Abstract: Disclosed is a grid-connected inverter and a method for filtering AC output thereof. The grid-connected inverter comprises an AC output filter which includes two or more switchable filtering modules, power capacity of each filtering modules corresponding to a different output power of the grid-connected inverter; a monitoring module which is used to perform realtime monitoring on voltage and current outputted by the grid-connected inverter; and a control circuit which is used to calculate an output power grade of the grid-connected inverter according to the voltage and the current monitored by the monitoring module and control switching to the filtering module having a corresponding power capacity according to the power grade, the power grade being selected from a plurality of power grades which are divided according to power capacities of the filtering modules.

Abstract: A power conversion apparatus includes an inverter for converting DC power to AC power for supply to a load, a converter for converting AC power from an AC power supply to DC power for supply to the inverter, and a DC voltage converter for converting a voltage value of power stored in a storage battery and supplying DC power from the storage battery to the inverter when power supply by the AC power supply is abnormal. The converter includes a first three-level circuit which is a multi-level circuit. Similarly, the DC voltage converter includes a second three-level circuit. A control device controls the first and second multi-level circuits to suppress potential fluctuation at a neutral point between first and second capacitors.

Abstract: We describe a photovoltaic power conditioning unit comprising: both dc and ac power inputs; a dc link; at least one dc-to-dc converter coupled between dc input and dc link; and a dc-to-ac converter coupled between dc link and ac output. The dc-to-dc converter comprises: a transformer having input and output windings; an input dc-to-ac converter coupled between dc input and input winding; and an ac-to-dc converter coupled between output winding the dc link. The output winding has a winding tap between the first and second portions. The ac-to-dc converter comprises: first and second rectifiers, each connected to a respective first and second portion of the output winding, to the dc link and winding tap; and a series inductor connected to the winding tap. Rectifiers are connected to the winding tap of the output winding via the series inductor wherein the series inductor is shared between the first and second rectifiers.

Abstract: A power supply module includes an AC/DC converter, a voltage transforming circuit, a feedback circuit, and a filtering circuit. The AC/DC converter is used for converting the AC voltage to a primary DC voltage. The voltage transforming circuit is configured for transforming the primary DC voltage to the first DC voltage. The voltage transforming circuit includes a transformer, the transformer includes a primary winding. The feedback circuit is coupled to the primary winding of the transformer and is configured for sampling a current flowing through the primary winding to generate a feedback signal; and the filtering circuit is structured and arranged for filtering any surge voltage transmitted from the feedback circuit to the voltage transforming circuit. Wherein the voltage transforming circuit maintains the first DC voltage at a predetermined value according to the feedback signal. A related power supply module assembly is also provided.

Abstract: The PWM signal generator of the present invention generates a first pulse waveform in which a first on-time ?T1 calculated by a first on-time calculator (401) is used as an on-duration, and a second pulse waveform in which a second on-time ?T2, calculated by a second on-time calculator (402) when a preset delay time has elapsed from the start of the calculation of the first on-time ?T1, is used as an on-duration. Also, a PWM signal generator (413) generates a PWM signal on the basis of a composite pulse in which the generated first pulse waveform and second pulse waveform are combined, and the first on-time calculator (401) calculates the first on-time ?T1 at the end of the composite pulse waveform.

Abstract: A method and apparatus for LCL resonant converter control utilizing Asymmetric Voltage Cancellation is described. The methods to determine the optimal trajectory of the control variables are discussed. Practical implementations of sensing load parameters are included. Simple PI, PID and fuzzy logic controllers are included with AVC for achieving good transient response characteristics with output current regulation.

Abstract: An inverter for converting an input direct current (DC) waveform from a DC source to an output alternating current (AC) waveform for delivery to an AC grid includes an input converter, an output converter, and an active filter, each of which is electrically coupled to a bus. The bus may be a DC bus or an AC bus. The input converter is configured to convert the input DC waveform to a DC or AC bus waveform. The output converter is configured to convert the bus waveform to the output AC waveform at a grid frequency. The active filter is configured to reduce a double-frequency ripple power of the bus waveform by supplying power to and absorbing power from the power bus.

Abstract: A device for converting a DC voltage into an AC voltage includes a passive electronic filter having a first and second energy storage element, a third energy storage element placed between the first and second energy storage elements, a fourth energy storage element connected between a junction of the first energy storage element and the third energy storage element and an AC terminal and a fifth energy storage element connected between a junction of the second energy storage element and the third energy storage element and the AC terminal. The energy storage elements are of two different types, capacitive and inductive, with values selected to provide reduction of frequency components at two times the fundamental frequency of the AC voltage and at three times the fundamental frequency of the AC voltage.

