A magnetic bearing control system and control method thereof and a magnetic suspension system

Abstract

The present invention discloses a magnetic bearing control system and a control method thereof and a magnetic suspension system. The device comprises: a collection unit, a main circuit and a magnetic bearing controller; in the main circuit, TSMC is used; wherein the collection unit is configured to collect the grid voltage signal of the AC power supply, the rotor displacement signal of the motor rotor of the magnetic bearing, and the current signal of the electromagnetic coil of the radial bearing and the axial bearing; the magnetic bearing controller is configured to determine the control instruction of the main circuit according to the grid voltage signal, the rotor displacement signal, and the current signal of the electromagnetic coil; the main circuit is configured to work according to the control instruction to adjust the current signal of the electromagnetic coil of the radial bearing and the axial bearing. This scheme can reduce the occupied space of the magnetic bearing control system by using TSMC as the main circuit of the power amplifier in the magnetic bearing control system.

Description

Technical Field

[0001] The present invention belongs to the field of motor technology, and specifically relates to a magnetic bearing control system and a control method thereof and a magnetic suspension system, and more particularly to a control method applied to a three-pole magnetic bearing control system, a magnetic suspension system, and a three-pole magnetic bearing control system. Background Art

[0002] In the magnetic levitation system, the DC power required by the magnetic bearing control system is converted from the power grid through a rectifier. However, the DC bus capacitor on the DC bus on the output side of the rectifier is large in size, resulting in a non-compact system structure and a large space occupation.

[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 magnetic bearing control system, a control method thereof and a magnetic levitation system, so as to solve the problem that the direct current required by the magnetic bearing control system is obtained by converting the direct current from the power grid through a rectifier, and the direct current bus capacitor on the output side of the conversion device is bulky, which makes the space occupied by the magnetic bearing control system huge. By using TSMC as the main circuit of the power amplifier in the magnetic bearing control system, the space occupied by the magnetic bearing control system can be reduced.

[0005] The present invention provides a magnetic bearing control system, wherein the magnetic bearing comprises: a radial bearing and an axial bearing; the magnetic bearing control system comprises: an acquisition unit, a main circuit and a magnetic bearing controller; TSMC is used in the main circuit; wherein the acquisition unit is configured to acquire a grid voltage signal of an AC power supply, a rotor displacement signal of a motor rotor of the magnetic bearing, and current signals of electromagnetic coils of the radial bearing and the axial bearing; the magnetic bearing controller is configured to determine a control instruction of the main circuit according to the grid voltage signal, the rotor displacement signal, and the current signal of the electromagnetic coil; the main circuit is configured to work according to the control instruction to adjust the current signals of the electromagnetic coils of the radial bearing and the axial bearing.

[0006] In some embodiments, the main circuit includes: a rectifier stage, an inverter stage and an axial power amplification unit; the rectifier stage adopts a TSMC rectifier stage, and / or the inverter stage adopts a TSMC inverter stage; wherein the rectifier stage or the TSMC rectifier stage is configured to receive a first alternating current input by an AC power supply, and convert the first alternating current into direct current according to the control instruction; the TSMC inverter stage or the inverter stage is configured to invert the direct current according to the control instruction to obtain a second alternating current to power the electromagnetic coil of the radial bearing; the axial power amplification unit is configured to use the direct current as a power supply, and power the electromagnetic coil of the axial bearing according to the control instruction.

[0007] In some embodiments, the main circuit further includes: a filtering unit; the filtering unit is arranged between the output end of the AC power supply and the rectification stage or the TSMC rectification stage, and is configured to filter the AC power output by the AC power supply to obtain the first AC power.

[0008] In some embodiments, the magnetic bearing control system further includes: a clamping unit; the clamping unit is arranged between the rectifier end and the inverter end of the magnetic bearing control system, and is configured to clamp the direct current output from the rectifier end before outputting it to the inverter end and the axial power amplification unit; the rectifier end is the rectifier stage or the TSMC rectifier stage; the inverter end is the inverter stage or the TSMC inverter stage.

[0009] In some implementations, the TSMC rectifier stage includes: a first rectifier switch module to a sixth rectifier switch module; each switch module in the first rectifier switch module to the sixth rectifier switch module includes: a bidirectional power switch and a unidirectional power switch.

[0010] In some embodiments, the axial power amplification unit includes: an axial power amplifier; the axial power amplifier includes: a first amplifying switch module to a fourth amplifying switch module; the first amplifying switch module to the fourth amplifying switch module form two bridge arms; the electromagnetic coil of the axial bearing of the magnetic bearing is arranged between the two bridge arms.

[0011] In some embodiments, the radial bearing includes: a first radial bearing and a second radial bearing; the TSMC inverter stage adopts the TSMC five-bridge-arm inverter stage; in the TSMC five-bridge-arm inverter stage, the first radial bearing and the second radial bearing share a common bridge arm.

