Method, apparatus and system for testing inertia coefficient and damping coefficient of grid-forming converter

An apparatus for testing an inertia coefficient and a damping coefficient of a grid-forming converter, comprising:

• a data obtaining module, configured to obtain a filter capacitor voltage in a three-phase LCL filter, an inverter-side current, an output-side current, and an output three-phase voltage;
• a frequency control module, configured to output a frequency output signal and a phase output signal through frequency control;
• a voltage control module, configured to:
• output a PWM control signal based on the phase output signal, the filter capacitor voltage, and the inverter-side current, to control turn-on time of a power semiconductor switch;
• an active power measurement module, configured to output an active power signal based on the output three-phase voltage, the output-side current, and the phase output signal;
• a frequency measurement module, configured to process the output three-phase voltage to obtain a real-time output frequency;
• and
• a damping coefficient and inertia coefficient measurement module, configured to:
• separately process the active power signal, the real-time output frequency, and related setting parameters to obtain the inertia coefficient and the damping coefficient.

A system for testing an inertia coefficient and a damping coefficient of a grid-forming converter, comprising:

• a power semiconductor switch, a three-phase LCL filter, a three-phase alternating-current relay, and a processor, wherein
• a first terminal of the power semiconductor switch is connected to a direct-current side power source, a second terminal of the power semiconductor switch is connected to the three-phase LCL filter, and the three-phase LCL filter is connected to a tested grid-forming converter through the three-phase alternating-current relay;
• the processor is configured to:
• receive a filter capacitor voltage in the three-phase LCL filter, an inverter-side current, an output-side current, and an output three-phase voltage, and process received data, and is configured to:
• output a frequency output signal and a phase output signal through frequency control;
• output a PWM control signal based on the phase output signal, the filter capacitor voltage, and the inverter-side current, to control turn-on time of a power semiconductor switch;
• output an active power signal based on the output three-phase voltage, the output-side current, and the phase output signal;
• process the output three-phase voltage to obtain a real-time output frequency;
• and
• separately process the active power signal, the real-time output frequency, and related setting parameters to obtain the inertia coefficient and the damping coefficient.