the same are provided. The system includes a three-phase motor and an inverter module. The three-phase motor includes a first set of windings each having a first magnetic polarity; and a second set of windings each having a second magnetic polarity that is opposite the first magnetic polarity. The first set of windings being electrically isolated from the second set of windings. The inverter module includes a first set of phase legs and a second set of phase legs. Each one of the first set of phase legs is coupled to a corresponding phase of the first set of windings, and each one of the second set of phase legs is coupled to a corresponding phase of the second set of windings.

Abstract: A brushless D.C. motor includes having a rotor and a plurality of stator windings that define a stator field when driven by a bridge circuit, where a microprocessor drives the bridge circuit using a pulse-width modulation logic. The brushless D.C. motor is driven by triggering a commutation of the stator field; voltage induced by rotating the rotor in a non-energized stator winding is monitored to determine whether the voltage reaches, exceeds or is below a threshold voltage. A delay time between triggering the commutation of the stator field and the voltage reaching, exceeding or being below the threshold voltage is determined; and using the determined delay time a triggering time point for a next commutation of the stator field.

Abstract: A motor control apparatus includes a current control unit which is configured to calculate dq-axis voltage commands to match d-axis and q-axis current commands with d-axis and q-axis currents of a motor current, respectively. A power conversion circuit is configured to drive the motor. A modulation factor command unit is configured to determine a modulation factor command. A modulation wave command unit is configured to determine modulation wave commands. A pulse width modulation generating unit is configured to generate a pulse width modulation pattern. A modulation factor saturation level calculating unit is configured to determine a modulation factor saturation level. A field-weakening control unit is configured to correct the d-axis current command.

Abstract: A power conversion device includes: an inverter that drives an alternating-current motor by converting a direct-current voltage into an alternating-current voltage of an arbitrary frequency; an alternating current disconnecting switching unit connected between the inverter and the alternating-current motor; a current detector that detects an output current of the inverter; and a controller that performs on/off-control of the plural switching elements in the inverter and switching control with respect to the switching unit, based on at least a current detected by the current detector. The controller has a configuration to be able to interrupt a fault current by setting the fault current to a state of generating a current zero point, when the fault current containing a direct-current component is generated between the inverter and the alternating-current motor.

Abstract: A motor drive system using a current source inverter (CSI) for providing the main power and an active filter for providing the reactive power and harmonics is disclosed. The CSI can be a load-commutated inverter (LCI) build using silicon-controlled rectifiers (SCRs), while the active filter can be based on a voltage-controlled inverter. An LCI circuit comprising of SCRs, wherein CSI is autosequentially turned off is provided. In other words, the negative voltage for turning the SCR off is not load dependent. A control scheme for operating the motor drive system through proper control of the SCRs in the LCI circuit is also provided. As presented, the motor drive system is able to feed medium to high voltage motors using a simple circuit, such that low-frequency torque pulsations are eliminated.

Abstract: An arrangement for exchanging power with a three-phase electric power network comprises a Voltage Source Converter having three phase legs with each a series connection of switching cells. The three phase legs are interconnected by forming a delta-connection. The arrangement also includes a control unit configured to calculate a value for amplitude and phase position for a zero-sequence current for which, when circulated in the delta-connection circuit of the three phase legs, the balance of the total direct voltage of each of the three phase legs with respect to the other two phase legs is restored will there be an unbalance and control the semiconductor devices of switching cells of the phase legs to add such a zero-sequence current to the currents of each phase leg of the converter.

Abstract: A second control unit includes a current-command generating unit that generates, based on a torque command T*, a current command of the motor, a voltage-amplitude-index calculating unit that calculates, based on the current command, a voltage amplitude index (a modulation ratio PMF), a current-command adjusting unit that generates, based on the modulation ratio PMF and a frequency FINV of the motor, a current command adjustment amount dV, and a voltage command/PWM signal generating unit including a pulsation-suppression-signal generating unit that generates, based on a DC voltage EFC, a pulsation suppression signal for suppressing a pulsation component of a power supply 2f component to generate a gate signal (a PWM signal) to an inverter.

