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.

Abstract: A system for moving an aircraft thrust reverser component includes a power drive unit, a thrust reverser actuator assembly, and a tertiary lock system. The power drive unit is operable to rotate and supply a rotational drive force. The thrust reverser actuator assembly receives the rotational drive force from the power drive unit and moves the thrust reverser component between a stowed position and a deployed position. The tertiary lock system selectively engages and disengages the thrust reverser component and includes a tertiary lock power unit, an electromechanical tertiary lock assembly, and a voltage limiting circuit. The voltage limiting circuit limits the voltage magnitude of a control signal supplied to the tertiary lock assembly to a predetermined value.

Abstract: A power converter is provided with a rectifying circuit, an inverter circuit, and a common mode filter including a common mode choke coil and a capacitor. The switching frequency of a PWM rectifying circuit is set at three times the switching frequency of a PWM inverter. Alternatively, the resonance frequency of the common mode filter is set at twice the carrier frequency of the rectifying circuit or the PWM inverter circuit or more.

Abstract: The inverter comprises a diode bridge (21) that rectifies an inputted three-phase AC voltage into a DC voltage, an inverter section (22) that converts the DC voltage converted by the diode bridge (21) into an AC voltage and outputs the resulting voltage, an LC filter that has an inductor Ldc connected between one output terminal of the diode bridge (21) and one input terminal of the inverter section and a capacitor Cdc connected across the input terminals of the inverter section, a voltage detecting section (24) that detects cross terminal voltage of the inductor Ldc, and a control section (100) that controls the inverter section (22). The control section (100) controls the inverter section (22) so that the transfer characteristic of the I/O voltage of the inverter section (22) becomes a characteristic of the first-order lag system on the basis of the cross terminal voltage of the inductor Ldc detected by the voltage detecting section (24).

Abstract: An active electromagnetic interference (EMI) filtering may reduce the requirements for high current differential mode inductors. The active EMI filtering of the present invention may be useful in power devices that use switching power converters. Conventional EMI differential mode filtering devices may occupy up to 30% of the total weight and volume of the power electronics. Conventional differential mode filtering inductors tend to be large and heavy, especially so for high current input power lines. The present invention may replace the large conventional differential mode filtering inductors with a smaller set of coupled inductors.

Abstract: The invention relates to a filtering device which includes a common-mode inductor (LF) comprising a winding (L1, L2) on each line of an AC power supply and a magnetic core made up of a first torus (T1) and a second torus (T2). The first torus (T1) has a first magnetic permeability (?1) and the second torus (T2) has a second magnetic permeability (?2, ??2), the first permeability being equal to or greater than three times the second permeability, in order to prevent the common-mode inductor from saturating in the resonant frequency range of the filtering device. Application to the EMC filter of a speed variator.

Abstract: A power converter includes an isolated or a nonisolated current-doubler rectification circuit including two magnetic circuit elements, each magnetic circuit element formed with a primary winding and a voltage-sensing winding. The primary windings are coupled in series. The voltage-sensing windings are also coupled in series but with a coupling sense opposite from that of the primary windings. A properly sized inductor and capacitor are coupled in series with the voltage-sensing windings to produce a ripple-cancellation current with slope opposite to a net slope error of currents produced in the two magnetic circuit elements. The current-doubler rectification circuit is preferably coupled to a rectangular ac input waveform. By sensing a scaled voltage difference between two magnetic circuit elements, a very low level of output ripple is produced by the circuit with very low power losses over a range of operating conditions.

Abstract: This deadbeat control method for regulating an output voltage Uc or an output current Il of a low-pass RLC filter includes: calculation (92) of a current setting ?uc for the average intensity ?u of a DC current Iu flowing through a first output point of the filter between instants ti and ti+1, this setting ?uc being established from discretized state equations of the filter in such a way that the voltage Uc or the line current Il is equal to a predetermined setting of voltage Ucc or of line current Ilc at the instant ti+1, control (100) of an electric converter in order to produce a current Iu flowing through the filter, the average intensity ?u of which between the instants ti and ti+1 is equal to the current setting ?uc.