[0012] In some embodiments, the TSMC five-bridge-arm inverter stage includes: a first inverter switch module to a tenth inverter switch module; the first inverter switch module to the tenth inverter switch module form five bridge arms, one of which is a common bridge arm; the electromagnetic coil of the first radial bearing and the electromagnetic coil of the second radial bearing are respectively connected to two of the five bridge arms and one common bridge arm.

[0013] Matching the above-mentioned device, the present invention further provides a magnetic suspension system on the other hand, including: the magnetic bearing control system described above.

[0014] Matching the above-mentioned magnetic levitation system, the present invention provides a control method for a magnetic bearing control system on another aspect, comprising: collecting, through a collection unit, a grid voltage signal of an AC power supply, a rotor displacement signal of a motor rotor of the magnetic bearing, and a current signal of an electromagnetic coil of the radial bearing and the axial bearing; determining, through a magnetic bearing controller, a control instruction of the main circuit according to the grid voltage signal, the rotor displacement signal, and the current signal of the electromagnetic coil; and working through the main circuit according to the control instruction to adjust the current signal of the electromagnetic wire of the radial bearing and the axial bearing; wherein the magnetic bearing comprises: a radial bearing and an axial bearing; the magnetic bearing control system comprises: a collection unit, a main circuit and a magnetic bearing controller; and TSMC is used in the main circuit.

[0015] In some embodiments, the main circuit includes: a rectifier stage, an inverter stage and an axial power amplification unit. The rectifier stage adopts a TSMC rectifier stage, and / or the inverter stage adopts a TSMC inverter stage; wherein, the control instruction of the main circuit is determined by the magnetic bearing controller according to the grid voltage signal, the rotor displacement signal, and the current signal of the electromagnetic coil, including: when determining the control instruction of the TSMC rectifier stage, the three-phase AC power input by the AC power supply is divided into a set number of intervals; in each interval, there is a phase with the largest absolute value of voltage, and the voltage polarities of the other two phases are opposite to the polarity of the voltage with the largest absolute value; in any interval, the TSMC rectifier stage outputs two line voltages with the largest amplitude in one switching cycle; when determining the TSMC inverter stage, the duty cycle signal of the common bridge arm in the TSMC inverter stage is allocated according to the average voltage signal and the given voltage signal output by the TSMC rectifier stage.

[0016] Therefore, the solution of the present invention, by using the TSMC rectifier stage in TSMC, replaces the rectifier stage in the magnetic bearing control system, thereby eliminating the bulky DC bus capacitor and reducing the occupied space of the magnetic bearing control system. In addition, the TSMC inverter stage in TSMC can also be used to replace the inverter stage in the magnetic bearing control system, and the six-way coil is driven by the five-bridge arm inverter stage, thereby reducing the number of switching devices, further reducing the occupied space of the magnetic bearing control system, and saving costs. Therefore, by using TSMC as the main circuit of the power amplifier in the magnetic bearing control system, the occupied space of the magnetic bearing control system can be reduced.

[0017] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention.

[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of an embodiment of a magnetic bearing control system of the present invention;

[0020] Figure 2 It is a structural schematic diagram of an embodiment of a magnetic bearing control system;

[0021] Figure 3 It is a structural schematic diagram of an embodiment of a main circuit of a magnetic bearing control system;

[0022] Figure 4 A schematic diagram of a power switch driving signal under a coordinated configuration of an embodiment of a magnetic bearing control system;

[0023] Figure 5 A schematic flow chart of an embodiment of a control method for a magnetic bearing control system;

[0024] Figure 6 It is a flow chart of an embodiment of a control method of a magnetic bearing control system of the present invention. DETAILED DESCRIPTION

[0025] 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.

[0026] In the magnetic levitation system, the magnetic bearing controls the size of the electromagnetic force to make the rotor suspend at the desired position of the magnetic bearing control system. It has the advantages of no lubricating oil, no mechanical friction, and long life. It has been used in centrifugal compressors, molecular pumps, flywheel energy storage and other occasions.

[0027] In the related scheme, in the five-degree-of-freedom three-pole radial magnetic bearing motor, two radial three-pole magnetic bearings are driven by two identical three-arm inverters. The DC power required by the magnetic bearing control system is converted from the power grid through a rectifier. However, the DC bus capacitor on the DC bus on the output side of the rectifier is bulky and has a short life, resulting in a non-compact structure and low reliability of the magnetic levitation system.

[0028] The two-stage matrix converter (TSMC) can input sinusoidal current and has the advantages of adjustable power factor and high power density. It can be structurally divided into AC-DC stage (AC-DC, i.e. rectifier stage) and DC-AC stage (DC-AC, i.e. inverter stage). Unlike the AC-DC-AC (AC-DC-AC) inverter in the related scheme, the DC link of TSMC has no energy storage elements, making the circuit structure more compact and the power density high. In addition, the intermediate DC link can connect multiple inverter stages to achieve independent control of multiple inverter stages. The input current is sinusoidal and has little harmonic pollution to the power grid; for example, the diode rectifier circuit in the related scheme has a non-sinusoidal input current and a low input power factor, which will cause harmonic pollution to the power grid.

