Output voltage turning-off control method and circuit of vehicle-mounted sine wave inverter

Abstract

The invention relates to an output voltage turning-off control method and a control circuit of a vehicle-mounted sine wave inverter, as well as the relevant vehicle-mounted sine wave inverter. The control method comprises the steps that when the vehicle-mounted sine wave inverter stops outputting, a real-time phase of output voltage is computed according to an SPWM (Sine Pulse Width Modulation) counting value; whether output voltage corresponding to the real-time phase is less than the preset voltage value is judged; if so, outputting of an SPWM wave is stopped immediately; if not, a waveform of the output voltage is further judged; if the waveform rises, the SPWM wave is output continuously after the SPWM pulse counting value is adjusted to allow the waveform of the output voltage to be changed from rising to dropping immediately; if the waveform drops, the SPWM wave is output continuously and normally; and the output voltage is monitored continuously whether the waveform rises or drops till the output voltage is less than the preset voltage value. According to the control method, the control circuit and the relevant vehicle-mounted sine wave inverter, the real-time waveform of the output voltage is monitored when the vehicle-mounted sine wave inverter stops the outputting, the output voltage is turned off by a zero voltage turning-off technology, and residual voltage at an output end is low after turning-off, so that the safety is good; no discharge resistor is required to be connected in parallel; and the product efficiency is improved.

Description

technical field [0001] The present invention relates to the technical field of vehicle-mounted inverters, and more specifically, relates to a control method for shutting off the output voltage of a sine wave vehicle-mounted inverter, a control circuit and a corresponding sine wave vehicle-mounted inverter. Background technique [0002] The module block diagram of the existing sine wave vehicle inverter is as follows: figure 1 As shown, it includes a DC filter circuit 10, a DC / DC boost circuit 20, a DC / AC inverter circuit 30 and an AC filter circuit 40, and a boost control circuit 50 for generating PWM waves to control the DC / DC boost circuit 20 And an inverter control circuit 60 for generating SPWM waves to control the DC / AC inverter circuit 30 . After the DC input, first pass through the DC filter circuit 10 to reduce ripple current and suppress electromagnetic interference, then pass through the DC / DC booster circuit 20 to convert DC12V or DC24V to high-voltage direct cur...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a solution for the defects that the residual voltage at the output end of the existing sine wave vehicle-mounted inverter is sometimes high after shutdown, the safety is poor, and the use of a discharge resistor to discharge the filter capacitor results in high product loss and low efficiency. Output voltage shutdown control method of sine wave vehicle-mounted inverter, control circuit and corresponding sine wave vehicle-mounted inverter

Images