A control device, method and maglev system for a power amplifier

Abstract

The present invention discloses a control device, a method and a magnetic levitation system for a power amplifier. The device includes: a control unit, which determines the PWM signal of the power amplifier and outputs the PWM signal; the number of the PWM signals is more than one; a chip selection unit, which multiplexes at least one of the PWM signals among more than one PWM signals to obtain at least two PWM multiplexed signals of the at least one PWM signal, so as to use one PWM multiplexed signal to drive and control a corresponding switching tube of the upper tube or the lower tube through a driving circuit of the corresponding switching tube of the upper tube or the lower tube. By multiplexing the signals of the PWM wave of the MCU, this solution can increase the resources of the PWM wave of the MCU.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic levitation, and particularly relates to a control device, a control method of a power amplifier (such as a power amplifier in a magnetic levitation bearing control system), and a magnetic levitation system, and more particularly to a magnetic levitation controller device, a magnetic levitation system and a control method thereof. Background Art

[0002] In a magnetic levitation bearing control system, by controlling the on-off of the switching tubes of the power amplifier to control the current of the magnetic force coil, the magnitude of the bearing magnetic force is controlled, so that the rotating shaft can maintain stable suspension during high-speed rotation or static suspension. In related solutions, the MCU (micro control unit) used in magnetic levitation products, such as DSP (digital signal processor), has the problem of insufficient resources of PWM waves (pulse width modulation waves, that is, pulse waveforms with variable duty cycles).

[0003] The above content is only used to assist in understanding the technical solution of the present invention, and does not represent an admission that the above content is prior art. Summary of the Invention

[0004] The purpose of the present invention is to provide a control device, a control method of a power amplifier, and a magnetic levitation system to solve the problem of insufficient resources of PWM waves of the MCU used in magnetic levitation products, and achieve the effect of increasing the resources of PWM waves of the MCU by multiplexing the signals of the PWM waves of the MCU.

[0005] In a control device of a power amplifier provided by the present invention, the power amplifier includes: an upper tube and a lower tube; the upper tube includes: more than one switching tube; the lower tube includes: more than one switching tube; the control device of the power amplifier includes: a control unit and a chip selection unit; wherein, the control unit is configured to determine the PWM signal of the power amplifier and output the PWM signal; the number of the PWM signals is more than one; the chip selection unit is configured to multiplex at least one of the more than one PWM signals to obtain at least two PWM multiplexing signals of the at least one PWM signal, so as to use one PWM multiplexing signal to drive and control a corresponding switching tube in the upper tube or the lower tube through a driving circuit of the corresponding switching tube in the upper tube or the lower tube.

[0006] In some embodiments, the chip select unit includes a chip select chip. The chip select unit multiplexes at least one of the PWM signals among one or more paths of the PWM signals, including: the chip select chip is configured to perform chip select separation on at least one of the PWM signals among one or more paths of the PWM signals to obtain at least two PWM multiplexed signals of the at least one PWM signal. Wherein, when multiplexing one PWM signal to obtain two PWM multiplexed signals, the two PWM multiplexed signals include a first PWM multiplexed signal and a second PWM multiplexed signal.

[0007] In some embodiments, it further includes a pull-down unit and a pull-up unit. Wherein, the pull-down unit is disposed between the common terminal between the driving circuit corresponding to the switching transistor in the upper transistor and the chip select unit and the ground, and is configured to enable the lower transistor and its corresponding driving circuit to be in a freewheeling state when not in chip select, the upper transistor corresponding to the lower transistor and its corresponding driving circuit are in an off state, the upper transistor corresponding to the lower transistor and its corresponding driving circuit are in an off state, and the lower transistor corresponding to the upper transistor and its corresponding driving circuit are in a freewheeling state. The pull-up unit is disposed between the common terminal between the driving circuit corresponding to the switching transistor in the lower transistor and the chip select unit and the DC power supply, and is configured to enable the lower transistor and its corresponding driving circuit to be in a freewheeling state when not in chip select, and the upper transistor corresponding to the lower transistor and its corresponding driving circuit are in an off state.

[0008] In some embodiments, the pull-down unit includes a pull-down resistor module. The pull-up unit includes a pull-up resistor module and a switching transistor module. The pull-up resistor module is disposed between the output terminal of the switching transistor module and the common terminal between the driving circuit corresponding to the switching transistor in the lower transistor and the DC power supply, and the input terminal of the switching transistor module is connected to the chip select unit.

[0009] In some embodiments, the power amplifier can be used in a magnetic levitation bearing control system. The control unit determines the PWM signal of the power amplifier, including: when the power amplifier is used in a magnetic levitation bearing control system, obtaining the current signal and displacement signal of the magnetic bearing coil in the magnetic levitation bearing control system; calculating the PWM signal of the power amplifier for controlling the magnetic bearing coil according to the current signal and displacement signal of the magnetic bearing coil. The control unit drives and controls one of the switching transistors in the upper transistor or the lower transistor, including: controlling the turning on or off of the switching transistor in the power amplifier for controlling the magnetic bearing coil according to the PWM multiplexed signal obtained by multiplexing the PWM signal of the power amplifier for controlling the magnetic bearing coil.

[0010] In some embodiments, the control unit controls the turning on or off of the switching tubes in the power amplifier for controlling the magnetic bearing coil according to the PWM multiplexing signal obtained by multiplexing the PWM signal of the power amplifier for controlling the magnetic bearing coil, including: after calculating the PWM signal of the power amplifier for controlling the magnetic bearing coil, counting the clock signal of the PWM signal, and determining whether the clock period of the clock signal obtained by counting is an odd period or an even period; if the clock period of the clock signal obtained by counting is an odd period, controlling the chip select unit to output the PWM multiplexing signal corresponding to the odd power amplifier in the power amplifier to drive the odd power amplifier in the power amplifier to work; if the clock period of the clock signal obtained by counting is an even period, controlling the chip select unit to output the PWM multiplexing signal corresponding to the even power amplifier in the power amplifier, and driving the even power amplifier in the power amplifier to work by the chip select unit.

