Isolated AC-DC power source for high-speed electric spindle driver

Abstract

The invention relates to an isolated AC-DC power source for a high-speed electric spindle driver. An input single-phase AC power source is connected with a PFC converter after passing through an EMI filter and a relay; the PFC converter outputs a direct-current voltage; after the direct-current voltage passes through an isolated DC-DC converter, a direct-current output voltage is obtained and is transmitted to a power module; an alternating-current input voltage passes through an auxiliary single-phase rectifying circuit, so that a direct-current voltage is obtained; the direct-current voltageis supplied for a flyback converter; the output voltage of the flyback converter is supplied for a PFC control chip, an isolated DC-DC control chip, a flyback control chip, a protection signal processing module and a control module; after detecting the related signals of the PFC converter, the PFC control chip outputs control signals to control the PFC converter; after detecting the related signals of the flyback converter, the flyback control chip outputs control signals to control the flyback converter; after detecting the related signals of the isolated DC-DC converter, the isolated DC-DCcontrol chip outputs control signals to control the isolated DC-DC converter; and after detecting the secondary-side related signals of the isolated DC-DC converter, the protection signal processing module outputs overvoltage and overcurrent signals to the control module.

Description

technical field [0001] The invention relates to an AC-DC power supply, in particular to an isolated AC-DC power supply for a high-speed electric spindle driver. Background technique [0002] The high-speed electric spindle driver is a device that converts direct current (DC) into high-frequency alternating current (AC) to drive the high-speed electric spindle in CNC machine tools. However, the original electricity used in general factories is in the form of AC, so an isolated AC-DC power supply is needed to convert the original AC power into DC power supply for the high-speed electric spindle drive. The high-speed electric spindle drive is a kind of equipment that requires high power supply reliability, and it needs to have reliable protection functions under various fault conditions and safe start-up and standby functions. In addition, the high-speed electric spindle drive also has high requirements on integration and cost, and it is necessary to reduce the complexity and ...

AI Technical Summary

Problems solved by technology

[0004] However, there are three disadvantages in the above-mentioned technical solution: first, the overall cost is high and the degree of integration is poor

Using a general digital control chip to control an isolated DC-DC converter requires a self-designed software control algorithm. The R&D cost and the complexity of the power supply are relatively high. At the same time, the cost of the general digital control chip and the second isolation module 7 is generally high. The control chip occupies a large area on the PCB (printed circuit board), so this solution has the disadvantages of high overall cost and poor integration

Second, the static loss is relatively large when the power supply is in standby

When the PFC converter is working, not only the diode loss in the bridge rectifier circuit, but also the power device in it is in a hard switching state, and the switching loss is relatively large. At the same time, there is also a certain loss on the PFC inductor. Therefore, this solution has relatively low static loss when the power supply is in standby Big

Third, the power supply of the control circuit is coupled with the main power circuit, which cannot guarantee reliable startup and standby of the power supply

In the transient state when the control circuit is started, the control signal Cntl_main output by the general digital control chip may appear at an uncertain level in a metastable state, which may cause a short circuit in the power device in the isolated DC-DC converter, and damage the entire power supply and high-speed spindle drive

On the other hand, this solution only guarantees that the final DC output DC voltage Vout is 0 when the control module 11b issues an instruction to make the power supply stand by, and cannot disconnect the input AC power supply from the main power circuit of the isolated AC / DC power supply. Vbus is always charged, and the power supply is not reliably on standby. If the control signal Cntl_main given by the general digital control chip is abnormal due to electromagnetic interference or other reasons, it may cause malfunction of the isolated DC-DC converter, and may also be damaged in severe cases. The entire power supply and high-speed spindle drive

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