According to an embodiment, disclosed are a DC-DC converter for compensating for a ripple, in a solar linked energy storage system, and a control method thereof. In particular, disclosed is a DC-DC converter for compensating for a ripple generated in a DC link where a single phase inverter and a converter are connected. The DC-DC converter may obtain a frequency of a grid to compensate for the ripple.

Disclosed is a low-pass filtering system having a phase-lock loop comprising a Park transform circuit, a first low-pass filter, a second low-pass filter, an inverse Park transform circuit, a phase-locked loop filter, and a voltage-controlled oscillator. The Park transform circuit, the first low-pass filter, the second low-pass filter, and the inverse Park transform circuit form a phase detector of a phase-locked loop, since the low-pass filter system of the present invention has the phase-locked loop mechanism, the phase and amplitude of a output signal remain the same with those of the original AC input signal.

A power quality compensation system and a power quality compensation method are provided. The power quality compensation apparatus includes an input filter, a power electronic converter, a controller configured to control the power electronic converter, and a plurality of inductors connected to the power electronic converter. The power quality compensation method includes receiving signals from one or more sensors configured to detect voltage and current from an input side and an output side of the power quality compensation system, calculating reference signals, and using model predictive control to track the reference signals.

A low-pass filter circuit is provided. The low-pass filter circuit includes a low-pass filter and a discharging circuit. The low-pass filter receives an input voltage signal through an input terminal of the low-pass filter circuit during a first period, performs a low-pass filter operation on the input voltage signal to generate a filtered voltage signal, and provides the filtered voltage signal to an output terminal of the low-pass filter circuit. The discharging circuit suppresses a leakage current flowing between the output terminal and a reference low voltage in response to the input voltage signal during the first period.

Disclosed are a regulation method and a regulation device for a converter of a wind turbine generator in a wind power plant. The regulation method comprises: acquiring real-time voltage and current signals of a grid connection point (701); acquiring real-time state information of each wind turbine generator on the same electrical circuit in a wind power plant (702); and generating a unified regulation instruction on the basis of the acquired real-time voltage and current signals and the acquired real-time state information (703). The real-time state information comprises the total number of three-phase bridge arms of converters of currently running wind turbine generators on the same electrical circuit in the wind power plant, serial numbers that are dynamically allocated for the converters of the currently running wind turbine generators and their respective three-phase bridge arms, and the real-time power of each currently running wind turbine generator. The unified regulation instruction comprises a regulation instruction for the converter of each currently running wind turbine generator, wherein the regulation instruction comprises a phase shift angle reference value of a carrier, a carrier ratio reference value, and a characteristic quantity reference value of a modulated wave, which are required for the regulation of each three-phase bridge arm in the converter.

The present disclosure relates a reactive power compensation system including a detection unit for acquiring loading state information of a plurality of loads, a reactive power compensation unit for compensating reactive power, and a controller for controlling the reactive power compensation unit to perform flicker compensation or power factor compensation based on a control signal according to the loading state information.

Disclosed are a voltage source converter based high voltage direct current (VSC-HVDC) high-frequency resonance suppression method, system, and device. The method includes: when an effective value of an actually input alternating current (AC) voltage is reduced from a normal value to meet a preset condition, making the virtual electrical quantity completely equal to the actual electrical quantity, and performing full real-time tracking for the actual electrical quantity to improve dynamic characteristics of a power system at the moment of a fault; and after performing the full tracking for a period of time, if the effective value of the actual AC voltage is less than a preset threshold, performing adaptive tracking until the actual electrical quantity recovers to a stable value. The present disclosure can reduce a risk of high-frequency resonance of a VSC-HVDC, avoid deteriorating dynamic characteristics of the VSC-HVDC, and improve safety of fault ride-through of the VSC-HVDC.

A harmonic component extraction unit obtains a command value of compensating current from a harmonic component of the load current. A difference current generation unit obtains a deviation between the compensating current and a value obtained by leading a phase of the command value by a predetermined phase difference. A current controller generates a control signal based on output of the difference current generation unit. A driving signal generation circuit generates, based on the control signal, a driving signal driving a parallel active filter.

The present disclosure relates to a reactive power compensation system including a reactive power compensation unit for measuring compensate reactive power, an impedance measurement unit for measuring an impedance value of each of a plurality of loads, and a learning control unit for controlling the reactive power compensation unit based on the measured impedance value.

The present invention discloses a modular intelligent combined wind power converter and a control method thereof. The modular intelligent combined wind power converter comprises separate bridge arm power units, wherein a plurality of the bridge arm power units are connected in parallel to form a high-capacity bridge arm power module, three bridge arm power modules form a three-phase full-controlled bridge power module, and the three-phase full-controlled bridge power module comprises an electric reactor, a capacitor, a fuse and a circuit breaker to form a basic converter module, and the basic converter module forms a high-capacity wind power converter through a modular intelligent combination method.