Abstract: A power supply has a single stage converter for performing power factor correction to reduce high-frequency harmonics in the input current and performs resonant conversion to achieve zero-voltage switching or zero-current switching for power conversion. The inventive single stage converter includes a switching circuit, a resonant circuit, a power control circuit, and a square wave generator. The switching circuit includes at least one switch and the resonant circuit includes a LLC resonant tank. The power control circuit includes a proportional differential circuit such as a power amplifier configured in a negative feedback topology, and the square wave generator is configured to generate driving signals based on the frequency modulation control signal generated by the comparison of the sensed input current and a user-defined power level input, thereby allowing the square wave generator to regulate the switching operation of the switching circuit.

Abstract: An inverter control is used to control the output of a distributed power generating station, such as a photovoltaic (PV) solar power station, connected to a power grid. The power station is connected to an inverter output. Pulse width modulation is used to shape the output in order to maximize power output within power quality parameters and provides control of a switching frequency of the inverter responsive to a sensed parameter. The technique allows an increase in output efficiency and provides for adjustment of power output to meet power quality parameters to an extent required in order to connect to the power grid.

Abstract: A method of controlling a motor is provided. The method may determine a speed of the motor, and engage a soft chopping routine on a first switch and a second switch of each phase if the motor speed is relatively low. The first switch may be driven by a first pulse width modulated PWM signal and the second switch being driven by a second PWM signal. The first and second PWM signals may be alternatingly configured such that at least one of the first switch and the second switch is closed at any point during the distributed soft chopping routine and both the first switch and the second switch are never simultaneously open.

Abstract: A neutral point clamped three-phase three-level inverter is connected to a first DC power supply and single-phase inverters are connected in series with AC output lines of individual phases of the three-phase three-level inverter such that sums of output voltages of the three-phase three-level inverter and output voltages of the respective single-phase inverters are output to a load through a smoothing filter. An output control unit controls the three-phase three-level inverter so that the individual phases of the three-phase three-level inverter output primary voltage pulses at a rate of one pulse per half cycle and controls the individual single-phase inverters by PWM, so that output voltages to the individual phases of the load form sine waves of which phases are offset by 2?/3 from one phase to another, the sine waves having the same peak value.

Abstract: In a control apparatus for an inverter generator having a generator unit driven by an engine, a converter connected to the generator unit to convert an alternating current from the generator unit to a direct current, and an inverter connected to the converter to invert the direct current from the converter to an alternating current and output it to an electric load, it is configured to detect an overload condition based on the alternating current from the inverter to the electric load; stop outputting from the inverter to the electric load with the engine being kept operating when the overload condition is detected; output a release command to release a stop condition where the outputting to the electric load is stopped upon manipulation by an operator; and restart the outputting to the electric load by releasing the stop condition when the release command is outputted.

Abstract: Provided is a resonant switching power supply device that can reduce a common mode noise as well as an increase in frequency when a load is light. A resonant switching power supply device 1 equipped with a PFM control circuit 10 to control a switching frequency in such a way that an output voltage is brought to a desired value includes: a resonant circuit where a primary winding N1 of a transformer T2, a current resonant capacitor Cri and a reactor Lr are connected in series; rectifying circuits D1, D2 and Co that are connected to secondary windings N2 and N3 of the transformer T2 and obtain the output voltage Vo; and an electrostatic shield plate S1 disposed between the primary winding N1 and secondary windings N2 and N3 of the transformer T2.

Abstract: A control section which repeats inverter control in units of an inverter control period having a predetermined length is provided. In the control section, a phase current detection period in which a phase current is detected is provided between predetermined two inverter control periods, each of switching states of switching elements of a inverter circuit is controlled so that a voltage pulse having a larger width than a width of a voltage pulse in the inverter control period is output from a shunt resistor in the phase current detection period.

Abstract: A means of providing solar powered electricity for day and nighttime use supported in part by power from the grid to allow a small generator to electrify the home or business with a small generator operating with much larger capacity. Excess solar energy is provided to the power company as needed.