Abstract: A control system includes an electric rotating machine; a driving circuit that is connected to a DC power supply, the driving circuit includes a frequency conversion unit configured such that, when the electric rotating machine is to be driven in a power running mode, the frequency conversion unit converts an output of the DC power supply into AC electric power, and when the electric rotating machine is to be driven in a regenerative operation mode, the frequency conversion unit converts an output of the electric rotating machine into DC electric power; and a control unit that controls the driving circuit, wherein the control unit judges whether a connection between the DC power supply and the driving circuit is being maintained, and is configured such that, when the connection is not being maintained, regenerative electric power generated by the electric rotating machine is reduced by controlling the driving circuit.

Abstract: A power supply device for supplying an electric power to a servo amplifier is configured by an AC/DC converter and a power accumulating device. Among a molding cycle, during a process where an amount of consumed power is small, a DC voltage is supplied to the servo amplifier from the AC/DC converter and a power is accumulated in the power accumulating device. In a process such as an injection process where a large power is required, a high DC voltage is supplied to the servo amplifier from the power accumulating device in place of the AC/DC converter.

Abstract: [Problem] In a pseudo-current source inverter which drives a motor at a high speed, a current phase adjustment is assured and facilitated to perform a field-weakening control or suppress a terminal voltage saturation at a time of the high-speed motor drive. [Means For Solving Problem] A phase advance correction is carried out for a magnetic flux phase information from which a 120 degree conduction pattern is obtained with a motor terminal voltage as a reference phase. The phase advance correction includes the correction of differentiating the terminal voltage detection signals of the motor, the adjustment of enlarging the phase advance correction quantity in a case where the motor load current is large, and delays the gate signals of the 120 degree conduction pattern in accordance with the speed estimation value through a delay counter and carries out the phase advance correction as the rising edge timing of the subsequent gate signal at the subsequent step phase.

Abstract: One embodiment of the invention includes a disk-drive spindle motor power regulator system. The system includes a switching system comprising at least one power transistor for each of a plurality of phases of a disk-drive spindle motor. The system also includes a switching controller configured to generate a plurality of switching signals configured to control the at least one power transistor for each of the plurality of phases of the disk-drive spindle motor. The system further includes a current monitor configured to measure a magnitude of an individual phase current through at least one of the plurality of phases of the disk-drive spindle motor.

Abstract: A solid state relay has independent charge pumps isolating each gate of a full bridge to achieve faster and proper gate turn on. The low side MOSFETs of the bridge are the current sensing device reducing loss and allowing a device controlled by the relay to achieve peak performance. Dynamic braking is achieved by the two low side MOSFETs being fully conducted and applying a load across the DC motor. Addition of a microprocessor to the device provides undervoltage sensing, current vs time readings, motor stall sensing, and motor temperature sensing. Motor temperature is detected by checking impedance of the motor at microsecond pulses to see if the motor is getting hot.

Abstract: In an AC motor driving circuit, a current-type rectifier circuit having a filter circuit and first bidirectional switches bridge-connected to the filter circuit is provided in an output of an AC power supply. An AC motor is connected to an output of the rectifier circuit through a voltage-type inverter. One terminal of each of second bidirectional switches is connected to corresponding one of output terminals of the current-type rectifier circuit. The other terminals of the second bidirectional switches are collectively connected to one terminal of a series circuit having a DC power supply and a reactor. The other terminal of the series circuit is connected to one output terminal of the current-type rectifier circuit. With this configuration, a large capacitor for a DC link can be dispensed with, so that a reduction in circuit size and weight can be attained.

Abstract: An alternating current motor control system constituted of: a control unit; a cycloconverter functionality; a phase control functionality; and a semiconductor switching unit comprising a plurality of electronically controlled semiconductor switches each associated with a particular winding of a target alternating current motor and each independently responsive to the control unit. In one embodiment the semiconductor switching unit is arranged to connect the windings of the target alternating current motor to a three phase power input in one of a star and a delta configuration responsive to the control unit.