[0011] Matched with the above device, on the other hand, the present invention provides a magnetic levitation system, including: the control device of the power amplifier described above.

[0012] Matched with the above magnetic levitation system, on the other hand, the present invention provides a control method for a power amplifier. The power amplifier includes: an upper tube and a lower tube; the upper tube includes: more than one switching tube; the lower tube includes: more than one switching tube; the control method of the power amplifier includes: determining the PWM signal of the power amplifier and outputting the PWM signal; the number of the PWM signals is more than one; for at least one of the PWM signals among the more than one PWM signals, performing signal multiplexing to obtain at least two PWM multiplexing signals of the at least one PWM signal, so as to use one PWM multiplexing signal to drive and control a corresponding switching tube in the upper tube or the lower tube through the driving circuit of the corresponding switching tube in the upper tube or the lower tube.

[0013] In some embodiments, determining the PWM signal of the power amplifier includes: when the power amplifier is used in a magnetic levitation bearing control system, acquiring the current signal and displacement signal of the magnetic bearing coil in the magnetic levitation bearing control system; calculating the PWM signal of the power amplifier for controlling the magnetic bearing coil according to the current signal and displacement signal of the magnetic bearing coil; driving and controlling a switching tube in the upper tube or the lower tube includes: controlling the turning on or off of the switching tube in the power amplifier for controlling the magnetic bearing coil according to the PWM multiplexing signal obtained by multiplexing the PWM signal of the power amplifier for controlling the magnetic bearing coil.

[0014] In some embodiments, according to the PWM multiplexing signal obtained by multiplexing the PWM signal of the power amplifier for controlling the magnetic bearing coil through the signal multiplexing, controlling the turning on or off of the switching tube in the power amplifier for controlling the magnetic bearing coil includes: after calculating the PWM signal of the power amplifier for controlling the magnetic bearing coil, counting the clock signal of the PWM signal, and determining whether the clock period of the clock signal obtained by counting is an odd period or an even period; if the clock period of the clock signal obtained by counting is an odd period, controlling the chip select unit to output the PWM multiplexing signal corresponding to the odd power amplifier in the power amplifier to drive the odd power amplifier in the power amplifier to work; if the clock period of the clock signal obtained by counting is an even period, controlling the chip select unit to output the PWM multiplexing signal corresponding to the even power amplifier in the power amplifier, and driving the even power amplifier in the power amplifier to work by the chip select unit.

[0015] Thus, the solution of the present invention realizes the control of two or more power amplifiers by a single PWM wave through the signal multiplexing of the PWM wave of the MCU. Therefore, by multiplexing the signal of the PWM wave of the MCU, the resources of the PWM wave of the MCU can be increased.

[0016] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention.

[0017] The technical solution of the present invention will be further described in detail below through the drawings and embodiments. Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of an embodiment of a bearing in a magnetic bearing control system;

[0019] Figure 2 It is a schematic structural diagram of an embodiment of a radial bearing in a magnetic bearing control system;

[0020] Figure 3 It is a schematic structural diagram of an embodiment of an axial bearing in a magnetic bearing control system;

[0021] Figure 4 It is a schematic structural diagram of an embodiment of a double closed-loop control system in a magnetic bearing control system;

[0022] Figure 5 It is a schematic structural diagram of an embodiment of a control device of a power amplifier of the present invention;

[0023] Figure 6 It is a schematic structural diagram of an embodiment of a PWM multiplexing structure in a magnetic bearing control system;

[0024] Figure 7 It is a schematic structural diagram of an embodiment of the structure of an active power amplifier in a magnetic bearing control system;

[0025] Figure 8 It is a schematic diagram of the output curves of the switching tube, current ripple, and voltage across the coil in a magnetic bearing control system;

[0026] Figure 9 It is a schematic flow diagram of an embodiment of the PWM output IO multiplexing process in a magnetic bearing control system;

[0027] Figure 10 It is a schematic flow diagram of an embodiment of the control method of the power amplifier of the present invention;

[0028] Figure 11 It is a schematic flow diagram of an embodiment of determining the PWM signal of the power amplifier in the method of the present invention;

[0029] Figure 12 It is a schematic flow diagram of an embodiment of controlling the turn-on or turn-off of the switching tube in the power amplifier for controlling the magnetic bearing coil in the method of the present invention. Detailed implementation manners

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] In related solutions, mainstream magnetic bearings all adopt a 5-degree-of-freedom control method. For example, for an active type, 10 electromagnetic coils are required, 2 switching tubes are required for each coil, and a total of 20 PWM waves are required for control.

[0032] In related solutions, the MCU generally does not exceed 20 PWM waves. To achieve 20 or more outputs, only a multi-chip control architecture can be adopted, such as a DSP+FPGA (programmable logic device)+ARM (i.e., a microprocessor of a reduced instruction set computer) architecture, which makes the controller hardware complex, the volume increase, and the software control more complex, resulting in an increase in cost.

[0033] Figure 1 It is a schematic structural diagram of an embodiment of a bearing in a magnetic bearing control system, Figure 2 It is a schematic structural diagram of an embodiment of a radial bearing in a magnetic bearing control system, Figure 3 It is a schematic structural diagram of an embodiment of an axial bearing in a magnetic bearing control system. Such asFigure 1 , Figure 2 and Figure 3 As shown in Figure 1 , Figure 2 and Figure 3 , there is a rotating shaft with five degrees of freedom. Each degree of freedom has 2 coils, and each coil is controlled by a power amplifier composed of two switching tubes. Therefore, 20 channels of PWM are required.

[0034] Figure 4 It is a schematic structural diagram of an embodiment of a double closed-loop control system in a magnetic bearing control system. In the magnetic levitation rotor double closed-loop control system as shown in Figure 4 , the displacement sensor detects the position change, and after a series of processes, it is converted into a PWM signal output by the inner loop. Figure 4 As shown in Figure 4 , in the magnetic levitation rotor double closed-loop control system, the displacement sensor detects the position change, and after a series of processes, it is converted into a PWM signal output by the inner loop.