Abstract: The inverter includes an electrolytic capacitor which receives DC power, a series resonant circuit connected in parallel with the electrolytic capacitor, and a switching device group which converts the DC power into AC power by switching using pulse width modulation.

Abstract: In one aspect, the invention provides a power system for providing power to a load.

Abstract: A method is disclosed for the operation of a converter circuit, wherein the converter circuit has a converter unit having a multiplicity of actuatable power semiconductor switches and an LCL filter which is connected to each phase connection of the converter unit, in which the actuatable power semiconductor switches are actuated by means of an actuation signal (S) formed from a hysteresis active power value (dP), from a hysteresis reactive power value (dQ) and from a selected flux sector (?n). The hysteresis active power value (dP) is formed from a differential active power value (Pdiff). In addition, the hysteresis reactive power value (dQ) is formed from a differential reactive power value (Qdiff). An apparatus for carrying out the method is also disclosed.

Abstract: Provided is a transformer having resonant inductance, the transformer including a core that includes a first leg formed in one side thereof, a second leg which is formed in the other side thereof so as to be electromagnetically coupled to the first leg, and a third leg which is formed between the first and second legs so as to be electromagnetically coupled to the first and second legs; a primary winding that is wound around one side of the third leg; a secondary winding that is wound around the other side of the third leg so as to induce power through electromagnetic induction with the primary winding; and a resonant inductance winding that is wound around the outside of the core so as not to be magnetically induced by magnetic fluxes generated from the primary and secondary windings.

Abstract: EMC filter, for connection between a mains supply network and a mains-operated appliance to reduce conduction noise between said supply network and said appliance, comprising a voltage divider connected to said mains network, for generating a voltage lower than a voltage of said mains network; rectifying means, connected to an output of said voltage divider, for generating a DC voltage; and an electronic active circuit, supplied by said DC voltage, for absorbing a noise current transmitted between said supply network and said appliance.

Abstract: A wiring arrangement and an appliance for limiting the harmonics of a current supplied to a frequency converter from an AC electricity supply network, which frequency converter can be connected to a three-phase AC electricity supply network, in which frequency converter is an uncontrolled network bridge (10) for rectifying the AC voltage of the AC electricity supply network, a DC intermediate circuit, in which is a filtering capacitor (CDC), and a load bridge (11) provided with power semiconductor switches for forming three-phase AC voltage (U, V, W), and which load bridge can be controlled with pulse-width modulation by means of a control unit, and in which DC intermediate circuit is a choke, in which is a choke part (L1, L2) arranged on both the positive and the negative pole, and in which wiring arrangement is an absorption circuit for limiting the harmonics of the current supplied from the AC electricity supply network, in which the absorption circuit is arranged in the DC intermediate voltage circuit,

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 t

Abstract: A model for modeling electromagnetic response in a conductor and in dielectric, a method of modeling the electromagnetic response in the conductor and dielectric and a program product therefor. Coupled supplies (delayed capacitive-current-controlled current sources or delayed inductance-voltage-controlled voltage sources) are low pass filtered in an electromagnetic model for the particular medium, e.g., a Partial Element Equivalent Circuit (PEEC) model for a conductor or dielectric. Thus, high frequency model instabilities are substantially reduced or eliminated.

Abstract: A line filter has a filter unit, which has an input and an output and also a current-compensated choke and a capacitance network. The choke has several phase windings on a common core. Each phase winding is connected in series with a phase conductor. The capacitance network has capacitors, which are each connected between a phase conductor and a neutral conductor. Another choke is provided in series to the neutral conductor, which is wound separately from the core.