Abstract: The invention relates to a switch arrangement of an electric motor drive (1). The electric motor drive comprises safety switches (3) determined by the safety of the drive, a controlled mechanical brake (4), a power supply circuit (5) of the brake control, a power converter (6), which power converter comprises a network rectifier (7) and a power rectifier (8) of the motor. The power rectifier of the motor is at least partly implemented with controlled semiconductor switches (9, 10) arranged into a bridge. The power converter comprises an intermediate circuit (11, 12) between the network rectifier and the power rectifier of the motor. The switch arrangement comprises normally-open switches (13, 14) in the intermediate circuit of the power converter (6).

Abstract: An HVAC/R system is configured with power storage for power back-up to maintain substantially uninterrupted power in the case of a main power failure. The power back-up system has a DC power source configured to be recharged, and provides power to the HVAC/R components.

Abstract: Embodiments of the present invention provide novel techniques for using a switched converter to provide for three-phase alternating current (AC) rectification, regenerative braking, and direct current (DC) voltage boosting. In particular, one of the three legs of the switched converter is controlled with a set of pulse width modulation (PWM) control signals so that the input AC phase having the highest voltage is rectified and one of the switches in the two other legs is turned on to allow for added voltage. This switching activity allows for voltage from multiple AC line mains to be combined, resulting in an overall boost of the DC voltage of the rectifier. The DC voltage boost can then be applied to the common DC bus in order to ameliorate voltage sags, help with motor starts, and increase the ride-through capability of the motor.

Abstract: In a method for field-oriented operation to zero speed of an encoder-less asynchronous machine, wherein the associated field-oriented regulation device has a monitor with a machine model and rotation-speed adaptation, a model flux and a model current are calculated from a calculated actuating voltage and an adapted rotation speed, from which, in conjunction with a determined machine current, a complex difference is calculated. Also calculated is a model slip rotation speed as a function of the model flux and the model current, which is then scaled. The adapted rotation speed is then superimposed, and the sum is used as the rotation speed actual value which supplied to a rotation-speed regulator. An asynchronous machine without an encoder can therefore be operated to zero speed on a field-oriented basis.

Abstract: The present invention relates to a control technology of a three-phase DC motor. In order to resolve a problem in the prior art that the good current closed-loop control has not been realized on a three-phase square-wave brushless DC motor, the present invention provides a brushless DC motor control system, wherein cathodes of freewheel diodes D1, D3 and D5 are independent of input terminals of their respective switch tubes and connected in parallel to a sampling coil L1, and anodes of freewheel diodes D4, D6 and D2 are independent of output terminals of their respective switch tubes and connected in parallel to a sampling coil L2. The present invention can use a single resultant current sensor to completely and continuously sample the three-phase current existing during the motor is on and performs current freewheel, and perform the continuous closed-loop control on the three-phase current with a single current closed-loop regulator, thereby increasing dynamic and static indexes of the motor significantly.

Abstract: In an AC motor driving circuit from an AC power supply and a DC power supply, a matrix converter and a power conversion circuit are provided. The matrix converter is connected between an output of the AC power supply and an input of the AC motor. In the power conversion circuit, switches back-to-back connected to diodes, and bidirectional switches are series-connected, respectively. Connection junctions between the switches and the bidirectional switches are connected to the input phases of the AC motor, respectively. The other terminal of each switch is connected to one terminal of the DC power supply while the other terminal of each bidirectional switch is connected to the other terminal of the DC power supply. In this manner, the number of switches through which electric power passes at the time of operation is reduced so that loss can be reduced. Accordingly, power conversion efficiency can be improved.

Abstract: A winding switching apparatus for switching windings of an AC three-phase motor is provided. In each winding switching section of the winding switching apparatus, a positive-side charging resistor, a negative-side charging resistor, and a capacitor are connected in series between a positive-side DC bus and a negative-side DC bus of an inverter; the positive side of the capacitor is connected to the cathodes of respective diodes of a diode unit; and switching between high-speed windings and low-speed windings is carried out, with a capacitor potential being the same as an inverter DC bus voltage. A state detector and a comparator are also provided for each winding switching section to detect erroneous wiring and component abnormalities.

