Magnetic bearing system and power amplification device and fault detection method thereof

Abstract

The invention discloses a power amplification device of a magnetic bearing system, the magnetic bearing system and a fault detection method of the magnetic bearing system. The power amplification device comprises a first H-bridge circuit and a second H-bridge circuit, a selection switch unit switchably connecting the bearing coil to any one of the first H-bridge circuit and the second H-bridge circuit; the magnetic bearing controller controls the magnetic bearing to stop working if it is determined that the bearing coil breaks down; and if it is determined that the power device in one H-bridge circuit currently connected with the bearing coil breaks down, the selection switch unit is controlled, so that the other H-bridge circuit is connected with the bearing coil to supply power to the bearing coil, and the magnetic bearing continues to work. According to the scheme, whether the bearing coil and the power device break down or not is detected and the fault point is positioned according to the current of the bearing coil in combination with the action of the selection switch unit, and the redundant H-bridge circuit is switched when the power device breaks down, so that time and labor are saved, and the reliability is good.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic bearing systems, and specifically relates to a power amplifier device of a magnetic bearing system, a magnetic bearing system having the power amplifier device, and a fault detection method of the magnetic bearing system, and more particularly to a power amplifier circuit of a magnetic bearing system, a magnetic bearing system having the power amplifier circuit, and a fault detection method of the magnetic bearing system and its power amplifier circuit. Background Art

[0002] Magnetic bearings (magnetic levitation bearings) are a new type of bearing that uses electromagnets to generate controllable electromagnetic force to suspend the rotor for contactless support. The magnetic bearing system (i.e., magnetic bearings and magnetic bearing control systems) detects the real-time displacement of the rotor through a displacement sensor, processes the output control signal through the MCU, and outputs the current required by the electromagnet through the power amplifier circuit to provide electromagnetic force to suspend the rotor in the middle position. In actual applications, damage to power devices in the power amplifier circuit, false triggering, open circuit of the bearing coil and other faults will cause the magnetic bearing current (i.e., the current of the bearing coil) to be abnormal, resulting in the rotor being unable to suspend normally. In related solutions, when a fault occurs in the power amplifier circuit, it is necessary to use detection equipment to gradually troubleshoot and locate the problem point (i.e., the fault point) of the hardware of the power amplifier circuit, which requires a lot of time and manpower.

[0003] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0004] The object of the present invention is to provide a power amplification device of a magnetic bearing system, a magnetic bearing system and a fault detection method thereof, so as to solve the problem that when a magnetic bearing system and its control system fails, it is necessary to manually use detection equipment to gradually check and locate the fault point, which is time-consuming and labor-intensive. The present invention can detect whether a magnetic bearing system fails and locate the fault point based on the current of the bearing coil and the action of the selective switch unit, and switch the redundant power amplification branch to enable the magnetic bearing to work normally when a power device fails, thereby saving time and labor and ensuring the reliability of the magnetic bearing system.

[0005] The present invention provides a power amplifying device of a magnetic bearing system, wherein the magnetic bearing system has a magnetic bearing and a magnetic bearing control system; the magnetic bearing has a bearing coil; the magnetic bearing control system has a power amplifying device and a bearing controller; the power amplifying device of the magnetic bearing system comprises: a first H-bridge circuit, a second H-bridge circuit, and a selection switch unit; wherein the first H-bridge circuit and the second H-bridge circuit are cascaded, and the first H-bridge circuit and the second H-bridge circuit are mutually redundant power amplifying branches; the first end of the bearing coil is connected to the selection switch unit, and the second end of the bearing coil is respectively connected to the first H-bridge circuit and the second H-bridge circuit; the selection switch unit can switch the bearing coil to either the first H-bridge circuit or the second H-bridge circuit H-bridge circuits are connected; one H-bridge circuit currently connected to the bearing coil among the first H-bridge circuit and the second H-bridge circuit is recorded as the current H-bridge circuit; the magnetic bearing controller is used to determine whether the magnetic bearing system has a fault according to the current of the bearing coil in combination with controlling the selection switch unit; the fault of the magnetic bearing system includes at least one of the following: a fault of the bearing coil, a fault of a power device in the current H-bridge circuit; and if it is determined that the bearing coil has a fault, the magnetic bearing is controlled to stop working; if it is determined that the power device in the current H-bridge circuit has a fault, the selection switch unit is controlled to connect the other H-bridge circuit among the first H-bridge circuit and the second H-bridge circuit to the bearing coil to power the bearing coil so that the magnetic bearing continues to work.

[0006] In some embodiments, the selection switch unit includes: a first switch and a second switch; the first H-bridge circuit includes: a first power device and a second power device; the second H-bridge circuit includes: a third power device and a fourth power device; wherein the control end of the first switch is used to receive the first PWM signal sent by the bearing controller; the first connection end of the first switch is connected to the control end of the first power device; the first connection end of the first power device is connected to a DC power supply; the second connection end of the first switch is connected to the control end of the third power device; the first connection end of the third power device is connected to a DC power supply; the control end of the second switch is connected to the first end of the bearing coil; the first connection end of the second switch is connected to the second connection end of the first power device; the second connection end of the second switch is connected to the second connection end of the third power device; the control end of the second power device is used to receive the second PWM signal sent by the bearing controller; the first connection end of the second power device is connected to the second end of the bearing coil; the second connection end of the second power device is grounded; the control end of the fourth power device is used to receive the third PWM signal sent by the bearing controller; the first connection end of the fourth power device is connected to the second end of the bearing coil; the second connection end of the fourth power device is grounded.

[0007] In some embodiments, the first H-bridge circuit further includes: a first diode and a second diode; the second H-bridge circuit further includes: a third diode and a fourth diode; wherein the cathode of the first diode is connected to a DC power supply, and the anode of the first diode is connected to the second end of the bearing coil; the cathode of the second diode is connected to the first end of the bearing coil, and the anode of the second diode is grounded; the cathode of the third diode is connected to the first end of the bearing coil, and the anode of the third diode is grounded; the cathode of the fourth diode is connected to a DC power supply, and the anode of the fourth diode is connected to the second end of the bearing coil.

[0008] In some embodiments, it further includes: a current detection unit; wherein the current detection unit is arranged at the second end of the bearing coil, and is used to detect the current of the bearing coil and transmit it to the magnetic bearing controller.

[0009] Matching the above-mentioned device, the present invention further provides a magnetic bearing system on the other hand, including: the power amplification device of the magnetic bearing system described above.

[0010] To match the above-mentioned magnetic bearing system, the present invention provides a fault detection method for a magnetic bearing system on another aspect, comprising: assuming that the current H-bridge circuit is the first H-bridge circuit, and when the first H-bridge circuit is connected to the bearing coil, obtaining the current of the bearing coil; determining whether the magnetic bearing system has a fault based on the current of the bearing coil in combination with controlling the selection switch unit; the fault of the magnetic bearing system comprises at least one of the following: a fault of the bearing coil, a fault of a power device in the first H-bridge circuit; and, if it is determined that the bearing coil has a fault, controlling the magnetic bearing to stop working; if it is determined that the power device in the first H-bridge circuit has a fault, controlling the selection switch unit to connect the second H-bridge circuit to the bearing coil and supply power to the bearing coil so that the magnetic bearing continues to work.

