Abstract: A method for smoothing input current to a power delivery system having regeneration capability. The method comprises evaluating input current to an input converter of the power delivery system for a first fundamental cycle, and shifting a window relative to a waveform of an input voltage after the first fundamental cycle. The method also comprises evaluating input current to the input converter for a second fundamental cycle, and determining whether the input current of the second fundamental cycle is smoother than the input current of the first fundamental cycle.

Abstract: An inverter is devised to avoid high-frequency voltages at input terminals and to allow good efficiency thanks to its simple and cost-optimized circuit layout. This is achieved by a method of converting a direct current voltage, more specifically from a photovoltaic source of direct current voltage, into an alternating current voltage at a frequency through a bridge circuit comprising switching elements (V1-V 4) and free-wheeling elements (D1-D4), said switching elements (V1-V4) being on the one side gated at the frequency and on the other side clocked at a high clock rate, a direct current voltage circuit, an alternating current voltage circuit and a plurality of free-wheeling phases being provided.

Abstract: Presented is a harmonic regulator that regulates a plurality of individual harmonics in a system having periodic torque disturbances to commanded values, including zero. For each harmonic being regulated, a feedback signal having at least one harmonic component due to the harmonic being regulated is transformed from a source reference frame to a harmonic reference frame of the harmonic being regulated to form a qd feedback signal. The qd feedback signal is subtracted from the commanded value to form a qd signal and regulated. The regulated qd signal is transformed to a destination reference frame to form a compensation signal and the compensation signal is added to a control signal to form a qd control signal that drives each harmonic being regulated towards the commanded value.

Abstract: In a power inverter system, an inverter unit includes first to third single-phase inverters. In the power inverter system, a reference-frequency calculating unit calculates a reference frequency of each of the first to third single-phase inverters. A reference-voltage-calculating unit calculates a reference voltage of each of the single-phase inverters. In the power inverter system, a voltage-correcting unit adds a correction voltage to the reference voltage calculated by the reference voltage-calculating unit. The correction voltage has a frequency three times as high as the reference frequency.

Abstract: A control and regulation system for use with a harmonic neutralization frequency changer system. In the generalized frequency changer system, a direct converter frequency changer is used to convert bulk power, but unwanted harmonics are introduced. Input and output power distortion is monitored by a control system, and groups of high performance inverters inject shunt/series harmonic currents/voltages into a specially designed transformer to neutralize the power distortion to a specific acceptable level. Two control strategies are used including one that is based on discrete narrow band harmonic regulation and another that is based on wide band harmonic control. Each of these control strategies can be used at the input and/or output of the frequency changer and can be injected using shunt-current and series-voltage schemes.

Abstract: An active filter for reducing the common mode current in a pulse width modulated drive circuit driving a load said drive circuit comprising an a-c source, a rectifier connected to said a-c source and producing a rectified output voltage connected to a positive d-c bus and a negative d-c bus, a PWM inverter having input terminals coupled to said positive d-c bus and negative d-c bus and having a controlled a-c output, a load driven by said a-c output of said PWM inverter, a ground wire extending from said load, and a current sensor for measuring the common mode current in said drive circuit, said current sensor producing an output current related to said common mode current; said active filter comprising a first and second transistor, each having first and second main electrodes and a control electrode, and an amplifier circuit driving said transistors; said first electrode of said first and second transistor coupled to a common node, said second electrodes of said first and second transistors being coupled to

Abstract: A power supply for inductively powering a remote device has an inverter operating at an operating frequency and a primary coil. A phase comparator compares the phase of the voltage or current delivered by the power supply. If the phase relationship detected by the comparator is unacceptable, the inverter is disabled. After a period of time, the inverter is re-enabled, and the phase relationship is again determined.

Abstract: The invention recognizes that filter size can be reduced substantially as power factor is permitted to deviate below unity in systematic ways. Preferred methods of the invention provide specific, computable waveforms that permit use of a minimum filter size given a desired target power factor.

