CONTROL SYSTEM OF H-BRIDGE 2-STRING GRID TIED PCS

摘要

PURPOSE: Control system for an H-bridge 2-string single phase grid connected power conditioning system (PCS) is provided to improve a harmonic characteristic by configuring a 2-string single phase grid connected power PCS using 5-level inverter topology. CONSTITUTION: A voltage control unit (100) controls intensity of AC current (Icon) and generates AC peak current (Ipeak). A synchronous loop unit (200) receives instantaneous system voltage (Vs) for unit power factor control and generates sinusoidal wave. A current control unit (300) generates a current control signal (Vcon*) for tracking control of a reference signal (Icon*). A calculation unit (400) generates an output power ratio of one PV string with respect to the total generation power. A control signal decoupling unit (500) generates a feedback control (FBC) signal of the each PV string using the current control signal. A phase shift pulse width modulation (PWM) unit (600) generates a pulse signal for driving a switch comprising each FBC. [Reference numerals] (600) Phase shift PWM unit; (AA) Sa1,Sa2,Sa3,Sa4 driving signal; (BB) Sb1,Sb2,Sb3,Sb4 driving signal; (CC,DD) Second LPF; (EE) Effective value calculation unit