A magnetic force control circuit for electromagnetic poles of magnetic suspension bearings based on double bridge structure

Abstract

The invention discloses a magnetic suspension bearing electromagnetic pole magnetic force control circuit based on a double-bridge structure. A main circuit with a double-bridge structure is adopted. The main circuit includes two power switching devices and two diodes: the first power switching device (Q1 ), the second power switching device (Q2), the first diode (D1) and the second diode (D2); the first power switching device and the second diode form the first bridge arm, and the second power switch The device and the first diode form the second bridge arm; the electromagnetic pole magnetic force control circuit of the magnetic suspension bearing based on the double bridge structure has high safety, low loss, and low magnetic force pulsation amplitude.

Description

technical field [0001] The present invention relates to a PWM control technology, in particular to a magnetic force control method for an electromagnetic pole of a magnetic suspension bearing, and a current drive control technology for inductive loads. Background technique [0002] Figure 1-2 It is a circuit diagram of an inductive load drive. When the MOSFET switch signal LIN is high, Q2 is turned on, and the bus voltage is loaded on both ends of the electromagnetic pole EMP, resulting in figure 1 The driving current i shown, when LIN is low level, Q2 is closed, and the current i is as figure 2 As shown, the freewheeling through the diode D1 adjusts the magnitude of the current by adjusting the duty ratio of LIN. This control method has high conduction loss, and the switching frequency is restricted by the reverse recovery time of the freewheeling diode D1 and the switching loss. Generally only suitable for low power occasions. [0003] Figure 3-4 A low-voltage and h...

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Problems solved by technology

The speed of the magnetic levitation rotor is usually above 10,000 rpm, and the safety requirements are high. However, the working environment of the magnetic levitation bearing will inevitably have electromagnetic pollution. External interference makes the switch tubes Q1 and Q2 tubes conduct at the same time. Instantaneous short circuit fault in voltage

[0009] Magnetic levitation bearings generally have more than 20 inputs and more than 10 outputs, and have high real-time requirements. Currently, the products are implemented with multiple DSP systems, and the control circuits are complicated. For the high switching frequency, low power consumption and High reliability requirements, it is necessary to invent a control circuit for electromagnetic pole

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