Abstract: Techniques are disclosed to regulate a power supply with a compensation signal generation circuit. One example regulated power supply includes a sense circuit coupled to sense an output voltage of the regulated power supply. The regulated power supply also includes a switching power converter circuit, which includes a switch coupled to be switched in response to a control signal received from the sense circuit to regulate the output voltage of the regulated power supply. The regulated power supply also includes a compensation signal generation circuit coupled to receive a switching signal representative of a switching of the switch in the switching power converter circuit. The compensation signal generation circuit is to generate a compensation signal responsive to the switching signal. The compensation signal is to be received by the sense circuit to modify the control signal.

Abstract: A motor driving apparatus makes a carrier signal of an inverter be synchronized with a carrier signal of a DC/DC converter, and determines a phase difference between both the carrier signals based on a ratio of an input voltage inputted to the DC/DC converter and an input voltage inputted to the inverter, and a percentage of modulation and a power factor which are operation parameters of the inverter. When the frequency of the carrier signal of the DC/DC converter is set to be twice as high as that of the carrier signal of the inverter, an optimal phase difference is determined based on the ratio of the input voltage of the DC/DC converter and the input voltage of the inverter.

Abstract: The present invention provides a voltage resonant converter that achieves ZVS over the entire allowable load range. A switching power supply circuit includes a class-E resonant converter as its primary-side switching converter that is supplied with a DC input voltage arising from the rectification and smoothing of a commercial AC voltage by a rectifier circuit (including a smoothing capacitor Ci). A choke coil of a primary-side series resonant circuit in the class-E switching converter is used as a primary winding N1 in an isolation converter transformer PIT. The total coupling coefficient between the primary side and secondary side is set to about 0.65 by the coupling coefficient of the isolation converter transformer PIT itself and equivalent parallel connection between a choke coil L10 and the primary winding N1. The resonant frequency fo1 of a primary-side parallel resonant circuit and the resonant frequency fo2 of the primary-side series resonant circuit are set to almost the same value of about 60 kHz.

Abstract: Variable speed drive comprising a main rectifier module (10) including thyristors (K1, K2, K3) to power a main continuous bus (15) from an external power network (5), an inverter module (30) delivering a variable control voltage to an electric motor from the main bus (15), an auxiliary rectifier module (20) connected to the external power network (5), an electronic control unit (50) controlling the thyristors, a powering module (29) supplying the control unit (50) from the auxiliary rectifier module (20) and from the main rectifier module (10). According to the invention, a switching device (40) controlled by the control unit (50) is used to disconnect the powering module (29) and the auxiliary rectifier module (20).

Abstract: An improved Single-Stage Buck-Boost inverter (S2B2 Inverter) is provided, using only three or four power semiconductor switches and two coupled inductors in a flyback arrangement. The inverter can handle a wide range of dc input voltages and produce a fixed ac output voltage. The inverter is well suited to distributed power generation systems such as photovoltaic and wind power and fuel cells, for standalone or grid connected applications. The inverter has a single charge loop, a positive discharge loop and a negative discharge loop.

Abstract: A voltage detector is connected to a connection terminal connected to one phase of an AC output of an inverter through a diode. A removable charge power supply is connected to said connection terminal and another connection terminal. A charge-power-supply connection judging circuit judges whether the charge power supply is or isn't connected, based on a charge power supply voltage detected by a voltage detector. A mode change control circuit outputs switch signal by the result of said judgment. By receiving this switch signal, the inverter controller switches the operation of the inverter between the Motor Drive mode or the Battery Charge mode. Thereby, a motor drive device detects a connecting status of an external charge power supply and steadily switches the operation of the inverter between the Motor Drive mode or the Battery Charge mode.

Abstract: Provided are a circuit and method for detecting an electric current which are capable of controlling the amount of electric current by detecting a load current of a current source using a switching type converter when controlling the load current of the current source which requires a high current, and compensating electric current flowing in the load. Accordingly, damage to the overall circuit is reduced compared to a related art method of detecting current using a resistor when detecting the load current of the current source with a high current, the amount of heat generated is reduced compared to such related art method, the overall efficiency of the current source device is enhanced and manufacturing costs are decreased.