Abstract: A power control system includes a switching power converter and a controller, and the controller responds to a time-varying voltage source signal by generating a switch control signal having a period that varies in accordance with at least one of the following: (i) the period of the switch control signal trends inversely to estimated power delivered to a load coupled to the switching power converter, (ii) the period of the switch control signal trends inversely to instantaneous voltage levels of the voltage source signal, and (iii) the period of the switch control signal trends directly with a line voltage level of the time-varying voltage source signal. In at least one embodiment, the controller achieves an efficient correlation between the switching period with associated switching losses and the instantaneous power transferred to the switching power converter while providing power factor correction (PFC).

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: 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: A power converter includes an isolated or a nonisolated current-doubler rectification circuit including two magnetic circuit elements, each magnetic circuit element formed with a primary winding and a voltage-sensing winding. The primary windings are coupled in series. The voltage-sensing windings are also coupled in series but with a coupling sense opposite from that of the primary windings. A properly sized inductor and capacitor are coupled in series with the voltage-sensing windings to produce a ripple-cancellation current with slope opposite to a net slope error of currents produced in the two magnetic circuit elements. The current-doubler rectification circuit is preferably coupled to a rectangular ac input waveform. By sensing a scaled voltage difference between two magnetic circuit elements, a very low level of output ripple is produced by the circuit with very low power losses over a range of operating conditions.

Abstract: The invention is directed to a network filter that comprises at least one phase input and a protective conductor in which each phase input is connected via a filter inductance to a corresponding phase output, in which the input side of each filter inductance is connected to the protective conductor via a filter capacitor, and in which an auxiliary inductance is connected between each filter capacitor and the protective conductor, permitting the inductances in the filter to be kept small, potentially realized by simply slipping a ferrite core over a conductor.

Abstract: Method for decreasing the existence of externally detectable revealing signals, so-called {umlaut over (R)}Ö{umlaut over (S)}, from keyboards (1), e.g. for computers, where the keyboard is fed with signals, so-called matrix signals, which are detected for detection of activity regarding the keys (2) of the keyboard, whereby said matrix signals are generated by means of signal devices. The method is especially characterized in that the matrix signals are high-frequency filtered before they are fed to the keyboard.

Abstract: The present invention provides a filter circuit realizing reduction in the number of magnetic cores on a circuit board and a space occupied by the magnetic cores, and a power supply unit using the filter circuit. A filter circuit includes a first filter part and a second filter part which are connected in series. The first filter part includes a center leg coil and a capacitor, and the second filter part includes an outer leg coil and a capacitor. The center leg coil is wound around a center leg of a magnetic core including the center leg, a first outer leg part configuring a loop magnetic path in common with the center leg, and a second outer leg part configuring another loop magnetic path in common with the center leg. The first and second outer leg parts share the center leg. The outer leg coil is wound around the outer leg parts in a manner such that magnetic fluxes generated in the outer leg parts by current flowing in the outer leg coil cancel each other in the center leg.

Abstract: A negative ions generating circuit design with decreasing high frequency noise includes a power indication circuit, an oscillation circuit, an amplifying circuit and a radial frequency filtering circuit. The power indicating circuit, the oscillation circuit and the amplifying circuit are used for generating negative ions. The radial frequency filtering circuit has a capacitance to be utilized for limiting the high frequency in a coil so that the high frequency will not be amplified by through the transistor of the oscillation circuit. The coil creates an inductance to limit the high frequency so as to effectively eliminate the high frequency created by the oscillation circuit.

Abstract: In a DC power supply or a battery charger, plural output filter capacitors remain highly charged after the load is removed and the converter is turned off. A transistor connected across the capacitors is non-conductive during normal power supply operation and a bleed resistor connecting the transistor to the output capacitors is not in the circuit during normal power supply operation. When the power supply is turned off and the load is removed, the transistor is automatically rendered conductive with the removal of the pulsed output of the power supply's power transformer to the transistor, with the energy stored in the capacitors safely and quickly discharged to the output return via the bleed resistor which is placed in circuit by the conducting transistor.