[0029] In addition, in some schemes, two direct matrix converters are used to control six coils with two radial degrees of freedom, which requires an excessive number of power switches, and the control of the axial bearing also requires an additional DC power supply, resulting in a high cost and bulky control system.

[0030] Among them, the direct matrix converter, that is, the matrix converter, is a new type of AC-AC power converter that can realize the conversion of various parameters of AC power (number of phases, phase, amplitude, frequency), does not require an intermediate DC energy storage link, can operate in four quadrants, has excellent input current waveform and output voltage waveform, and can freely control the power factor.

[0031] According to an embodiment of the present invention, a magnetic bearing control system is provided. Figure 1 The structural schematic diagram of an embodiment of the device of the present invention is shown. The magnetic bearing includes: a radial bearing and an axial bearing. The magnetic bearing control system includes: a collection unit, a main circuit and a magnetic bearing controller. The main circuit is connected to the magnetic bearing controller. TSMC is used in the main circuit.

[0032] Wherein, the acquisition unit is configured to acquire a grid voltage signal of an AC power supply, a rotor displacement signal of a motor rotor of the magnetic bearing, and current signals of electromagnetic coils of the radial bearing and the axial bearing.

[0033] The magnetic bearing controller is configured to determine the control instruction of the main circuit according to the grid voltage signal, the rotor displacement signal, and the current signal of the electromagnetic coil, so as to control the operation of the main circuit according to the control instruction.

[0034] The main circuit is configured to work according to the control instruction to adjust the current signals of the electromagnetic coils of the radial bearing and the axial bearing.

[0035] The solution of the present invention provides a magnetic bearing control system, such as a control solution applied to a three-pole magnetic bearing, by using TSMC as the main circuit of the power amplifier in the three-pole radial magnetic bearing control system, and driving the six-way coil with a five-bridge-arm inverter stage, the number of switch devices is reduced. In this way, two three-pole radial magnetic bearings are driven by a five-bridge-arm DC-AC stage, the number of power switches is reduced, and the cost is saved. In addition, no intermediate DC energy storage element is required, the system volume is reduced, and the reliability of the magnetic suspension bearing control system is improved.

[0036] In some embodiments, the main circuit includes: a rectifier stage, an inverter stage and an axial power amplification unit, such as an axial power amplifier. The rectifier stage and the inverter stage are sequentially arranged between the output end of the AC power supply and the magnetic bearing controller. The axial power converter takes power from the output end of the rectifier stage and is connected to the magnetic bearing controller. The rectifier stage adopts a TSMC rectifier stage, and / or the inverter stage adopts a TSMC inverter stage. Of course, when in use, at least one of the rectifier stage and the inverter stage can adopt a TSMC stage according to the use requirements.

[0037] The rectification stage or the TSMC rectification stage is arranged at the output end of the AC power supply, and is configured to receive the first AC power input by the AC power supply, and convert the first AC power into DC power according to the control instruction.

[0038] The TSMC inverter stage or the inverter stage is arranged at the output end of the TSMC rectifier stage, and is configured to invert the direct current according to the control instruction to obtain a second alternating current to supply power to the electromagnetic coil of the radial bearing.

[0039] The axial power amplification unit is arranged at the output end of the rectifier stage or the TSMC rectifier stage, and is configured to use the direct current as a power supply to supply power to the electromagnetic coil of the axial bearing according to the control instruction.

[0040] Thus, the scheme of the present invention divides the two-stage matrix converter into a rectifier stage and an inverter stage, wherein the rectifier stage converts AC power into DC power, and the inverter stage converts DC power into the electric energy required by the magnetic bearing. The five-bridge-arm inverter stage structure and control method are applicable to any structure that can provide DC power to the inverter stage.

[0041] In some implementations, the main circuit further includes: a filtering unit, such as an LC filter.

[0042] The filtering unit is disposed between the output end of the AC power source and the rectification stage or the TSMC rectification stage, and is configured to obtain the first AC power after filtering the AC power output by the AC power source.

[0043] For example: Figure 2 FIG. 1 is a schematic diagram of the structure of an embodiment of a magnetic bearing control system. Figure 2 As shown, the magnetic bearing control system includes a three-phase power grid, a filter circuit, a rectifier stage, a bearing controller, a five-bridge-arm inverter stage, a motor rotor, and an axial power converter. The three-phase power grid can provide an AC voltage source. The filter circuit uses a filter. The rectifier stage uses a TSMC rectifier stage. The five-bridge-arm inverter stage uses a TSMC five-bridge-arm inverter stage.