Abstract: A wind turbine controlled to damp subsynchronous resonance oscillations on a grid is provided. The wind turbine includes rotor blades for turning by the wind, an electric generator rotatably coupled to the rotor blades, a power converter responsive to electricity generated by the electric generator, the power converter for converting the generated electricity to a frequency and voltage suitable for supply to the power grid, and the power converter for regulating voltage on the grid for damping the subsynchronous oscillations. Additionally, in one embodiment voltage regulation is supplemented by modulating real power to damp the subsynchronous oscillations.

Abstract: An exemplary power conversion system is disclosed including a DC bus for receiving DC power; a line side converter electrically coupled to the DC bus for converting the DC power to AC power; and a voltage source controller to provide control signals to enable the line side converter to regulate the AC power. The voltage source controller comprises a signal generator to generate the control signals based at least in part on a power command signal and a power feedback signal. The voltage source controller further comprises a current limiter to, during a transient event, limit the control signals based at least in part on an electrical current threshold. The voltage source controller further comprises a voltage limiter to, during the transient event, limit the control signals based at least in part on a DC bus voltage feedback signal and a DC boundary voltage threshold.

Abstract: A hybrid conditioner for filtering harmonics in a power system that includes a non-linear load. The hybrid conditioner includes an active filter structured and controlled to filter one or more high-order harmonic currents of the fundamental frequency, and a passive filter structured to filter one or more low-order harmonic currents of the fundamental frequency. The active filter and the passive filter are electrically connected in parallel with one another. The hybrid conditioner may also be for providing reactive power compensation for the power system, wherein the active filter is further controlled to provide a compensatory reactive power for compensating for the reactive power that is consumed by the load. The hybrid conditioner may also provide oscillation dampening for the power system, wherein the active filter is further controlled to damp oscillating currents that exist between the passive filter and the AC source.

Abstract: A system-interconnected inverter connected to a commercial system for supplying AC power, which inverter includes a switching device for turning on and off DC power based on a predetermined duty value to output a voltage whose frequency is the same as that of a system power source and a controller for controlling the switching device. The controller changes the duty value of the switching device in accordance with the value obtained by dividing the maximum value by the effective value of the output current from the switching device measured with the system-interconnected inverter disconnected from the system power source.

Abstract: A method and apparatus for converting DC electricity to AC electricity, the AC electricity having a sine wave shape. DC electricity is supplied to a pulse width modulator. A pulse width modulated signal is formed from the DC electricity, the pulse width modulated signal comprising a plurality of pulses, each pulse having a duration representing an amplitude of the sine wave during an interval of the sine wave represented by the pulse, the pulse width modulated signal comprising a plurality of pulses (or a pulse train) during one sine wave period. The sine wave is generated from the pulse width modulated signal, values of the sine wave during successive sine wave intervals responsive to the duration of the pulse that represents the sine wave interval.

Abstract: The object is to effectively reduce the resonant current flowing inside a converter unit and an inverter unit in a power conversion apparatus for an electric vehicle. The power conversion apparatus includes a converter unit that converts an alternating-current power into a direct-current power, an inverter unit that converts the direct-current power into an intended alternating-current power and supplies the intended alternating-current power to an electric motor that drives an electric vehicle, a housing that accommodates the converter unit and the inverter unit and a part of which is connected to ground, and a magnetic core that is disposed inside the housing and that suppresses the resonant current flowing between the converter unit and the inverter unit.

Abstract: A power converter that is able to lower the level of switching noise in a wide frequency range is disclosed. In detail, the power converter converts an input power by controlling a switching element on the basis of a switching frequency discrete pattern. The switching frequency discrete pattern is composed in such a manner that a main discrete pattern and a sub discrete pattern are synthesized. The main discrete pattern is regulated by a plurality of transitionally discrete frequencies. Also the sub discrete pattern is regulated by a plurality of transitionally discrete frequencies in which a gap of the magnitude among consequent frequencies is smaller than that of the main discrete pattern.

Abstract: A converter is provided as a power conversion device. The converter includes a switching circuit that performs switching on the basis of switching signals; and a control circuit that changes switching frequency of switching signals in a predetermined pattern with the elapse of time, and repeats the changes in switching frequency in the predetermined pattern at every repetition time. The converter sets the repetition time such that a repetition frequency that is the inverse of the repetition time does not coincide with a frequency band that can be demodulated as sound by a radio that receives radio broadcasts.