Abstract: Method for controlling a load with a predominantly inductive character, whereby in order to feed a phase of the above-mentioned load (3), use is made of at least two connected output voltages, derived from one or several power electronic inverters (11,12;34,35,36), with a given period for switching, modulation or sampling, characterized in that the waveforms of the output voltages concerned are different or have been shifted in time, and in that they are supplied to the load (3) via a differential-mode device (6), whereby during every complete above-mentioned period, at least one of the above-mentioned output voltages is maintained constant and thus is not connected.

Abstract: An AC machine control system for an AC machine (motor, generator, transformer, etc.) having open-ended windings, the control system comprising a drive circuit configured to transfer AC power between a first set of voltages and each end of the open-ended windings without the use of a substantial energy storage device, while eliminating common mode voltage and/or injecting zero sequence voltages.

Abstract: A motor control apparatus has a start control section. When the motor control apparatus receives a motor start command from a host control unit when a motor is in a stop state or a low-speed rotating state where a sensorless control cannot be applied, the control section starts the motor that rotates a vehicle fan by a forced commutation which supplies a pseudo sinusoidal drive signal caused by a complementary PWM control. Thereafter, the motor control apparatus switches over to a sensorless control using a rectangular wave drive signal at an energization angle of lower than 180°.

Abstract: A system for realizing rotor variable frequency speed control asynchronously and simultaneously is disclosed. Multiple motors are driven via one inverter, which consists of a motor group, a rectifier group, a chopper group, an isolator group, an amperite group, a power capacitor group, a full-bridge or a half-bridge, a speed feedback voltage detector group, and a current feedback voltage detector group. Using inversion control theory, the voltage outputs by a full or half-bridge inverter are an inverse electromotive force of each functional motor, and each motor operates asynchronously and simultaneously. This system may be used in crane operations. As a crane rises, redundant electricity is fed back to the motor via an inverter; and as the crane lowers, the motor will generate electricity, and the electricity is fed back to the motor via the inverter.

Abstract: A control apparatus for an electric railcar includes an inverter that exchanges power with an AC rotating machine, a filter capacitor connected in parallel to a DC side of the inverter, a filter reactor provided between the filter capacitor and an overhead line, an overhead line voltage measuring instrument that measures a voltage value of the overhead line, a voltage increase detection unit that senses an amount of voltage increase occurring when, with an overhead line voltage being supplied, the overhead line voltage goes beyond a reference voltage value and rises at a rate equal to or higher than that by a predetermined time constant.

Abstract: A machine has a basic body and a machine element. The machine element can be moved relative to the basic body by an electric working drive which is connected to an electric supply system via a working converter. An electric buffer drive is connected to the electric supply system via a buffer converter. The working converter and the buffer converter are controlled by a control device in line with a predetermined travel movement of the machine element in a coordinated manner. The coordination is such that a total load on the supply system by both converters together during the total travel movement of the machine element remains below a maximum load prompted by the working converter alone. The buffer drive has a drive shaft which has no flywheel connected to it.

Abstract: A motor control apparatus includes a step-up/down converter and an inverter. The converter includes a coil, MOSFETs, capacitors and a control circuit. The control circuit turns on the MOSFET in the high potential side, while tuning off the MOSFET in the low potential side. After a predetermined time, the control circuit turns off the MOSFET in the high potential side and then turns on the MOSFET in the low potential side. It is checked whether the MOSFET, which is switched in the step-down operation, is normal or abnormal based on the voltages of the capacitors. The capacitors produce specific changes in the respective voltages in correspondence to the check result. Thus, the abnormality of the MOSFET can be determined based on the changes.

Abstract: A component for introducing disturbances into the magnetic field of an asynchronous motor by altering a reluctance of the motor is disclosed. An asynchronous motor is provided that includes a stator having a plurality of windings that is configured to generate a rotating magnetic field when a current is provided to the plurality of windings. The asynchronous motor also includes a rotor positioned within the stator configured to rotate relative thereto responsive to the rotating magnetic field and a component separate from the stator and the rotor that is positioned within the rotating magnetic field, with the component being configured to alter a magnetic reluctance of the rotor so as create a disturbance in the rotating magnetic field.

