Device and method for reactive power compensation and harmonic suppression of grid-connected potovoltaic system

The invention discloses a device and a method for reactive power compensation and harmonic suppression of a grid-connected potovoltaic system. The method comprises the following steps of: directly acquiring current on a harmonic source, decomposing the acquired current into harmonic current, fundamental current, reactive current and active current through Fourier transformation, doing a summation on the harmonic current requiring compensation and the reactive current to obtain compensating current, comparing the compensating current with command current, utilizing PWM (pulse width modulation) tracking control method to output PWM waveforms according to the comparison results and driving the PWM waveforms to first control the state of every switching tube in an inversion unit and then control the current output by the inversion unit. Therefore, current on a load can track the command current in a sawtooth wave form, the harmonic current and the reactive current can be offset and the purposes of harmonic suppression and reactive power compensation are achieved. The device and the method can be realized on the basis of the traditional grid-connected potovoltaic system, and the device has a simple structure, carries out detection and control in a real-time manner and has fast responding current.