The Study Of Control Method For Double-Frequency Half-Bridge Power Amplifier

The power amplifier has been extensive used in audio application, industry and other areas. As the switch frequency higher and higher, the power electronic productions get smaller and smaller; so many traditional power amplifiers have been taken by the switching power amplifiers. Now, the switching power amplifiers have became a hotspot in power electronics field.The switching power amplifier modulates the input signal and magnifies the PWM signal, then demodulates the PWM signal to get the output signal. The operation of switching power amplifier makes sure the high efficiency. However, the operation also makes the output distortion bigger than the traditional amplifier. Many domestic and overseas researchers are now focusing on how to improve the output quality and the efficiency at the same time.Our research team has done many researches about the switching power amplifiers. And many achievements had been obtained. Based on these achievements, the contents in this paper are as follows:①Introduced the principle and configuration of the double-frequency half-bridge switching audio amplifier. And the high frequency and low frequency circuits'analysis models had been built.②As the feedback loop is good for improving the output signal quality, in this paper, the PID feedback combined the OCC controller has been introduced to the double-frequency half-bridge switching power amplifier. And built the compensated model, analyzed the theory of restraining distortion. The way of low-frequency inductor current following high-frequency inductor current had been raised to reduce the switching frequency of low-frequency part.③Simulated the designed double-frequency half-bridge switching power amplifier. The differences between the single high-frequency and double-frequency power amplifier, compensated and un-compensated double-frequency power amplifier, with and without the high-frequency inductor current filter had been analyzed.④Completed the whole circuit design of a double-frequency half-bridge power amplifier, and debugged the circuit. Some theories had been validated.