Magnetic bearing redundancy circuit and control method

Abstract

The application relates to a magnetic suspension bearing redundancy circuit and a control method. The circuit comprises a bridge structure composed of four power switching devices, wherein one power switching device is arranged on each bridge arm; the power switching devices are used for providing working current for coils of the magnetic suspension bearing; a coil control module of the magnetic suspension bearing is connected with the output end of a first power switching device and the input end of a second power switching device respectively; the output end of the first power switching device and the output end of a third power switching device are connected through a third diode; the output end of the third power switching device and the input end of the second power switching device are connected through a second diode; one end of a first diode is connected with the output end of the first power switching device, and the other end is grounded; the input end of the first power switching device and the output end of the second power switching device are respectively connected with two ends of a direct-current power supply. The method can realize redundancy control of the magnetic suspension bearing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of control circuit, in particular to a magnetic suspension bearing redundancy circuit and control method. BACKGROUND

[0002] The magnetic suspension bearing is mainly applied in high speed field. In the magnetic suspension bearing rotor system, in order to avoid the failure of the magnetic suspension control system leading to the failure or mechanical damage of the rotor system, a protection bearing is generally configured. However, the protection bearing can only be used for short-term support, and the service life is also short, and regular maintenance is required. The magnetic suspension bearing system mainly consists of a magnetic suspension bearing driver and a magnetic suspension bearing. The magnetic suspension bearing mainly consists of a steel core and a copper coil, and the failure rate is extremely low. The bearing driver is composed of a power amplifier and a controller. The power amplifier provides working current for the magnetic suspension bearing coil, which is one of the main reasons for failure. Therefore, there is an urgent need for a control circuit that can solve the problem of magnetic suspension bearing failure. SUMMARY

[0003] Therefore, it is necessary to provide a magnetic suspension bearing redundancy circuit and control method in view of the above technical problems.

[0004] A magnetic suspension bearing redundancy circuit, the circuit comprising:

[0005] A bridge structure composed of four power switching devices, wherein one power switching device is arranged on each bridge arm; the power switching device is used to provide working current for the coil of the magnetic suspension bearing;

[0006] The coil control module of the magnetic suspension bearing is connected to the output end of the first power switching device and the input end of the second power switching device, respectively. The input end of the first power switching device is connected to the input end of the third power switching device. The output end of the first power switching device and the output end of the third power switching device are connected through a third diode. The output end of the third power switching device and the input end of the second power switching device are connected through a second diode. One end of a first diode is connected to the output end of the first power switching device, and the other end is grounded. The input end of the first power switching device and the output end of the second power switching device are respectively connected to the two ends of the DC power supply.

[0007] In one embodiment, in the first working state, the first power switching device and the second power switching device are both turned on, the first power switching device and the second power switching device form a control loop of the coil control module, and the third power switching device and the fourth power switching device are redundant.

[0008] In one of the embodiments, in the second working state, the first power switch device is off, the second power switch device, the first diode and the second power switch device form a control loop of the coil control module; the first diode and the second power switch device and the second diode and the third diode are redundant to each other.

[0009] In one of the embodiments, in the third working state, the first power switch device is on, the second power switch device is off, and the second diode and the third diode form a control loop of the coil control module.

[0010] In one of the embodiments, the circuit further comprises a first voltage sensor, a second voltage sensor and a third voltage sensor.

[0011] The two ends of the first voltage sensor are connected to the two ends of the DC power supply respectively, the second voltage sensor is connected in parallel with the first diode, and the third voltage sensor is connected in parallel with the second power switch device.

[0012] The first voltage sensor is used to detect the voltage of the DC power supply, the second voltage sensor is used to detect the voltage of the first end of the coil control module, and the third voltage sensor is used to detect the voltage of the second end of the coil control module.

[0013] In one of the embodiments, the coil control module comprises a current sensor and a coil of the magnetic suspension bearing; the current sensor is used to collect the current value through the coil.

