The Working Principle Of The Inverter

Time：[2017-4-3]     Views：1850

1.Full-controlled inverter works

A full-bridge inverter main circuit commonly used single-phase output AC components using the IGBT Q11,Q12,Q13,Q14.By the PWM pulse width modulation control of the IGBT is turned on or off.

When the inverter circuit connected to a DC power source,first Q11,Q14 isturned on,Q1,Q13 is turned off,the current from the positive output of the DC power supply,the Q11,L or flu,the transformer primary winding 1-2,back to Q14 to the negative power supply.When Q11,Q14 after the deadline,Q12,Q13 is turned on,current flows from the positive power supply via Q13,electrical transformer primary winding 2-1 Q12 was back negative power.In this case,the transformer primary winding is formed of alternating positive and negative square wave,with high frequency PWM control,two pairs of IGBT tube alternately repeated AC voltage on the transformer.Since LC AC filter action,so that the output voltage of the AC sine wave is formed.

When Q11,Q14 when turned off,in order to release the stored energy in the IGBT of the parallel diode D11,D12,the energy returned to the DC power supply to go.

2.Semi-controlled inverter works

Semi-controlled inverter with thyristor element.Improved parallel main circuit of the inverter shown in Figure 4.FIG,Th1,working alternately thyristors of Th2,Th1 first trigger set is turned on,a current flows through the transformer Th1,and because of the inductive effect of the transformer,the commutating capacitor C is charged to 2 times larger supply voltage.According to Th2 is triggered conduction,because the anode reverse biased Th2,Th1 off,return to the blocking state.Thus,Th1 and Th2 commutation capacitor C and then reverse polarity charge.So alternately triggered thyristor,transformer primary current alternately flows in the secondary of the transformer to get AC.

In the circuit,the inductance L can limit the commutation capacitor C discharge current,discharge time is extended,ensure that the circuit is greater than the turn-off time of the thyristor off-time,without the need for large capacity capacitor.D1 and D2 are two feedback diode,inductor L may be in the release of energy,it will be sent back to the rest of the energy supply,complete the feedback energy.