DC-to-AC voltage conversion circuit and its control method

Abstract

The present invention is one kind of DC-to-AC voltage conversion circuit and its control method. The DC-to-AC voltage conversion circuit is connected to a DC voltage source and used to convert the DCvoltage into stable output AC voltage. It includes mainly one power level transistor switch, one LC filter, one current sensor, one voltage feedback ctrl, one load current sensor, one pulse width modulator and one current command compensator. The present invention aims at utilizing the current sensor to feed back the inductive current of the LC filter for stabilizing voltage and utilizing the load current sensor to widen the controlled frequency band width and raise the voltage stabilizing precision so as to provide stable output AC voltage.

Description

technical field [0001] The invention relates to a DC-AC voltage conversion circuit and a control method, in particular to a DC-AC conversion circuit and a control method. Background technique [0002] At present, the existing DC-AC voltage converters often use Pulse Width Modulation (PWM) technology for output voltage regulation control. A typical system control block diagram is as follows: Figure 1 As shown, the DC-AC voltage converter includes a power stage transistor switch 1 , an LC filter 2 , an inner control loop 3 and an outer control loop 4 . Wherein, the control outer loop 4 is responsible for adjusting the output voltage amplitude, and the control inner loop 3 controls the output voltage waveform. Also, if Figure 1 The shown control outer loop 4 includes: a peak value or RMS calculation circuit 41, a reference voltage generator 42, a subtractor 43, a DC voltage compensator 44, a mains voltage sampler 45, a lock Phase circuit 46 , a sine table (sine table) 47 and...

AI Technical Summary

Problems solved by technology

[0004] (1) In order to adjust the output voltage amplitude of the DC-AC voltage converter, it is necessary to include a peak or root mean square calculation circuit of the output voltage in the controller, which increases the complexity of the electronic circuit

[0005] (2) The controller of the DC-AC voltage converter needs to use the multiplication command to perform the voltage regulation command operation. However, no matter whether the multiplication operation is performed by an analog or digital circuit, it will consume a lot of hardware circuit resources.

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