[0014] A control method of a magnetic suspension bearing redundancy circuit, applied to the magnetic suspension bearing redundancy circuit, the method comprising:

[0015] The switching states of the first power switch device and the second power switch device are determined through the measurement values of the first voltage sensor, the second voltage sensor and the third voltage sensor.

[0016] The coils of the magnetic suspension bearing are redundantly controlled according to the switching states of the first power switch device and the second power switch device.

[0017] The magnetic suspension bearing redundancy circuit and control method adopt a bridge structure to control the coils of the magnetic suspension bearing, analyze the failure causes of the coil control circuit of the magnetic suspension bearing, and find that the power switch device is prone to failure. Due to the particularity of the bridge structure, the failure analysis is simplified to the failure analysis of two power switch devices. By considering different failure modes of the first power switch device and the second power switch device, different situations are analyzed, and corresponding redundancy measures are set for each situation to avoid the problem that the magnetic suspension bearing control circuit cannot work normally when failure occurs. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The circuit diagram of the magnetic suspension bearing redundancy circuit in one embodiment is shown in the figure.

[0019] Figure 2 The circuit diagram when Q1 is open in one embodiment is shown in the figure.

[0020] Figure 3 The circuit diagram when Q1 is short-circuited in one embodiment is shown in the figure.

[0021] Figure 4 The circuit diagram when Q2 is open in one embodiment is shown in the figure.

[0022] Figure 5 The circuit diagram when Q2 is short-circuited in one embodiment is shown in the figure.

[0023] Figure 6 The circuit diagram in the third state in one embodiment is shown in the figure. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0025] In one embodiment, as shown in Figure 1 , a magnetic suspension bearing redundancy circuit is provided, comprising the following steps:

[0026] A bridge structure composed of four power switch devices, wherein one power switch device is arranged on each bridge arm; the power switch device is used to provide working current for the coils TR1 of the magnetic suspension bearing.

[0027] The coil control module of the magnetic suspension bearing is connected with the output end of the first power switch device Q1 and the input end of the second power switch device Q2 respectively, the input end of the first power switch device Q1 is connected with the input end of the third power switch device Q3, the output end of the first power switch device Q1 is connected with the output end of the third power switch device Q3 through the third diode D3, the output end of the third power switch device Q3 is connected with the input end of the second power switch device Q2 through the second diode D2, one end of the first diode D1 is connected with the output end of the first power switch device Q1, and the other end is grounded, and the input end of the first power switch device Q1 and the output end of the second power switch device Q2 are connected with the two ends of the direct current power supply DC respectively.

[0028] In the above magnetic suspension bearing redundancy circuit, the bridge structure is used for the coil control of the magnetic suspension bearing. By analyzing the failure reasons of the coil control circuit of the magnetic suspension bearing, the power switch device is prone to failure. Due to the particularity of the bridge structure, the fault analysis of the two power switch devices is simplified during specific fault analysis. By considering different failure modes of the first power switch device and the second power switch device, different situations are analyzed, and corresponding redundancy measures are set for each situation to avoid the problem that the magnetic suspension bearing control circuit cannot work normally when failure occurs.

[0029] It is worth noting that the control method in the working state, the analysis circuit has three working states, the first working state is that Q1 and Q2 are turned on, TR1 is connected with the power supply voltage, the current increases, and in this working state, Q3 is redundant with Q1, and Q4 is redundant with Q2; the second working state is that Q1 is disconnected, TR1 works through D1, Q2 or D2, D3 loop current continuation, the current decreases, wherein by controlling Q2, D1, Q2 and D2, D3 form a parallel relationship and are redundant with each other. The third working state is that Q1 is turned on, Q2 is disconnected, TR1 works through D2, D3 loop current continuation, the current decreases, and this working state is mainly used for Q2 short circuit detection.