Abstract: A common mode noise cancellation circuit eliminates common mode noise generated by a high-frequency switching device. The common mode noise reduction circuit includes a single switching device and a transformer. The switching device receives a rectified voltage and produces a switched voltage. The transformer includes a first primary winding, a second primary winding, and a secondary winding. The transformer couples the switched output from the first and the second primary winding to the secondary winding to generate a transformed voltage. A positive signed common mode noise waveform generated by the switching device is coupled from the first primary winding to the first secondary winding, and a negative signed common mode noise waveform generated by the switching device is coupled from the second primary winding to the first secondary winding, which results in a lower magnitude common mode noise waveform being present at the secondary winding.

Abstract: A DC/AC inverter for a backlight can include a support, a printed circuit board (PCB) on the support, a transformer on the PCB, and a blocking member formed on at least a portion of at least one side of the transformer. The blocking member can be formed of a ferrite material.

Abstract: A stabilized power supply for X-ray tubes having a first rectifier circuit, an inverter circuit comprising main switches, a transformer, a second rectifier circuit an oscillation circuit and an inverter circuit. The power supply includes an auxiliary circuit that can be, driven and is parallel-connected to the oscillation circuit. The auxiliary circuit duplicates changeover switching times of the switches of the inverter in order to limit an overlapping phenomenon that occurs for these switches during the changeover switching operations.

Abstract: A protection scheme to protect pulse width modulated drives is described. The scheme is implantable in both hardware and software and combinations thereof. The semiconductor devices of the drive are protected from transient signals such as power line spikes and loss of line. The present scheme uses an adaptive technique to determine the normal or steady state distortion (transients and harmonics) value in an unfiltered power signal. The present distortion value is compared to the normal distortion. If the present distortion exceeds the steady state value by a given amount, then the drive is placed in freewheel mode to protect the semiconductor devices in the drive.

Abstract: A control device receives an output voltage of a voltage-up converter from a voltage sensor, and calculates a feedback preliminary voltage control value determined by the difference between a voltage control value and the output voltage. The control device corrects the calculated feedback preliminary voltage control value in accordance with the output voltage to calculate a feedback voltage control value where the follow-up property of the output voltage with respect to the voltage control value is equal to a reference property. The control device controls the voltage-up converter using a feedback voltage control value. The voltage-up converter converts a direct current voltage from a DC power supply into the output voltage maintaining the follow-up property of the output voltage with respect to the voltage control value at the reference property.

Abstract: An output control device of a generation device including: a rectifier circuit that rectifies an output of an AC generator and applies the output across a battery; an inverter circuit provided between the battery and the generator; inverter control means for controlling the inverter circuit to convert a voltage across the battery into an AC control voltage and apply the voltage to an armature winding of the generator; and phase detection means for detecting a phase of a phase current flowing through the armature winding of the generator as a maximum output current phase, wherein the inverter control means is comprised to control a phase of the AC control voltage so as not to be delayed with respect to the maximum output current phase, and thus prevent a reduction in the output of the generator caused by an excessive delay of the phase of the AC control voltage.

Abstract: The present invention discloses an improved passive power filter circuit, wherein a rated compensating voltage is provided for the power factor compensating circuit in order to solve the problem of instable power output resulting from that the rated voltage is obtained via bypassing the standby power supply circuit in the conventional technology. Further, in the present invention, a circuit is used to pre-charge two filter capacitors, which are coupled to the DC output terminals of a rectifier, in order to offset the current phase advance or the current phase lag, which the conventional passive power filter circuit cannot solve, and thereby, the power factor is improved.