[0044] exist Figure 2 In the example shown, the AC voltage source is connected to the TSMC rectifier stage after passing through the filter. The output end of the TSMC rectifier stage is connected to the first input end of the TSMC five-arm inverter stage and the first input end of the axial power converter. The bearing controller is connected to the TSMC rectifier stage. The bearing controller is also connected to the AC voltage source, the TSMC five-arm inverter stage, the motor rotor and the bearing power converter. The TSMC five-arm inverter stage drives the radial six electromagnetic coils of the two radial three-pole bearings, and the axial power amplifier drives the axial electromagnetic coil of the axial bearing. The bearing controller is powered by the AC voltage source, and by collecting the voltage signal of the three-phase power grid, the rotor displacement signal of the motor, and the electromagnetic coil current signal of the axial bearing and the radial bearing, the power switch drive signal of the TSMC and the axial power amplifier is obtained through a certain algorithm, thereby controlling the output and obtaining the current required to maintain the stable suspension of the rotor.

[0045] Among them, the algorithm may include: first, the collected rotor displacement signal is passed through a displacement loop control algorithm (such as PID+filter control, or LQG control, or robust control, etc.) to obtain a reference current of the coil; then, the coil current reference current and the collected coil current signal are passed through a current loop algorithm (generally PID control) to obtain an output voltage reference of the TSMC; finally, the three-phase grid voltage signal and the TSMC output voltage reference signal are passed through a space vector modulation algorithm to obtain a power switch drive signal.

[0046] In the related scheme, a three-phase inverter is used to control the three-pole bearing, and the radial bearing is powered by two inverters, which requires 12 power switches. In the scheme of the present invention, the two radial coils in the TSMC five-bridge-arm inverter stage share one phase common bridge arm, which is a total of 10 power switches, and can reduce 2 power switches. Moreover, in the scheme of the present invention, there is no large capacitor energy storage link on the DC side, which improves the reliability of the magnetic suspension bearing control system.

[0047] Compared with the scheme in which the matrix converter is the main circuit in the related scheme, the scheme of the present invention directly connects the axial power amplifier to the DC link after the TSMC rectifier stage, and no additional DC power supply is required. In addition, in the related scheme, the technology with the matrix converter as the main circuit is composed of 18 bidirectional switches, requiring 36 switch drive control signals. The scheme of the present invention is composed of 6 bidirectional switches and 10 unidirectional switches, requiring 22 switch drive control signals, and the scheme of the present invention can reduce the control cost.

[0048] In some embodiments, the magnetic bearing control system further includes: a clamping unit, such as a clamping circuit.

[0049] Among them, the clamping unit is arranged between the rectifier end and the inverter end of the magnetic bearing control system, and is configured to clamp the direct current output from the rectifier end and then output it to the inverter end and the axial power amplification unit.

[0050] The rectifier end is the rectifier stage or the TSMC rectifier stage. The inverter end is the inverter stage or the TSMC inverter stage.

[0051] Figure 3 FIG. 1 is a schematic diagram of the structure of an embodiment of the main circuit of a magnetic bearing control system, specifically, the main circuit topology structure of a five-degree-of-freedom magnetic bearing control system proposed by the solution of the present invention. Figure 3 As shown, the main circuit of the magnetic bearing control system includes: a three-phase power grid, an LC filter, a rectifier stage (preferably a TSMC rectifier stage), a clamping circuit, a five-bridge arm inverter stage (preferably a TSMC five-bridge arm inverter stage) and an axial power amplifier.

[0052] exist Figure 3 In the example shown, the three-phase grid inputs three-phase AC power, such as the input three-phase AC voltage u a 、u b and u c The LC filter is composed of inductors and capacitors respectively connected to the three-phase lines of the three-phase AC voltage.

[0053] exist Figure 3 In the example shown, the clamping circuit is located in the middle DC link and consists of a diode, a small-capacity electrolytic capacitor and a bleeder resistor to protect the main circuit.

[0054] In some implementations, the TSMC rectifier stage includes: a first rectifier switch module to a sixth rectifier switch module (eg, 6 power switches). Each switch module in the first rectifier switch module to the sixth rectifier switch module includes: a bidirectional power switch and a unidirectional power switch.

[0055] exist Figure 3 In the example shown, the TSMC rectifier stage is composed of 6 power switches, which convert the input three-phase AC power into DC power. In the TSMC rectifier stage, when energy needs to flow in both directions, the 6 power switches are bidirectional switches. If energy is not required to flow from the inverter stage back to the rectifier stage, the 6 power switches are unidirectional switches. The 6 power switches include: switch S ap , switch S bp , switch S cp , switch S an , switch S bn , switch S cn . Six power switches form a rectifier bridge, switch S ap With switch S an Form a bridge arm, switch S bp With switch S bn Form a bridge arm, switch S cp With switch S cn Form a bridge arm. The first phase voltage u a The output end of the inductor is connected to the switch S ap With switch S an The common end of the second phase voltage u b The output end of the inductor is connected to the switch S bp With switch S bn The common end of the third phase voltage u c The output end of the inductor is connected to the switch S cp With switch S cn The public end of the

[0056] In some embodiments, the axial power amplification unit includes: an axial power amplifier. The axial power amplifier includes: a first amplification switch module to a fourth amplification switch module (such as four power switch tubes with anti-parallel diodes). The first amplification switch module to the fourth amplification switch module form two bridge arms. The electromagnetic coil of the axial bearing of the magnetic bearing is arranged between the two bridge arms.