[0035] When using a multi-chip control architecture, first, it is necessary to match on the hardware (such as matching voltage, impedance, etc.), and then at least achieve clock matching in software. For example: when using a DSP+FPGA architecture, external interface communication protocols are required for communication between MCUs. Both ends of the communication need to be set by software matching. The CPU (Central Processing Unit) also needs to add logic for processing communication content, and communication delay needs to be avoided.

[0036] According to an embodiment of the present invention, a control device for a power amplifier is provided. Refer to Figure 5 the schematic structural diagram of an embodiment of the device of the present invention as shown in Figure 5 . The power amplifier includes: an upper tube and a lower tube. Here, the upper tube and the lower tube are abbreviations for the upper bridge arm diode and the lower bridge arm diode, which are relative to each other. In the subsequent control logic, the upper tube is pulled down and the lower tube is pulled up; actually, it is also possible to pull up the upper tube and pull down the lower tube vice versa. The only difference is that the freewheeling circuit changes from the lower bridge arm circuit 1A2, L1, D1A2 to the upper bridge arm circuit 1A1, L1, D1A1 (as shown in Figure 7 ).

[0037] The upper tube includes: more than one switching tube. The lower tube includes: more than one switching tube. The control device of the power amplifier includes: a control unit (such as an MCU) and a chip select unit (such as a chip select chip). The control unit, the chip select unit, and the power amplifier are connected in sequence.

[0038] Among them, the control unit is configured to determine the PWM signal (such as a PWM wave) of the power amplifier and output the PWM signal. The number of the PWM signals is more than one. The PWM signal is used to generate a drive signal for the switching tube in the power amplifier.

[0039] The chip select unit is configured to multiplex at least one of the PWM signals among more than one path of the PWM signals to obtain at least two PWM multiplexed signals of the at least one PWM signal, so as to use one PWM multiplexed signal to drive and control a corresponding switching transistor in the upper transistor or the lower transistor through a driving circuit of the corresponding switching transistor in the upper transistor or the lower transistor.

[0040] In this way, the solution of the present invention realizes the control of two or more power amplifiers by a single PWM wave by multiplexing the signals of the PWM wave, and solves the problem of insufficient PWM resources of the chip. Moreover, by multiplexing the signals of the PWM wave of the MCU, the problems of too large volume, too high cost and complex control of the controller can also be solved. Specifically, when the solution of the present invention is used in a magnetic levitation system, a high-integration magnetic levitation system power amplifier and control method provided by the solution of the present invention solve the problems of insufficient chip PWM resources, too large volume, too high cost and complex control in the design of the magnetic levitation bearing.

[0041] In some embodiments, the chip select unit includes: a chip select chip.

[0042] The chip select unit multiplexes at least one of the PWM signals among more than one path of the PWM signals, including: the chip select chip is configured to perform chip select separation on at least one of the PWM signals among more than one path of the PWM signals to obtain at least two PWM multiplexed signals of the at least one PWM signal.

[0043] Wherein, in the case of multiplexing one PWM signal to obtain two PWM multiplexed signals, the two PWM multiplexed signals include: a first PWM multiplexed signal and a second PWM multiplexed signal.

[0044] Taking a half-bridge power amplifier as an example below, an exemplary description of the PWM multiplexing chip select circuit is given.

[0045] In the related solution, for 5-degree-of-freedom suspension, 10 magnetic coils, 10 power amplifiers and 20 PWM waves are required. In the solution of the present invention, for 5-degree-of-freedom suspension, 10 magnetic coils, 10 power amplifiers and 10 PWM waves are required.

[0046] Figure 6 It is a schematic structural diagram of an embodiment of the PWM multiplexing structure in the magnetic bearing control system. In Figure 6 In the shown example, a chip select chip is added outside the IO port of the MCU, realizing the control of one path to multiple paths.

[0047] Such as Figure 6As shown, the I / O ports of the MCU output a total of 10 PWM waves, which are divided into two categories, namely type A PWM waves and type B PWM waves. The type A PWM waves control the upper tubes of all power amplifiers, and the type B PWM waves control the lower tubes of all power amplifiers.

[0048] In Figure 6 the example shown, the type A PWM waves are PWM_1A to PWM_nA, such as PWM_1A to PWM_5A. The type B PWM waves are PWM_1B to PWM_nB, such as PWM_1B to PWM_5B. n is a positive integer.

[0049] In Figure 6 the example shown, each PWM is divided into two paths by a chip select chip: PWM_1A is divided into two paths, PWM_1A1 and PWM_1A2, corresponding to switch tube 1A1 and switch tube 1A2 respectively. PWM_nA is divided into two paths, PWM_nA1 and PWM_nA2, corresponding to switch tube nA1 and switch tube nA2 respectively. PWM_1B is divided into two paths, PWM_1B1 and PWM_1B2, corresponding to switch tube 1B1 and switch tube 1B2 respectively. PWM_nB is divided into two paths, PWM_nB1 and PWM_nB2, corresponding to switch tube nB1 and switch tube nB2 respectively. And so on for the rest.

[0050] In this way, the solution of the present invention multiplexes the PWM wave ports, cooperates with the corresponding control logic and hardware circuit to realize single PWM control of two or more power amplifiers, and uses one MCU to realize the functions of two or more MCUs. Thus, by adopting PWM port multiplexing, that is, multiplexing the PWM ports, the problem of insufficient PWM IO resources in the maglev product is solved, so redundant MCUs are omitted, the chip cost is saved, and the hardware design is simplified.

[0051] In some embodiments, it further includes: a pull-down unit and a pull-up unit.