Abstract: A wind powered turbine with low voltage ride-through capability. An inverter is connected to the output of a turbine generator. The generator output is conditioned by the inverter resulting in an output voltage and current at a frequency and phase angle appropriate for transmission to a three-phase utility grid. A frequency and phase angle sensor is connected to the utility grid operative during a fault on the grid. A control system is connected to the sensor and to the inverter. The control system output is a current command signal enabling the inverter to put out a current waveform, which is of the same phase and frequency as detected by the sensor. The control system synthesizes current waveform templates for all three-phases based on a sensed voltage on one phase and transmits currents to all three-phases of the electrical system based on the synthesized current waveforms.

Abstract: Provided is an inverter circuit including a rectification and filter circuit and an inverter driver circuit interconnected the rectification and filter circuit and a load. The inverter driver circuit comprises a second controller for receiving light adjustment cycle signals and outputting electrical conduction cycle signals wherein the second controller is either electrically connected to a power source or electrically connected to the rectification and filter circuit for obtaining a wave current, and an electrical conduction of the electrical conduction cycle signals depends on input on/off of the wave current at the second controller; and a driver operates in response to electrical conduction cycle signals and on/off of DC. A flashing effect is produced on the load and thus a power factor correction effect is produced without power factor corrector being involved.

Abstract: A power system that increases the power capability of a DC/AC converter includes a processor coupled to the DC/AC converter and a memory subsystem coupled to the processor. The memory subsystem stores code that when executed by the processor instructs the processor to perform a number of steps. The processor determines when an electrical load that is coupled to the DC/AC converter causes a link voltage of the DC/AC converter to fall below a first predetermined link voltage level. The processor then controls a DC/AC output inverter of the DC/AC converter to cause the DC/AC converter to provide a non-sinusoidal output waveform. The processor also controls the DC/AC output inverter to cause the DC/AC converter to provide a sinusoidal output waveform, when the link voltage exceeds the first predetermined link voltage level or a second predetermined link voltage level.

Abstract: A contactless power supply has a dynamically configurable tank circuit powered by an inverter. The contactless power supply is inductively coupled to one or more loads. The inverter is connected to a DC power source. When loads are added or removed from the system, the contactless power supply is capable of modifying the resonant frequency of the tank circuit, the inverter frequency, the inverter duty cycle or the rail voltage of the DC power source.

Abstract: A noise suppressor capable of achieving reduction in size and weight of devices is provided. The noise suppressor is a circuit for suppressing normal mode noise which is transmitted through a first current-carrying wire and a second current-carrying wire, and causes a potential difference between the current-carrying wires, and the noise suppressor includes a magnetic core including one magnetic material portion and another magnetic material portion magnetically coupled to the one magnetic material portion, and forming two magnetic loops so as to share the one magnetic material portion between them, an inductor including a first coil and a second coil which are wound around the one magnetic material portion so as to have an odd number of turns in total, and are inserted into and connected to the first current-carrying wire in series; and a capacitor having one end connected to a connecting point between the first coil and the second coil and the other end connected to the second current-carrying wire.

Abstract: A method for controlling a device including a plurality of switching devices operated in accordance with a pulse width modulation technique includes receiving a reference voltage signal associated with a first pair of the switching devices. A switching signal is generated. The first pair of switching devices are controlled based on the reference voltage signal and the switching signal in accordance with the pulse width modulation technique. A frequency of the switching signal is varied based on the value of the reference voltage signal.

Abstract: A switching power source apparatus has a series circuit connected to both ends of a DC power source Vdc1 and having a reactor L3, a primary winding 5a of a transformer T, and a switch Q1, a series circuit connected to both ends of the primary winding and having an auxiliary switch Q2 and a clamp capacitor C3, a saturable reactor SL1 connected in parallel with the primary winding, a rectifying-smoothing circuit D1, D2, L1, C4 for rectifying and smoothing a voltage generated on a secondary winding 5b, and a control circuit 10 for alternately turning on/off the switches Q1 and Q2 and turning off the switch Q2 if a current of the switch Q2 increases due to saturation of the saturable reactor SL1. The reactor L3 is made of leakage inductance between the primary and secondary windings.

