A reversible converter includes a first field effect transistor and a second field effect transistor coupled in series between a first terminal and a second terminal for a DC voltage. A first thyristor and a second thyristor are coupled in series between the first and second terminals for the DC voltage. A third thyristor and a fourth thyristor are also coupled in series between the first and second terminals for the DC voltage terminals, but have an opposite connection polarity with respect to the first and second thyristors. A midpoint of connection between the first and second field effect transistors and a common midpoint of connection between the first and second thyristors and the third and fourth thyristors are coupled to AC voltage terminals. Actuation of the transistors and thyristors is controlled in distinct manners to operate the converter in an AC-DC conversion mode and a DC-AC conversion mode.

A method for estimating capacitance applied to a three phase converting device is disclosed. The three phase converting device includes a three phase converter and a processor. The processor executes following steps: (a) outputting a non-baseband signal to the three phase converter, such that a bus voltage of the three phase converter generates a non-baseband flutter; (b) obtaining the bus voltage of the three phase converter; (c) obtaining a bus voltage estimating value based on the bus voltage, a bus capacitance estimating value, an input power, and an output power of the three phase converter; (d) respectively outputting a first AC component and a second AC component corresponding to the non-baseband flutter through filtering the bus voltage and the bus voltage estimating value by a filter segment; (e) estimating a bus capacitance based on the first AC component, the second AC component and a bus capacitance initial value.

The present disclosure provides an electric vehicle, a vehicle-mounted charger and a method for controlling the same. The method includes: obtaining a first total charging time and a second total charging time in a second manner, and a first total discharging time and a second total discharging time in the second manner; calculating a first total working time in the first manner and a second total working time in the second manner; obtaining a first predetermined charging time in the first manner, a second predetermined charging time in the second manner, a first predetermined discharging time in the first manner and a second predetermined discharging time in the second manner; selecting a manner according to the first and second total working time; and performing an alternate control according to the first and second predetermined charging time or according to the first and second predetermined discharging time.

The present disclosure provides an electric vehicle, a vehicle-mounted charger and a method for controlling the same. The method includes: obtaining a first total charging time and a second total charging time in a second manner, and a first total discharging time and a second total discharging time in the second manner; calculating a first total working time in the first manner and a second total working time in the second manner; obtaining a first predetermined charging time in the first manner, a second predetermined charging time in the second manner, a first predetermined discharging time in the first manner and a second predetermined discharging time in the second manner; selecting a manner according to the first and second total working time; and performing an alternate control according to the first and second predetermined charging time or according to the first and second predetermined discharging time.

There is provided a power supply apparatus for supplying power to an external electrical load , including a power transmission line or cable through which an alternating or direct current may flow, a power supply module, a control unit, an output terminal for connection to the external electrical load, and a converter. The power supply module includes an input terminal connected to the power transmission line or cable, and includes switching elements and energy storage device(s). The control unit controls the switching elements to selectively switch each energy storage device into circuit to direct a current flowing in the power transmission line or cable to flow through each energy storage device so as to store energy to form a power source. The converter draws power from the power source and supplies the drawn power to the output terminal.

A high voltage direct current power transmission series valve group control device, is used for regulating a series circuit having two or more valve groups provided with controllable power semiconductors respectively. Each valve group is provided with a current regulation unit and a voltage regulation unit. The current regulation unit controls a direct current current flowing through a valve group corresponding thereto, and the voltage regulation unit controls a voltage across two ends of a valve group corresponding thereto. One valve group is selected from the series valve group as a master control valve group, while the others are taken as slave control valve groups. The master control valve group selects a trigger angle output by the current regulation unit to control same, and the slave control valve group selects a trigger angle obtained after the trigger angle transmitted from the master control valve group and an output value of the voltage regulation unit pass through a subtractor to control same.

A power grid frequency flexible operation system is provided. The system comprises a generating unit, which includes a base-load unit and a peak-load unit; a high voltage direct-current (HVDC) transmission unit, which transmits the power generated in the generating unit as direct current (DC) power; and a load, which is supplied with the power generated by the generating unit; wherein the high-voltage direct current (HVDC) transmission unit comprises a converter, which transforms to direct current (DC) power, alternating current (AC) power generated in the generating unit and having a first frequency variation allowance range; an inverter, which is connected to the converter and transforms the direct current (DC) power to alternating current (AC) power having a second frequency variation allowance range, wherein the first frequency variation allowance range is larger than the second frequency variation allowance range.

A synchronous rectification converter circuit is provided, including three transformer secondary-windings, three current transformers, a synchronous rectification switching circuit, a diode rectification circuit, and a control circuit. Each of three current transformers includes a primary-winding and secondary-winding. The three transformer secondary-windings and the three current transformer primary-windings are alternately connected in series to form a first triangular structure circuit. Three vertices of the first triangular structure circuit are connected to the synchronous rectification switching circuit. The three current transformer secondary-windings are connected in series to form a second triangular structure circuit. Three vertices of the second triangular structure circuit are connected to the diode rectification circuit. The diode rectification circuit is connected to the control circuit and the synchronous rectification switching circuit is connected to the control circuit.

A line commutated converter, LCC, for a high-voltage, direct current, HVDC, power converter comprises at least one bridge circuit for connection to at least one terminal of a DC system. Each bridge circuit comprises a plurality of arms, and each arm is associated with a respective phase of an AC system. Each arm comprises an upper and lower thyristor connected in series, an associated branch extending from between the upper and lower thyristors, and at least one capacitor module for each phase. The, or each capacitor module is operable to insert a capacitor into the respective arm of the bridge circuit.

A switching power converter controller is provided that transitions between constant voltage pulse frequency modulation operation and constant current operation responsive to a comparison of a peak voltage for the constant voltage pulse frequency modulation operation and a peak voltage for the constant current operation.