[0052] Among them, the pull-down unit is arranged between the common terminal between the drive circuit corresponding to the switch tube in the upper tube and the chip select unit and the ground, and is configured to enable the lower tube and its corresponding drive circuit to be in a freewheeling state when not in chip select, the upper tube corresponding to the lower tube and its corresponding drive circuit to be in an off state, the upper tube corresponding to the lower tube and its corresponding drive circuit to be in an off state, and the lower tube corresponding to the upper tube and its corresponding drive circuit to be in a freewheeling state. Here, the function of the pull-down unit is to pull the voltage to 0 when there is no input, so when there is no chip select signal input, the voltage is 0, the MOS tube is turned off, and the upper bridge arm is turned off. Freewheeling occurs because the upper bridge arm is turned off and the lower bridge arm is turned on.

[0053] The pull-up unit is arranged between the common terminal between the driving circuit corresponding to the switching tube in the lower tube and the chip select unit and the DC power supply, and is configured to enable the lower tube and its corresponding driving circuit to be in a freewheeling state when not in chip select, and the upper tube corresponding to the lower tube and its corresponding driving circuit to be in an off state. Here, the operating principle of the pull-up unit is that when there is a voltage input to the base of the triode, the triode conducts and the voltage output to the driving circuit is 0; when there is no voltage input, the triode turns off and the voltage output to the driving circuit is approximately 3.3V. Because when not in chip select, there is a voltage output, the lower bridge arm MOS tube conducts, and at the same time the upper bridge arm turns off, and the circuit is in a freewheeling state; when there is a chip select input, the pull-up circuit outputs a PWM signal with an inverse duty cycle (when the MCU outputs a high level, the pull-up circuit outputs a low level, and when the MCU outputs a low level, the pull-up circuit outputs a high level).

[0054] In some embodiments, the pull-down unit includes: a pull-down resistor module, such as a 4.7KΩ pull-down resistor.

[0055] The pull-up unit includes: a pull-up resistor module and a switching tube module. The pull-up resistor module is arranged between the common terminal between the output terminal of the switching tube module and the driving circuit corresponding to the switching tube in the lower tube and the DC power supply, and the input terminal of the switching tube module is connected to the chip select unit. The output terminal of the switching tube module can be the collector of the triode Qn. The input terminal of the switching tube module can be the base of the triode Qn.

[0056] The power amplifier actuator will be described exemplarily below. After chip select, in theory, one PWM can control any bridge arm. In the following embodiments, only one PWM is used to control the upper bridge arm (or only to control the lower bridge arm) for exemplary illustration.

[0057] Figure 7 It is a schematic structural diagram of an embodiment of the active power amplifier structure in the magnetic bearing control system. As Figure 7As shown, in the structure of the active power amplifier in the magnetic bearing control system, after the PWM wave 1A passes through the first chip select chip, the PWM wave 1A1 and the PWM wave 1A2 are output. The PWM wave 1A1 is grounded through a 4.7KΩ pull-down resistor and is also input to the gate of the MOS transistor 1A1 after passing through the first drive circuit. The drain of the MOS transistor 1A1 is connected to the DC power supply +Vin and is also connected to the cathode of the diode D1A1. The source of the MOS transistor 1A1 is connected to the cathode of the diode D1A2, and after passing through the coil L1, it is connected to the anode of the diode D1A1 and the drain of the MOS transistor IA2. The anode of the diode D1A2 is grounded. The source of the MOS transistor IA2 is grounded. The gate of the MOS transistor IA2 is connected to the output terminal of the second drive circuit. The input terminal of the second drive circuit is connected to the collector of the triode Q1. The collector of the triode Q1 is connected to the +3.3V DC power supply through a 4.7KΩ pull-up resistor. The emitter of the triode Q1 is grounded, and the base of the triode Q1 is connected to the first output terminal of the second chip select chip, that is, the output terminal of the PWM wave 1B1. The MOS transistor 1A1, the MOS transistor 1A2, the diode D1A1, and the diode D1A2 constitute the power amplifier U1.

[0058] After the PWM wave 1B passes through the second chip select chip, the PWM wave 1B1 and the PWM wave 1B2 are output. The second output terminal of the second chip select chip outputs the PWM wave 1B2 to the base of the triode Q2. The emitter of the triode Q2 is grounded, and the collector of the triode Q2 is connected to the +3.3V DC power supply through a 4.7KΩ pull-up resistor. The collector of the triode Q2 is connected to the gate of the MOS transistor IB2 after passing through the third drive circuit. The source of the MOS transistor IB2 is grounded. The drain of the MOS transistor IB2 is connected to the anode of the diode D1B1 and is also connected to the source of the MOS transistor 1B1 and the cathode of the diode D1B2 after passing through the coil L2. The anode of the diode D1B2 is grounded. The drain of the MOS transistor 1B1 is connected to the DC power supply +Vin and is also connected to the cathode of the diode D1B1. The PWM wave 1A2 is grounded through a 4.7KΩ pull-down resistor and is also input to the gate of the MOS transistor 1B1 after passing through the fourth drive circuit. The MOS transistor 1B1, the MOS transistor 1B2, the diode D1B1, and the diode D1B2 constitute the power amplifier U2.

[0059] In Figure 7 the example shown, Figure 6 the example shown is applied to the active magnetic suspension bearing. Through the pull-up and pull-down design, the circuit can be in the freewheeling state when not selected.

[0060] As Figure 7 shown, PWM_1A and PWM_1B are a group, which cooperate to control the two power amplifiers U1 and U2. ……, and so on. PWM_5A and PWM_5B are a group, which cooperate to control the two power amplifiers U9 and U10.

[0061] The upper transistor drive of the power amplifier is positive logic. When the chip select chip outputs a high level of the PWM wave, the MOS transistors in the power amplifier are turned on. When the chip select chip outputs a low level of the PWM wave, the MOS transistors in the power amplifier are turned off. When the output of the chip select chip's PWM wave is floating, the MOS transistors in the power amplifier are turned off. Among them, the MOS transistors in the upper transistor of the power amplifier, such as MOS transistor 1A1 and MOS transistor 1B1.