[0030] In one embodiment, the circuit further comprises: a first voltage sensor TV1, a second voltage sensor TV2 and a third voltage sensor TV3; the two ends of the first voltage sensor TV1 are connected with the two ends of the direct current power supply respectively, the second voltage sensor TV2 is connected with the first diode D1 in parallel, and the third voltage sensor TV3 is connected with the second power switch device Q2 in parallel; the first voltage sensor TV1 is used for detecting the voltage of the direct current power supply DC, the second voltage sensor TV2 is used for detecting the voltage of the first end of the coil control module, and the third voltage sensor TV3 is used for detecting the voltage of the second end of the coil control module.

[0031] In one of the embodiments, in the first working state, the first power switch device and the second power switch device are both turned on, the first power switch device and the second power switch device form a control loop of the coil control module, and the third power switch device and the fourth power switch device are redundant.

[0032] In one of the embodiments, in the second working state, the first power switch device is turned off, the second power switch device, the first diode and the second power switch device form a control loop of the coil control module; the second diode and the third diode form a control loop of the coil control module; the first diode and the second power switch device and the second diode and the third diode are redundant.

[0033] In one of the embodiments, in the third working state, the first power switch device is turned on, the second power switch device is turned off, and the second diode and the third diode form a control loop of the coil control module.

[0034] Specifically, for the circuit structure, mainly need to consider Q1, Q2 failure, power switch device failure generally has two states, namely short circuit and open circuit. When Q1 is open circuit failure, as shown in FIG. 1, in the first working state, the voltage of circuit node A can be detected by TV2 as zero, and the circuit works normally when TV2 detects the power supply voltage, at this time, it is judged that Q1 is open circuit failure, Q3 can be turned on, and Q3, D3 and Q2 form a loop to work normally. When Q1 is short circuit failure, as shown in FIG. 2, the voltage of circuit node A can be detected by TV2 as the power supply voltage in the second working state, and as zero in normal working state, then it can be judged that Q1 is short circuit failure, at this time, in the first working state, Q1 and Q2 continue to form a loop in normal working mode, and in the second working state, Q2 is turned off, and the freewheeling loop is formed by D2 and D3. Figure 2 Figure 3 When Q1 is short circuit failure, as shown in FIG. 2, D1, Q2 and D2, D3 form a parallel relationship, and are redundant, the circuit works in a normal state, a periodic detection method is adopted to judge the Q2 failure state, that is, in a certain period, enter the third working state once, when Q1 is turned on and Q2 is normally turned off to enter the third working state, as shown in FIG. 3, the voltage of circuit node A can be detected by TV2 as zero, and the circuit works normally when TV2 detects the power supply voltage, at this time, it is judged that Q2 is short circuit failure, Q1 can be turned off, and the freewheeling loop is formed by D1 and D2.

[0035] When Q2 is open circuit failure, as shown in FIG. 4, in the first working state, the voltage of circuit node B can be detected by TV3 as the power supply voltage, and as zero in normal working state, at this time, it is judged that Q2 is open circuit failure, Q4 can be turned on, and Q4 and D2 form a loop to work normally. Figure 4 Figure 5 When Q2 is short circuit failure, as shown in FIG. 5, because D1, Q2 and D2, D3 form a parallel relationship, and are redundant, the circuit works in a normal state, a periodic detection method is adopted to judge the Q2 failure state, that is, in a certain period, enter the third working state once, when Q1 is turned on and Q2 is normally turned off to enter the third working state, as shown in FIG. 3, the voltage of circuit node A can be detected by TV2 as zero, and the circuit works normally when TV2 detects the power supply voltage, at this time, it is judged that Q2 is short circuit failure, Q1 can be turned off, and the freewheeling loop is formed by D1 and D2. Figure 6 ​​As shown, at this time, the circuit node B voltage can be detected by TV3 as the power supply voltage, if the detection result is zero, it is judged that Q2 is short-circuited, because D1, Q2 and D2, D3 constitute a parallel relationship, and are redundant to each other, after Q2 is short-circuited, the circuit will continue to work in the first and second working conditions.

