Phase-shift transformers: working principles and applications

Phase-shift transformer is a special transformer whose main function is to reduce the harmonic current on the grid side by changing the phase of the voltage. Phase-shift transformer has different phases through secondary windings, and connects the rectifier circuit of high voltage frequency converter, thus forming a polyphase rectifier system. This design helps to reduce the harmonic current on the grid side and improve the stability of the power system. ‌‌

‌The working principle of the phase-shift transformer ‌is to change the phase difference of the current by adjusting the coupling inductance between the primary coil and the secondary coil. The phase-shift transformer is mainly composed of a main coil (main winding) and a phase modulation coil (secondary winding). The main coil is usually connected to the power supply, while the phase modulation coil is connected to the load circuit. By adjusting the coupling inductance, the coupling degree between the main coil and the phase modulation coil can be changed, and the phase difference of the current ‌.

Specifically, when the current passes through the main coil, the resulting magnetic field is transferred to the phase modulation coil, causing the current to be generated in the secondary coil. The phase difference between this current and the current of the main coil is controllable. The phase difference between the main coil and the phase modulation coil can be changed by adjusting the size of the coupling inductance. Increasing the coupling inductance decreases the phase difference of the current, and decreasing the coupling inductance increases the phase difference of the current ‌.

Phase-Shifting-Rectifier-Adjustable-Voltage-Transformer

Application of phase-shift transformer

1. Power system field

Phase-shift transformers are widely used in power systems and mainly used to regulate the voltage of transmission lines and the phase of AC circuits. In the transmission line, due to the existence of line resistance, inductance, capacitance and other factors, the long distance transmission will cause voltage drop, harmonic generation, phase offset and other problems. The phase-shift transformer can correct these problems by phase shifting, ensure the quality of power transmission and improve the stability of the system.

At the same time, in the power system, phase-shift transformers are also used to coordinate the voltage of transformers at all levels, solve the power imbalance on the high-voltage side of the substation, reduce overvoltage and ensure the safe operation of power equipment.

2. Electronic equipment field

In the field of electronic equipment, phase-shift transformers are widely used in power control and transformer regulation of DC power supplies. By connecting the phase-shift transformer in the input circuit, the input voltage and power can be adjusted and the working state of the circuit can be controlled. Finally, the energy-saving control of electronic equipment can be realized.

3. Communication systems

In the field of communication systems, phase-shift transformers are mainly used to protect equipment and improve signal transmission quality. In the communication system, due to the different baud rate and speed of different equipment, it is easy to produce crosstalk, noise and other problems. The phase-shift transformer can improve the adaptability of the system, reduce interference and improve the transmission quality of the signal.

At the same time, in the communication system, the phase-shift transformer can also be used to solve the problem of the signal common mode level asymmetry, prevent the relative deviation of the equipment, and further improve the communication quality.

The future development trend of phase-shift transformers

With the continuous progress of science and technology and the growing demand of power system, phase-shift transformers will face more development opportunities and challenges. In the future, phase-shift transformers may develop in the following directions:

1. Intelligent: Through the introduction of advanced sensors, control systems and communication technology, intelligent management of phase-shifting transformers can be achieved. This will help to monitor the operation status of the transformer in real time, discover and deal with potential faults in time and improve the safety and reliability of the power system.

2. High efficiency and energy saving: With the increasingly serious global energy shortage and environmental pollution problems, high efficiency and energy saving have become an important trend in the development of power equipment. In the future, phase-shift transformers may use more efficient materials and design schemes to reduce energy consumption and environmental impact.

3. Multifunctional integration: In order to meet the increasingly complex needs of power systems, phase-shift transformers may be multifunctional integration with other power equipment. For example, the phase shift function is combined with reactive power compensation, filtering and other functions to improve the overall performance and utilization of the equipment.

As an important power equipment, phase-shift transformer plays an irreplaceable role in power system. With the continuous progress of technology and the expansion of application fields, phase-shift transformers will usher in a broader development space and application prospects.