[0062] The lower transistor drive of the power amplifier is reverse logic. When the PWM wave output by the chip select chip is at a high level, the triode Qn (such as triode Q1, triode Q2, etc.) is turned on, and the MOS transistors in the power amplifier are turned off. When the PWM wave output by the chip select chip is at a low level, the triode Qn (such as triode Q1, triode Q2, etc.) is turned off, and the MOS transistors in the power amplifier are turned on. When the output of the chip select chip's PWM wave is floating, the MOS transistors in the power amplifier are turned on. Among them, the MOS transistors in the lower transistor of the power amplifier, such as MOS transistor 1A2 and MOS transistor 1B2.

[0063] In some embodiments, the power amplifier can be used in a magnetic levitation bearing control system.

[0064] The control unit determines the PWM signal of the power amplifier, including:

[0065] Specifically, the control unit is further configured to obtain the current signal and displacement signal of the magnetic bearing coil in the magnetic levitation bearing control system when the power amplifier is used in the magnetic levitation bearing control system.

[0066] Specifically, the control unit is further configured to calculate the PWM signal of the power amplifier for controlling the magnetic bearing coil according to the current signal and displacement signal of the magnetic bearing coil.

[0067] Correspondingly, the control unit controls the driving of one of the switching transistors in the upper transistor or the lower transistor, including: Specifically, the control unit is further configured to control the turning on or off of the switching transistor in the power amplifier for controlling the magnetic bearing coil according to the PWM multiplexing signal obtained by multiplexing the PWM signal of the power amplifier for controlling the magnetic bearing coil.

[0068] In this way, the solution of the present invention proposes a high-integration magnetic levitation power amplifier control method, which separates PWM waves through a chip selection chip to control the positive and negative logic drive circuits, and further realizes the control of multiple power amplifiers by one PWM wave, solving the problems of insufficient chip PWM resources, too large controller volume, too high cost, and complex control in the design of magnetic levitation bearings. Thus, it can be applied to magnetic levitation products and all MCUs, generally solving the problem of insufficient PWM IO resources in related solutions, and can avoid communication delay, that is, avoid the communication delay problem introduced by multi-chip control. Moreover, compared with multi-MCUs, the hardware design is simplified, the logic control is simple, and the software implementation is simple.

[0069] In some embodiments, the control unit controls the on or off of the switching tubes in the power amplifier for controlling the magnetic bearing coil according to the PWM multiplexing signal obtained by multiplexing the PWM signal for controlling the power amplifier of the magnetic bearing coil, including:

[0070] Specifically, the control unit is further configured to count the clock signal of the PWM signal after calculating the PWM signal for controlling the power amplifier of the magnetic bearing coil, and determine whether the clock period of the clock signal obtained by counting is an odd period or an even period.

[0071] Specifically, the control unit is further configured to, if the clock period of the clock signal obtained by counting is an odd period, control the chip selection unit to output the PWM multiplexing signal corresponding to the odd power amplifier in the power amplifier to drive the odd power amplifier in the power amplifier to work.

[0072] Specifically, the control unit is further configured to, if the clock period of the clock signal obtained by counting is an even period, control the chip selection unit to output the PWM multiplexing signal corresponding to the even power amplifier in the power amplifier, and the chip selection unit drives the even power amplifier in the power amplifier to work.

[0073] Figure 8 It is a schematic diagram of the output curves of the switching tubes, current ripple, and voltages at both ends of the coil in the magnetic bearing control system. When the current is stable, the working schematic diagrams of two cycles are as Figure 8 shown:

[0074] In the odd period, the chip selection chip drives the odd power amplifiers to work, such as 1, 3... 9. The odd power amplifiers output an effective duty cycle to ensure the required output current. At this time, the lower tubes of the even power amplifiers are turned on, and freewheeling is carried out through MOS tube 1B2 and diode D1B2 to keep the current stable.

[0075] During even cycles, the chip drives the even-numbered power amplifiers to work, such as 2, 4... 10. The even-numbered power amplifiers output an effective duty cycle to ensure the required output current. At this time, the lower transistors of the odd-numbered power amplifiers are turned on, and freewheeling is performed through MOS transistor 1A2 and diode D1A2 to maintain current stability.

[0076] Among them, the number of cycles is determined by the number of switching transistors controlled by a single PWM. In the exemplary description of the solution of the present invention, a single PWM is used to control two switching transistors, so odd cycles and even cycles are adopted. For example, if a single PWM controls n switching transistors, the MCU needs one cycle to send the PWM wave of one MOS transistor, and n cycles to send n MOS transistors. After the MCU sends a round of PWM, it completes one control of the MOS transistors.

[0077] Figure 9 It is a schematic flowchart of an embodiment of the PWM output IO multiplexing process in the magnetic bearing control system. As Figure 9 shown, the PWM output IO multiplexing process in the magnetic bearing control system includes:

[0078] Step 1: Set the PWM frequency of the MCU. The sensor samples the current and displacement signals and sends them to the MCU.

[0079] Step 2: The MCU calculates the PWM signal to be output, counts the clock signal, and determines whether the clock cycle is the odd-numbered clock cycle.

[0080] Specifically, the MCU subtracts the target current from the feedback of the current sensor, performs a PID operation on the obtained value, calculates a duty cycle to be output, and the MCU outputs the corresponding PWM wave according to this duty cycle. The principle of the PWM generator is: for example, using the up-down counting mode, first increment from 0 to 100, then decrement from 100 to 0. When a 60% duty cycle is required, 40 is output to the MCU. When it is lower than 40, a low level is output, and when it is higher than 40, a high level is output, and a PWM wave with a 60% duty cycle can be obtained.

[0081] If it is the odd-numbered clock cycle, the MCU outputs the control signals of the odd channels (such as PWM_nA1 and PWM_nB1).

[0082] Otherwise, if it is the even-numbered clock cycle, the MCU outputs the control signals of the even channels (such as PWM_nA2 and PWM_nB2).