Abstract: A DC/DC converter for converting an input DC voltage between input lines into an output DC voltage between output lines includes: an AC current forward path connected via switching electric components to at least one of the output lines and at least one of the output lines; an AC current backflow path connected via same electric connections to at least one of the input lines and at least one of the output lines; and an auxiliary converter for compensating a sum of currents flowing via all forward and backflow paths, the auxiliary converter connecting one end of an compensation current path via two pulsed switches alternately to two lines at one side, the other end of the compensation path being connected to at least one line at the other side of the converter. The input lines are galvanically separated from the output lines by capacitances in all current paths.

Abstract: A pulse width modulation controller and method for output ripple reduction of a jittering frequency switching power supply detect the current of a power switch of the switching power supply to generate a current sense signal, and adjust the gain or the level of the current sense signal according to the switching frequency of the power switch to adjust the on time of the power switch, to reduce the output ripple of the switching power supply caused by the jittering frequency of the switching power supply.

Abstract: A ripple compensation apparatus comprises a ripple detection unit to detect a ripple on a dual DC bus, a waveform generation unit to generate a modulated waveform based on a base waveform and the detected ripple, and a multi-phase control signal generation unit to receive the modulated waveform and to generate at least one pulse width modulated control signal based on the modulated waveform.

Abstract: A method and apparatus to drive a load using a pulse-width modulated (PWM) signal and spread a spectrum of the PWM signal across a plurality of frequencies while maintaining a constant duty cycle for the load.

Abstract: An automatic synchronous parallelization apparatus capable of suppressing an inrush current by automatically adjusting the magnitude, the frequency, and the phase of the voltage when a single-phase voltage-type DC-to-AC converting device performing an autonomous parallel operation is connected in parallel with an external single-phase AC voltage source. The automatic synchronous parallelization apparatus includes a synchronization detecting circuit, a voltage amplitude command value generating circuit, and a frequency command value generating circuit.

Abstract: When applying a high frequency voltage which alternates on positive and negative sides to a permanent magnet synchronous motor, a driving system of synchronous motor switches the applied voltage phase by 120 degrees successively and applies resultant voltages to three phases. A pulsating current generated by applying a high frequency voltage is detected at timing of elapse of a predetermined time ?t since an output voltage of at least one phase has changed from a state in which all output voltages of the three phases of a power converter are positive or negative. Current detection is conducted by using a DC resistor or a phase current sensor provided on a DC bus. A magnetic pole estimation unit calculates the rotor magnetic pole position of the permanent magnet synchronous motor on the basis of differences between positive side and negative side change quantities in three-phase currents obtained from detected current values.

Abstract: A voltage source converter station including a multilevel voltage source converter, for conversion of electrical power between AC and DC, and a control system. The voltage source converter includes a plurality of switching cells including switchable semiconductors, and the control system includes at least one main control unit for providing a voltage reference signal and a plurality of cell control units. Each cell control unit uses carrier based pulse width modulation for controlling the switching of a respective cell, where the main control unit is communicatively connected to the cell control units and provides the reference voltage signal to each cell control unit and each cell control unit creates a switching signal to each respective switching cell using the reference voltage signal and a carrier signal to effectuate the conversion.

Abstract: An example controller for use in a power supply regulator includes a switch signal generator, a modulation circuit, and a multi-cycle modulator circuit. The modulation circuit modulates the period of a modulation switching signal when an equivalent switching frequency is greater than a reference frequency and fixes the switching period when the equivalent switching frequency is less than the reference frequency. The multi-cycle modulator circuit enables the switch signal generator to provide a switch signal uninterrupted if the equivalent switching frequency is greater than the reference frequency and disables the switch signal generator for a first time period and then enables the switch signal generator for a second time period when the equivalent frequency is less than the reference frequency. The multi-cycle modulator circuit varies the first time period to regulate the output.

Abstract: A method, system and apparatus for controlling a pulse width modulator (PMW) converter for direct AC/AC conversion and/or AC voltage regulation. According to some embodiments of the invention, an output voltage may be provided, independent of the input voltage quality, thereby avoiding or minimizing power company irregularities, brownouts and the like. Embodiments of the present invention may be useful, for example, for use in connection with motors and motored devices or other applications.

