The variable frequency phase-shifting rectifier transformer is a type of transformer specifically designed to provide multi-phase rectified power supply for medium- and high-voltage variable frequency drives. It adopts the extended delta phase-shifting principle, and through multiple secondary windings with different phase-shift angles, it can form rectifier transformers with equivalent phase numbers of 6-phase, 12-phase, 18-phase, 24-phase, 30-phase, 36-phase, 48-phase, etc. The rectified power supply, after combination through variable frequency power units, can effectively reduce harmonics and improve the output waveform of the variable frequency drive. Our company has developed the NOMEX paper insulation series, resin cast series, and oil-immersed series variable frequency phase-shifting rectifier transformers, designed with Class H, Class F, and Class A insulation respectively. They feature large temperature rise margins, capable of fully withstanding local overheating caused by harmonics and avoiding potential insulation damage. The products fully consider the performance requirements of various medium- and high-voltage variable frequency drive types for transformers and can be designed as air natural cooling, air forced air cooling, oil natural cooling, etc., according to user requirements and operating environment to meet the needs of different users. The products have been matched with many world-renowned variable frequency drive manufacturers such as ABB, AB, Hitachi, Siemens, etc., and have won the trust and praise of users.

Product Features:

1.Effectively reduce harmonic interference.

Multi-winding secondary output improves the power factor and provides independent phase-shifting power supply for the variable frequency drive power units, which can greatly improve the grid-side current waveform and reduce harmonic pollution to the grid from the equipment.

In the design, the magnetic flux density is reduced by 10% compared to power transformers, and the current density of the conductors is lowered. In addition, electrical shielding is added between the grid-side and valve-side windings to effectively reduce high-order harmonic components on the grid-valve side from polluting the grid, while also preventing grid-side harmonics from being transmitted to the valve side and interfering with the control system.

2.Effectively ensure multiple impedance values for the primary and secondary windings of the transformer.

Specific product structure design is carried out for users' requirements for special operating impedances, ensuring small short-circuit impedance deviation between the primary winding and any secondary winding, small output voltage deviation, and thus ensuring balanced voltage on the variable frequency drive.

3.Good high-strength insulation structure and excellent heat dissipation.

Efficient cooling system and high-strength insulation structure ensure safe operation of the transformer under long-term high load. Cooling systems can be specifically designed according to the operating conditions of the product. Forced air-cooled products use German EBM fans with large air volume, long service life, and stable operation. Efficient simulation programs, optimized structural design, and strict process control effectively reduce the temperature rise of the transformer, improve the overload capacity of the product, reduce the size of the transformer, lower the cost of the transformer, and extend the service life of the transformer.

Technical Parameters

Capacity: 315kVA–12240kVA

Voltage Level: 6kV, 10kV, 35kV

Pulse Number: 6, 12, 18, 24, 30, 36, 48

Frequency: 50Hz

Phase Number: Three-phase

Insulation Class: Class F, Class H, Class A

Cooling Method: AN, AF, ONAN

Other parameters comply with national standards or meet customers’ special design requirements.