[0083] Step 3: The chip select chip is set to trigger the switching of the switch state at the rising edge of each clock. In the odd-numbered clock cycles, the chip select chip sends the signal sent by the MCU to the odd channels, and in the even-numbered clock cycles, the chip select chip sends the received signal to the even channels. The output signal acts on the switching tube to control the conduction and cutoff of the switching tube, thereby controlling the current and displacement. The odd-numbered clock cycles achieve the control of the odd coils, and the even-numbered clock cycles achieve the control of the even coils. Two consecutive clock cycles, one odd and one even, achieve the control of the entire magnetic bearing.

[0084] In summary, the solution of the present invention starts from the magnetic levitation power amplifier and takes the characteristic of the small duty cycle of the PWM in the magnetic levitation system. It extends the control period of a single PWM, controls multiple PWMs in one period, and cooperates with the improvement of the hardware circuit. It improves the PWM control logic in terms of method and optimizes the controller architecture design in terms of structure, eliminating the MCU. Moreover, the solution of the present invention is not only applicable to the field of magnetic levitation power amplifiers but also applicable to other fields. It can be understood that when multiple MCUs are performing the same function, this multiplexing method can be implemented for the I / O of one MCU, and other MCUs can be omitted.

[0085] In addition, it should be noted that the solution of the present invention is not only applicable to active magnetic levitation but also applicable to all magnetic levitation bearings and other types of power amplifiers and drive circuits. It is not only applicable to PWM multiplexing but also applicable to the multiplexing of all I / O ports of the MCU.

[0086] Verified by a large number of experiments, adopting the technical solution of the present invention, by multiplexing the signal of the PWM wave of the MCU, a single PWM wave can be used to control two or more power amplifiers. Thus, by multiplexing the signal of the PWM wave of the MCU, the resources of the PWM wave of the MCU can be increased.

[0087] According to an embodiment of the present invention, there is also provided a magnetic levitation system corresponding to a control device of a power amplifier. The magnetic levitation system may include: the control device of the power amplifier described above.

[0088] Since the processing and functions implemented by the magnetic levitation system of this embodiment are basically corresponding to the embodiments, principles, and examples of the foregoing device, the details not described in the description of this embodiment can be referred to the relevant descriptions in the foregoing embodiments and will not be elaborated here.

[0089] Verified by a large number of experiments, adopting the technical solution of the present invention, by multiplexing the signal of the PWM wave of the MCU, a single PWM wave can be used to control two or more power amplifiers. Thus, by adopting PWM port multiplexing, that is, multiplexing the PWM port, the problem of insufficient I / O resources of PWM in magnetic levitation products is solved. Therefore, redundant MCUs are omitted, the chip cost is saved, and the hardware design is simplified.

[0090] According to an embodiment of the present invention, there is also provided a control method for a power amplifier corresponding to a magnetic levitation system, as Figure 10 shown in the flowchart of an embodiment of the method of the present invention. The power amplifier includes: an upper transistor and a lower transistor. The upper transistor includes: more than one switching transistor. The lower transistor includes: more than one switching transistor. The control method of the power amplifier includes: step S110 to step S120.

[0091] At step S110, determine the PWM signal (such as a PWM wave) of the power amplifier and output the PWM signal. The number of the PWM signals is more than one. The PWM signal is used to generate a drive signal for the switching transistor in the power amplifier.

[0092] At step S120, perform signal multiplexing on at least one of the more than one PWM signals to obtain at least two PWM multiplexed signals of the at least one PWM signal, so as to use one PWM multiplexed signal to drive and control a corresponding switching transistor in the upper transistor or the lower transistor through a drive circuit of a corresponding switching transistor in the upper transistor or the lower transistor.

[0093] In this way, the solution of the present invention realizes the control of two or more power amplifiers with a single PWM wave by multiplexing the signals of the PWM wave, and solves the problem of insufficient chip PWM resources. Moreover, by multiplexing the signals of the PWM wave of the MCU, the problems of too large a volume, too high a cost, and complex control of the controller can also be solved. Specifically, when the solution of the present invention is used in a magnetic levitation system, a high-integration magnetic levitation system power amplifier and control method provided by the solution of the present invention solve the problems of insufficient chip PWM resources, too large a volume, too high a cost, and complex control in the design of magnetic levitation bearings.

[0094] In some embodiments, in combination with Figure 11 the flowchart of an embodiment of determining the PWM signal of the power amplifier in the method of the present invention as shown, the specific process of determining the PWM signal of the power amplifier in step S110 is further described, including: step S210 and step S220.

[0095] Step S210, when the power amplifier is used in a magnetic levitation bearing control system, obtain the current signal and displacement signal of the magnetic bearing coil in the magnetic levitation bearing control system.

[0096] Step S220, calculate the PWM signal for controlling the power amplifier of the magnetic bearing coil according to the current signal and displacement signal of the magnetic bearing coil.

[0097] Correspondingly, driving and controlling one of the upper switch or the lower switch in step S120 includes: controlling the turning on or off of the switch in the power amplifier for controlling the magnetic bearing coil according to the PWM multiplexed signal obtained by multiplexing the PWM signal of the power amplifier for controlling the magnetic bearing coil.

[0098] Thus, the solution of the present invention proposes a high-integration magnetic levitation power amplifier control method. By separating the PWM wave through a chip selection chip to control the positive and negative logic drive circuits, one PWM wave can be used to control multiple power amplifiers simultaneously, solving the problems of insufficient chip PWM resources, too large controller volume, too high cost, and complex control in the design of magnetic levitation bearings. Therefore, it can be applied to magnetic levitation products and all MCUs, generally solving the problem of insufficient PWM IO resources in related solutions, and can avoid communication delay, that is, avoid the communication delay problem introduced by multi-chip control. Moreover, compared with multi-MCUs, the hardware design is simplified, the logic control is simple, and the software implementation is simple.