Abstract: A power converter system includes a converter configured to be coupled to a power generation unit for receiving power from the power generation unit, and a bus coupled to the converter, wherein a voltage is generated across the bus when electricity is conducted through the power converter system. The power converter system also includes an inverter coupled to the bus and configured to supply power to an electrical distribution network, and a control system coupled to the converter and to the inverter. The control system is configured to gradually adjust the voltage across the bus during at least one of a shutdown sequence and a startup sequence of the power converter system.

Abstract: A control apparatus and a control method for an AC electric motor detect DC bus current plural times at predetermined intervals during first and second predetermined periods and multiply vectors having integrated values of detected values during respective periods as elements by an inverse matrix of a matrix having integrated values during respective periods of sine and cosine functions of output voltage phase of an inverter at the moment that detection is made as elements to thereby estimate reactive and active currents.

Abstract: A display includes a power supply system using a power controller to switch a power switch to control power delivery, and an image scalar receiving a supply voltage and a supply current from the power supply system. An apparatus and method are proposed to determine a control signal in a standby mode by monitoring the supply voltage or the supply current, to wake up or turn off the power controller to reduce the switching times of the power switch in the standby mode, thereby reducing the switching loss of the power switch and the standby power consumption of the display.

Abstract: A control device for performing PWM control of an inverter includes a synchronous PWM control circuit for generating a control command for the inverter by performing PWM control based on a comparison between a sinusoidal voltage command signal for operating the AC motor according to, an operation command and a carrier signal, and a carrier generating unit for keeping an integer as a synchronization number being a frequency ratio between the voltage command signal and the carrier signal, and producing the carrier signal by switching the synchronization number according to an operation state of the AC motor. The carrier generating unit adjusts a phase relationship between the voltage command signal and the carrier signal according to the synchronization number such that an AC current transmitted between the inverter and the AC motor according to the control command provided from the synchronous PWM control circuit is symmetrical with respect to a boundary between positive and negative portions.

Abstract: The present invention includes: an inverter 1 configured to perform pulse wide modulation on an output from a DC power source 5; a first capacitor pair 41 provided at an input side of the inverter and including two capacitors serially connected to form a neutral point; a second capacitor pair 42 provided at an output side of the inverter and including two capacitors serially connected to form a neutral point; a bypass path g for a leakage current formed by connecting the neutral point of the first capacitor pair and the neutral point of the second capacitor pair to each other; at least one common mode choke coil 3 provided between the first capacitor pair and the second capacitor pair and configured to suppress a common mode current generated in the inverter; and an output filter 2 configured to convert a voltage, which is outputted from the inverter and subjected to the pulse wide modulation, into a voltage in a sine wave form.

Abstract: A power conversion apparatus includes two power conversion circuits, two direct-current inductors, and a pulse-width-modulation control circuit. One of the two power conversion circuits is connected in parallel to a direct-current load or a single-phase alternating-current load, and the other of the two power conversion circuits is connected in parallel to a three-phase alternating-current load. The two power conversion circuits are connected in reverse polarity to each other via the two direct-current inductors. The pulse-width-modulation control circuit pulse-width-modulates the two power conversion circuits, allows switching between the two power conversion circuits, and realizes a bidirectional step-up/down operation between the direct-current load or single-phase alternating-current load and the three-phase alternating-current load.

Abstract: A PWM signal for driving power transistors of a half-bridge of a converter is generated with the aid of a digital circuit, in which an internal reference value is compared to the counter content of a counting ramp. In this context, a logic state of the PWM signal depends upon whether the internal reference value is greater than the counter content of the counting ramp. After each comparison between the internal reference value and the counter content, an n-bit long data word dependent on the result of this comparison is output serially as PWM signal, n being greater than or equal to 2. The resolution of the PWM signal is thereby improved by the factor n in comparison to conventional systems, without markedly increasing the circuit expenditure.