Abstract: An exemplary method for controlling transfer of electrical power in island mode in an arrangement having a converter and a load connected to the converter through a filter. The method including determining voltage reference components for one or more frequency components of an output voltage of the converter. An effect of a load current is compensated for by forming one or more voltage feedforward terms based on the load current and using the feedforward terms to adjust the voltage reference components. Control reference components for one or more of the frequency components are formed based on the voltage reference components, and a control reference is formed based on the control reference components. The output voltage of the converter is controlled based on the control reference.

Abstract: The system for offsetting the input voltage unbalance in multilevel inverters or the like comprises a control unit operatively associated with a multilevel inverter for converting direct current into alternate current, the control unit being suitable for piloting the multilevel inverter for generating an output current depending on a reference current, and an equalisation unit for equalising the input voltages of the multilevel inverter having first generation means of a harmonic component of order equal to the reference current, out of phase with respect to the fundamental component of the reference current, detection means of the unbalance of the input voltages to the multilevel inverter, regulation means of the amplitude of the harmonic component depending on the detected unbalance, for offsetting the unbalance.

Abstract: According to one embodiment, a grid-tie inverter includes: a inverter performing pulse width modulation for a DC voltage; a first capacitor circuit connected to an input side of the inverter so as to form a neutral point; a second capacitor circuit connected to an output side of the inverter so as to form a neutral point; a common mode current bypass channel formed by connecting the neutral points of the first capacitor circuit and the second capacitor circuit; a grounded capacitor provided between the bypass channel and a ground; a first common mode choke coil unit including a common mode choke coil at least one of between the first capacitor circuit and the inverter and between the inverter and the second capacitor circuit; and an output filter converting a pulse width-modulated voltage outputted from the inverter into a sine AC voltage.

Abstract: A power conversion system comprises a power converter comprising a plurality of semiconductor power switches, an LC filter coupled between an output of the power converter and an electric grid, and a power conversion control system. The LC filter comprises an inductor coupled in series to the electric grid, and a capacitor. The LC filter and the grid result in an equivalent LC circuit comprising an impedance of the LC filter and an impedance of the electric grid. The power conversion control system comprises a damper and a converter controller. The damper receives an LC filter signal and an equivalent LC circuit impedance signal and generates a damping signal. The converter controller receives a current or voltage reference signal, a current or voltage command signal, and the damping signal to generate control signals for driving switching operations of the semiconductor power switches.

Abstract: An inverter for converting an input direct current (DC) waveform from a DC source to an output alternating current (AC) waveform for delivery to an AC grid includes an input converter, an output converter, and an active filter, each of which is electrically coupled to a bus. The bus may be a DC bus or an AC bus. The input converter is configured to convert the input DC waveform to a DC or AC bus waveform. The output converter is configured to convert the bus waveform to the output AC waveform at a grid frequency. The active filter is configured to reduce a double-frequency ripple power of the bus waveform by supplying power to and absorbing power from the power bus.

Abstract: Provided herein are unified control methods and implementations for controlling single and three-phase power converters. In an exemplary embodiment, a unified controller is provided that can be used to control a three-phase three-wire Voltage Source Inverter (VSI), a three-phase four-wire VSI, a three-phase grid-connected power converter for current shaping, and a single-phase full bridge VSI.

Abstract: A power converter includes a first electric power conversion unit having an inverter for converting a first DC electric power to an AC electric power, an AC circuit connected to the first electric power conversion means; a second electric power conversion unit for receiving the first DC electric power and converting the same to a second DC electric power having a voltage level that differs from the voltage level of the first DC electric power, a power storage unit for storing the second DC electric power of the second electric power conversion unit; and a ripple suppressor having a first inductance for guiding the second DC electric power of the second electric power conversion unit to the power storage means and a second inductance for suppressing the ripple component included in the second DC electric power arranged between the second electric power conversion unit and the power storage unit.

Abstract: A method and apparatus are provided for operation of a converter circuit, which includes a converter unit having a multiplicity of controllable power semiconductor switches, and which is connected via a transformer to a three-phase electrical AC voltage power supply system. The method includes controlling the controllable power semiconductor switches by means of a control signal which is formed from a regulating signal. In order to damp oscillations of a power supply system voltage above the fundamental frequency, a filtered power supply system current is formed by filtering a power supply system current using a low-pass filter characteristic. A filtered transformer inductance voltage is formed by filtering a transformer inductance voltage, which is formed from the power supply system current, using a low-pass filter characteristic. A filtered power supply system voltage is formed by filtering a power supply system voltage using a low-pass filter characteristic.