Abstract: A device for controlling an induction motor includes a voltage/frequency controller, a pulse width modulation controller, and a converter. The voltage/frequency controller receives a controlling frequency, and outputs a controlling voltage corresponding to the controlling frequency. The pulse width modulation controller receives the controlling voltage and the controlling frequency, and generates PWM signals according to the controlling voltage and the controlling frequency. The converter receives the PWM signals, and controls the induction motor according to the PWM signals. There is a predetermined relationship between the controlling voltage and the controlling frequency stored in the voltage/frequency controller. The controlling voltage is greater than zero in response to the controlling frequency being zero, and increasing the controlling frequency increases the controlling voltage as in the predetermined relationship.

Abstract: A motor control system for heating, ventilation, and air conditioning (HVAC) applications is described. The motor control system includes a thermostat and an electronically commutated motor (ECM) coupled to the thermostat. The ECM is configured to retrofit an existing non-ECM electric motor included in an HVAC application and to operate in one of a plurality of HVAC modes. The HVAC modes include at least one of a heating mode, a cooling mode, and a continuous fan mode. The HVAC mode is determined based at least partially on outputs provided by the thermostat.

Abstract: A motor controller capable of effectively utilizing electrical energy accumulated in a capacitor and achieving a reduction in capacitance of the capacitor. The motor controller includes a converter that receives an input AC voltage and performs AC-to-DC power conversion thereon, an inverter that receives DC power and performs DC-to-AC conversion thereon, and a capacitor and a charging/discharging control circuit connected in parallel with a DC link between the converter and the inverter. Electrical energy is supplied from the capacitor to the DC link via the charging/discharging control circuit. The charging/discharging control circuit has a circuit for discharging electrical energy accumulated in the capacitor and for stepping up a voltage of the capacitor when discharging the electrical energy.

Abstract: A phase current estimation apparatus for a motor capable of suitably improving estimation accuracy of phase currents is provided. The phase current estimation apparatus 10 of the motor includes a control unit 24 that decomposes a command voltage vector Vdq into two vector components V?dq in the case where a magnitude of the command voltage vector Vdq is less than a predetermined lower limit voltage Vlow, so that the command voltage vector Vdq is allowed to have the magnitude equal to or more than the predetermined lower limit voltage Vlow for every two adjacent periods in units of a period of a carrier signal and to have the phase outside a predetermined phase range including phases of reference voltage vectors. Accordingly, the control unit 24 can quantitatively analyze harmonic components, which are generated by decomposing the command voltage vector Vdq into the two vector components V?dq, by using mathematical equations.

Abstract: An inverter control apparatus includes: a state estimator that calculates an estimated current vector and an estimated magnetic flux vector from a motor command voltage vector, a detected current vector, and a motor parameter; a correction voltage calculator that calculates a correction voltage vector on the basis of a current error between the detected current vector and the estimated current vector; and a correction voltage unit that adds the correction voltage vector to the motor command voltage vector.

Abstract: A ripple detection unit detects a ripple current width of a motor current controlled according to PWM control. A ripple reference setting unit sets a reference value of the ripple current width. A frequency adjusting unit sets a control signal indicating a carrier frequency of the PWM control according to a ripple current width deviation. A carrier generation unit generates a carrier of the frequency based on the control signal. Thus, it is possible to realize feedback control of the carrier frequency for maintaining the ripple current width at an appropriate level.

Abstract: The present invention relates to a motor controller for an air conditioner and a motor control method. The motor controller including a converter converting AC utility power into DC power and an inverter having a plurality of switching elements, the inverter receiving the DC power, converting the received DC power into AC power by switching operations of the switching elements, and supplies the AC power to a motor, the motor controller further including: a current detector detecting a current flowing in the motor controller; a temperature detector detecting a temperature in the motor controller or a temperature ambient to the motor controller; and a controller calculating a loading based on at least one of room temperature, setup temperature, and inner unit capacity and setting up a final target frequency for driving the motor based on the calculated loading and at least one of the detected current and the detected temperature.