Abstract: An optimized pseudo-random period pattern can reduce audible noise in a system that includes an inverter circuit configured to provide power to an electric machine. A system can include a PWM optimization module (POM) comprising the PPP. A carrier period for a carrier signal used to provide PWM inverter drive signals can be selected in accordance with the PPP. The PPP can be expressed as an array of 200-400 elements, each element a period belonging to a finite set of 2 or more predetermined periods. A period can be selected by index from the array, and the index incremented to progress through the PPP, which can be repeated upon its completion. The PPP can be optimized to reduce audible noise while mitigating inverter losses. Modeling techniques can determine the number of array elements, the number of possible periods, and the period values that optimize the PPP.

Abstract: A method and an arrangement of measuring inverter current, where the inverter is connected to and supplied by a DC intermediate circuit having two or more parallel capacitor branches connected between the positive and negative rail of the DC intermediate circuit, and the capacitance of the capacitor branches being known. The method comprises the steps of measuring the current of one of the parallel capacitor branches, and determining from the measured current the magnitude of the inverter current.

Abstract: An apparatus and method for controlling the delivery of a pre-determined amount of power from a DC source to an AC grid includes an inverter and an inverter controller. The inverter includes an input converter, an energy storage capacitor, and an output converter. The inverter controller includes an input converter controller and an output converter controller. The input converter controller includes feedforward controller configured to perform a calculation to determine a value for the duty cycle for the input converter such that: (1) the input converter delivers the pre-determined amount of power and (2) the magnitude of a ripple signal reflected into the input source is attenuated toward zero. The input converter controller may also include a quadrature corrector configured to determine the effectiveness of the calculation in attenuating the ripple and to adaptively alter the calculation to improve the effectiveness.

Abstract: A control system and method for a multi-phase motor substantially reduces or eliminates jitter resulting from. drive mismatch by replacing a conventional trapezoidal drive profile with a drive profile that causes the voltage applied across active phases of the motor to match the back-EMF across those phases. In an ideal motor, the back-EMF is substantially sinusoidal, and although the drive profile applied to each phase is not truly substantially sinusoidal, the drive voltage across the active phases is substantially sinusoidal. In a non-ideal motor, the back-EMF is not truly sinusoidal and the drive profiles applied to each phase are calculated to cause the drive voltage across the active phases to match the back-EMF across those phases.

Abstract: A timing controller includes a controller that controls an operation timing of a controlled unit, and a setting unit that associates a timing obtained by dividing a setting of the operation timing into a plurality of timings, each timing having an identification number, and sets the control unit so that an offset period based on the associated timing is added to the operation timing of the controlled unit.

Abstract: A pulse width modulator based on a pair of rotary traveling wave oscillators. The first oscillator operates freely or as part of a phase-locked loop. The second oscillator operates at the same frequency as the first oscillator, but with a controllable phase offset from the first oscillator. The phase offset is set by an input voltage. A block takes the outputs of the first and second oscillators and combines them so that the output is a pulse whose width is the overlap of the oscillation signals from the first and second oscillators. The output pulse width is thus a function of the input voltage. When the pulse width modulator receives the input voltage from the output of a switching power supply, it can use the modulated pulse width to control the switching transistor of the power supply to maintain the output at a regulated voltage.

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: An A/D conversion apparatus includes an N-stage pulse circulating circuit including N (N is a natural number, N?3) inverting circuits connected in a ring shape, the inverting circuits delaying an input pulse signal by a delay time corresponding to an amplitude of a separately input analog input signal, and outputting inverted pulse signals obtained by inverting the pulse signal, a counter unit that counts a number of circulations by which the pulse signal has circulated in the pulse circulating circuit within a predetermined time based on the inverted pulse signal output from one of the N inverting circuits, and a switching unit that switches an output destination of the inverted pulse signal, which is output from an inverting circuit of an Mth (M is an odd natural number, 1?M?N?1) stage of the pulse circulating circuit, according to a change in an operation environment.