Abstract: An air conditioner is provided. A control unit of an outdoor unit of the air conditioner is divided into a plurality of blocks according to a set of rules. Then, the blocks are mounted on different substrates. Therefore, it is possible to simplify wiring, facilitating the interconnection of the blocks and enable the control unit to be managed in units of the blocks. In addition, it is possible to improve user convenience.

Abstract: There is provided a controller for a converter and a respective method of operating such a controller. The converter receives an input power and provides an output power by a switching operation wherein in an embodiment the output power has at least two phases. The controller includes an input for receiving a feedback signal depending on the output power of the converter, and an output for providing a control signal to the converter to thereby control the switching operation of the converter. The control signal corresponds to a switching pattern that is updated in response to the feedback signal. The control signal includes a harmonic compensation signal which reduces higher harmonics in the output power, the higher harmonics originating from a time delay between taking the feedback signal and the updating of the switching pattern.

Abstract: The specification discloses a wireless power charging system in which undesired frequencies in the primary coil are cancelled. Exemplary undesired frequencies are the harmonics of the primary coil drive signal. The system includes a sense transformer/coil, an injection transformer/coil, and a compensation signal generator. The sense transformer/coil senses the signal in the primary coil. The compensation signal generator receives the sensed signal and generates an injection signal whose constituent parts are equal in amplitude to, but pi phase different from, each undesired frequency. The combined signal is injected into the primary through the injection transformer/coil so that the injection signal cancels the undesired frequencies in the primary coil.

Abstract: A method and system for controlling a power converter system with first, second, and third phase legs with respective first, second, and third associated phase currents determine direction of current flow in at least two phase legs and switch states of the power converter system in response to the current flow directions to reduce ripple current in a connected direct current (DC)-bus capacitor.

Abstract: Current source converter drives and common mode voltage reduction techniques are presented in which a space vector modulation zero vector for current source inverter (or rectifier) control is selected according to the switching state of the current source rectifier (or inverter) and according to the AC input power and the AC output power to control the output common mode voltage.

Abstract: The present invention relates to a method and a control system for driving a three-strand brushless, electronically commutated electric motor (2), wherein a line AC voltage (UN) is rectified and fed via a slim DC link (8) with minimum DC link reactance as a DC link voltage (UZ) to an inverter (10) that can be driven to supply and commutate the electric motor (2). A pulsating DC voltage (UG) initially generated by rectifying the line AC voltage (UN) is dynamically increased with respect to its instantaneous values by a step-up chopper (18) in such a manner that the resulting DC link voltage (UZ) with a reduced ripple always lies above a defined limit voltage (U18/U1) over time. The control system consists of a network rectifier (6), a downstream slim DC link (8) with minimum DC link reactance and a controllable inverter (10) that can be supplied via the DC link and driven to commutate the electric motor (2).

Abstract: A power converting apparatus is provided with a step-up chopper circuit (2) that steps-up an input voltage (Vi) from a distributed power supply, an inverter circuit (3) that converts the output voltage (Vd) of the step-up chopper circuit (2) into alternating current, a first control circuit for controlling the output voltage (Vd), and a second control circuit for controlling the chopper input current (Ii). The first control circuit generates a target current value (Ir) so as to make the output voltage (Vd) become a target output voltage value (Vr). The second control circuit controls the step-up chopper circuit (2) so as to make the chopper input current (Ii) become the target current value (Ir). The first control circuit also has a low-pass filter (23a) that removes ripple components included in the output voltage (Vd).

Abstract: A snubber circuit for a switching converter. A power source has a first rail and a second rail. A snubber transformer has a primary winding and a secondary winding, a first end of each of the primary and secondary windings being coupled together to form a transformer common point and a second end of the primary winding being connected to a half-bridge switching converter. A first capacitor is connected between the first rail and the transformer common point. A second capacitor is connected between the second rail and the transformer common point. A first diode is connected between the secondary winding and the first rail. A second diode is connected between the secondary winding and the second rail. The snubber circuit suppresses voltage transients and recovers energy from said voltage transients. In one embodiment the switching converter is a half-bridge configuration with zero current switching in a multi-level topology.