[0099] In some embodiments, for the specific process of controlling the turning on or off of the switch in the power amplifier for controlling the magnetic bearing coil according to the PWM multiplexed signal obtained by multiplexing the PWM signal of the power amplifier for controlling the magnetic bearing coil, refer to the following exemplary description.

[0100] The following combines Figure 12 the schematic flowchart of an embodiment of the method for controlling the turning on or off of the switch in the power amplifier for controlling the magnetic bearing coil in the present invention shown in the figure to further illustrate the specific process of controlling the turning on or off of the switch in the power amplifier for controlling the magnetic bearing coil, including: step S310 to step S330.

[0101] Step S310, after calculating the PWM signal of the power amplifier for controlling the magnetic bearing coil, count the clock signal of the PWM signal and determine whether the clock period of the clock signal obtained by counting is an odd period or an even period.

[0102] Step S320, if the clock period of the clock signal obtained by counting is an odd period, control the chip selection unit to output the PWM multiplexed signal corresponding to the odd power amplifier in the power amplifier to drive the odd power amplifier in the power amplifier to work.

[0103] Step S330, if the clock period of the clock signal obtained by counting is an even period, control the chip selection unit to output the PWM multiplexed signal corresponding to the even power amplifier in the power amplifier, and the chip selection unit drives the even power amplifier in the power amplifier to work.

[0104] Figure 8 It is a schematic diagram of the output curves of the switching tube, current ripple, and voltage across the coil in the magnetic bearing control system. When the current is stable, the schematic diagrams of two cycles of operation are as Figure 8 shown:

[0105] In odd cycles, the chip selects the odd-numbered power amplifiers to drive them to work, such as 1, 3... 9. The odd-numbered power amplifiers output an effective duty cycle to ensure the required output current. At this time, the lower transistors of the even-numbered power amplifiers are turned on, and freewheeling is carried out through MOS transistor 1B2 and diode D1B2 to keep the current stable.

[0106] In even cycles, the chip drives the even-numbered power amplifiers to work, such as 2, 4…10. The even-numbered power amplifiers output an effective duty cycle to ensure the required output current. At this time, the lower transistors of the odd-numbered power amplifiers are turned on, and freewheeling is carried out through MOS transistor 1A2 and diode D1A2 to keep the current stable.

[0107] Figure 9 It is a schematic diagram of the process of an embodiment of the PWM output IO multiplexing process in the magnetic bearing control system. As Figure 9 shown, the PWM output IO multiplexing process in the magnetic bearing control system includes:

[0108] Step 1: Set the PWM frequency of the MCU. The sensor samples the current and displacement signals and sends them to the MCU.

[0109] Step 2: The MCU calculates the PWM signal to be output, counts the clock signal, and determines whether the clock cycle is the odd-numbered clock cycle.

[0110] If it is the odd-numbered clock cycle, the MCU outputs the control signals of the odd channels (such as PWM_nA1 and PWM_nB1).

[0111] Otherwise, if it is the even-numbered clock cycle, the MCU outputs the control signals of the even channels (such as PWM_nA2 and PWM_nB2).

[0112] Step 3: The chip selection chip is set to trigger the switching of the switch state at the rising edge of each clock. In the odd-numbered clock cycle, the chip selection chip sends the signal sent by the MCU to the odd channels. In the even-numbered clock cycle, the chip selection chip sends the received signal to the even channels. The output signal acts on the switching tube to control the on and off of the switching tube, and further controls the current and displacement. The odd-numbered clock cycle realizes the control of the odd coils, and the even-numbered clock cycle realizes the control of the even coils. Two consecutive clock cycles, one odd and one even, realize the control of the entire magnetic bearing.

[0113] In summary, the solution of the present invention starts from the magnetic levitation power amplifier. Taking the characteristics of the magnetic levitation system PWM with a small duty cycle, the control period of the primary PWM is extended, and multiple PWMs are controlled in one cycle. Combined with the improvement of the hardware circuit, the PWM control logic is improved in method, and the controller architecture design is optimized in structure, eliminating the MCU. Moreover, the solution of the present invention is not only applicable to the field of magnetic levitation power amplifiers, but also applicable to other fields. It can be understood that when multiple MCUs are performing the same function, this multiplexing method can be implemented for the IO of one MCU, and other MCUs can be eliminated.

[0114] Since the processing and functions implemented by the method of this embodiment are basically corresponding to the embodiments, principles and examples of the foregoing magnetic levitation system, for the details not described in the description of this embodiment, reference can be made to the relevant descriptions in the foregoing embodiments and will not be elaborated here.

[0115] Through a large number of experimental verifications, by adopting the technical solution of this embodiment, the signal multiplexing of the PWM wave of the MCU is realized, and two or more power amplifiers are controlled by a single PWM wave. Thus, it can be applied to magnetic levitation products and all MCUs. Generally, the problem of insufficient PWM IO resources in the related solutions is solved, and communication delay can be avoided, that is, the communication delay problem introduced by multi-chip control can be avoided. And, compared with multiple MCUs, the hardware design is simplified, the logic control is simple, and the software implementation is simple.

[0116] In summary, it is easy for those skilled in the art to understand that, on the premise of no conflict, the above advantageous ways can be freely combined and superimposed.

