A multi-phase power converter with current matching is provided. The apparatus may include a control circuit to control a first phase of a power converter having a plurality of phases, and a phase matching circuit. The phase matching circuit may remove a DC component from an output ripple voltage of the converter, detect when respective ones of the plurality of phases begins generating its respective phase current and output a phase detector signal, extract a signal proportional to the first phase current and a signal proportional to either the remaining or total phase currents, output first and second voltages respectively proportional to the average of the first phase current and the remaining or total phase current, and output a corrective signal based on the difference between the first and second voltage. The control circuit may control the first phase based on the corrective signal.

Systems, methods, and devices which eliminate the DC current from the output of grid-connected inverters. A current controller is provided which interfaces with a grid-connected DC/AC inverter. The current controller uses a nonlinear adaptive filter which receives, as input, the output current of the inverter along with grid current frequency. The nonlinear adaptive filter estimates the DC value of the grid current and, in conjunction with an integrator, removes this DC current component. This is done by adjusting the duty cycle of the grid-connected inverter.

A power control apparatus, comprising: a first wiring and a second wiring connected to a power source; a first capacitor connected to the first wiring and the second wiring; an electrical component including a plurality of switches connected in parallel with the first capacitor through the first wiring and the second wiring; and a second capacitor which is connected to one of the first wiring and the second wiring and is connected to a reference potential portion having a constant potential, wherein an impedance of a first conducting path between another side connection point, which is connected to the first capacitor, of the other one of the first wiring and the second wiring and the power supply not through the first capacitor, is higher than an impedance of a second conducting path between the another side connection point and the second capacitor through the first capacitor.

The present invention relates to a voltage converter comprising a primary side which has a full bridge device which is configured for the purpose of receiving a first DC voltage from a voltage source at a first amplitude and to transmit same to a primary coil arranged in the primary side, comprising a control unit which is designed for the purpose of controlling the full bridge device using PWM signals having phases shifted counter to one another, wherein the control unit is configured to detect an asymmetry in the current supplied to the primary coil based on a current profile in the primary coil, wherein the control unit is designed to compensate for a detected asymmetry by adjusting the PWM signals. The present invention further relates to a corresponding method.

A symmetry control circuit for a trailing edge phase control dimmer circuit for controlling alternating current (AC) power to a load, the symmetry control circuit including: a bias signal generator circuit configured to monitor non-conduction periods of each half cycle of said AC power for an elapsed duration of the non-conduction periods, and generate a bias signal voltage based on the elapsed duration, whereby an amplitude of the bias signal voltage is proportional to the elapsed duration of the non-conduction periods; and a bias signal converter circuit configured to convert the bias signal voltage to a bias signal current, wherein the bias signal current is added to a reference current of a conduction period timing circuit configured to determine said conduction periods, and wherein the conduction period timing circuit is configured to alter one of the conduction periods immediately following one of the non-conduction periods based on the bias signal current when added to the reference current to compensate for a phase shift of a zero-crossing of said one of the non-conduction periods corresponding to an elapsed duration of said one of the non-conduction periods so as to restore symmetry of the non-conduction periods of each half cycle of AC power.

A setting unit sets a duty ratio of a PWM signal based on a target voltage value, and outputs the duty ratio to a voltage conversion circuit. An estimated value calculation unit cyclically calculates an estimated duty ratio value based on the detected input voltage value and the detected output voltage value. An abnormality detection unit cyclically calculates, as a difference value, a difference between an updated estimated value and a comparison reference value, and detects abnormality of a voltage detection unit based on a change in calculated difference value. The updated estimated value is a newly calculated estimated duty ratio value. The comparison reference value is a value based on the estimated duty ratio value calculated in a cycle prior to a cycle in which the updated estimated value is calculated.

The present invention relates to an AC/DC converter station for interconnection of a DC transmission line and an AC network, the AC/DC converter station including an AC/DC converter and a control system configured to control the AC/DC converter. The AC/DC converter station comprises a capacitor connected in series between the AC/DC converter and the AC network, and a voltage measurement device arranged to measure the voltage across the capacitor. The AC/DC converter further comprises a control system connected to the voltage measurement device and arranged to receive, from the voltage measurement device, a signal indicative of a measured voltage. The control system is arranged to perform the control of the AC/DC converter in dependence of the signal received from the voltage measurement device. The invention further relates to a method of operating an AC/DC converter station.

A motor control apparatus includes: a smoothing capacitor; an inverter circuit; a torque limiter; and a field-weakening control device. The smoothing capacitor smooths the direct current power. The inverter circuit converts the smoothed direct current power to alternating current power. The torque limiter limits motor torque based on a torque limit value calculated from a direct current voltage applied to the smoothing capacitor, limiting the motor torque in a power running direction to a first torque value when the direct current voltage drops to a first threshold. The field-weakening control device weakens a field and raises an induced motor voltage and the direct current voltage when the power running direction motor torque is limited to the first value. The torque limiter limits the power running direction motor torque to a second value greater than the first value when the direct current voltage rises from the first to a second threshold.