[0011] In some embodiments, the power devices in the first H-bridge circuit include a first power device and a second power device, and the power devices in the second H-bridge circuit include a third power device and a fourth power device; the fault of the power device in the first H-bridge circuit includes at least one of the following: a fault of the first power device, a fault of the second power device; the selection switch unit includes: a first switch and a second switch; according to the current of the bearing coil, combined with controlling the selection switch unit, determining whether the magnetic bearing system fails, including: in the current control cycle, determining for the first time whether the current of the bearing coil is greater than the set maximum current; if it is determined for the first time that the current of the bearing coil is greater than the set maximum current, then controlling The second switch in the selection switch unit is operated to stop sending the first PWM signal to the control end of the first power device in the first H-bridge circuit, and to send the first PWM signal to the control end of the third power device in the second H-bridge circuit, and then determine again whether the current of the bearing coil is greater than the set maximum current; if it is determined again that the current of the bearing coil is greater than the set maximum current, it is determined that the first power device has a breakdown fault, and a reminder message of the breakdown fault of the first power device is initiated; if it is determined again that the current of the bearing coil is less than or equal to the set maximum current, it is determined that the second power device in the first H-bridge circuit has a breakdown fault, and a reminder message of the breakdown fault of the second power device is initiated.

[0012] In some embodiments, determining whether the magnetic bearing system has a fault based on the current of the bearing coil in combination with controlling the selection switch unit also includes: if it is first determined that the current of the bearing coil is less than or equal to the set maximum current, then determining whether the current of the bearing coil is equal to 0 for the first time; if it is first determined that the current of the bearing coil is not equal to 0, then determining that neither the bearing coil nor the power device in the first H-bridge circuit has a fault, and still allowing the first H-bridge circuit to power the bearing coil so that the magnetic bearing continues to work; if it is first determined that the current of the bearing coil is equal to 0, then issuing a third PWM signal so that the third PWM signal outputs a PWM wave identical to the second PWM signal to control a fourth power device in the second H-bridge circuit. After the first H-bridge circuit is connected to the bearing coil, it is determined whether the current of the bearing coil is equal to 0 for the second time. If the current of the bearing coil is determined to be 0 for the second time, the first switch and the second switch in the selection switch unit are controlled to act simultaneously, so as to switch from being connected to the first H-bridge circuit and the bearing coil to being connected to the second H-bridge circuit and the bearing coil, so that the second H-bridge circuit supplies power to the bearing coil, and then it is determined whether the power devices in the bearing coil and the first H-bridge circuit are faulty. If it is determined for the second time that the current of the bearing coil is not equal to 0, it is determined that the second power device has an open circuit fault, and a reminder message of an open circuit fault in the second power device is initiated, and then it is determined whether the bearing coil and the power devices in the first H-bridge circuit are faulty.

[0013] In some embodiments, continuing to determine whether the bearing coil and the power device in the first H-bridge circuit have a fault includes: determining for a third time whether the current of the bearing coil is equal to 0; if it is determined for the third time that the current of the bearing coil is not equal to 0, determining that an open circuit fault has occurred in the bearing coil; if it is determined for the third time that the current of the bearing coil is equal to 0, determining that an open circuit fault has occurred in the first power device, and initiating a reminder message that the first power device has an open circuit fault.

[0014] In some embodiments, the power devices in the first H-bridge circuit include a first power device and a second power device, and the power devices in the second H-bridge circuit include a third power device and a fourth power device; the failure of the power device in the first H-bridge circuit includes at least one of the following: a failure of the first power device, a failure of the second power device; the selection switch unit includes: a first switch and a second switch; if it is determined that the power device in the first H-bridge circuit fails, the selection switch unit is controlled to connect the second H-bridge circuit to the bearing coil and power the bearing coil to enable the magnetic bearing to continue to work, including at least one of the following: if it is determined that the first power device has a breakdown failure, or if it is determined that the second power device in the first H-bridge circuit has a breakdown failure, the first switch in the selection switch unit is controlled to be connected to the bearing coil by the first H-bridge circuit. The state in which the first power device in the circuit is connected to the bearing coil is switched to the state in which the third power device in the second H-bridge circuit is connected to the bearing coil, so that the second H-bridge circuit supplies power to the bearing coil and sends out a third PWM signal, so that the third PWM signal outputs a PWM wave identical to the second PWM signal, so that the magnetic bearing continues to work; if it is determined that an open circuit fault occurs in the first power device, or it is determined that an open circuit fault occurs in the second power device, then when the third PWM signal is sent out so that the third PWM signal outputs a PWM wave identical to the second PWM signal, the first switch and the second switch in the selection switch unit are controlled to operate simultaneously, so that the first H-bridge circuit is connected to the bearing coil and switched to the second H-bridge circuit being connected to the bearing coil, so that the second H-bridge circuit supplies power to the bearing coil, so that the magnetic bearing continues to work.

[0015] Therefore, the scheme of the present invention is to set a selection switch unit and two H-bridge circuits for the power amplifier circuit of the control system of the magnetic bearing, and the two H-bridge circuits are cascaded, the first end of the bearing coil is connected to the selection switch unit, and the second end of the bearing coil is respectively connected to the two H-bridge circuits, and by controlling the selection switch, the two H-bridge circuits can be switched to be connected to the bearing coil; when the magnetic bearing is working, it is judged whether the bearing coil of the magnetic bearing system and the two H-bridge circuits are faulty and the fault point is determined according to the current of the bearing coil, and the two H-bridge circuits are switched to make the magnetic bearing work normally when a fault occurs; thus, through the power amplifier circuit of the control system of the magnetic bearing, redundant power amplifier branches are set, and according to the current of the bearing coil and combined with the action of the selection switch unit, whether the magnetic bearing system is faulty and the fault point is located, and when the power device fails, the power amplifier branch is switched to make the magnetic bearing work normally, which can not only save time and effort to detect the fault point, but also ensure the normal operation of the magnetic bearing system and ensure the reliability of the magnetic bearing system.

[0016] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention.

[0017] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of an embodiment of a power amplification device of a magnetic bearing system of the present invention;

[0019] Figure 2 It is a structural schematic diagram of an embodiment of a power amplifier circuit of a magnetic bearing system in a related scheme;

[0020] Figure 3 It is a structural schematic diagram of an embodiment of a power amplifier circuit of a magnetic bearing system of the present invention;

[0021] Figure 4 A logical diagram of fault judgment control of an embodiment of a fault detection method for a magnetic bearing system of the present invention;

[0022] Figure 5 A schematic diagram of a flow chart of an embodiment of a method for detecting a fault of a magnetic bearing system according to the present invention;

[0023] Figure 6 A schematic flow chart of an embodiment of a first process for determining whether a fault occurs in the magnetic bearing system in the method of the present invention;

[0024] Figure 7 A schematic flow chart of an embodiment of a second process for determining whether a fault occurs in the magnetic bearing system in the method of the present invention;

[0025] Figure 8 The present invention is a flowchart of an embodiment of continuing to determine whether the bearing coil and the power device in the first H-bridge circuit are faulty.

[0026] In conjunction with the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0027] 1, 2-Analog selector switch. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] Figure 2 FIG. 1 is a schematic diagram of a structure of an embodiment of a power amplifier circuit of a magnetic bearing system in a related scheme. Figure 2 The power amplifier circuit of the magnetic bearing system shown in the figure, that is, the power amplifier circuit of the magnetic suspension bearing control system, includes: switch tube S1, switch tube S2, diode D1, diode D2. When the switch tube S1 and the switch tube S2 are both MOS tubes, the DC power supply V cc The drain of the switch tube S1 is connected, the source of the switch tube S1 is connected to the cathode of the diode D2, and the anode of the diode D2 is grounded; the DC power supply V cc It is also connected to the cathode of the diode D1, the anode of the diode D1 is connected to the drain of the switch tube S2, and the source of the switch tube S2 is grounded. The first connection end of the bearing coil of the magnetic bearing in the magnetic bearing system is connected to the cathode of the diode D2, and the second connection end of the bearing coil is connected to the anode of the diode D1.