Abstract: Voltage synthesis using virtual quadrature sources may be provided. First, a quadrature wave form may be created. The quadrature wave form may have the same frequency as an input voltage and may be ninety degrees out of phase with the input voltage. Next, a harmonic wave form may be created. The harmonic wave form may be based upon an even harmonic of the input voltage and may comprise a triplen wave form. Then, the quadrature wave form and the harmonic wave form may be added to create a resultant wave form. The resultant wave form may be contained within an envelope defined by the input voltage. Next, duty cycle control may be applied to the resultant wave form to create an output voltage. The duty cycle control may be applied without using an energy storage device.

Abstract: Systems and methods for improved VSDs are provided. One embodiment relates to an apparatus for common mode and differential mode filtering for motor or compressor bearing protection when operating with VSDs, including conducted EMI/RFI input power mains mitigation. Another embodiment relates to a method to extend the synchronous operation of an Active Converter to the AC mains voltage during complete line dropout. Another embodiment relates to an Active Converter-based Variable Speed Drive system with Improved Full Speed Efficiency.

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: The present invention relates to a multilevel inverter comprising: a converter unit converting an inputted AC power source to a direct current (DC) power source; a film capacitor rectifying the DC power source converted by the converter unit; an inverter unit converting the rectified DC power source to a three-phase current in response to a pulse width modulation (PWM) control signal and outputting the current; a current detector detecting a current outputted from the inverter unit; a power cell main controller generating a voltage instruction and a voltage instruction using the detected current; and a PWM controller generating the pulse width modulation (PWM) control signal using the voltage instruction and frequency instruction.

Abstract: A power conversion system comprises a power converter comprising a plurality of semiconductor power switches, an LC filter coupled between an output of the power converter and an electric grid, and a power conversion control system. The LC filter comprises an inductor coupled in series to the electric grid, and a capacitor. The LC filter and the grid result in an equivalent LC circuit comprising an impedance of the LC filter and an impedance of the electric grid. The power conversion control system comprises a damper and a converter controller. The damper receives an LC filter signal and an equivalent LC circuit impedance signal and generates a damping signal. The converter controller receives a current or voltage reference signal, a current or voltage command signal, and the damping signal to generate control signals for driving switching operations of the semiconductor power switches.

Abstract: Various embodiments of the present invention provide voltage converters and methods for using such. As one example, a voltage converter is disclosed that includes a transformer, an operational detector, and a controllable oscillator. The transformer includes a first winding and a second winding, and the operational detector provides an electrical output corresponding to an operational characteristic of the transformer. The controllable oscillator provides a clock output with a frequency corresponding to the electrical output. This clock output at least in part controls application of a voltage input to the first winding.

Abstract: An apparatus to convert a direct current to an alternating current includes a power module disposed between an input terminal of the direct current and output terminal of the alternating current, the power module comprising an on/off switch element, a first smoothing condenser connected in parallel with the power module, a second smoothing condenser connected in parallel with the power module, the second smoothing condenser comprising an electrostatic capacity less than the first smoothing condenser, a first wiring connecting the power module and the first smoothing condenser, and a second wiring connecting the power module and the second smoothing condenser, the second wiring comprising an inductance greater than the first wiring.

Abstract: A power source device includes: a switching section switching an input voltage supplied to a load section; a smoothing inductor section smoothing and outputting an output current to be supplied to the load section in accordance with a switching of the switching section; a first inductor section decreasing an output inductance value of the smoothing inductor section; a second inductor section increasing the output inductance value of the smoothing inductor section; an electromagnetic induction activating section activating the electromagnetic induction between the smoothing inductor section and the first or the second inductor section; a load current fluctuation detecting section detecting a steep fluctuation in a load current; and a control section controlling the electromagnetic induction activating section so as to activate the electromagnetic induction between the smoothing inductor section and the first or the second inductor section when the steep fluctuation of the load current is detected.

Abstract: An inverter filter is for a plurality of phases. The inverter filter includes a node; a differential mode filter including for each of the phases a first terminal, a second terminal, an inductor electrically connected between the first terminal and the second terminal, and first capacitor electrically connected between the inductor and the node. The inverter filter also includes a third terminal structured to be grounded, and a common mode filter. The common mode filter includes a resistor, and a second capacitor electrically connected in series with the resistor between the node and the third terminal.

Abstract: Power converter systems with high accuracy signal generation and associated methods are disclosed herein. In one embodiment, a method for controlling an inverter coupled to a grid includes receiving data representing a voltage signal of the grid, analyzing the received data in frequency domain, and extracting a fundamental frequency component from the analyzed data in frequency domain. The method can also include calculating a waveform based on the fundamental frequency component and controlling an output of the inverter based on the calculated waveform.