Abstract: An active filter for reducing the common mode current in a pulse width modulated drive circuit driving a load, said drive circuit comprising an a-c source, a rectifier connected to said a-c source and producing a rectified output voltage connected to a positive d-c bus and a negative d-c bus, a PWM inverter having input terminals coupled to said positive d-c bus and negative d-c bus and having a controlled a-c output, a load driven by said a-c output of said PWM inverter, a ground wire extending from said load, and a current sensor for measuring the common mode current in said drive circuit in said ground wire, said current sensor producing an output current related to said common mode current, said active filter comprising a first and second MOSFET transistor, each having first and second main electrodes and a control electrode, and an amplifier driving a respective one of the transistors; said first electrode of said first and second transistor coupled to a common node, said second electrodes of said first

Abstract: To suppress a DC component in AC power in a power converter for converting DC power to AC power. DC power is converted to AC power by a converter 2, and the AC power is supplied to output terminals u1 and u2 via an inductor 3. The converter 2 is controlled based on an error ?(t) between an output current ip(t) outputted from the converter 2 and a target current j(t) outputted from a target current generation means 110 as a target value for the output current ip(t), and a DC component VD in an output terminal voltage v(t) is detected by a voltage detection means 18. A DC component ID is suppressed by correcting a target current j(t) by a DC component suppression means 8.

Abstract: Independent phase output voltage control for a 3-phase 4-wire DC/AC inverter, for example, is provided. With the independent phase output voltage control, all three phase output voltages from the DC/AC inverter can be separately and effectively controlled to provide balanced 3-phase voltages from the DC/AC inverter to an unbalanced load, and/or to provide unbalanced 3-phase voltages from the DC/AC inverter to a balanced or unbalanced load. The independent phase output voltage control method can be applied to an inverter power system, with outputs of N-phase (N+1) wire configurations. Here, N can be any integer number greater than zero.

Abstract: The present invention relates to a multifunction power convertor in the field of power transmission. The multifunction power convertor consists of a rectifier circuit, a filter circuit connecting with the rectifier circuit, an inverter circuit connecting with the filter circuit, and differential mode voltage suppression reactors (LS1, LS2, LS3) and filter capacitor group that connect in series with the output lines (U, V, W) of the inverter circuit respectively. The characteristic of the present invention is that a closed magnetic ring is provided on the output lines (U, V, W) between the differential mode voltage suppression reactors and the filter capacitor group, and the output lines (U, V, W) wind in parallel on the closed magnetic ring.

Abstract: A power inverter control adjusts input power to track with output power to reduce energy handling requirements for an inverter DC bus. Input power to the power inverter circuit is measured and compared with a measurement of inverter output power. The comparison result is applied to a power factor correction circuit to adjust input power to track with output power, while obtaining a good power factor for the power inverter circuit. The energy requirements and ripple voltages or ripple currents on the DC bus are reduced, leading to a reduction in rating specifications for passive energy storage elements on the DC bus.

Abstract: The disclosure concerns a a motor drive apparatus, an electric actuator and an electric power steering apparatus capable of continuous torque control up to the high drive speed and high torque area, in order to enable quick acceleration and deceleration. A controller comprises a voltage saturation detecting apparatus for detecting the voltage saturation of the output voltage of an inverter circuit, based on the battery voltage, and a waveform controller that converts the drive waveform of the inverter circuit into the waveform created by superimposing harmonics of high odd-numbered order on a sinusoidal wave as a fundamental wave of the modulated wave modulated by a PWN carrier wave; and continuously changes the ratio of superimposing the high-order harmonics in response to the voltage saturation detected by a voltage saturation detecting means. This arrangement allows the controller to continuously change the drive waveform of the inverter circuit.

Abstract: A ripple current reduction circuit is provided that reduces the ripple current of a transformer by providing a substantially opposite or inverse ripple of an auxiliary current that can be combined with the ripple current of the transformer for cancellation or reduction of the ripple current.

