What Is a Phase Shifter?

Phaser A device capable of adjusting the phase of a wave. Any transmission medium will introduce phase shift to the wave conducted in it. This is the principle of early analog phase shifters; after the development of modern electronic technology, digital phase shift was realized by A / D and D / A conversion. Discontinuous phase shifting technology, but is characterized by high phase shifting accuracy.

Phase shifter (Phaser)

A device for adjusting the phase of AC voltage. The phase shifter is generally multi-phase, and its structure is shown in the figure. It is similar to a wound three-phase asynchronous motor. Usually the stator winding is used as the primary winding and the rotor winding is used as the secondary winding. A set of worm gears is installed on the rotor shaft of the phase shifter. Rotating the worm gear can make the rotor of the phase shifter rotate within a certain range relative to the stator. When the primary winding on the stator is connected to a three-phase AC power source, the rotating magnetic field generated in the air gap will induce electromotive forces E 1 and E 2 in the primary and secondary windings, respectively. Its size is proportional to the effective number of turns of each winding, and the phase is determined by the relative position between the axes of the primary and secondary windings. For example, the axes of the primary and secondary windings are different from each other by an electrical angle in the spatial position, and ignoring their leakage impedance voltage drop, the relationship between the primary and secondary voltages can be obtained as

U 1 E 1

formula Where n sr is the transformation ratio of the primary and secondary windings. Changing the position of the rotor can change the phase of the secondary voltage with respect to the primary voltage, but the size of the output voltage does not change.

Phase shifter characteristics

The phase shifter organically combines the transformer phase shifting technology with digital measurement technology.

Phase shifter The section has high accuracy, accurate and intuitive readings, adjustable output voltage and current, good output waveform, reliable operation and convenient operation. It can meet the test and verification of single-phase and three-phase AC power and phase meters with higher accuracy. It can also be used. In the verification device of the watt-hour meter.

Phaser application

When the system load is heavy and there is a continuous and rapid climbing trend, it is necessary to perform voltage emergency situation points, and watch how the operating conditions may approach the critical point of the load supply capacity of the power grid. When the load rises rapidly at a high level, how the power supply shares the load increase can find the clues from the peak regulation characteristics of the operating mode. Between the main peak shaving power supply and the load center, the connection lines often have different steps in terms of approaching the rising limit of the flow. When the line flow suddenly increases, special attention should be given to the connection line that may trip first because of its protection Trip will inevitably cause power transfer, cause other contact lines to trip in succession, and produce a vicious chain reaction, which may cause the system to be decommissioned. Phase shifters are widely used to regulate power flow in foreign countries. The "Static Phase Shifter" (SPS) in the Flexible AC Transmission System (FACTS) device family, due to the use of power electronics technology, has made great progress in regulating performance, eliminating any mechanical operation, and has good safety and stability control The application prospects of the SPS are affirmed that SPS can be used to improve transient stability, damp sub-synchronous oscillations, mitigate inter-regional oscillations, reduce transient torque of shafting, and steady-state circulation control.

The effect of the phase shifter is to shift the phase of the signal by an angle. The phase shifter is used to regulate the flow of sensitive contact lines to ensure that the voltage stability is not damaged by the chain line tripping and successive withdrawal, which can significantly increase the voltage stability limit. Its working principle differs depending on the composition. For example, in the transistor circuit, a control signal can be added to the input to control the phase shift; in some circuits, the delay of the resistor-capacitor circuit is used to achieve the phase shift; in the microcontroller control system, an internal timer can also be used to achieve the phase shift.