[0057] exist Figure 3In the example shown, the axial power amplifier is composed of 4 power switch tubes with anti-parallel diodes, which are used to convert direct current into alternating current required to control the axial coil. The 4 power switch tubes with anti-parallel diodes are power switch tube S1, power switch tube S2, power switch tube S3 and power switch tube S4. Power switch tube S1 and power switch tube S2 form a bridge arm, and power switch tube S3 and power switch tube S4 form a bridge arm. The electromagnetic coil of the axial bearing is connected between the midpoints of the two bridge arms.

[0058] In some embodiments, the radial bearing includes: a first radial bearing and a second radial bearing. For example, the first radial bearing is radial bearing 1, and the second radial bearing is radial bearing 2.

[0059] The TSMC inverter stage adopts the TSMC five-bridge-arm inverter stage. In the TSMC five-bridge-arm inverter stage, the first radial bearing and the second radial bearing share a common bridge arm.

[0060] Thus, the scheme of the present invention proposes a magnetic bearing control system, such as a three-pole radial magnetic bearing control system based on a two-stage matrix converter, which drives two radial three-pole bearings with a five-phase inverter stage, reduces the number of switch tubes, reduces the control cost, eliminates the intermediate energy storage capacitor, improves the compactness and reliability of the system, and reduces the number of power switches. It has the advantages of no intermediate energy storage link and compact structure. In addition to eliminating the intermediate energy storage capacitor, the two radial coils share a common bridge arm, which can reduce two power switches. Figure 3 In the example shown, the bridge arm C is a common bridge arm. On this basis, the solution of the present invention proposes a control method to improve voltage utilization and obtain better dynamic performance.

[0061] In some embodiments, the TSMC five-bridge-arm inverter stage includes: a first inverter switch module to a tenth inverter switch module (e.g., 10 power switch tubes with anti-parallel diodes). The first inverter switch module to the tenth inverter switch module form five bridge arms, one of which is a common bridge arm. The electromagnetic coil of the first radial bearing and the electromagnetic coil of the second radial bearing are respectively connected to two of the five bridge arms and one common bridge arm.

[0062] exist Figure 3 In the example shown, the five-leg inverter stage, i.e., the TSMC five-leg inverter stage, is composed of 10 power switches with anti-parallel diodes for converting direct current into alternating current required for controlling the radial coil. Ap , power switch tube S Bp , power switch tube S Cp , power switch tube SDp , power switch tube S Ep , power switch tube S An , power switch tube S Bn , power switch tube S Cn , power switch tube S Dn , power switch tube S En . Power switch tube S Ap And power switch tube S An Forming bridge arm A, power switch tube S Bp And power switch tube S Bn Forming the B bridge arm, the power switch tube S Cp And power switch tube S Cn Forming the C bridge arm, the power switch tube S Dp And power switch tube S Dn Forming D bridge arm, power switch tube S Ep And power switch tube S En Forming the E bridge arm. Radial bearing 1 and radial bearing 2 are the front radial bearing and the rear radial bearing, respectively. In order to reduce the number of power devices, one bridge arm (C bridge arm) is used as a common bridge arm to drive the two electromagnetic coils of radial bearing 1 and radial bearing 2 at the same time, that is, five bridge arms (i.e., A bridge arm, B bridge arm, C bridge arm, D bridge arm, and E bridge arm) are used to control the two radial bearings at the same time. The three electromagnetic coils of radial bearing 1 are connected to the midpoints of A bridge arm, B bridge arm, and C bridge arm, respectively. The three electromagnetic coils of radial bearing 2 are connected to the midpoints of C bridge arm, D bridge arm, and E bridge arm, respectively.

[0063] After a large number of tests and verifications, the technical solution of the present invention is adopted, and the rectifier stage in the magnetic bearing control system is replaced by the TSMC rectifier stage in TSMC, which saves the bulky DC bus capacitor and can reduce the occupied space of the magnetic bearing control system. In addition, the TSMC inverter stage in TSMC can be used to replace the inverter stage in the magnetic bearing control system, and the six-way coil is driven by the five-bridge arm inverter stage, which reduces the number of switching devices, further reduces the occupied space of the magnetic bearing control system, and can also save costs. Therefore, by using TSMC as the main circuit of the power amplifier in the magnetic bearing control system, the occupied space of the magnetic bearing control system can be reduced.

[0064] According to an embodiment of the present invention, a magnetic suspension system corresponding to the magnetic bearing control system is also provided. The magnetic suspension system may include: the magnetic bearing control system described above.

[0065] Since the processing and functions implemented by the magnetic levitation system of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned devices, 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.

