The inverter is an electronic device that converts low voltage (12 or 24 volts or 48 volts) of direct current into 220 volts AC. The opposite of the role of the inverter. Inverter is the DC (12-36v) into AC power equipment.
1. Transistor inverter is the use of transistors and transformers self-excited or excited to form a frequency of about 50hz frequency AC signal, and then amplified by the crystal transistor, the transformer boost to 220v or other voltage for the load. A big weight.
2. Switch-type inverter is the use of transistor integrated circuit frequency of about 20-50KHz AC high-frequency signal amplification to 220v rectifier to be 300V-, and then by the SCR chopped into 220v , 50hz power supply for the load use. Small body light, high efficiency.
3. Pulse converter, is the pulse signal into the converter amplifier (voltage, current, power) is still in this form of pulse waveform to the load.
In addition to the main circuit converter (rectifier circuit, inverter circuit, AC conversion circuit and DC conversion circuit), but also need to control the power switching element on and off the trigger circuit (or drive circuit) and to achieve the power regulation, Control of the control circuit.
The trigger circuit of the converter includes the pulse generator and the pulse output device. The former according to the requirements of the control signal to produce a certain frequency, a certain width or a certain phase of the pulse; The latter amplifies the level of the pulse into a drive signal suitable for the power switching element in the converter.
Trigger circuit according to the control function can be divided into phased trigger circuit (for controllable rectifier, AC voltage regulator, direct down converter and active inverter), cut off the trigger circuit and frequency control trigger circuit. The use of sine wave frequency control circuit can not only control the inverter output voltage
, but also improve the quality of the output voltage.
The control circuit of the converter divides the ring control circuit and the closed-loop control circuit according to the control way.
The former is mainly used in the requirements of some special equipment; the latter has the role of automatic control and regulation, widely used in a variety of work machinery.
According to the nature of the control signal analog control circuit and digital control circuit. Analog signals are most commonly used in DC voltage and current, easy to use electricity to be processed and transformed; digital signal is a set of information parameters with discrete values of the discontinuous signal.
Digital control with high precision, but the circuit is more complex and expensive. Therefore, in fact, widely used digital analog hybrid control circuit. In addition, the use of micro-computer control circuit also has many advantages.