Magnetic suspension power amplifier digital control device

Abstract

The utility model belongs to the technical field of power control instruments and meters, and discloses a magnetic suspension power amplifier digital control device, which is characterized in that a core controller is connected with an output signal end of a current Hall sensor module, and the current Hall sensor module is connected with a power supply module; the core controller is connected with a matrix keyboard; the core controller is connected with the input end of the optocoupler module; the power amplifier module is provided with a signal input end, a power input end and a control voltage output end, the signal input end is connected with the output end of the optocoupler module, the power input end is connected with a high-voltage switching power supply, and the control voltage output end is connected with a brake resistor; the core controller is also connected with a screen; the output end of the voltage reduction module is connected with the core controller and the current display module. According to the utility model, the generation of PWM is solved through the core controller, the reliability is high, the size is small, the software debugging is convenient, and the like, and various control algorithms are easier to research especially under the condition that a hardware circuit is not changed.

Description

Technical Field

[0001] The utility model belongs to the technical field of power control instruments and meters, and in particular relates to a digital control device for a magnetic suspension power amplifier. Background Art

[0002] In electronic experiments involving power control and power amplifier modules, adjusting electrical variables is a critical step. By adjusting the gain, bandwidth and other parameters of the power amplifier module, the experimental results can be optimized and the system stability and energy efficiency can be improved.

[0003] The digital control device of the magnetic levitation power amplifier is characterized by its ability to simulate the working principle of the magnetic levitation motor, that is, to generate magnetic force by controlling the current of the coil on the stator, thereby suspending the rotor in the center of the stator. The core of this device lies in its digital control system, which can accurately control the magnitude and direction of the coil current, thereby achieving precise control of the magnetic force. In the magnetic levitation motor, the magnetic field interaction between the rotor and the stator generates repulsive or attractive force, allowing the rotor to suspend and rotate in the air. The digital control device of the magnetic levitation power amplifier achieves precise control of the rotor suspension position by simulating this process. This device has broad application prospects in the fields of motor education and teaching, electronics industry, flexible manufacturing, processing and transmission systems. The analog power amplifier has temperature drift and ticket collection problems, which affect the accuracy, and the control algorithm needs to be implemented in hardware circuits, which is not conducive to debugging.

[0004] The Chinese patent application with the publication number CN102013856A, named "An integrated, highly reliable magnetic levitation flywheel digital control device", includes an interface circuit, an FPGA system, a magnetic bearing control power module, a motor control power module, a magnetic levitation flywheel system, and a sensor circuit. The FPGA system obtains data such as the magnetic bearing rotor displacement signal, speed signal, magnetic bearing coil current, and motor winding current through the interface circuit. On the one hand, the FPGA system actively controls the electromagnetic bearing according to the magnetic bearing rotor displacement signal, magnetic bearing coil current, and speed signal; on the other hand, the FPGA system controls the flywheel output torque according to the output torque command, motor winding current, and speed signal. This patent application can realize digital control of the system, but it is large in size and not convenient for experimental debugging. Utility Model Content

[0005] The purpose of the utility model is to provide a digital control device for a magnetic levitation power amplifier, which solves the generation of PWM through a core controller, has high reliability, small size, convenient software debugging, etc., and is particularly easy to study various control algorithms without changing the hardware circuit.

[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0007] A magnetic levitation power amplifier digital control device comprises: a core controller, a current Hall sensor module, an optocoupler module, a current display module, a power amplifier module, a power module and a step-down module; wherein the core controller is connected to the output signal end of the current Hall sensor module, and the current Hall sensor module is connected to the power module; the core controller is connected to a matrix keyboard; the core controller is connected to the input end of the optocoupler module; the power amplifier module has a signal input end, a power input end and a control voltage output end, the signal input end is connected to the output end of the optocoupler module, the power input end is connected to a high-voltage switching power supply, and the control voltage output end is connected to a braking resistor; the core controller is also connected to a screen; the output end of the power module is respectively connected to the step-down module, the current Hall sensor module and the optocoupler module, and the output end of the step-down module is respectively connected to the core controller and the current display module.

[0008] Optionally, the model of the core controller is STM32F103ZET6.

[0009] Optionally, the matrix keyboard has four rows and four columns with a total of sixteen keys.

[0010] Optionally, the voltage of the power module is 15V.

[0011] Optionally, the power module has a power switch.

[0012] Optionally, the voltage of the high-voltage switching power supply is 80V.

[0013] Optionally, the screen is a thin film transistor screen.

[0014] Optionally, the interface type of the screen is a 16-bit parallel port, which is plugged into a 37-pin female header of the core controller via a 37-pin header.

[0015] Optionally, the high-voltage switching power supply has a braking resistor power switch.

[0016] Optionally, the braking resistor is connected to the braking resistor power switch through a base plate.

[0017] Compared with the prior art, the utility model has the following beneficial effects:

[0018] The utility model solves the problem of PWM generation through the core controller, has high reliability, small size, convenient software debugging, etc., and is easier to study various control algorithms without changing the hardware circuit. The digital power amplifier lays the foundation for reducing the size of the magnetic suspension system, and is especially conducive to better integration of the digital power amplifier and the digital control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are for explanation purposes only and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the components in the drawings are only for illustration purposes to help understand the present invention and are not intended to specifically limit the shapes and proportional dimensions of the components of the present invention. In the drawings:

[0020] Figure 1 It is a top view of the digital control device of the magnetic suspension power amplifier of the utility model;

[0021] Figure 2 This is a circuit flow chart of a digital control device for a magnetic levitation power amplifier of the utility model;

[0022] Figure 3 This is a wiring diagram of a digital control device for a magnetic suspension power amplifier of the utility model;