[0117] The above are only the embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A control device for a power amplifier, characterized in that, The power amplifier includes: an upper transistor and a lower transistor; the upper transistor includes: more than one switching transistor; the lower transistor includes: more than one switching transistor; the control device of the power amplifier includes: a control unit and a chip selection unit; wherein, the control unit is configured to determine the PWM signals of the power amplifier and output the PWM signals; the number of the PWM signals is more than one; the chip selection unit is configured to multiplex at least one of the PWM signals among more than one PWM signals to obtain at least two PWM multiplexed signals of the at least one PWM signal, so as to use one PWM multiplexed signal to drive and control a corresponding switching transistor in the upper transistor or the lower transistor through a driving circuit of the corresponding switching transistor in the upper transistor or the lower transistor; It further includes: a pull-down unit and a pull-up unit; wherein, the pull-down unit is arranged between the common terminal between the driving circuit corresponding to the switching transistor in the upper transistor and the chip selection unit and the ground, and is configured to enable the lower transistor and its corresponding driving circuit to be in a freewheeling state when not chip-selected, the upper transistor corresponding to the lower transistor and its corresponding driving circuit to be in an off state, the upper transistor corresponding to the lower transistor and its corresponding driving circuit to be in an off state, and the lower transistor corresponding to the upper transistor and its corresponding driving circuit to be in a freewheeling state; the pull-up unit is arranged between the common terminal between the driving circuit corresponding to the switching transistor in the lower transistor and the chip selection unit and the DC power supply, and is configured to enable the lower transistor and its corresponding driving circuit to be in a freewheeling state when not chip-selected, and the upper transistor corresponding to the lower transistor and its corresponding driving circuit to be in an off state.

2. The control device of the power amplifier according to claim 1, wherein The chip selection unit includes: a chip selection chip; The chip selection unit multiplexes at least one of the PWM signals among more than one PWM signals, including: the chip selection chip is configured to perform chip selection separation on at least one of the PWM signals among more than one PWM signals to obtain at least two PWM multiplexed signals of the at least one PWM signal; wherein, in the case of multiplexing one PWM signal to obtain two PWM multiplexed signals, the two PWM multiplexed signals include: a first PWM multiplexed signal and a second PWM multiplexed signal.

3. The control device of the power amplifier according to claim 1, characterized in that, The pull-down unit includes: a pull-down resistor module; The pull-up unit includes: a pull-up resistor module and a switching transistor module; the pull-up resistor module is arranged between the output terminal of the switching transistor module and the common terminal between the driving circuit corresponding to the switching transistor in the lower transistor and the DC power supply, and the input terminal of the switching transistor module is connected to the chip selection unit.

4. The control device of the power amplifier according to claim 1 or 2, characterized in that The power amplifier can be used in a magnetic levitation bearing control system; The control unit determines the PWM signals of the power amplifier, including: in the case that the power amplifier is used in a magnetic levitation bearing control system, acquiring the current signal and displacement signal of the magnetic bearing coil in the magnetic levitation bearing control system; Calculate a PWM signal for a power amplifier that controls the magnetic bearing coil according to the current signal and displacement signal of the magnetic bearing coil; The control unit drives and controls one of the upper switch or the lower switch, including: Controlling the turn-on or turn-off of a switch in the power amplifier that controls the magnetic bearing coil according to a PWM multiplexed signal obtained by multiplexing the PWM signal of the power amplifier that controls the magnetic bearing coil.

5. The control device of the power amplifier according to claim 4, wherein The control unit controls the turn-on or turn-off of a switch in the power amplifier that controls the magnetic bearing coil according to a PWM multiplexed signal obtained by multiplexing the PWM signal of the power amplifier that controls the magnetic bearing coil, including: After calculating the PWM signal for the power amplifier that controls the magnetic bearing coil, count the clock signal of the PWM signal and determine whether the clock period of the clock signal obtained by counting is an odd period or an even period; If the clock period of the clock signal obtained by counting is an odd period, control the chip select unit to output the PWM multiplexed signal corresponding to the odd power amplifier in the power amplifier to drive the odd power amplifier in the power amplifier to work; If the clock period of the clock signal obtained by counting is an even period, control the chip select unit to output the PWM multiplexed signal corresponding to the even power amplifier in the power amplifier, and the chip select unit drives the even power amplifier in the power amplifier to work.

6. A magnetic levitation system, characterized in that, Including: The control device of the power amplifier according to any one of claims 1 to 5.

7. A control method for a power amplifier corresponding to a control device of a power amplifier as described in any one of claims 1 to 5, characterized in that, The power amplifier includes an upper tube and a lower tube; the upper tube includes more than one switch; the lower tube includes more than one switch; the control method of the power amplifier includes: Determine the PWM signal of the power amplifier and output the PWM signal; the number of PWM signals is more than one; For at least one of the PWM signals among the one or more PWM signals, perform signal multiplexing to obtain at least two PWM multiplexed signals of the at least one PWM signal, so as to use one PWM multiplexed signal to drive and control a corresponding switch in the upper tube or the lower tube through a drive circuit of the corresponding switch.

8. The control method of the power amplifier according to claim 7, wherein Wherein, Determining the PWM signal of the power amplifier includes: When the power amplifier is used in a magnetic levitation bearing control system, obtain the current signal and displacement signal of the magnetic bearing coil in the magnetic levitation bearing control system; Calculate a PWM signal for a power amplifier that controls the magnetic bearing coil according to the current signal and displacement signal of the magnetic bearing coil; Driving and controlling one of the upper switch or the lower switch includes: Controlling the turn-on or turn-off of a switch in the power amplifier that controls the magnetic bearing coil according to a PWM multiplexed signal obtained by multiplexing the PWM signal of the power amplifier that controls the magnetic bearing coil.

9. The control method of the power amplifier according to claim 8, characterized in that Controlling the on or off of the switching tube in the power amplifier for controlling the magnetic bearing coil according to the PWM multiplexing signal obtained by multiplexing the PWM signal of the power amplifier for controlling the magnetic bearing coil includes: After calculating the PWM signal of the power amplifier for controlling the magnetic bearing coil, counting the clock signal of the PWM signal, and determining whether the clock period of the clock signal obtained by counting is an odd period or an even period; If the clock period of the clock signal obtained by counting is an odd period, controlling the chip select unit to output the PWM multiplexing signal corresponding to the odd power amplifier in the power amplifier to drive the odd power amplifier in the power amplifier to work; If the clock period of the clock signal obtained by counting is an even period, controlling the chip select unit to output the PWM multiplexing signal corresponding to the even power amplifier in the power amplifier, and driving the even power amplifier in the power amplifier to work by the chip select unit.

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