[0066] A large number of experiments have verified that the technical solution of the present invention uses TSMC as the main circuit of the power amplifier in the three-pole radial magnetic bearing control system, eliminating the need for intermediate DC energy storage elements, reducing the system volume and improving the reliability of the magnetic suspension bearing control system.

[0067] According to an embodiment of the present invention, a control method for a magnetic bearing control system corresponding to a magnetic suspension system is also provided. Figure 6 The control method of the magnetic bearing control system may include: steps S110 to S130.

[0068] In step S110, a grid voltage signal of an AC power supply, a rotor displacement signal of a motor rotor of the magnetic bearing, and current signals of electromagnetic coils of the radial bearing and the axial bearing are collected by a collection unit.

[0069] In step S120, the control instruction of the main circuit is determined by the magnetic bearing controller according to the grid voltage signal, the rotor displacement signal, and the current signal of the electromagnetic coil, so as to control the operation of the main circuit according to the control instruction.

[0070] At step S130, the main circuit operates according to the control instruction to adjust the current signals of the electromagnetic coils of the radial bearing and the axial bearing.

[0071] The magnetic bearing includes a radial bearing and an axial bearing. The magnetic bearing control system includes a collection unit, a main circuit and a magnetic bearing controller. The main circuit is connected to the magnetic bearing controller. TSMC is used in the main circuit.

[0072] Figure 4 FIG. 1 is a flow chart of an embodiment of a control method of a magnetic bearing control system. Figure 4 As shown, a control method of a magnetic bearing control system proposed by the solution of the present invention mainly includes the following steps:

[0073] Step 1: The displacement sensor collects the radial and axial displacement signals of the rotor, and sends them to the bearing controller after being processed by the relevant circuit. After being processed by the relevant algorithm of the displacement loop, the current given signal of each coil is obtained.

[0074] Related circuit processing includes: the signal collected by the displacement sensor is output as a voltage signal, which contains interference signals and is generally sent to the bearing controller for calculation after being processed by limiting and filtering circuits.

[0075] Related algorithm processing includes: the collected rotor displacement signal is passed through a displacement loop control algorithm (such as PID+filter control, or LQG control, or robust control, etc.) to obtain a reference current of the coil.

[0076] Step 2: The current sensor collects the current signals of the electromagnetic coils of radial bearing 1, radial bearing 2 and axial bearing, and sends them to the bearing controller after being processed by relevant circuits. It is compared with the current given signal calculated in the first step, and the output voltage given signal of TSMC five-arm inverter and axial power amplifier is obtained through the relevant algorithm of the current loop.

[0077] The third step: collect the voltage signal of the voltage source, and send it to the bearing controller after processing by relevant circuits, which is used to calculate the TSMC rectifier stage switching signal. Combined with the output voltage given signal in the second step, the switching signal for controlling the TSMC five-arm inverter (i.e., the TSMC five-arm inverter stage) and the axial power amplifier is calculated.

[0078] Step 4: Send the switch signal to each power switch through the drive circuit to control the electromagnetic force of each coil, so as to make the rotor stably suspended.

[0079] The solution of the present invention provides a magnetic bearing control system, such as a control solution applied to a three-pole magnetic bearing, by using TSMC as the main circuit of the power amplifier in the three-pole radial magnetic bearing control system, and driving the six-way coil with a five-bridge-arm inverter stage, the number of switch devices is reduced. In this way, two three-pole radial magnetic bearings are driven by a five-bridge-arm DC-AC stage, the number of power switches is reduced, and the cost is saved. In addition, no intermediate DC energy storage element is required, the system volume is reduced, and the reliability of the magnetic suspension bearing control system is improved.

[0080] In some embodiments, the main circuit includes: a rectifier stage, an inverter stage and an axial power amplification unit, such as an axial power amplifier. The rectifier stage and the inverter stage are sequentially arranged between the output end of the AC power supply and the magnetic bearing controller. The axial power converter takes power from the output end of the rectifier stage and is connected to the magnetic bearing controller. The rectifier stage adopts a TSMC rectifier stage, and / or the inverter stage adopts a TSMC inverter stage. Of course, when in use, the TSMC stage can be used for at least one of the rectifier stage and the inverter stage according to the use requirements. In this way, the solution of the present invention divides the two-stage matrix converter into a rectifier stage and an inverter stage, the rectifier stage converts AC power into DC power, and the inverter stage converts DC power into the electrical energy required for the magnetic bearing. The five-bridge arm inverter stage structure and control method are applicable to structures that can provide DC power to the inverter stage.

[0081] Wherein, in step S130, the magnetic bearing controller determines the control instruction of the main circuit according to the grid voltage signal, the rotor displacement signal, and the current signal of the electromagnetic coil, including:

[0082] When determining the control instruction of the TSMC rectifier stage, the three-phase AC power input by the AC power supply is divided into a set number of intervals. In each interval, there is a phase with the largest absolute value of voltage, and the polarities of the voltages of the other two phases are opposite to the polarities of the voltage with the largest absolute value. In any interval, the TSMC rectifier stage outputs two line voltages with the largest amplitudes in one switching cycle.