[0030] In the related scheme, the power amplifier circuit of the magnetic bearing control system is Figure 2 In the three-level power amplifier circuit of the H-bridge structure shown, when the switch tube S1 and the switch tube S2 are turned on at the same time, the bearing coil is in a charging state, and the current of the bearing coil increases; when the switch tube S1 is turned off and the switch tube S2 is turned on, the bearing coil is in a freewheeling state, and the switch tube S2 and the diode D2 form a freewheeling loop; when the switch tube S1 and the switch tube S2 are turned off at the same time, the bearing coil discharges and feeds back to the bus voltage, and the bearing coil is in a discharging state. The above three states constitute a three-level power amplifier circuit. When any of the switch tubes or the bearing coil fails, the magnetic bearing cannot operate normally. When troubleshooting, the bearing controller needs to be disassembled and checked one by one.

[0031] When a magnetic bearing and its control system fail and need to be stopped, each component needs to be disassembled and the fault needs to be gradually checked and located using detection equipment, which requires a lot of manpower and time. The solution of the present invention proposes a power amplifier circuit of a magnetic bearing system and a fault detection scheme for the magnetic bearing system and its power amplifier circuit, which can automatically detect the fault of the magnetic bearing system and its power amplifier circuit and report the fault point by the host computer, and can ensure the normal operation of the magnetic bearing when the power device fails, which can not only save time and effort to detect the fault point, but also ensure the normal operation of the magnetic bearing system and the reliability of the magnetic bearing system.

[0032] According to an embodiment of the present invention, a power amplification device for a magnetic bearing system is provided. Figure 1The structure diagram of an embodiment of the device of the present invention is shown. The magnetic bearing system has a magnetic bearing and a magnetic bearing control system; the magnetic bearing has a bearing coil; the magnetic bearing control system has a power amplifier and a bearing controller, and the bearing controller has a main control chip (such as MCU); the power amplifier of the magnetic bearing system, that is, the power amplifier of the magnetic bearing control system, includes: a first H-bridge circuit, a second H-bridge circuit, and a selection switch unit.

[0033] Wherein, the first H-bridge circuit and the second H-bridge circuit are cascaded, and the first H-bridge circuit and the second H-bridge circuit are mutually redundant power amplification branches. The first end of the bearing coil is connected to the selection switch unit, and the second end of the bearing coil is connected to the first H-bridge circuit and the second H-bridge circuit respectively. Under the control of the bearing controller, the selection switch unit can switch the bearing coil to any one of the first H-bridge circuit and the second H-bridge circuit, so that any one of the first H-bridge circuit and the second H-bridge circuit is connected to the bearing coil to supply power to the bearing coil; the one of the first H-bridge circuit and the second H-bridge circuit that is currently connected to the bearing coil is recorded as the current H-bridge circuit.

[0034] The magnetic bearing controller is used to determine whether the magnetic bearing system fails according to the current of the bearing coil and in combination with controlling the selection switch unit; the failure of the magnetic bearing system includes at least one of the following: failure of the bearing coil and failure of the power device in the current H-bridge circuit. And,

[0035] The magnetic bearing controller is further used to control the magnetic bearing to stop working if it is determined that the bearing coil fails, specifically to control the magnetic bearing to stop floating due to shaft failure.

[0036] The magnetic bearing controller is further used to control the selection switch unit to connect the other H-bridge circuit of the first H-bridge circuit and the second H-bridge circuit to the bearing coil to power the bearing coil so that the magnetic bearing continues to work if it is determined that the power device in the current H-bridge circuit fails. Specifically, the bearing controller, when the current H-bridge circuit powers the bearing coil, specifically when one of the first H-bridge circuit and the second H-bridge circuit currently connected to the bearing coil powers the bearing coil to make the magnetic bearing work, determines whether the magnetic bearing system fails according to the current of the bearing coil; when one of the first H-bridge circuit and the second H-bridge circuit currently connected to the bearing coil powers the bearing coil to make the magnetic bearing work, if the power device in the one H-bridge circuit fails, the other H-bridge circuit of the first H-bridge circuit and the second H-bridge circuit that is not currently connected to the bearing coil is connected to the bearing coil through the selection switch unit to power the bearing coil so that the magnetic bearing continues to work. That is, in the event that a power device in one of the first H-bridge circuit and the second H-bridge circuit that is currently connected to the bearing coil fails, the other H-bridge circuit in the first H-bridge circuit and the second H-bridge circuit that is currently not connected to the bearing coil is connected to the bearing coil through the selection switch unit, and power is supplied to the bearing coil so that the magnetic bearing continues to work.

[0037] The scheme of the present invention proposes a power amplifier circuit of a magnetic bearing system, and a fault detection scheme for the magnetic bearing system and its power amplifier circuit. By setting a first H-bridge circuit, a second H-bridge circuit, and a selection switch unit, and using a current sensor to detect the current of the bearing coil, the fault of the magnetic bearing system and its power amplifier circuit can be automatically detected according to the current of the bearing coil, and the fault point can be reported by the host computer. When the fault is detected, it also switches to a circuit that can work normally. When a power device fails, the fault point can be avoided and stable operation can be continued. Not only can the fault point be detected in a time-saving and labor-saving manner, but the normal operation of the magnetic bearing system can also be ensured to ensure the reliability of the magnetic bearing system.

[0038] In some embodiments, the selection switch unit includes: a first switch and a second switch, the first switch is such as analog selection switch 1, and the second switch is such as analog selection switch 2; the first H-bridge circuit includes: a first power device and a second power device, the first power device is such as switch tube S1, and the second power device is such as switch tube S2; the second H-bridge circuit includes: a third power device and a fourth power device, the third power device is such as switch tube S3, and the fourth power device is such as switch tube S4.

[0039] The control end of the first switch is used to receive the first PWM signal sent by the bearing controller; the first connection end of the first switch is connected to the control end of the first power device (such as connected to the gate of the switch tube S1); the first connection end of the first power device is connected to a DC power supply (such as the drain of the switch tube S1 is connected to the DC power supply V cc ); the second connection end of the first switch is connected to the control end of the third power device (such as connected to the gate of the switch tube S3); the first connection end of the third power device is connected to a DC power supply (such as the drain of the switch tube S3 is connected to the DC power supply V cc ). The control end of the second switch is connected to the first end of the bearing coil; the first connection end of the second switch is connected to the second connection end of the first power device (such as connected to the source of the switch tube S1); the second connection end of the second switch is connected to the second connection end of the third power device (such as connected to the source of the switch tube S3).

[0040] The control end of the second power device (such as the gate of the switch tube S2) is used to receive the second PWM signal sent by the bearing controller; the first connection end of the second power device (such as the drain of the switch tube S2) is connected to the second end of the bearing coil; the second connection end of the second power device (such as the source of the switch tube S2) is grounded. The control end of the fourth power device (such as the gate of the switch tube S4) is used to receive the third PWM signal sent by the bearing controller; the first connection end of the fourth power device (such as the drain of the switch tube S4) is connected to the second end of the bearing coil; the second connection end of the fourth power device (such as the source of the switch tube S4) is grounded.