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: 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: A method in connection with a network inverter, an LCL network filter (3) being connected between the network inverter (1) and network (2), and the network inverter being arranged to operate as an active converter of harmonic components of electricity, and the method comprises the steps of forming a current reference (i1, ref) for the network inverter (1) for producing a desired voltage, selecting a harmonic electric component (v), the proportion of which needs to be changed, forming a current reference (i1, refv) altering the selected harmonic component (v), summing the generated current reference (i1, refv) altering the selected harmonic component with the current reference (i1, ref) of the network inverter to produce a summed current reference (i1, ref, tot), and controlling the network inverter with the summed current reference (i1, ref, tot) in a coordinate system bound to the virtual flux linkage of the network inverter by using DTC control.

Abstract: A circuit (1) used for power factor correction, corresponds to a known circuit that includes a high-frequency frequency source (15) for generating a high-frequency voltage (Uf) for a pump capacitor (14). The high-frequency voltage source (15) has two on/off switches (151, 152) connected in series that generate, at an electric connection point (153), a square wave voltage (U1) that varies between these two switches with a frequency (f) of at least 1 megahertz. The voltage source further includes a smoothing device (150) for generating from the square wave voltage a smoothed voltage (Uf) for the pump capacitor, whereby the smoothed voltage varies with a frequency (f) of at least 1 megahertz.

Abstract: An electric machine drive (50) has a plurality of inverters (50a, 50b) for controlling respective electric machines (57, 62), which may include a three-phase main traction machine (57) and two-phase accessory machines (62) in a hybrid or electric vehicle. The drive (50) has a common control section (53, 54) for controlling the plurality of inverters (50a, 50b) with only one microelectronic processor (54) for controlling the plurality of inverters (50a, 50b), only one gate driver circuit (53) for controlling conduction of semiconductor switches (S1–S10) in the plurality of inverters (50a, 50b), and also includes a common dc bus (70), a common dc bus filtering capacitor (C1) and a common dc bus voltage sensor (67). The electric machines (57, 62) may be synchronous machines, induction machines, or PM machines and may be operated in a motoring mode or a generating mode.

Abstract: The switched-mode power supply contains a transformer, a switching transistor in series with the primary winding of the transformer, and a damping network on the secondary side, which has a connection for a further secondary winding via which energy is transferred from this damping network, by way of example, to a charge-storage capacitor which is coupled to this secondary winding. The connection is advantageously produced via a rectifying element, for example a diode, which is coupled after the rectifying diode (D5) for the second secondary winding. In a further exemplary embodiment, the diode in the series circuit, which is connected in parallel with the rectifier diode for the first secondary winding, is not coupled to the charge-storage capacitor for the first secondary winding, but is likewise coupled to the charge-storage capacitor for the second secondary winding.

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.

Abstract: A method of determining the inductance required to maintain the amplitudes of harmonic current waveforms in a rectifier circuit below a predetermined level includes a rectifier circuit that has an inductor and a capacitor. The circuit draws power from a varying power source and supplies power to a load. The method includes the steps of calculating, using a resonant analysis method, an expression for the input current waveform in the rectifier circuit in terms of the inductance of the inductor when a predetermined input voltage waveform is applied to the rectifier circuit. The capacitor has a predetermined capacitance and the load drawing has a predetermined current from the rectifier circuit.

Abstract: The invention relates to a method for compensating for a voltage unbalance in an electrical network, which is fed by using an apparatus based on controlling a flux linkage vector or a voltage vector. Concerning the apparatus based on controlling the flux linkage vector, the method comprises the steps of determining a flux linkage reference vector comprising a positive sequence component and a negative sequence component, and controlling the feeding apparatus of the network in such a manner that the flux linkage vector thereof follows the reference vector with predetermined precision. The negative sequence component of the flux linkage reference vector is arranged to compensate for the amplitude and phase unbalance of the voltage in the electrical network to be fed.