[0083] When determining the TSMC inverter stage, the duty cycle signal of the common bridge arm in the TSMC inverter stage is allocated according to the average voltage signal output by the TSMC rectifier stage and the given voltage signal.

[0084] exist Figure 4 In the example shown, in the third step, the calculation method of the switching signals of the TSMC rectifier stage and the TSMC five-bridge inverter stage specifically includes:

[0085] Rectification stage: The input three-phase power is divided into 6 intervals. The division principle is that in each interval, one phase has the largest absolute voltage value, and the other two phases have opposite voltage polarities. In any interval, the TSMC rectification stage outputs two line voltages with the largest amplitude in one switching cycle. Figure 5 FIG. 1 is a schematic diagram of a power switch drive signal under a coordinated configuration of an embodiment of a magnetic bearing control system. Figure 5 As shown, the two output line voltages are u bc and u ba For example, the corresponding vectors are X10 and 01X (where "X" represents that the upper and lower power switches of the bridge arm are turned off at the same time, "0" represents that the upper power switch of the bridge arm is turned off and the lower power switch is turned on. "1" represents that the upper power switch of the bridge arm is turned on and the lower power switch is turned off), then the duty cycle of the line voltage is d bc =-u c / u b , d ba =-u a / u b In one switching cycle, the average voltage output by the rectifier stage is u pn =d bc u bc +d ba u ba The duty cycle signal of each power switch in the rectifier stage can be obtained from the line voltage duty cycle.

[0086] TSMC five-arm inverter stage: Because phase C is a common arm, in order to obtain the maximum voltage utilization, its duty cycle signal needs to be reasonably distributed during control. According to the average voltage of the rectifier stage and the output voltage given signal, the duty cycle signal of each power switch is calculated according to the SVPWM control. Assume that the duty cycle of the upper power switch of the C arm is d Cp1 and d Cp2 The duty cycle of the lower power switch is d Cn1 and d Cn2 , where d Cp1 +d Cn1 ≤1,d Cp2 +d Cn2 ≤1. Take d Cp =max{d Cp1 , d Cp2}, d Cn =max{d Cn1 , d Cn2}. If d Cp +d Cn ≤1, indicating that the bridge arm C can control the two coils simultaneously without affecting each other. Cp +d Cn >1, indicating that bridge arm C can no longer meet the control requirements of the two coils at the same time. In order for the system to work properly, the duty cycle signal needs to be compromised.

[0087] Take η=1 / (d Cp +d Cn ), d Cp and d Cn The duty cycle of the six power switches of the corresponding coils is reduced by η times at the same time, so that the duty cycle signal of each power switch of the inverter stage after compromise processing is obtained. Finally, the rectifier stage and the inverter stage are coordinated and controlled to obtain the final switch action sequence of the inverter stage.

[0088] To further illustrate the proposed modulation strategy, Figure 5 As shown in the figure, assuming that in one switching cycle, after SVPWM calculation, the vectors corresponding to radial bearing 1 are 100 and 101 (where "0" represents that the upper power switch of the bridge arm is turned off and the lower power switch is turned on. "1" represents that the upper power switch of the bridge arm is turned on and the lower power switch is turned off), and the duty cycle is d1, d2. The vectors corresponding to radial bearing 2 are 100 and 110, and the duty cycle is d3, d4, then d Cp1 =d2,d Cp2 =d3+d4,d Cn1 =d1,d Cn2 = 0. Figure 5 As shown, Figure 5 is the output line voltage u of the rectifier stage bc and uba , d2>d3, d Cp1 <d Cp2 , and d Cp2 +d Cn1 >1, the switching sequence and duty cycle after coordinated configuration.

[0089] Thus, the solution of the present invention proposes a main circuit topology of a magnetic bearing control system based on TSMC, which does not require an intermediate energy storage link, can reduce the volume and improve reliability. The electromagnetic coils of the two radial bearings of the TSMC five-bridge-arm inverter stage have a one-phase common bridge arm, which can reduce two power switches compared with the two three-phase inverter drive structures used in the related scheme. Based on the main circuit topology of the magnetic bearing control system based on TSMC, a control method is proposed to achieve maximum voltage utilization by controlling the duty cycle of the common bridge arm C.

[0090] 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 control system, for the details not exhaustive in the description of this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0091] After a large number of experimental verifications, the technical solution of this embodiment is adopted. By using TSMC as the main circuit of the power amplifier in the three-pole radial magnetic bearing control system, the two three-pole radial magnetic bearings are driven by a five-bridge-arm DC-AC stage, and the six-way coils are driven by a five-bridge-arm inverter stage, the number of switching devices is reduced and the cost is saved.

[0092] 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.