Abstract: A control circuit for linear motors driving pumps or compressors that provides a programmable pressure versus flow behavior. The duty cycle of a pulse width modulated drive signal to a coil in the motor is controlled by a parameter determined by the shape of the back EMF signal generated by that coil when it is not driven. The measured parameter value is compared to a target value for the present drive pulse width, and the pulse width is adjusted to reduce the difference between the measured value and the target value. The target value is stored in a table of calibrated values that determines the desired pressure versus flow behavior and can also compensate for manufacturing differences between individual pumps.

Abstract: An open-loop and/or closed-loop control device for operating an asynchronous machine which is fed by a 3-phase power converter. The open-loop and/or closed-loop control structure has a stator flux controller and a pulse pattern generator for generating pulse signals based on mean values. An output of the stator flux controller is connected to an input of the pulse pattern generator, with the result that the pulse pattern generator can generate the pulse signals as a function of a manipulated variable which is generated by the stator flux controller. The stator flux controller is configured so as to generate the manipulated variable as a function of a desired value of the stator flux of the asynchronous machine and as a function of a desired value of the torque of the asynchronous machine. The stator flux controller has a dead-beat control response.

Abstract: A motor control circuit (MC) comprising input terminals (IT1, IT2) to receive a rectified input voltage (Vrm), and output terminals (OT1, OT2) to supply a motor drive signal (Vm). A switching circuit (1) is alternately in an on-state (Ton) and an off-state (Toff) for intermittently coupling the input terminals (IT1, IT2) to the output terminals (OT1, OT2). A controller (2) controls the switching circuit (1) to be (i) in the on-state (Ton) during a first period in time (T1) when an amount of magnetic saturation of the motor is smaller than a predetermined value, and (ii) alternately in the on-state (Ton) and the off-state (Toff) to obtain a pulse width control of the motor drive signal (Vm) during a second period in time (T2) when the amount of magnetic saturation of the motor is larger than the predetermined value.

Abstract: Systems and methods for providing electrical power and to downhole oil production equipment such as electrical submersible pumps, wherein the outputs of multiple power modules are individually filtered before being added together to obtain a high voltage output that is provided to the downhole equipment. In one embodiment, an electrical drive system includes multiple power modules and corresponding filters. Each of the power modules is configured to receive an input power signal and to provide a corresponding pulse width modulated or stepped intermediate signal. The signal output by each power module is individually filtered to remove at least a portion of high-frequency components in the signal. The power modules and filters are coupled together in a configuration in which the filtered signals of the power modules are added to produce an output drive signal that is used to drive equipment such as an electrical submersible pump.

Abstract: Methods and apparatus are provided for operation of a voltage source inverter. A method of operating a voltage source inverter having an output with multiple voltage phases having a DC voltage level, the method comprising sensing a low output frequency condition; determining a DC voltage offset responsive to the low output frequency condition; and applying the DC voltage offset when operating the voltage source inverter resulting in a change to the DC voltage level of the multiple voltage phases.

Abstract: A motor drive circuit has a converter for coupling to an AC voltage source and an inverter coupled to the converter for providing a drive current for a motor. A common mode circulation loop is coupled to the converter and to the inverter, and circulates common mode current from both the converter and the inverter.

Abstract: A control system of a three phase induction motor driver and a field weakening control method. The control system includes a driver control module, a field weakening control module, an AC power source, a power loop module, a current sensing module, and an AC motor module. A switching period of an inverter PWM control is used for the AC motor and an inverter control thereof to analyze and obtain the difference value of the sum of effective switching times. The field weakening control module generates an adaptive magnetizing current command in real time to achieve a maximum utilization of a DC link voltage so as to let the AC motor module achieve maximum output torque under different field weakening regions of different speeds when a rated speed is exceeded.

Abstract: There is provided a vector control device for an alternating-current electric motor having a damping controller which automatically calculates an optimum damping operation amount and does not require any gain setting itself, whereby an adjustment work of a control system can be simplified. The vector control device is equipped with a vector controller 30 for executing vector control on the alternating-current electric motor 6 in accordance with a current command or a torque command, and a damping controller 40 for calculating a damping operation amount for suppressing variation of a capacitor voltage Efc.