The inverter uses frequency conversion technology and microelectronics technology to control the power control device of the AC motor by changing the working power frequency of the motor. Domestic inverters are mainly composed of rectification (AC  DC), filter, inverter (DC  AC), brake device, drive device, sensor device microprocessor, etc.

The inverter adjusts the voltage and frequency of the output power supply by the internal IGBT disconnection, and provides the necessary power supply voltage according to the actual needs of the motor to achieve the purpose of energy saving and speed regulation.

1.Working principle of frequency converter

Frequency converters can be divided into two types: current type and voltage type.

The current type is a converter that converts the DC power of the current source into AC power, and the DC circuit filter is an inductor.

The voltage type is a converter that converts the DC power of the voltage source into AC power, and the DC circuit filter is a capacitor.

The main circuit of the frequency converter consists of three parts: a rectifier, a smoothing circuit and an inverter. The rectifier converts the industrial frequency power supply into DC power, the current absorber and the smoothing circuit of the voltage pulses generated by the inverter.

2. Inverter wiring diagram

There are several issues that need to be paid attention to during the installation of the inverter. For example, the inverter itself has strong electromagnetic interference, which hinders the operation of some equipment, so you can add a cable cover to the output cable of the inverter. Or the control line in the inverter or control box should be at least 100 mm away from the power cable.

3. The control circuit of the inverter can be roughly divided into analog and digital.

1. The control circuit terminal wiring should use shielded wire or twisted pair wire, and be separated from the main circuit and ferroelectric circuit (including 200V relay program circuit).

2. The frequency input signal in the control circuit is a micro-current. In order to prevent poor contact during contact input, the small signal contact point must use two parallel nodes, or use twin contact points.

3. The control circuit wiring generally uses 0.3 ~ 0.75 square meters of cable.

Ground wire connection

1. Because the inverter has leakage current, grounding is required to prevent electric shock.

2. The inverter grounding uses a special grounding terminal. For the connection of the grounding wire, use a tinned crimping terminal. When tightening the screw, be careful not to damage the screw buckle.

3. Use a thicker wire diameter for the grounding wire as much as possible. It must be greater than or equal to the specified standard. The grounding point should be as close to the inverter as possible, and the shorter the grounding wire, the better.

4.The role of the frequency converter

1. The frequency converter can adjust the power of the motor and realize the variable speed operation of the motor to achieve the purpose of saving electricity. For example, in centrifugal fans and water pumps, the frequency converter is used for centrifugal fans and water pumps. The operator can adjust the speed and easily control the flow as needed, thereby saving energy.

2. It can reduce the voltage fluctuation on the power line. Once the voltage is abnormal, it can avoid equipment tripping or abnormal operation.