Abstract: An inverter controlled generator set including: a power supply unit that uses a generator driven by an engine as a power supply to output a DC voltage; an inverter device that converts the output voltage of the power supply unit into an AC voltage; and a rotational speed control unit that controls a rotational speed of the engine so as to be kept at a target rotational speed suitable for a load applied to the inverter device, wherein the rotational speed control unit is comprised so that a settling time when the rotational speed of the engine is caused to converge to the target rotational speed in a state where the load is above a set value is longer than a settling time when the rotational speed is caused to converge to the target rotational speed in a state where the load is below the set value, in order to minimize an operation sound of the engine when the load is intermittently driven.

Abstract: Filter network for the reduction of the voltage switching speed between an electrical motor drive and an electrical motor and/or between an electrical distribution network and a motor drive, comprising for each electrical phase a self-damped inductor having a complex impedance determined by a magnitude (Z) and a phase (?), the phase (?) of the complex impedance being comprised between 80 and 90 degrees in the frequency range of the motor's current, and being less than 60 degrees in the frequency range of the overvoltage oscillations. Using the inventive filter network, it is possible to manufacture low cost and small size du/dt-filters generating low voltage overshoot and low losses.

Abstract: The present invention pertains to a method of determining a working voltage of an inverter, which utilizes a rectifying method to transform an alternating current into a pulse direct current, and then via a working frequency, divides a direct current cycle, which ranges in a lowest voltage–highest voltage–lowest voltage manner, into multiple continuous voltage pulses. The inverter receives each one of the multiple continuous voltage pulses and acts in response to each one of the multiple continuous voltage pulses and corresponding to the voltage cycle ranging between the lowest voltage and the highest voltage to output a variable voltage signal to a load. Thus, the working voltage of the inverter is analogous to the input voltage of the alternating current, and a power-factor regulating effect can be accomplished directly by the inverter.

Abstract: A method is described of regulating the instantaneous electromagnetic torque of a polyphase rotating electrical machine equipped with stator and/or rotor windings supplied by a voltage and a current generated by an inverter formed of switches whose switching is controllable. The method comprises a step of commanding the switching of the switches of the inverter using the fundamental frequency of the voltage generated by the inverter and a form of synchronous pulse width modulation configured as a function of an input set point, and a step of calculating the input set point from an instantaneous torque set point at each regulation time. The method further comprises a step of determining the time interval between two successive regulation times so that the time interval corresponds to an integer multiple of the period of oscillation of the instantaneous torque of the machine.

Abstract: A three-phase three-wire active power filter includes a dc power capacitor, a power converter, a filter inductor set, a reactive power compensating capacitor set, a combined capacitor/resistor filtering set and a control circuit. The dc power capacitor provides with a regulated voltage. The power converter includes a two-arm bridge power converter, and has a pair of ac terminals and a pair of dc terminals. A phase of the three-phase three-wire active power filter, without control of the power electronic switch set, directly connects with any one of the dc terminals. Consequently, the number of power electronic switches employed in the two-arm bridge power converter of the three-phase three-wire active power filter can be reduced.

Abstract: A first condenser is connected between output terminals of a rectifier circuit which receives an AC power as an input, and a three phase inverter is connected in parallel with respect to the first condenser, and output of the three phase inverter is supplied to a motor, and a second condenser is connected in parallel to the input side of the three phase inverter, and a current detector is connected between the first condenser and the second condenser, and a third condenser is connected in parallel to the first condenser at a position slightly power side with respect to the current detector, and the capacitance of the second condenser is determined as small as possible within the range in which power devices are not destroyed by surge voltage due to switching, therefore, ringing is suppressed, and taking of current is performed rapidly and with high accuracy.

Abstract: In a device for removing inverter noise, a pair of bus bars extending in parallel are grounded via a pair of capacitors. The capacitors are connected to the bus bars and to a grounding terminal at positions symmetrical to the pair of bus bars. Therefore, the inductance components are balanced from the source of noise to the grounded point, and impedance components are decreased from the two bus bars to a point grounded through the capacitors, making it possible to effectively remove high-frequency noise on the DC bus line of the inverter without requiring a large amount of space.