[0093] 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 magnetic bearing control system, characterized in that: The magnetic bearing comprises: a radial bearing and an axial bearing; the magnetic bearing control system comprises: a collection unit, a main circuit and a magnetic bearing controller; TSMC is used in the main circuit; in, The acquisition unit is configured to acquire a grid voltage signal of an AC power supply, a rotor displacement signal of a motor rotor of the magnetic bearing, and current signals of electromagnetic coils of the radial bearing and the axial bearing; The magnetic bearing controller is configured to determine a control instruction of the main circuit according to the grid voltage signal, the rotor displacement signal, and the current signal of the electromagnetic coil; The main circuit is configured to operate according to the control instruction to adjust the current signals of the electromagnetic coils of the radial bearing and the axial bearing; The main circuit includes: a rectifier stage, an inverter stage and an axial power amplification unit; the rectifier stage adopts a TSMC rectifier stage, and the inverter stage adopts a TSMC inverter stage; wherein, The TSMC rectifier stage is configured to receive a first alternating current inputted from an alternating current power source and convert the first alternating current into direct current according to the control instruction; The TSMC inverter stage is configured to invert the direct current according to the control instruction to obtain a second alternating current to supply power to the electromagnetic coil of the radial bearing; The axial power amplification unit is configured to use the direct current as a power supply and supply power to the electromagnetic coil of the axial bearing according to the control instruction; The magnetic bearing control system further includes: a clamping unit; the clamping unit is arranged between the rectifier end and the inverter end of the magnetic bearing control system, and is configured to clamp the direct current output from the rectifier end before outputting it to the inverter end and the axial power amplification unit; the rectifier end is the TSMC rectifier stage; the inverter end is the TSMC inverter stage; The radial bearing comprises: a first radial bearing and a second radial bearing; the TSMC inverter stage adopts the TSMC five-bridge-arm inverter stage; in the TSMC five-bridge-arm inverter stage, the first radial bearing and the second radial bearing share a common bridge arm; The rectifier stage in the magnetic bearing control system adopts the TSMC rectifier stage in the TSMC, thereby eliminating the DC bus capacitor; and the inverter stage in the magnetic bearing control system adopts the TSMC inverter stage in the TSMC, thereby reducing the number of switch devices.

2. The magnetic bearing control system according to claim 1, characterized in that: The main circuit further includes: a filtering unit; The filtering unit is disposed between the output end of the AC power source and the TSMC rectification stage, and is configured to obtain the first AC power after filtering the AC power output by the AC power source.

3. The magnetic bearing control system according to claim 1 or 2, characterized in that: The TSMC rectifier stage includes: a first rectifier switch module to a sixth rectifier switch module; each switch module in the first rectifier switch module to the sixth rectifier switch module includes: a bidirectional power switch and a unidirectional power switch.

4. The magnetic bearing control system according to claim 1 or 2, characterized in that: The axial power amplification unit includes: an axial power amplifier; the axial power amplifier includes: a first amplifying switch module to a fourth amplifying switch module; the first amplifying switch module to the fourth amplifying switch module form two bridge arms; the electromagnetic coil of the axial bearing of the magnetic bearing is arranged between the two bridge arms.

5. The magnetic bearing control system according to claim 1, characterized in that: The TSMC five-bridge-arm inverter stage includes: a first inverter switch module to a tenth inverter switch module; the first inverter switch module to the tenth inverter switch module form five bridge arms, one of which is a common bridge arm; the electromagnetic coil of the first radial bearing and the electromagnetic coil of the second radial bearing are respectively connected to two of the five bridge arms and one common bridge arm.

6. A magnetic levitation system, characterized in that: include: A magnetic bearing control system as claimed in any one of claims 1 to 5.

7. A control method for a magnetic bearing control system according to any one of claims 1 to 5, characterized in that: include: The acquisition unit is used to acquire a grid voltage signal of an AC power supply, a rotor displacement signal of a motor rotor of the magnetic bearing, and current signals of electromagnetic coils of the radial bearing and the axial bearing; Determining the control instruction of the main circuit according to the grid voltage signal, the rotor displacement signal, and the current signal of the electromagnetic coil by means of a magnetic bearing controller; The main circuit operates according to the control instruction to adjust the current signals of the electromagnetic coils of the radial bearing and the axial bearing.

8. The control method of the magnetic bearing control system according to claim 7, characterized in that: Determining the control instruction of the main circuit by the magnetic bearing controller according to the grid voltage signal, the rotor displacement signal, and the current signal of the electromagnetic coil includes: When determining the control instruction of the TSMC rectifier stage, the three-phase AC power input by the AC power supply is divided into a set number of intervals; in each interval, there is a phase with the largest absolute value of voltage, and the polarities of the voltages of the other two phases are opposite to the polarities of the voltage with the largest absolute value; in any interval, the TSMC rectifier stage outputs two line voltages with the largest amplitudes in one switching cycle; When determining the TSMC inverter stage, the duty cycle signal of the common bridge arm in the TSMC inverter stage is allocated according to the average voltage signal output by the TSMC rectifier stage and the given voltage signal.

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