CONTROL SYSTEM OF PCS FOR H-BRIDGE 2-STRING SINGLE-PHASE POWER SYSTEM INTERCONNECTION

摘要

The present invention relates to a control system of a PCS for an H-bridge 2-string single-phase power system interconnection, comprising: a voltage control unit for adjusting the size of an alternating current (Icon) for transmitting the direct current power generated in a PV-string to an alternating current system so as to generate alternating current peak current (Ipeak); a phase locked loop for taking momentary system voltage (Vs) as an input for unit power factor control and generating system voltage and a sine wave sinθ having the same phase as the system voltage; a current control unit for generating a current control signal Vcon* for a reference signal (Icon*) obtained by multiplying the alternating current peak current generated by the voltage control unit and the system voltage and the sine wave sinθ having the same phase as the system voltage generated by the phase locked loop; an arithmetic operation unit for generating feed-forward current (Iff) and generating the output power ratio (k) of one PV-string to the total generated power; a control signal decoupling unit for generating a FBC control signal of each PV-string using the current control signal Vcon* generated by the current control unit; and a phase shift PWM unit for taking the FBC control signal generated by the control signal decoupling unit as an input and generating a pulse signal for driving each FBC switching circuit. According to the above-described control system of the present invention, a PCS for a 2-string single-phase power system interconnection using 5-level inverter topology is constituted to achieve improved harmonic wave characteristics, configuration of a power circuit can be simplified and the weight of the system can be reduced, and a current control signal is distributed proportionally to control the power generated by two PV-strings independently of each other.