How Does the Inverter Realize Single Phase 220KV to Three Phase 380KV

I believe many people want to know how to convert a single-phase to three-phase frequency converter, but if you really want to change this voltage, you need to change the voltage of the drive motor, and you must also consider the problem of boosting voltage. We also encountered this kind of problem when repairing the frequency converter before, because it was difficult to find a three-phase power supply in the local market before, and it could only be completed by changing from single-phase to three-phase. Several methods are described in detail below.

1. The idea of using variable frequency power supply

a. It is realized through a single-phase 220-380-volt transformer and frequency converter
The single-phase transformer is easy to find, and the price is not expensive. The inverter drives the motor is also very mature. The single-phase 220 volts output 380 volts to the inverter through the transformer, and the inverter then outputs three-phase 380 volts to the motor. This is a reliable practice. , In the early days, we used this method for repairing inverter tests.

Since the input part of the inverter is a simple rectification circuit, most of them have no phase loss protection, and some of them can be shielded by software, so there will be no alarm, which can fully meet the requirements of no-load testing.

But this method also has a problem, that is, the output power of the inverter itself is limited, and the efficiency is relatively low. The bigger problem is that the output waveform is not a real sine wave. Except for simple testing of the motor, it cannot be equipped with capacitive or resistive loads.

b. The real practice of variable frequency power supply
The variable frequency power supply converts the alternating current in the mains through AC→DC→AC, and the output is a pure sine wave, and the output frequency and voltage are adjustable within a certain range. It is different from the frequency conversion speed regulation controller used for motor speed regulation, and it is also different from ordinary AC regulated power supply. The characteristics of an ideal AC power supply are stable frequency, stable voltage, zero internal resistance, and a pure sine wave (no distortion) for the voltage waveform.

The variable frequency power supply is very close to the ideal AC power supply. Therefore, the advanced developed countries increasingly use the variable frequency power supply as the standard power supply to provide the best power supply environment for the electrical appliances and facilitate the objective assessment of the technical performance of the electrical appliances. There are two main types of frequency conversion power supply: linear amplification type and SPWM switching type. The frequency conversion power supply can really solve the problem of single-phase conversion to three-phase, and can directly drive resistive and capacitive loads.

2. Simple and original method

A single-phase motor is used to drive a three-phase generator to output a standard three-phase motor. This method was used by many people in remote mountainous areas in the early days, but it has low efficiency and low power, and almost no one uses it now. There are also methods such as parallel capacitors, which are actually of no economic value, and are basically eliminated now.

The above content is our introduction to the method of converting single-phase to three-phase inverters. I hope the above content will be helpful to friends. If you have any questions or intend to inquire about inverter prices, maintenance and other services, please contact customer service personnel through the official website for details.