Two-stage voltage reduction control power supply for power unit in chain-type var generator

The invention relates to a control power supply for a power unit in a chain-type var generator and belongs to the field of electrical automation equipment. The control power supply comprises first, second and third voltage reduction high-frequency inverter circuits which are used as pre-stage parts and a DC (direct current) stabilized voltage supply serving as a post-stage part. For any one power unit X, input ends of the first, second and third voltage reduction high-frequency inverter circuits are respectively connected to DC capacitors of the power unit X, an adjacent last power unit X-1 and an adjacent next power unit X+1. Each voltage reduction high-frequency inverter circuit comprises a high-frequency DC/AC (alternate current) circuit with a fixed duty ratio and a high-frequency step-down transformer. The post-stage DC stabilized voltage supply comprises three single-phase high-frequency rectifier bridges and a DC/DC circuit. Due to the adoption of the control power supply, an isolation transformer has small volume and light weight, the cost is reduced, parameters of pre-stage and post-stage power circuits are subjected to optimal selection design, the requirement on the redundant work of a power module can be met, and the reliability of the control power supply is greatly improved.