Abstract: In a grid-tie inverter, the DC input is phase and pulse-width modulated to define multiple phase shifted voltage pulses with the width of each pulse being modulated according to the grid AC amplitude for the corresponding portion of the AC phase.

Abstract: This invention deals with an advanced Real-time Grid Monitoring System (RTGMS) suitable for both single-phase and three-phase electric power systems. This invention provides an essential signal processing block to be used as a part of complex systems either focused on supervising and diagnosing power systems or devoted to control power processors interacting with the grid. This invention is based on a new algorithm very suitable for real-time characterization of the grid variables under distorted and unbalanced grid conditions. The main characteristic of this invention is the usage of a frequency-locked loop, based on detecting the grid frequency, for synchronizing to the grid variables. It results in a very robust system response in relation to existing technique based on the phase-angle detection since grid frequency is much more stable variable than the grid voltage/current phase-angle, mainly during grid faults.

Abstract: A power conversion device includes a power switching circuit that has a plurality of series circuits in each of which a switching element that operates as an upper arm and a switching element that operates as a lower arm are connected in series, and a control circuit that generates control signals for controlling the continuity or discontinuity of the switching elements, and, if the relationship between the state of a switching element in a control cycle and the state of the switching element in the next control cycle is a discontinuous relationship, that additionally performs control to make the switching element continuous or discontinuous on the basis of the state of the switching element in the control cycle and the state of the switching element in the next control cycle.

Abstract: A control circuit for a switching power supply (SPS) includes power input and output interfaces, a relay, a relay driving circuit, a microprocessor, and an alternating current/directing current (AC/DC) converter. The power input interface receives an external alternating current (AC) power signal, and transmits the AC power signal to the SPS via the power output interface. The AC/DC converter transforms the AC power signal into a direct current (DC) power signal to supply for the relay, the relay driving circuit, and the microprocessor. When a computer is turned on, the microprocessor sends a first control signal to control the relay driving circuit to drive the relay to connect the power input and output interfaces. When the computer is turned off, the microprocessor sends a second control signal to control the relay driving circuit to drive the relay to cut off connection between the power input and output interfaces.

Abstract: A device for converting a DC voltage into an AC voltage and vice versa comprises at least one phase leg with a first voltage source and a first inductor connected in series between a first DC terminal and a first AC terminal and with a second inductor and a second voltage source connected in series between the first AC terminal and a second DC terminal, where each of the voltage sources comprises at least a first and a second submodule in series-connection, each submodule comprising at least one power electronic switch connected in parallel with at least one capacitor. In the device, a passive electronic filter is arranged between the first and the second inductor as well as the first AC terminal for reducing harmonics in a circulating current.

Abstract: We describe a switch mode power supply having a power input, a switch, a transformer, and a power output. The transformer has a primary winding coupled to said power input via said switch, and a secondary winding coupled to said power output. The transformer further comprises an auxiliary winding and a coupling structure capacitatively coupled to said secondary winding of said transformer; wherein said coupling structure does not comprise a shield or screen between said primary and secondary windings. The switch mode power supply further comprises a coupling capacitor connected between said coupling structure and said auxiliary winding to provide a noise suppression voltage from said auxiliary winding to said secondary winding to at least partially cancel a common mode noise voltage on said secondary winding from unshielded coupling from said primary winding.

Abstract: A motor control system of the present invention includes an accurate electrical insulation deterioration detecting system. A voltage divider circuit is arranged between a negative DC output portion and a ground, through a normally open switch circuit. A detecting operation control section closes the normally open switch while a circuit breaker is opened, and places at least one of transistors electrically connected to a positive DC output portion into a conductive state, from among six transistors included in three arm circuits. A voltage across the first resistor is inputted as a divided voltage into a voltage comparator of a voltage comparison section. The voltage comparison section compares a divided voltage outputted from the voltage divider circuit and a reference voltage using the voltage comparator and outputs an alarm signal if the divided voltage exceeds the reference voltage.

Abstract: Exemplary embodiments of the present disclosure provide a method and controller for damping multimode electromagnetic oscillations in electric power systems which interconnect a plurality of generators and consumers. The controller for damping such oscillations includes a phasor measurement unit (PMU) and a power oscillation damper (POD) controller. Each oscillating mode signal is damped and then superposed to derive a control signal. A feedback controller is used to feedback the control signal to a power flow control device in the power system.