The Research And Design For Automotive Inverter Power Supply Of500W

In recent years, the car has gradually developed into a collection of office and entertainment transportation from an original traffic tool:besides the common car DVD system, car TV, car fridge, laptop and other electronic products also become the demands of people, but most of these appliances require a sinusoidal AC power supply of220V/50Hz.The private car batteries can only provide a DC voltage of12V, the power inverter can convert the DC voltage into a sinusoidal voltage of220V/50Hz for the electronic products, so it would be very meaningful to develop a high performance automotive inverter power supply.Most of traditional automotive inverter power supplies are controlled by the typical sinusoidal integrated chips, so it is difficult to do the further design, the circuit structure is complicated, and they are hard to start. This paper introduces a design idea of two-stage automotive inverter power supply controlled by a single-chip microcomputer (SCM):improving the drive circuit design to ensure the switches turn on-off at the right time, improving the control strategies so the hard-start problem was solved, besides that the bridge arm short protection circuit was added.In the boost converter part, the high-frequency transformer was used in push-pull circuit whose input is12V DC, which is controlled by the pwm chip called TL494. Because the first-stage circuit and second-stage circuit was not in the same GND, with the help of the secondary winding auxiliary power supply, the precise programmable regulated voltage chip called TL431and the linear optocoupler called PC817were used in the design of DC bus voltage negative feedback circuit whose function is to ensure the output voltage within the setting range. In order to prevent the undervoltage or overvoltage of the batteries, the protection circuit was designed. The selection principles of the power switches, rectifier diodes and filter components were introduced, but the design processes of the high-frequency transformer and the operation principles of circuits were introduced in detail words.The invertion section includes hardware design and software design two parts. The hardware circuits which are controlled by a SCM of STC called STC12C5A60S2, using SPWM control technology, combined the dead time generating circuit with the drive circuit to control the single-phase full-bridge inverter circuit. In order to ensure the inverter power supply work in the right condition, the overcurrent protection circuit, the bridge arm short protection circuit and snubber circuit were designed. In the software design part, the SPWM trigger waves are generated by SCM, output voltage feedback circuit, overvoltage and undervoltage of the batteries protection circuit, overcurrent protection circuit, the bridge arm short protection circuit are also controlled by the SCM. In order to watch the input and output state of the inverter power supply, the serial communication was used.In the end, the control theories were verified through the Matlab/simulink software and the hardware prototype was developed. The key working points waves of the boost circuit and inverter circuit were tested and the performance of the inverter power supply was tested, too. The experimental results show that the inverter power supply operates steadily, and further verify the control strategies of the system are rational. The inverter power supply is small, easy to start, has low noise and good heat dissipation characteristics, so it is easy to install and good to produce.