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: In a neutral-point-clamped power inverter, gate drive circuit comprises four drive blocks providing bipolar DC signals to control switch gates. The first and third drive blocks are bootstrapped to the second and fourth. Inverter's neutral bus is commonly connected to the positive and negative DC buses through clamping capacitors. An arm of four serially-stacked-switches bridges DC buses. The switch arm midpoint is an output of the inverter. A first clamping diode connects the neutral bus to the first switch emitter; a second clamping diode connects the neutral bus to the third switch emitter. In one embodiment, a second switch arm mirrors the first, providing a second output; a second gate drive circuit mirrors the first. A bias circuit provides two reference voltages for the gate drive circuits. Three isolated DC sources provide signals that, when used by the gate drive circuit, result in seven isolated bipolar DC signals.

Abstract: Systems and methods are provided for delivering energy from an input interface to an output interface. An electrical system includes an input interface, an output interface, an energy conversion module coupled between the input interface and the output interface, and a control module. The control module determines a duty cycle control value for operating the energy conversion module to produce a desired voltage at the output interface. The control module determines an input power error at the input interface and adjusts the duty cycle control value in a manner that is influenced by the input power error, resulting in a compensated duty cycle control value. The control module operates switching elements of the energy conversion module to deliver energy to the output interface with a duty cycle that is influenced by the compensated duty cycle control value.

Abstract: A system and method for processing an analog signal output by a sensor. The system and method converting, using at least one analog-to-digital converter (ADC), the analog output signal to a digital signal, the digital signal including a plurality of samples at a predetermined resolution, detecting whether a trigger condition is met by analyzing the digital signal, detecting an event based on trigger information from the detecting whether a trigger condition is met, generating event information having time information included therein when the event is detected, defining one or more time windows based on the time information included in the event information, performing decimation on the digital signal based on the defined one or more time windows to generate a decimated signal, and outputting the decimated signal.

Abstract: A power supply for converting AC to a regulated DC output current, utilizing two serial switched mode power supplies, the first providing an intermediate DC output voltage with only moderate ripple properties, this output being input to the second, which operates as a DC/DC converter to provide the desired output with low ripple and good regulation. The diode rectifier assembly has no reservoir/smoothing capacitor, or one of much smaller capacitance than in prior art power supplies. The large resulting rectifier output ripple is overcome by use of the two power supply units, at least the first having a smoothing capacitor at its output. A majority of the energy stored in this capacitor is utilized during each AC half cycle. Such power supplies also provide improved hold-up times. The power supply is also constructed to have low standby power consumption, by use of a double burst configuration.

Abstract: A method of controlling a pulse width modulated (PWM) voltage regulator including a control circuit of a power stage, and a circuit configured to determine a duration of charge phases and further configured to receive a charge signal and to generate a logic command may include controlling, using the control circuit, switches of the power stage as a function of the logic command at an end of a charge phase and at a start of a discharge phase of an output capacitance. The method may also include generating the charge signal to be one of enabled and disabled during charge phases and another of enabled and disabled during discharge phases, and delaying, at each PWM cycle, the logic command with respect to a previous PWM cycle to compensate at least one of a phase and a frequency difference between each PWM cycle and a reference clock signal.

Abstract: In a method for optimizing a space vector pulse width modulation, a voltage is connected to a load, by combining discrete switching states of a plurality of switches to control the load, the load being switched to zero potential by two of the switching states. In the case the maximum degree of control is increased, during a pulse width modulation period, at least one of the switching states, that switches to zero potential, is omitted.

Abstract: A power conversion device includes a first inverter circuit and a second inverter circuit, a capacitor, and a microcomputer. The microcomputer switches a control operation, according to the steering state of a steering wheel, between a first state where a first duty center value is shifted to be lower than an output center value and a second duty center value is shifted to be higher than the output center value, and a second state where the first duty center value is shifted to be higher than the output center value and the second duty center value is shifted to be lower than the output center value. This can reduce a difference in heat loss between FETs while reducing the ripple current of the capacitor.

