An active inductor for controlling transistor bridge switching carrier frequency current components in the power mains connected to a three-phase AC/DC switched bridge converter includes a transformer for each phase, each having a secondary between the AC main and the switched bridge, the primary of which is driven by a bridge switched at much higher frequency in response to a synthesized waveform which ideally will completely cancel the main power bridge switching current components. Reduction of the current carrying requirement of the active inductor is achieved by providing negative feedback of the fundamental power frequency from the primary of each transformer; deviations in the synthesized waveform from the ideal waveform, due to delays and distortions in real circuits and/or processing, are reduced by providing negative feedback from the resultant current (the secondary of the active filter transformer).

A rectifying circuit and method to produce a DC output by rectifying a sinusoidal source having a plurality of output phase voltages and a plurality of phase-to-phase voltages, the rectifying circuit including a bridge circuit coupled to the output phase voltages, the bridge circuit having a plurality of switches; and a control circuit coupled to the output phase voltages and to the bridge circuit, the control circuit being configured to control the switches in accordance with respective absolute values of the phase-to-phase voltages; wherein the output phase voltages are rectified to produce the DC output. When the sinusoidal source is inductive, switch turn-off may be timed to provide synchronous rectification related to estimates of source periodicity.

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 damping resistance for resonance suppression.

A voltage signal rectifier produces a rectified voltage signal from an input offset voltage signal. The voltage signal rectifier includes input offset, output, and reference nodes, two actively controlled current regulation elements (ACCREs), and two controllers. The input offset node is coupled to the input offset voltage signal. The rectified voltage signal is generated onto the output node. The reference node is coupled to a reference voltage for the input offset and rectified voltage signals. The ACCREs are coupled to the input offset node and one of the ACCREs is coupled to the output node. Each controller is configured to control the one of the ACCREs so that the ACCRE coupled to the output node allows current flow through it when the input offset voltage signal is higher than the rectified voltage signal and the other ACCRE is configured to allows current flow through it when the input offset voltage signal is lower than the rectified voltage signal.

A power conversion device according to the invention of the present application includes: an active current controller that calculates a phase angle reference value for determining the ON/OFF phase with reference to the AC power source voltage phase, from the deviation of the input active current with respect to an active current reference value; and a fixed pulse pattern generator that controls the self-excited voltage type power converter by generating switching signals of fixed pulse pattern whose fundamental frequency is synchronized with the AC power source frequency, based on the phase angle reference value calculated by this active current controller. In this way, with the invention of the present application, the harmonic components contained in the AC input current can be reduced without raising the switching frequency of the PWM power conversion device.