[0041] Figure 3 FIG. 1 is a schematic diagram of a structure of an embodiment of a power amplifier circuit of a magnetic bearing system of the present invention. Figure 3 The power amplifier circuit of the magnetic bearing system proposed by the solution of the present invention is composed of two cascaded H-bridge circuits, two analog selection switches (such as analog selection switch 1 and analog selection switch 2), and a current sensor for the user to measure the current of the bearing coil. The two H-bridge circuits are powered by the same power supply such as a DC power supply V cc power supply; three PWM waves (i.e., the first PWM signal, the second PWM signal, and the third PWM signal) respectively control the opening and closing of switch tubes S1, S2, S3, and S4; the two analog selection switches are controlled by control signals issued by the MCU of the bearing controller.

[0042] The solution of the present invention, by setting two H-bridge circuits and two analog selection switches, automatically detects the fault point by opening and closing the analog selection switch and reports the fault point on the host computer. While detecting the fault point, it can switch to a circuit that can work normally, so that the magnetic levitation bearing can work normally while waiting for technicians to solve the fault. The detection saves time and effort, and can ensure the reliable operation of the magnetic levitation bearing.

[0043] In some embodiments, the first H-bridge circuit further includes: a first diode and a second diode, the first diode being such as diode D1, and the second diode being such as diode D2; the second H-bridge circuit further includes: a third diode and a fourth diode, the third diode being such as diode D3, and the fourth diode being such as diode D4.

[0044] The cathode of the first diode is connected to a DC power supply, and the anode of the first diode is connected to the second end of the bearing coil; the cathode of the second diode is connected to the first end of the bearing coil, and the anode of the second diode is grounded. The cathode of the third diode is connected to the first end of the bearing coil, and the anode of the third diode is grounded; the cathode of the fourth diode is connected to a DC power supply, and the anode of the fourth diode is connected to the second end of the bearing coil.

[0045] In such Figure 3 The power amplifier circuit of the magnetic bearing system shown in the figure specifically includes: switch tube S1, switch tube S2, switch tube S3, switch tube S4, diode D1, diode D2, diode D3, diode D4, analog selection switch 1 and analog selection switch 2, and a current sensor arranged at the second end of the bearing coil. Switch tube S1, switch tube S2, diode D1, diode D2 form an H-bridge circuit, and switch tube S3, switch tube S4, diode D3, diode D4 form another H-bridge circuit. Among them, when switch tube S1, switch tube S2, switch tube S3, switch tube S4 are all MOS tubes, the DC power supply V cc Connected to the drain of switch tube S1, the source of switch tube S1 is connected to the first connection end of analog selection switch 1, the gate of switch tube S1 is connected to the first connection end of analog selection switch 2, the second connection end of analog selection switch 2 is connected to the gate of switch tube S3, and the control end of analog selection switch 2 is connected to the input end of the first PWM signal. The second connection end of analog selection switch 1 is connected to the source of switch tube S3, and the control end of analog selection switch 1 is connected to the first connection end of the bearing coil; the second connection end of the bearing coil is connected to the anode of diode D1 through the current sensor. DC power supply V ccIt is also connected to the cathode of the diode D1, the anode of the diode D1 is connected to the drain of the switch tube S2, the source of the switch tube S2 is grounded GND, and the gate of the switch tube S2 is connected to the input end of the second PWM signal. The cathode of the diode D2 is connected to the first connection end of the bearing coil, and the anode of the diode D2 is grounded GND. DC power supply V cc It is also connected to the drain of the switch tube S3. DC power supply V cc The gate of the switch tube S4 is connected to the input end of the third PWM signal, the drain of the switch tube S4 is connected to the anode of the diode D4, and the source of the switch tube S4 is connected to the ground GND.

[0046] The solution of the present invention can detect the current of the bearing coil and determine the fault point based on the current of the bearing coil and the action of the selective switch unit, so that the magnetic suspension bearing control system can automatically report the fault point and change the circuit connection for normal operation when a power device fault is detected. For example, a redundant design structure is adopted for the power amplifier circuit, and when one circuit of the power amplifier circuit is detected to be damaged, another circuit can be replaced, thereby saving troubleshooting time and manpower and improving production efficiency.

[0047] In some embodiments, the power amplification device of the magnetic bearing system described in the scheme of the present invention further includes: a current detection unit (such as a current sensor); wherein the current detection unit is arranged at the second end of the bearing coil, for detecting the current of the bearing coil, and transmitting it to the magnetic bearing controller, specifically to the MCU in the magnetic bearing controller.

[0048] The power amplifier circuit of the magnetic bearing system proposed in the solution of the present invention can ensure the normal operation of the magnetic bearing when the power device fails by detecting the current of the bearing coil and judging the fault point according to the current of the bearing coil and combining with the action of the selection switch unit. Specifically, the fault point can be automatically checked and reported on the host computer by simulating the opening and closing of the selection switch. While detecting the fault point, it can switch to a circuit that can work normally, so that the magnetic bearing can work normally while waiting for technicians to solve the fault, thereby improving production efficiency.

[0049] By adopting the technical solution of the present invention, a selection switch unit and two H-bridge circuits are set through a power amplifier circuit of a control system for a magnetic bearing, and the two H-bridge circuits are cascaded. The first end of the bearing coil is connected to the selection switch unit, and the second end of the bearing coil is respectively connected to the two H-bridge circuits. By controlling the selection switch, the two H-bridge circuits can be switched to be connected to the bearing coil; when the magnetic bearing is working, it is judged whether the bearing coil and the two H-bridge circuits of the magnetic bearing system are faulty and the fault point is determined according to the current of the bearing coil, and the two H-bridge circuits are switched to make the magnetic bearing work normally when a fault occurs; thus, through the power amplifier circuit of the control system for the magnetic bearing, a redundant power amplifier branch is set, and according to the current of the bearing coil and combined with the action of the selection switch unit, whether the magnetic bearing system is faulty and the fault point is located, and when a power device fails, the power amplifier branch is switched to make the magnetic bearing work normally, which can not only save time and effort to detect the fault point, but also ensure the normal operation of the magnetic bearing system and the reliability of the magnetic bearing system.

[0050] According to an embodiment of the present invention, a magnetic bearing system corresponding to a power amplifying device of the magnetic bearing system is also provided. The magnetic bearing system may include: the power amplifying device of the magnetic bearing system described above.

[0051] Since the processing and functions implemented by the magnetic bearing system of this embodiment basically correspond to the embodiments, principles and examples of the device, for the details not described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0052] According to an embodiment of the present invention, a fault detection method for a magnetic bearing system corresponding to the magnetic bearing system is also provided, such as Figure 5 The flowchart of an embodiment of the method of the present invention is shown in FIG. The fault detection method of the magnetic bearing system may include: steps S110 to S140.

[0053] At step S110, the current H-bridge circuit is assumed to be the first H-bridge circuit, and when the first H-bridge circuit is connected to the bearing coil, the current of the bearing coil (such as the current I of the bearing coil) is obtained. Wherein, when the first H-bridge circuit is connected to the bearing coil, the control end of the second switch is connected to the first connection end of the second switch so that the first PWM signal sent by the magnetic bearing controller can be input to the control end of the first power device, and the control end of the first switch is connected to the first connection end of the second switch so that the second connection end of the first power device is connected to the first end of the bearing coil. When the first H-bridge circuit is connected to the bearing coil, the magnetic bearing controller sends a first PWM signal and a second PWM signal so that the first H-bridge circuit supplies power to the bearing coil and the magnetic bearing works.

