I. Introduction
The vehicle-mounted inverter (power converter, Power Inverter) is a convenient vehicle power converter that can convert DC 12V direct current into AC 220V alternating current, which is the same as the mains power. It is provided for general electrical appliances.
With the advancement of automotive product technology, the electronic technology owned by cars is also constantly improving. The development of electric vehicles and plug-in hybrid vehicles with on-board inverters as important components is rapidly accelerating. The development prospects of the on-board inverter market will be Very vast. The increasing popularity of vehicle-mounted inverters has also promoted the use of MOS tubes in vehicle-mounted inverters.
2. Product application and working principle
Vehicle-mounted inverters can achieve power specifications of 20W, 40W, 80W, 120W and up to 500W. The application range is: mobile phones, laptops, digital camcorders, cameras, lighting, electric shavers, CD players, game consoles, and handheld computers. , power tools, car refrigerators, etc.
A general vehicle inverter is mainly composed of an inverter bridge, filter circuit, control circuit, oscillator, etc. Its working principle is to first convert the 12V DC power provided by the car battery through high-frequency PWM (pulse width modulation) switching power supply technology. Into an alternating current of about 30kHz-50kHz, 220V. Then bridge rectification, filtering, pulse width modulation and switching power output and other technologies are used to convert the AC power of about 30kHz to 50kHz and 220V into the AC power of 50Hz and 220V.
3. Product application topology diagram
4. Line selection recommendations
Two series of MOS solutions are provided for the DC-DC boost circuit + control circuit (push-pull type) and DC-AC inverter circuit of the inverter circuit shown above:
DC-DC boost circuit (anti-reverse connection) + control circuit (push-pull type)
In the DC-DC boost circuit, MOSFET is used as the switching device. The maximum voltage that the field effect tube needs to withstand is about 20-30V. When selecting, there should be a margin for the maximum withstand voltage of the MOS tube. Generally, 40V is selected. MOS above. It is recommended to use Reasunos Semiconductor's low-voltage MOS series for MOS tubes. The selection is as follows:
DC-AC inverter circuit (full-bridge PWM control)
The main circuit of the DC-AC inverter circuit adopts a full-bridge structure, and the diode connected in parallel with the switching tube plays a protective role. It is recommended to use Reasunos Semiconductor's high-voltage MOS series for MOS tubes. Reasunos Semiconductor's high-voltage MOS series has ultra-small internal resistance, moderate junction capacitance, good heat dissipation performance, small high-temperature leakage, and small high-temperature voltage drop, and is widely praised by the market.