Abstract: The invention provides a filter circuit comprising inductors (6, 15) and capacitors (11) interconnected to form filter stages, the capacitors (11) being distributed over at least two printed circuit cards (7, 8) disposed facing each other and spaced apart by a gap (H), at least one inductor (15) extending across the gap (H) between the cards and connected to both cards (7, 8). The invention also provides a power supply device equipped with such a filter circuit.

Abstract: A switched mode power supply which uses a shieldless transformer (11) in the dc to dc converter. Common mode switching noise is reduced by connecting two capacitors (17, 18) in series between the transformer primary (12) and secondary (13) circuits and connecting an inductor (19) between the junction of the two capacitors (17, 18) and chassis earth. The values of the capacitors (17, 18) and inductor (19) are selected such that the capacitors (17, 18) present a low impedance to noise signals and the inductor (19) presents a high impedance to noise signals.

Abstract: A DC-to-AC inverter includes a switch stage having a switch output, a switch controller coupled to the switch stage, and a filter coupled to the switch output. The switch stage includes switch means coupled to the switch output for switching the switch output between a pair of power supply rails. The switch controller is configured to cyclically linearly vary the duty cycle of the output signal at the switch output. The filter is configured to produce a piece-wise linear approximated sinusoidal output waveform from the output signal.

Abstract: The present invention is to provide a switching power supply device for preventing the change of characteristic of the line filter due to filler such as resin which covers the circuits.

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: An active EMI filter for reducing common mode noise current in a circuit, comprising: at least one transistor stage, each having two transistors, a current sensor coupled to the circuit and an output driving the transistor stage, a capacitor coupling the transistor stage and the ground return line, providing a cancellation current to cancel the common mode current in the ground return line. In a feed forward arrangement the transistor stage is coupled between the rectifier and the current sensor, which provide an amplitude gain of approximately unity. The transistor stage may have a local power source and a drive transistor.

Abstract: A new method in the design for an electronic power supply for suppressing signal interference in equipment of an electronic system due to ground current in a ground loop is provided. In a power supply comprising a transformer, a primary circuit, a secondary circuit, and ground conductors, the method is done by connecting the common signal references of secondary side to the ground conductors through a capacitor and an inductor connected in series. The added capacitor is to reject DC and low frequency noise and interference, and the added inductor is to reject high frequency noise and interference. Most noise and interference signals therefore cannot pass through the formed paths. As a result, the degree of signal interference problem is greatly reduced.

Abstract: An active clamped-mode DC-to-DC converter with synchronous rectifiers and a combined transformer-inductor device is provided. The power converter includes a combined transformer-inductor device having a primary winding, a secondary winding, and an auxiliary winding where the primary and the secondary windings perform a transformer function and the auxiliary winding performs an output filter function, a switching circuit for periodically providing a positive voltage to the primary winding and a negative voltage to reset the primary winding, and a synchronous rectification circuit connected for enabling conduction from the secondary winding to an output port in which the auxiliary winding is coupled between the output port and the synchronous rectification circuit for providing an inductance to filter an output signal.

Abstract: A switching power supply capable of translating a.c. voltage of sinusoidal waveform into d.c. voltage, having a rectifier circuit connected to a pair of a.c. input terminals for rectifying the incoming commercial a.c. voltage. A first main switch is connected between the pair of outputs of the rectifier circuit via a main inductor. A smoothing capacitor is connected in parallel with the first main switch via a rectifying diode. A second main switch is connected in parallel with the smoothing capacitor via the primary winding of a transformer. The first and the second main switch are each provided with a soft-switching capacitor connected in parallel therewith. A first and a second ancillary inductor, electromagnetically coupled respectively to the main inductor and to the transformer primary, are connected in parallel with the first and the second soft-switching capacitor via a first and a second ancillary switch, respectively.