[0054] At step S120, according to the current of the bearing coil, combined with controlling the selection switch unit, it is determined whether the magnetic bearing system has a fault; the fault of the magnetic bearing system includes at least one of the following: a fault of the bearing coil, a fault of a power device in the first H-bridge circuit. And,

[0055] In step S130, if it is determined that the bearing coil fails, the magnetic bearing is controlled to stop working, specifically, the shaft of the magnetic bearing is controlled to stop floating due to a shaft failure.

[0056] At step S140, if it is determined that a power device in the first H-bridge circuit fails, the selection switch unit is controlled so that the second H-bridge circuit is connected to the bearing coil to supply power to the bearing coil so that the magnetic bearing continues to work. Wherein, when the second H-bridge circuit is connected to the bearing coil, the control end of the second switch is connected to the second connection end of the second switch so that the first PWM signal issued by the magnetic bearing controller can be input to the control end of the third power device, and the control end of the first switch is connected to the second connection end of the second switch so that the second connection end of the third power device is connected to the first end of the bearing coil. When the second H-bridge circuit is connected to the bearing coil, the magnetic bearing controller sends the first PWM signal and the third PWM signal so that the second H-bridge circuit supplies power to the bearing coil so that the magnetic bearing continues to work.

[0057] The scheme of the present invention, by setting a first H-bridge circuit, a second H-bridge circuit, and a selection switch unit, uses a current sensor to detect the current of the bearing coil, can automatically detect the fault of the magnetic bearing system and its power amplifier circuit according to the current of the bearing coil, and the fault point is reported by the host computer. When the fault is detected, it also switches to a circuit that can work normally. When a power device fails, the fault point can be avoided and stable operation can be continued. Not only can the fault point be detected in a time-saving and labor-saving manner, but the normal operation of the magnetic bearing system can also be ensured to ensure the reliability of the magnetic bearing system.

[0058] In some embodiments, the power devices in the first H-bridge circuit include a first power device and a second power device, and the power devices in the second H-bridge circuit include a third power device and a fourth power device; the failure of the power devices in the first H-bridge circuit includes at least one of the following: a failure of the first power device, a failure of the second power device; the selection switch unit includes: a first switch and a second switch. In step S120, determining whether the magnetic bearing system fails according to the current of the bearing coil in combination with controlling the selection switch unit includes: a first process of determining whether the magnetic bearing system fails.

[0059] Combine the following Figure 6 The flowchart of an embodiment of the first process of determining whether the magnetic bearing system fails in the method of the present invention further illustrates the specific process of the first process of determining whether the magnetic bearing system fails in step S140, including: steps S210 to S240.

[0060] Step S210, in the current control cycle, determining for the first time whether the current of the bearing coil is greater than a set maximum current; wherein the set maximum current is such as setting a maximum value Imax of the current of the bearing coil.

[0061] Step S220, in the current control cycle, if it is determined for the first time that the current of the bearing coil is greater than the set maximum current, the second switch action in the selection switch unit is controlled to stop sending the first PWM signal to the control end of the first power device in the first H-bridge circuit, and send the first PWM signal to the control end of the third power device in the second H-bridge circuit, and then determine again whether the current of the bearing coil is greater than the set maximum current.

[0062] Among them, if the first power device such as the switch tube S1 breaks down at this time, it is in a short-circuit state equivalent to a wire, and the first PWM signal cannot control the opening and closing of the first power device such as the switch tube S1. Therefore, it is necessary to control the second switch action in the selection switch unit to stop sending the first PWM signal to the control end of the first power device in the first H-bridge circuit, and send the first PWM signal to the control end of the third power device in the second H-bridge circuit, and then determine again whether the current of the bearing coil is greater than the set maximum current.

[0063] Step S230, in the current control cycle, if it is determined again that the current of the bearing coil is greater than the set maximum current, it is determined that the first power device has a breakdown fault, and a reminder message of the breakdown fault of the first power device is initiated. Then, when the second switch in the selection switch unit has been actuated, the first switch in the selection switch unit is controlled to act, so as to switch from the state in which the first power device in the first H-bridge circuit is connected to the bearing coil to the state in which the third power device in the second H-bridge circuit is connected to the bearing coil, so that the second H-bridge circuit supplies power to the bearing coil through the third power device and the fourth power device in the second H-bridge circuit, and sends out a third PWM signal, so that the third PWM signal outputs the same PWM wave as the second PWM signal, so that the magnetic bearing continues to work.

[0064] Among them, if the first power device such as switch tube S1 fails, then by switching the first switch in the selection switch unit such as analog selection switch 1 when the second switch in the selection switch unit such as analog selection switch 2 has been switched, the flow path can be changed to VCC-switch tube S3-switch tube S4, thereby ensuring the normal operation of the magnetic bearing.

[0065] Step S240, in the current control cycle, if it is determined again that the current of the bearing coil is less than or equal to the set maximum current, it is determined that the second power device in the first H-bridge circuit has a breakdown fault, and a reminder message of the breakdown fault of the second power device is initiated. Then, the first switch action in the selection switch unit is controlled to switch from the state where the first power device in the first H-bridge circuit is connected to the bearing coil to the state where the third power device in the second H-bridge circuit is connected to the bearing coil, so that the second H-bridge circuit supplies power to the bearing coil and sends out a third PWM signal, so that the third PWM signal outputs the same PWM wave as the second PWM signal, so that the magnetic bearing continues to work.

[0066] Compatible with a power amplifier circuit of a magnetic bearing system proposed in the solution of the present invention, the solution of the present invention also proposes a fault detection scheme for a magnetic bearing system and its power amplifier circuit, including fault judgment control logic and a switching circuit. Figure 4 FIG. 1 is a logic diagram of a fault judgment control of an embodiment of a fault detection method for a power amplifier circuit of a magnetic bearing system of the present invention. Figure 4 As shown, the fault detection method of the power amplifier circuit of the magnetic bearing system includes:

[0067] Step 1: first set the maximum value Imax of the current of the bearing coil, collect the current signal of the bearing coil through the current sensor, record it as the current I of the bearing coil, and then execute step 2.

[0068] Step 2: Determine whether the current I of the bearing coil is greater than Imax: if so, execute step 2; otherwise, execute step 4.

[0069] Step 2, when the current I of the bearing coil is greater than Imax, the simulation selection switch 2 is actuated, and the first PWM signal controlling the switch tube S1 is converted to control the switch tube S3, and then it is determined whether the current I of the bearing coil is greater than Imax: if so, a breakdown fault of the switch tube S1 is reported and step 3 is executed; otherwise, a breakdown fault of the switch tube S2 is reported and step 3 is executed.

[0070] In step 2, by default, the control end of the analog selection switch 2 is connected to the first connection end of the analog selection switch 2, and the first PWM signal controls the switch tube S1; the magnetic bearing works normally under the control of the first PWM signal and the second PWM signal. When the analog selection switch 2 is in action, the control end of the analog selection switch 2 is connected to the second connection end of the analog selection switch 2, and the first PWM signal controls the switch tube S3.

[0071] Step 3, simulate the action of the selection switch 1, connect the second end of the bearing coil to the source of the switch tube S3, and control the third PWM signal to work, so that the magnetic bearing works normally, that is, the shaft is suspended normally.