[0036] In summary, the technical scheme adopted by the present application is as follows: under normal working conditions, Q1, Q2, D1, D2, D3 and TR1 form a working loop, TV1 detects the power supply voltage; TV2 detects the voltage of circuit node A to ground; TV3 detects the voltage of circuit node B to ground; CT1 detects the working loop current of TR1. The current control suspension control method is adopted, the differential value of the gap between the electromagnet and the bearing is calculated by the controller to obtain the current expected value of the electromagnet, the current expected value and the actual current value of the end of the electromagnet are used to calculate the signals of the driving power switches Q1 and Q2, and the signals are amplified and then used to drive Q1 and Q2 respectively; by adjusting the working current of the electromagnet during suspension, the suspension force between the electromagnet and the bearing is changed accordingly, so that the gap between the electromagnet and the bearing is kept stable.

[0037] In one embodiment, a control method of a magnetic suspension bearing redundancy circuit is provided, which is applied to the magnetic suspension bearing redundancy circuit, and the switching states of the first power switch device and the second power switch device are determined by the measurement values of the first voltage sensor, the second voltage sensor and the third voltage sensor; the coils of the magnetic suspension bearing are redundantly controlled according to the switching states of the first power switch device and the second power switch device.

[0038] The technical features of the above embodiments can be combined in any way, and to make the description concise, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0039] The above-described embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be pointed out that for ordinary skilled persons in the art, some modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. A magnetic bearing redundancy circuit, comprising: The circuit comprises: A bridge structure composed of four power switch devices, wherein one power switch device is arranged on each bridge arm; the power switch device is used to provide working current for the coil of the magnetic suspension bearing; The coil control module of the magnetic suspension bearing is connected with the output end of the first power switch device and the input end of the second power switch device respectively, the input end of the first power switch device is connected with the input end of the third power switch device, the output end of the first power switch device is connected with the output end of the third power switch device through the third diode, the output end of the third power switch device is connected with the input end of the second power switch device through the second diode, one end of the first diode is connected with the output end of the first power switch device, and the other end is grounded, and the input end of the first power switch device and the output end of the second power switch device are respectively connected with two ends of the direct current power supply.

2. The circuit of claim 1, wherein, In the first working state, the first power switch device and the second power switch device are both turned on, the first power switch device and the second power switch device form a control loop of the coil control module, and the third power switch device and the fourth power switch device are redundant.

3. The circuit of claim 1, wherein, In the second working state, the first power switch device is turned off, the second power switch device, the first diode and the second power switch device form a control loop of the coil control module; the second diode and the third diode form a control loop of the coil control module; the first diode and the second power switch device and the second diode and the third diode are redundant.

4. The circuit of claim 1, wherein, In the third working state, the first power switch device is turned on, the second power switch device is turned off, and the second diode and the third diode form a control loop of the coil control module.

5. The circuit according to any one of claims 1 to 4, characterized in that, The circuit further comprises: a first voltage sensor, a second voltage sensor and a third voltage sensor; Two ends of the first voltage sensor are respectively connected with two ends of the direct current power supply, the second voltage sensor is connected with the first diode in parallel, and the third voltage sensor is connected with the second power switch device in parallel; The first voltage sensor is used to detect the voltage of the direct current power supply, the second voltage sensor is used to detect the voltage of the first end of the coil control module, and the third voltage sensor is used to detect the voltage of the second end of the coil control module.

6. The circuit according to any one of claims 1 to 4, characterized in that The coil control module comprises: a current sensor and the coil of the magnetic suspension bearing; the current sensor is used to collect the current value passing through the coil.

7. A control method of a magnetic bearing redundancy circuit, characterized by, The method is applied to the magnetic suspension bearing redundant circuit of claim 5, and the method comprises: The switching states of the first power switch device and the second power switch device are determined through the measurement values of the first voltage sensor, the second voltage sensor and the third voltage sensor; The coil of the magnetic suspension bearing is redundantly controlled according to the switching states of the first power switch device and the second power switch device.

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