Abstract: A single-stage converter improving power factor. The single-stage converter includes a power factor improving unit, a bridge diode unit, a voltage smoothing condenser, a transformer circuit unit, and a main switch. The power factor improving unit is connected to a input power source, the bridge diode unit is located next to the power factor improving unit and provides a current path, the voltage smoothing condenser stores electrical energy provided through the bridge diode unit, the transformer circuit unit is located between the bridge diode unit and the voltage smoothing condenser, and the main switch is connected to each of the bridge diode unit, the voltage smoothing condenser, and the transformer circuit unit and controls provision of voltage to the transformer circuit unit. Thus, the single-stage converter can improve the power factor of the input terminal.

Abstract: An active filter reduces the common mode current in the ground wire of a PWM controlled motor drive circuit. The active filter is, in part, integrated into an integrated circuit chip and contains a buffer amplifier which drives two junction type or MOSFET transistors linearly to divert common mode current from a ground wire and through the transistors. The transistors are connected between positive and negative d-c busses which supply d-c power to a PWM inventor which drives an a-c motor, producing the common mode ground current in its grounded frame. A current transformer monitors the common mode current and its output is coupled to the input of the buffer amplifier to control the transistors. An internal power supply for the amplifiers is formed at the nodes between two current sources and two zener diodes which are connected between the d-c bus conductors. Headroom control circuits are disclosed to insure sufficient headroom voltage for each of the transistors under all input a-c voltage conditions.

Abstract: A switching power supply includes a noise filter; a bridge rectifying circuit; a smoothing capacitor; a primary winding of a transformer and a switching element; and a control circuit for controlling the switching element. Further, the first reactor and the first diode are connected sequentially in series between one output terminal of the bridge rectifying circuit and one terminal of the smoothing capacitor. The second reactor and the second diode are connected in series between a node that mutually connects the first reactor and the first diode and a node that mutually connects the primary winding and the switching element.

Abstract: An unified constant-frequency integration (UCI) control method based on one-cycle control employs an integrator with reset as its core component along with a few logic and linear components to control the pulse width of a three-phase recitifier, active power filter, or grid-connected inverter so that the all three phase current draw from or the current output to the utility line is sinusoidal. No multipliers and reference calculation circuitry are needed for controlling active power filters. The UCI control employs constant switching frequency and operates in continuous conduction mode (CCM). If in some cases a DSP is desired for some other purposes, the Unified Constant-frequency Control function can be realized by a low cost DSP with a high reliability, because no high speed calcutation, high speed A/D converter, and mutipliers are required.

Abstract: A DC/DC converter is provided that includes a switch device for converting a DC voltage into an AC voltage, a piezoelectric transformer for changing the AC voltage and a current doubler type rectification-smoothing device, which includes a first diode, a second diode, a first inductor, a second inductor, and a capacitor. The piezoelectric transformer has one output terminal connected to a cathode of the first diode and to one terminal of the first inductor, and the other output terminal connected to a cathode of the second diode and to one terminal of the second inductor. Anodes of the first and the second diodes are respectively grounded. The other terminal of the first inductor is connected at a predetermined connection point to the other terminal of the second inductor. The connection point is connected to one terminal of the capacitor, whose other terminal is grounded.

Abstract: In a power conversion device comprising an AC filter 2 for harmonic current suppression having a combination of at least some of a reactor, capacitor and resistance and a power conversion circuit 3 that converts AC power into DC power or DC power into AC power and is connected to an AC power source 1 through AC filter 2, by providing: voltage reference calculation means (unit) 5 that calculates and outputs a voltage reference corresponding to the voltage that is to be output by the power conversion device main unit; current detection means (unit) 4 that detects and outputs current flowing through a prescribed location between AC power source 1 and power conversion circuit 3; and voltage reference correction means (unit) 8 that uses the output from current detection means (unit) 4 as a voltage reference correction signal to correct the voltage reference that is output from voltage reference calculation means (unit) 5, resonance of the AC filter for harmonic current suppression is suppressed without employing a