[0072] In step 3, by default, the first connection end of the analog selection switch 1 is connected to the source of the switch tube S1, the control end of the analog selection switch 1 is connected to the first connection end of the analog selection switch 1, that is, the first end of the bearing coil connected to the control end of the analog selection switch 1 is connected to the source of the switch tube S1, the switch tube S1, the switch tube S2, the diode D1, and the diode D2 form an H-bridge circuit for the magnetic bearing, and the magnetic bearing works normally under the control of the first PWM signal and the second PWM signal. When the analog selection switch 1 is in action, the second connection end of the analog selection switch 1 is connected to the source of the switch tube S3, the control end of the analog selection switch 1 is connected to the second connection end of the analog selection switch 1, that is, the first end of the bearing coil connected to the control end of the analog selection switch 1 is connected to the source of the switch tube S3, the switch tube S3, the switch tube S4, the diode D3, and the diode D4 form another H-bridge circuit for the magnetic bearing, and the magnetic bearing works normally under the control of the first PWM signal and the third PWM signal.

[0073] The solution of the present invention determines whether the magnetic bearing system has a fault based on the current of the bearing coil in combination with controlling the selection switch unit, automatically detects the fault point by simulating the opening and closing of the selection switch and reports the fault point on the host computer, and can switch to a circuit that can work normally while detecting the fault point, so that the magnetic bearing can work normally while waiting for technicians to solve the fault, thereby improving production efficiency.

[0074] In some embodiments, step S120 determines whether the magnetic bearing system fails based on the current of the bearing coil in combination with controlling the selection switch unit, and also includes: a second process of determining whether the magnetic bearing system fails.

[0075] Combine the following Figure 7The flowchart of an embodiment of the second process of determining whether the magnetic bearing system fails in the method of the present invention further illustrates the specific process of the second process of determining whether the magnetic bearing system fails in step S140, including: steps S310 to S350.

[0076] Step S310, in the current control cycle, after first determining whether the current of the bearing coil is greater than the set maximum current, if it is first determined that the current of the bearing coil is less than or equal to the set maximum current, then in the current control cycle, determine for the first time whether the current of the bearing coil is equal to 0.

[0077] Step S320, in the current control cycle, if it is determined for the first time that the current of the bearing coil is not equal to 0, it is determined that neither the bearing coil nor the power devices in the first H-bridge circuit are faulty, and the first H-bridge circuit is still used to power the bearing coil so that the magnetic bearing continues to work.

[0078] Step S330, in the current control cycle, if it is determined for the first time that the current of the bearing coil is equal to 0, then in the current control cycle, a third PWM signal is issued, so that the third PWM signal outputs a PWM wave that is the same as the second PWM signal, so as to control the fourth power device in the second H-bridge circuit to be turned on, and then it is determined for the second time whether the current of the bearing coil is equal to 0.

[0079] Among them, the third PWM signal such as PWM3 controls the fourth power device such as switch tube S4 to turn on. At this time, the path changes from the original VCC-switch tube S1-bearing coil-switch tube S2 to two paths VCC-switch tube S1-bearing coil-switch tube S2 (switch tube S4), specifically: VCC-switch tube S1-bearing coil-switch tube S2, VCC-switch tube S1-bearing coil-switch tube S4. Turning on switch tube S4 adds a path to better determine subsequent faults.

[0080] Step S340, in the current control cycle, if it is determined for the second time that the current of the bearing coil is equal to 0, the first switch and the second switch in the selection switch unit are controlled to operate simultaneously, so as to switch from the first H-bridge circuit connected to the bearing coil to the second H-bridge circuit connected to the bearing coil, so that the second H-bridge circuit supplies power to the bearing coil, and then continue to determine whether the bearing coil and the power devices in the first H-bridge circuit are faulty.

[0081] Among them, if the current of the bearing coil is still 0 in the case of the two paths VCC-switch tube S1-bearing coil-switch tube S2 (switch tube S4), the first switch such as analog selection switch 1 and the second switch such as analog selection switch 2 in the selection switch unit are controlled to operate simultaneously, and the path can be changed to VCC-switch tube S3-bearing coil-switch tube S4. If there is current in the bearing coil under no path, it can be determined that the bearing coil is faulty.

[0082] Step S350, in the current control cycle, if it is determined for the second time that the current of the bearing coil is not equal to 0, it is determined that the second power device has an open circuit fault, and a reminder message of the open circuit fault of the second power device is initiated, and then the first switch and the second switch in the selection switch unit are controlled to operate simultaneously, so that the first H-bridge circuit is connected to the bearing coil, and then the second H-bridge circuit is connected to the bearing coil, so that the second H-bridge circuit supplies power to the bearing coil, and then it continues to determine whether the bearing coil and the power device in the first H-bridge circuit are faulty.

[0083] Specifically, Figure 4 As shown, the fault detection method of the power amplifier circuit of the magnetic bearing system also includes:

[0084] Step 4: When the current I of the bearing coil is less than or equal to Imax, determine whether the current I of the bearing coil is equal to 0: if so, execute step 5; otherwise, control the magnetic bearing to work normally.

[0085] Step 5, control the third PWM signal to output the same PWM wave as the second PWM signal to control the on and off of the switch tube S4, and then re-judge whether the current I of the bearing coil is satisfied = 0: if so, execute step 6, otherwise, execute step 6 after reporting an open circuit fault of the switch tube S2.

[0086] Step 6: Control the analog selection switch 1 and the analog selection switch 2 to operate simultaneously, and then re-judge whether the current I of the bearing coil satisfies 0.

[0087] The solution of the present invention detects the current of the bearing coil, determines the fault point based on the current of the bearing coil and in combination with the action of the selection switch unit, and can ensure the normal operation of the magnetic bearing when the power device fails. Specifically, the fault point can be automatically checked and reported on the host computer by simulating the opening and closing of the selection switch. While detecting the fault point, it can switch to a circuit that can work normally, so that the magnetic bearing can work normally while waiting for technicians to solve the fault, thereby improving production efficiency.

[0088] In some implementations, in step S350, in the current control cycle, the specific process of continuing to determine whether the bearing coil and the power device in the first H-bridge circuit are faulty is described in the following exemplary embodiments.

[0089] Combine the following Figure 8 The flowchart of an embodiment of the method of the present invention further illustrates whether the bearing coil and the power device in the first H-bridge circuit are faulty, and further illustrates the wavelet packet analysis process of online monitoring of step S350, including: step S410 to step S430.

[0090] Step S410: in the current control cycle, determine for the third time whether the current of the bearing coil is equal to 0.

[0091] Step S420, in the current control cycle, if it is determined for the third time that the current of the bearing coil is not equal to 0, it is determined that an open circuit fault occurs in the bearing coil, and then the shaft of the magnetic bearing is controlled to stop floating due to a shaft fault.

[0092] Step S430, in the current control cycle, if it is determined for the third time that the current of the bearing coil is equal to 0, it is determined that the first power device has an open circuit fault, and a reminder message of the open circuit fault of the first power device is initiated. After that, a third PWM signal has been sent so that the third PWM signal outputs a PWM wave that is the same as the second PWM signal, and the second H-bridge circuit has been switched to be connected to the bearing coil so that the second H-bridge circuit powers the bearing coil, so that the magnetic bearing continues to work.

