Medium frequency and high frequency DC inverter transformers: core differences and application scenarios

A transformer is a device that uses the principle of electromagnetic induction to change the AC voltage. Its main components are the primary coil, the secondary coil and the iron core (magnetic core). The main functions are: voltage conversion, current conversion, impedance conversion, isolation, voltage stabilization (magnetic saturation transformer), etc. Transformers can be divided into: distribution transformers, power transformers, fully sealed transformers, combined transformers, dry-type transformers, oil-immersed transformers, single-phase transformers, electric furnace transformers, rectifier transformers, reactors, anti-interference transformers, lightning protection transformers, box-type transformer test transformers, corner transformers, high current transformers, excitation transformers, etc.

We will focus on two types of transformers, medium frequency DC inverter transformers and high frequency DC inverter transformers.

1. High-frequency DC inverter transformer

Application scenarios

Clean energy field: used for solar photovoltaic power generation and wind power generation systems to convert DC power into AC power and connect to the grid.

Industrial automation: drive motors, compressors and other loads to achieve precise control.

Transportation field: power supply systems for electric vehicles, high-speed railways, ships and other means of transportation.

Communications and data centers: signal processing, equipment power supply and redundant power supply guarantee.

Aerospace: aircraft power supply system to meet the needs of high-precision electrical equipment.

Advantages

Small size and light weight: high-frequency core materials greatly reduce the size, making medium-frequency inverter resistance welding transformer easy to carry and install.

High efficiency: peak conversion efficiency of more than 90%, low no-load loss.

Voltage adjustability: precise control of output voltage is achieved through high-frequency PWM technology.

Wide range of application: supports a wide input voltage range and adapts to different DC power inputs.

Disadvantages

Large electromagnetic interference (EMI): high-frequency switching generates interference, and additional electromagnetic compatibility circuits need to be designed.

Weak overload capacity: inductive loads (such as motors) cannot be driven at full load and are easily damaged by impact.

Complex circuit: Relying on precision control technology, the manufacturing cost and maintenance difficulty are high.

High stability requirements: Strict requirements on heat dissipation and device performance, high-frequency filtering circuit is required to optimize the waveform.

2. Medium frequency DC inverter transformer

Application scenarios

Industrial heating equipment: such as induction heating furnace, frequency range 1kHz-10kHz, suitable for metal smelting.

Medical equipment: medical power supply systems that require specific frequencies such as medium frequency electrotherapy devices.

Power electronics testing: Medium frequency inverters are used in laboratories to simulate grid conditions or equipment aging tests.

Special power supplies: such as aviation power supplies (400Hz) and medium frequency power supply systems for military equipment.

Advantages

Balanced performance: smaller than industrial frequency, stronger anti-interference ability than high frequency.

Moderate efficiency: conversion efficiency is usually 85%-90%, suitable for medium power demand scenarios.

Strong driving ability: can partially support inductive loads, such as small motors or transformers.

Disadvantages

Limited application range: mainly concentrated in specific industrial scenarios, and less versatile than high-frequency inverters.

High cost: Customized design is required, and the cost of device selection (such as medium-frequency transformer) is high.

Poor frequency compatibility: A matching filter circuit is required to adapt to the needs of different equipment.

3. Comparison and selection suggestions