Abstract: A fault ride-through circuit with a variable frequency transformer (VFT) and a control method thereof are provided, and the control method comprises: pretreating acquired voltages of grids, a voltage of a stator interface and a voltage of a rotor interface to obtain a rotor voltage DC component and a rotor voltage DC component; testing and treating a voltage frequency of a first grid and a voltage frequency of a second grid; carrying out a reference voltage calculation for a stator voltage DC component, a rotor voltage DC component, the voltage frequencies of the first grid and the second grid to obtain a positive voltage reference value of the first PWM convertor and the second PWM convertor; and processing the voltage reference values to obtain the switch signals for controlling the first PWM convertor and the second PWM convertor.

Abstract: A fault ride-through circuit with a variable frequency transformer (VFT) and a control method thereof are provided, and the control method comprises: pretreating acquired voltages of grids, a voltage of a stator interface and a voltage of a rotor interface to obtain a rotor voltage DC component and a rotor voltage DC component; testing and treating a voltage frequency of a first grid and a voltage frequency of a second grid; carrying out a reference voltage calculation for a stator voltage DC component, a rotor voltage DC component, the voltage frequencies of the first grid and the second grid to obtain a positive voltage reference value of the first PWM convertor and the second PWM convertor, and processing the voltage reference values to obtain the switch signals for controlling the first PWM convertor and the second PWM convertor.

Abstract: An alternating current/direct current home smart micro-grid coordination system is provided, which includes an alternating current power quality screening modulator, a direct current power quality screening modulator and a power coordination module, where the power coordination module is configured to receive parameters of buses detected by the alternating current power quality screening modulator and the direct current power quality screening modulator, perform optimization calculation to obtain optimal solutions of a voltage on the power quality-insensitive load alternating current bus and a voltage on the power quality-insensitive load direct current bus, and issue an instruction to control the alternating current power quality screening modulator and the direct current power quality screening modulator to adjust the voltage on the power quality-insensitive load alternating current bus and the voltage on the power quality-insensitive load direct current bus.

Abstract: The invention provides a light emitting diode (LED) centralized DC (direct-current) power supply system and operating methods thereof. The proposed DC power supply system comprises a three-phase AC (alternating-current) input interface, a DC power supply output interface, N+1 three-phase PWM (pulse width modulation) rectifier modules, LED cluster loads and a power supply management module. The proposed operating methods are described as following: the power supply management module adjusts the duty ratio of the three-phase PWM rectifier modules, based on the control signals formed by synthesizing the information about voltage and current of the positive and negative output buses, the three-phase AC input ends, control signals and output of the three-phase PWM rectifier modules, hence AC voltage of power grid can be directly converted into adjustable DC voltage by the PWM rectifier.

Abstract: The invention provides a light emitting diode (LED) centralized DC (direct-current) power supply system and operating methods thereof. The proposed DC power supply system comprises a three-phase AC (alternating-current) input interface, a DC power supply output interface, N+1 three-phase PWM (pulse width modulation) rectifier modules, LED cluster loads and a power supply management module. The proposed operating methods are described as following: the power supply management module adjusts the duty ratio of the three-phase PWM rectifier modules, based on the control signals formed by synthesizing the information about voltage and current of the positive and negative output buses, the three-phase AC input ends, control signals and output of the three-phase PWM rectifier modules, hence AC voltage of power grid can be directly converted into adjustable DC voltage by the PWM rectifier.