[0093] Specifically, Figure 4 As shown, the fault detection method of the power amplifier circuit of the magnetic bearing system also includes: in step 6, it is re-determined whether the current I of the bearing coil is satisfied = 0: if so, an open circuit fault of the bearing coil is reported and the shaft is controlled to stop floating; otherwise, an open circuit fault of the switch tube S1 is reported and the shaft is controlled to suspend normally, that is, the magnetic bearing is made to work normally under the control of another H-bridge circuit formed by the switch tube S3, the switch tube S4, the diode D3, and the diode D4, and the magnetic bearing is controlled by the first PWM signal and the third PWM signal.

[0094] The solution of the present invention can automatically detect the fault point by simulating the opening and closing of the selection switch and report the fault point on the host computer. While detecting the fault point, it can switch to a circuit that can work normally, so that the magnetic bearing can work normally while waiting for technicians to solve the fault, thereby improving production efficiency.

[0095] In some embodiments, the power device in the first H-bridge circuit includes a first power device and a second power device, and the power device in the second H-bridge circuit includes a third power device and a fourth power device; the failure of the power device in the first H-bridge circuit includes at least one of the following: the failure of the first power device, the failure of the second power device; the selection switch unit includes: a first switch and a second switch. In step S140, if it is determined that the power device in the first H-bridge circuit fails, the selection switch unit is controlled to connect the second H-bridge circuit to the bearing coil and power the bearing coil so that the magnetic bearing continues to work, including at least one of the following, that is, including at least one of the following control situations: the first control situation and the second control situation.

[0096] Among them, the first control scenario: if it is determined that the first power device has a breakdown fault, or it is determined that the second power device in the first H-bridge circuit has a breakdown fault, the first switch action in the selection switch unit is controlled to switch from the state in which the first power device in the first H-bridge circuit is connected to the bearing coil to the state in which the third power device in the second H-bridge circuit is connected to the bearing coil, so that the second H-bridge circuit supplies power to the bearing coil and sends out a third PWM signal, so that the third PWM signal outputs the same PWM wave as the second PWM signal, so that the magnetic bearing continues to work.

[0097] Specifically, Figure 4 As shown, the fault detection method of the power amplifier circuit of the magnetic bearing system also includes: in step 2 and step 3, when the current I of the bearing coil is greater than Imax, the simulation selection switch 2 is actuated, and the first PWM signal controlling the switch tube S1 is converted to control the switch tube S3. At this time, if the current I of the bearing coil continues to maintain the current I of the bearing coil greater than Imax, it is determined that the switch tube S1 is broken down; if the current of the bearing coil decreases by I less than Imax, it is determined that the switch tube S2 is broken down; regardless of the type of fault, the simulation selection switch 1 is actuated, the third PWM signal outputs the same PWM wave as the second PWM signal, the three-level working state is completed by the switch tube S3, the switch tube S4 and the diode D3, the diode D4, and the magnetic suspension bearing works normally.

[0098] Among them, the simulation selection switch 2 is operated to determine the fault condition of the switch tube S1: if the simulation selection switch 2 is operated, the switch tube S1 can still be turned on, that is, I>Imax, which proves that the switch tube S1 is short-circuited and broken down. The simulation selection switch switch 1 is operated to disconnect the path of the switch tube S1. In addition, the PWM wave output by PWM signal 1 is the same as that of PWM signal 2 or 3, because the upper and lower tubes cannot be directly connected, otherwise they will be short-circuited and there must be a dead zone. In theory, the PWM wave output by PWM signal 1 and the waveform output by PWM signal 2 or 3 are complementary waveforms.

[0099] The second control scenario: If it is determined that the first power device has an open circuit fault, or it is determined that the second power device has an open circuit fault, then when a third PWM signal is sent out so that the third PWM signal outputs a PWM wave that is the same as the second PWM signal, the first switch and the second switch in the selection switch unit are controlled to operate simultaneously, so that the first H-bridge circuit is connected to the bearing coil and switched to the second H-bridge circuit being connected to the bearing coil, so that the second H-bridge circuit supplies power to the bearing coil, so that the magnetic bearing continues to work.

[0100] Specifically, Figure 4 As shown, the fault detection method of the power amplifier circuit of the magnetic bearing system also includes: in steps 4 to 6, if the current I of the bearing coil is less than Imax, it is determined whether the current I of the bearing coil is 0, if the current I of the bearing coil is not 0, the magnetic bearing is in a normal working state without fault; if the current I of the bearing coil is 0, the third PWM signal is output as a PWM wave identical to the second PWM signal to control the on and off of the switch tube S4, if the current I of the bearing coil is not 0 at this time, it is determined that the switch tube S2 has an open circuit fault; if the current I of the bearing coil is still 0 at this time, the analog selection switch 1 and the analog selection switch 2 are simultaneously actuated, and it is determined whether the current I of the bearing coil is 0 at this time, if the current I of the bearing coil is not 0, it is determined that the switch tube S1 has an open circuit fault, the three-level working state is completed by the switch tube S3, the switch tube S4 and the diode D3, the diode D4, the magnetic bearing operates normally, if the switch tube I is 0, it is determined that the coil has an open circuit fault, and the magnetic bearing is protected and suspended. In this case, the third PWM signal is firstly made to output the same PWM wave as the second PWM signal, and then the analog selection switch 1 and the analog selection switch 2 are simultaneously operated, so as to switch the redundant circuit to judge whether the fault is the open circuit of the bearing coil. By opening each switch one by one, the faulty component can be effectively located.

[0101] The solution of the present invention can detect the current of the bearing coil and determine the fault point based on the current of the bearing coil and the action of the selective switch unit, so that the magnetic suspension bearing control system can automatically report the fault point and change the circuit connection for normal operation when a power device fault is detected. For example, a redundant design structure is adopted for the power amplifier circuit, and when one circuit of the power amplifier circuit is detected to be damaged, another circuit can be replaced, thereby saving troubleshooting time and manpower and improving production efficiency.

[0102] Since the processing and functions implemented by the method of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned magnetic bearing system, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0103] In summary, it is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0104] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A power amplification device for a magnetic bearing system, characterized in that: The magnetic bearing system comprises a magnetic bearing and a magnetic bearing control system; the magnetic bearing comprises a bearing coil; the magnetic bearing control system comprises a power amplifier and a bearing controller; the power amplifier of the magnetic bearing system comprises: a first H-bridge circuit, a second H-bridge circuit, and a selection switch unit; wherein, The first H-bridge circuit and the second H-bridge circuit are cascaded, and the first H-bridge circuit and the second H-bridge circuit are mutually redundant power amplification branches; The first end of the bearing coil is connected to the selection switch unit, and the second end of the bearing coil is connected to the first H-bridge circuit and the second H-bridge circuit respectively; The selection switch unit is capable of switching the bearing coil to be connected to any one of the first H-bridge circuit and the second H-bridge circuit; the one of the first H-bridge circuit and the second H-bridge circuit that is currently connected to the bearing coil is recorded as the current H-bridge circuit; The magnetic bearing controller is used to determine whether the magnetic bearing system fails according to the current of the bearing coil and in combination with controlling the selection switch unit; the failure of the magnetic bearing system includes at least one of the following: failure of the bearing coil, failure of the power device in the current H-bridge circuit; and, If it is determined that the bearing coil fails, controlling the magnetic bearing to stop working; If it is determined that a power device in the current H-bridge circuit fails, the selection switch unit is controlled to connect the other H-bridge circuit of the first H-bridge circuit and the second H-bridge circuit to the bearing coil, and power is supplied to the bearing coil so that the magnetic bearing continues to work.