Abstract: A generating device that includes an AC/DC conversion unit having a rectifier circuit that rectifies an output of a magneto rotor and applies the output to a battery, and an inverter circuit that converts a voltage of the battery into an AC control voltage and applies the AC control voltage to an armature coil of the magneto generator, performs chopper control that controls switch elements of the inverter circuit so as to interrupt an output current of the magneto generator to control the output of the magneto generator when a rotational speed of the magneto generator is lower than a set speed, and performs drive control that applies the AC control voltage from the battery through the inverter circuit to the armature coil when the rotational speed becomes higher than the set speed, and changes a phase angle of the AC control voltage to control the output of the magneto generator.

Abstract: A system and method are provided to increase the horsepower of an induction motor. One technique for increasing the horsepower of a motor is to connect the motor to a variable speed drive that is providing an output voltage and frequency greater than the standard line voltage and frequency. The connection of the variable speed drive to the induction motor enables the motor to be operated in constant flux or constant volts/Hz mode and provide a greater output horsepower. Another technique for increasing the horsepower of a motor is to use a dual voltage motor configured for lower voltage operation and then provide the motor with the corresponding voltage and frequency for higher voltage operation. The higher voltage and higher frequency can be provided by a variable speed drive with or without voltage boost. A variable speed drive without voltage boost, but with frequency boost, can be used in situations where the standard main voltage is greater than the lower voltage rating.

Abstract: A half-bridge flyback power converter is provided. The half-bridge flyback power converter comprises a high-side switch and a low-side switch periodically conducting an input voltage to a primary winding of a transformer. When the high-side switch and the low-side switch are switched off, energy stored in the transformer is transmitted to a secondary circuit and serves to charge a bulk capacitor. A forward diode facilitates to combine the input voltage with a voltage across the bulk capacitor for powering the secondary circuit. Therefore, the power consumption of the leakage inductance is reduced and circuit topology is simplified.

Abstract: A motor control apparatus having a fundamental wave current control circuit that implements feedback control on a fundamental wave component of a motor current in a dq coordinate system rotating in synchronization with the rotation of the motor and a higher harmonic current control circuit that implements feedback control on a higher harmonic components of the motor current in a dhqh coordinate system rotating with a frequency which is an integral multiple of the frequency of the fundamental wave component of the motor current, eliminates the higher harmonic component of the motor current from the control deviation between a fundamental wave current command value and a motor current feedback value.

Abstract: An active damping arrangement for a power conditioning circuit comprising a converter or an inverter and an electronically driven output line having an output terminal for connecting to an external load, the active damping arrangement comprising an inductor-capacitor low-pass output filter (OPF) for connecting between an output of the inverter/converter (PWMVC or BBHCC) and the output terminal; means for sensing current in or voltage across the capacitor or voltage between one end of the capacitor (C) and an effective neutral point; means for multiplying the sensed voltage or current by a coefficient G to provide a damping signal, and means for feeding back the damping signal to an input of the inverter/converter (PWMVC or BBHCC), thereby to damp the output of the inverter/converter.

Abstract: Disclosed is a power supply for measuring the line impedance of an underground cable, which includes an input terminal section having a plurality of input terminals, a plurality of autotransformers, a transformer adjustment tap, a plurality of 3rd-harmonics cancellation transformers, and an output terminal section having a plurality of output terminals. The autotransformers are connected respectively to the input terminals. The transformer adjustment tap is connected to all of the autotransformers. The 3rd-harmonics cancellation transformers are connected respectively to the autotransformers. The output terminals are connected respectively to the 3rd-harmonics cancellation transformers.

Abstract: An AC ripple current reduction circuit for an AC converter having: an AC voltage source at the input; a first capacitor across which the circuit output voltage is provided; a first, main inductor in series with the first capacitor and the input; an auxiliary circuit including a second capacitor and a transformer coupled to the main inductor, the secondary of the transformer being in series with the second capacitor; and a means for enabling the flow of a time varying voltage across the first and second capacitors that has a frequency much less than the ripple frequency of the current in the main inductor.