Abstract: A circuit for operating a household appliance, wherein the circuit includes a switched-mode power supply for converting the power supply of a public power supply network into direct supply voltage. The circuit also includes a controller that is connected to the switched-mode power supply for being supplied with the direct supply voltage and for controlling processes of the household appliance. An EMC filter is provided to protect the public supply network from interference signals from the household appliance. The EMC filter includes a condenser that is connected between a phase conductor pole and a neutral conductor pole of the public power supply network; a bleeder resistor that is connected in parallel with the condenser; and a switch that can be activated by the controller to connect the condenser and the bleeder resistor to the neutral conductor pole.

Abstract: A signal processor is configured to perform a process equivalent to performing a series of fixed-to-rotating coordinate conversion, a predetermined process and then rotating-to-fixed coordinate conversion, while maintaining linearity and time-invariance. The signal processor performs a process given by the following matrix G: G = [ F ? ( s + j? 0 ) + F ? ( s - j? 0 ) 2 F ? ( s + j? 0 ) - F ? ( s - j? 0 ) 2 ? j - F ? ( s + j? 0 ) - F ? ( s - j? 0 ) 2 ? j F ? ( s + j? 0 ) + F ? ( s - j? 0 ) 2 ] where F(s) is a transfer function representing the predetermined process, ?0 is a predetermined angular frequency and j is the imaginary unit.

Abstract: An interface arrangement is provided for coupling between an AC system and a DC system. The arrangement includes a converter for conversion between AC and DC and having a DC side and an AC side, a transformer having a primary side with primary windings for coupling to the AC system and a secondary side with secondary windings coupled to the converter, where the secondary windings are coupled to ground via a neutral point of the secondary side, and a filter with filter elements set for removing a frequency component of at three times the fundamental frequency of an AC voltage appearing on the AC side of the converter. The filter is connected between the neutral point of the secondary side of the transformer and ground.

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: A control device that controls an electric motor drive device. The control device is configured with a first voltage control section that derives a modulation rate representing a ratio of an effective value of the voltage command values to the DC voltage and a voltage command phase. A second voltage control section generates a control signal for controlling the DC/AC conversion section on the basis of the modulation rate, the voltage command phase, and a magnetic pole position representing a rotational angle of a rotator of the AC electric motor. A computation cycle of the first voltage control section is set to be longer than a computation cycle of the second voltage control section.

Abstract: In one embodiment, a method is provided for a power converter system comprising a switching circuit having a plurality of switches operable to be turned on and off to cause current to flow to deliver power to a load. The method includes the following: generating PWM control signals for turning on and off the switches in the switching circuit; sensing the direction of current flow, wherein the direction of current flow is related to a likelihood of shoot-through in the switching circuit; providing a current vector signal indicative of the direction of current flow; and enabling or disabling introduction of a dead time into the PWM control signals for the switches in the switching circuit in response the current vector signal.

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 power converter for effectively reducing switching noise is provided. The power converter comprises a capacitor 111; switching devices Q11a and Q11b connected to the capacitor 111 in parallel; and a controller 105 that controls each switching device individually to perform switching operations. Each of the switching devices Q11a and Q11b forms a closed circuit together with the capacitor 111. The controller 105 controls the switching devices Q11a and Q11b to perform switching operations of switching ON or OFF at different timings such that at least two closed circuits including the switching devices Q11a and Q11b mutually cancel ringing voltages occurring therein, each ringing voltage occurring due to the switching operations performed by a corresponding switching device and having a frequency defined by an inductance of a corresponding closed circuit and an output capacity of a switching device included in the corresponding closed circuit.

Abstract: A DC motor is provided. The DC motor prevents rush or overload of current in the DC motor during and/or after power input irregularities to the DC motor. A control circuit of the DC motor is configured to control current provided to the DC motor. When power irregularities in the power input to the DC motor are detected by the control circuit, the control circuit stops generating PWM (Pulse Width Modulated) signals and stops the current provided to the DC motor. After the stoppage of PWM signals, the control circuit can perform a soft-start of the PWM signals when the power irregularities are no longer detected. The soft starting of the PWM signals generates gradual increase in current to the DC motor, thus, preventing sudden rush of current that cause malfunction of the DC motor.

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.