2. The power amplification device of the magnetic bearing system according to claim 1, characterized in that: The selection switch unit includes: a first switch and a second switch; the first H-bridge circuit includes: a first power device and a second power device; the second H-bridge circuit includes: a third power device and a fourth power device; wherein, The control end of the first switch is used to receive the first PWM signal sent by the bearing controller; the first connection end of the first switch is connected to the control end of the first power device; the first connection end of the first power device is connected to a DC power supply; the second connection end of the first switch is connected to the control end of the third power device; the first connection end of the third power device is connected to a DC power supply; The control end of the second switch is connected to the first end of the bearing coil; the first connection end of the second switch is connected to the second connection end of the first power device; the second connection end of the second switch is connected to the second connection end of the third power device; The control end of the second power device is used to receive the second PWM signal sent by the bearing controller; the first connection end of the second power device is connected to the second end of the bearing coil; the second connection end of the second power device is grounded; The control end of the fourth power device is used to receive the third PWM signal sent by the bearing controller; the first connection end of the fourth power device is connected to the second end of the bearing coil; the second connection end of the fourth power device is grounded.

3. The power amplification device of the magnetic bearing system according to claim 2, characterized in that: The first H-bridge circuit further includes: a first diode and a second diode; the second H-bridge circuit further includes: a third diode and a fourth diode; wherein, The cathode of the first diode is connected to a DC power supply, and the anode of the first diode is connected to the second end of the bearing coil; the cathode of the second diode is connected to the first end of the bearing coil, and the anode of the second diode is grounded; The cathode of the third diode is connected to the first end of the bearing coil, and the anode of the third diode is grounded; the cathode of the fourth diode is connected to a DC power supply, and the anode of the fourth diode is connected to the second end of the bearing coil.

4. The power amplification device of the magnetic bearing system according to any one of claims 1 to 3, characterized in that: Also includes: A current detection unit; wherein, The current detection unit is arranged at the second end of the bearing coil, and is used to detect the current of the bearing coil and transmit it to the magnetic bearing controller.

5. A magnetic bearing system, characterized in that: include: A power amplification device for a magnetic bearing system according to any one of claims 1 to 4.

6. A fault detection method for a magnetic bearing system as claimed in claim 5, characterized in that: include: set up The current H-bridge circuit is the first H-bridge circuit, and when the first H-bridge circuit is connected to the bearing coil, the current of the bearing coil is obtained; According to the current of the bearing coil, combined with controlling the selection switch unit, determining whether the magnetic bearing system fails; the failure of the magnetic bearing system includes at least one of the following: failure of the bearing coil, failure of the power device in the first H-bridge circuit; and, If it is determined that the bearing coil fails, controlling the magnetic bearing to stop working; If it is determined that the power device in the first H-bridge circuit fails, the selection switch unit is controlled to connect the second H-bridge circuit to the bearing coil and supply power to the bearing coil so that the magnetic bearing continues to work.

7. The fault detection method of the magnetic bearing system according to claim 6, characterized in that: Determining whether the magnetic bearing system fails according to the current of the bearing coil and in combination with controlling the selection switch unit includes: In the current control cycle, determining for the first time whether the current of the bearing coil is greater than a set maximum current; If it is determined for the first time that the current of the bearing coil is greater than the set maximum current, the second switch in the selection switch unit is controlled to stop sending the first PWM signal to the control end of the first power device in the first H-bridge circuit, and send the first PWM signal to the control end of the third power device in the second H-bridge circuit, and then determine again whether the current of the bearing coil is greater than the set maximum current; If it is determined again that the current of the bearing coil is greater than the set maximum current, it is determined that a breakdown fault occurs in the first power device, and a reminder message of a breakdown fault occurs in the first power device is sent; If it is determined again that the current of the bearing coil is less than or equal to the set maximum current, it is determined that the second power device in the first H-bridge circuit has a breakdown fault, and a reminder message of the breakdown fault of the second power device is initiated.

8. The fault detection method of the magnetic bearing system according to claim 7, characterized in that: According to the current of the bearing coil, combined with controlling the selection switch unit, determining whether the magnetic bearing system fails, further comprising: If it is determined for the first time that the current of the bearing coil is less than or equal to the set maximum current, then determining for the first time whether the current of the bearing coil is equal to 0; If it is determined for the first time that the current of the bearing coil is not equal to 0, it is determined that the bearing coil and the power devices in the first H-bridge circuit are not faulty, and the first H-bridge circuit is still used to supply power to the bearing coil so that the magnetic bearing continues to work; If it is determined for the first time that the current of the bearing coil is equal to 0, a third PWM signal is issued, so that the third PWM signal outputs a PWM wave identical to the second PWM signal, so as to control the fourth power device in the second H-bridge circuit to be turned on, and then it is determined for the second time whether the current of the bearing coil is equal to 0; If it is determined for the second time that the current of the bearing coil is equal to 0, the first switch and the second switch in the selection switch unit are controlled to act simultaneously, so that the first H-bridge circuit is connected to the bearing coil, and the second H-bridge circuit is connected to the bearing coil, so that the second H-bridge circuit supplies power to the bearing coil, and then it is continuously determined whether the bearing coil and the power device in the first H-bridge circuit are faulty; If it is determined for the second time that the current of the bearing coil is not equal to 0, it is determined that the second power device has an open circuit fault, and a reminder message of the open circuit fault of the second power device is initiated, and then it is further determined whether the bearing coil and the power device in the first H-bridge circuit have faults.

9. The fault detection method of the magnetic bearing system according to claim 8, characterized in that: Continuing to determine whether the bearing coil and the power device in the first H-bridge circuit are faulty, includes: determining for the third time whether the current of the bearing coil is equal to 0; If it is determined for the third time that the current of the bearing coil is not equal to 0, it is determined that an open circuit fault occurs in the bearing coil; If it is determined for the third time that the current of the bearing coil is equal to 0, it is determined that an open circuit fault occurs in the first power device, and a reminder message of the open circuit fault occurs in the first power device is initiated.

10. The fault detection method of a magnetic bearing system according to any one of claims 6 to 9, characterized in that: If it is determined that a power device in the first H-bridge circuit fails, the selection switch unit is controlled to connect the second H-bridge circuit to the bearing coil and supply power to the bearing coil so that the magnetic bearing continues to work, including at least one of the following: If it is determined that the first power device has a breakdown fault, or it is determined that the second power device in the first H-bridge circuit has a breakdown fault, the first switch in the selection switch unit is controlled to switch from the state where the first power device in the first H-bridge circuit is connected to the bearing coil to the state where the third power device in the second H-bridge circuit is connected to the bearing coil, so that the second H-bridge circuit supplies power to the bearing coil and sends out a third PWM signal, so that the third PWM signal outputs a PWM wave that is the same as the second PWM signal, so that the magnetic bearing continues to work; If it is determined that an open circuit fault occurs in the first power device, or it is determined that an open circuit fault occurs in the second power device, then when a third PWM signal is sent so that the third PWM signal outputs a PWM wave that is the same as the second PWM signal, the first switch and the second switch in the selection switch unit are controlled to operate simultaneously, so that the first H-bridge circuit is connected to the bearing coil and switched to the second H-bridge circuit being connected to the bearing coil, so that the second H-bridge circuit supplies power to the bearing coil, so that the magnetic bearing continues to work.

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