Single-phase Frequency Inverter Developed Based On New Technology Of PWM Of The Arm Rotation Method

Single-phase full-bridge inverter circuit is widely used in batteries, solar inverter output of DC power supply. Currently unipolar SPWM control method is usually used on single-phase full-bridge inverter circuit, ie one arm fixed clamp Power frequency signal, the other applying a high frequency SPWM wave signal, making the bridge between the two arms output power frequency alternating SPWM voltage is then filtered links to reach sine wave output. The method has a simple algorithm, the output waveform advantages. However, the IGBT will generate the switching losses when it worked in inverter circuit, causing heating of the device. The two bridge arms are usually mounted on the same heat sink, the heat sink temperature change inside the same, but different frequencies of the switching arm, the switching losses is also different, IGBT device with the internal junction temperature big difference. Arm which is controlled by high-frequency SPWM wave has big switching loss, the maximum junction temperature, engine prone lived effect, adversely affect the reliable operation of the inverter circuit, resulting in severe damage to the device.Can be found in a controlled manner, while maintaining a single-phase full-bridge inverter circuit SPWM output waveform unipolar good benefits, and sharing their two-leg to reduce switching losses in high-frequency switching arm of the original state loss and the junction temperature, to enhance the reliability of the inverter circuit purposes. To this end, we propose a novel algorithm of SPWM-PWM technology of the arm rotation method to achieve the above objectives. Bridge arm rotation method of PWM control principle of new technology: one arm of inverter circuit use square wave power frequency control, the other applying high frequency SPWM wave control in the previous modulation wave cycle, changing the two bridge arm control mode in the next cycle, again and again.According to the new technology of PWM bridge arm rotation method control theory and algorithms, using DSP programming to realize SPWM real-time computing and controlling, and design and product a single-phase full-bridge inverter circuit hardware system, carried out load and temperature experiment on the platform, the results prove that the new technology of PWM bridge arm rotation method has the advantage of sharing two-arm switching losses; the output voltage waveform of harmonic analysis of two control principle; Applying Melcosim software calculate the arm switching losses and the junction temperature inside of IGBT of two SPWM control mode, the results proved the superiority of the new technology of SPWM bridge arm rotation method that IGBT junction temperature significantly lower than the maximum junction temperature in using unipolar SPWM technology, thereby enhancing the reliability of IGBT work. The new technology also maintained a unipolar SPWM waveform advantages.