[0023] Figure 4 This is an oblique view of the digital control device for the magnetic suspension power amplifier of the utility model;

[0024] Figure 5 The voltage and current change curves of the digital control device for the magnetic suspension power amplifier of the utility model along with the PID parameters are set;

[0025] Figure 6 It is the image of the set voltage and the PWM duty cycle of the optical coupling output when the proportional gain Kp of the magnetic suspension power amplifier digital control device of the utility model is 2.5 and the set voltage is 0.5V;

[0026] Figure 7 It is the image of the set voltage and the PWM duty cycle of the optical coupling output when the proportional gain Kp of the magnetic suspension power amplifier digital control device of the utility model is 2.5 and the set voltage is 1V;

[0027] Figure 8 It is the image of the set voltage and the PWM duty cycle of the optical coupling output when the proportional gain Kp of the magnetic suspension power amplifier digital control device of the utility model is 2.5 and the set voltage is 2.5V;

[0028] Fig. 9 It is the image of the set voltage and the PWM duty cycle of the optical coupling output when the proportional gain Kp of the magnetic suspension power amplifier digital control device of the utility model is 2.5 and the set voltage is 4V;

[0029] Fig.10 It is the image of the set voltage and the PWM duty cycle of the optical coupling output when the proportional gain Kp of the magnetic suspension power amplifier digital control device of the utility model is 2.6 and the set voltage is 0.5V;

[0030] Fig.11 It is the image of the set voltage and the PWM duty cycle of the optical coupling output when the proportional gain Kp of the magnetic suspension power amplifier digital control device of the utility model is 2.6 and the set voltage is 1V;

[0031] Fig.12 It is the image of the set voltage and the PWM duty cycle of the optical coupling output when the proportional gain Kp of the magnetic suspension power amplifier digital control device of the utility model is 2.6 and the set voltage is 2.5V;

[0032] Fig.13 It is the image of the set voltage and the PWM duty cycle of the optical coupling output when the proportional gain Kp of the magnetic suspension power amplifier digital control device of the utility model is 2.6 and the set voltage is 4V;

[0033] Fig.14 It is the image of the set voltage and the PWM duty cycle of the optical coupling output when the proportional gain Kp of the magnetic suspension power amplifier digital control device of the utility model is 2.7 and the set voltage is 0.5V;

[0034] Fig.15 It is the image of the set voltage and the PWM duty cycle of the optical coupling output when the proportional gain Kp of the magnetic suspension power amplifier digital control device of the utility model is 2.7 and the set voltage is 1V;

[0035] Fig.16 It is the image of the set voltage and the PWM duty cycle of the optical coupling output when the proportional gain Kp of the magnetic suspension power amplifier digital control device of the utility model is 2.7 and the set voltage is 2.5V;

[0036] Fig.17 It is the image of the set voltage and the PWM duty cycle of the optical coupling output when the proportional gain Kp of the magnetic suspension power amplifier digital control device of the utility model is 2.7 and the set voltage is 4V;

[0037] Fig.18 It is the PWM and current simulation waveform image of the digital control device of the magnetic suspension power amplifier of the utility model when the duty cycle is 10%;

[0038] Fig.19 It is the PWM and current simulation waveform image of the digital control device of the magnetic suspension power amplifier of the utility model when the duty cycle is 30%;

[0039] Fig. 20 It is the PWM and current simulation waveform image of the digital control device of the magnetic suspension power amplifier of the utility model when the duty cycle is 60%;

[0040] Fig.21It is the PWM and current simulation waveform image of the digital control device of the magnetic suspension power amplifier of the utility model when the duty cycle is 90%;

[0041] Among them, 1. core controller; 2. current Hall sensor module; 3. matrix keyboard; 4. optocoupler module; 5. braking resistor; 6. current display module; 7. power amplifier module; 8. braking resistor power switch; 9. power switch; 10. low-voltage power switch; 11. power module; 12. step-down module; 13. studs; 14. base plate; 15. screen. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work should fall within the scope of protection of the present invention.

[0043] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only embodiment.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed utility models.

[0045] The utility model is described in detail below in conjunction with the accompanying drawings.

[0046] like Figure 1As shown, a digital control device for a magnetic levitation power amplifier of the utility model comprises: a core controller 1; the core controller 1 is integrated with algorithms for controlling screen display, PWM output, PID regulation, ADC voltage signal acquisition and key adjustment. The pin header led out of the core board of the core controller 1 is connected to the output signal end of the current Hall sensor module 2 with a DuPont line, and the output voltage signal of the current Hall sensor module 2 is collected by the ADC voltage signal acquisition algorithm. The current Hall sensor module 2 converts the current signal in the circuit into a voltage signal and transmits it to the core controller 1. The pin header led out of the core board of the core controller 1 is connected to the input end of the optocoupler module 4 through a DuPont line.

[0047] The PWM signal output by the core controller 1 is amplified and isolated by the optical coupling module to adjust the power amplifier. The control method is:

[0048] The core controller 1 outputs a PWM signal to the optical coupling module 4 for signal isolation.

[0049] The power amplifier module 7 outputs the controlled voltage, causing the brake resistor 5 to generate current, and the current display module 6 displays the current in the circuit in real time.

[0050] The current in the circuit is collected by the current Hall sensor module 2 and converted into a voltage signal. The core controller 1 uses it as a feedback signal and compares it with the set voltage to perform PID adjustment, and then outputs a PWM signal through the core controller 1.

[0051] According to this cycle, when the set voltage minus the voltage converted by the current Hall sensor module 2 is equal to zero, the circuit is in a balanced state. At this time, the core controller 1 outputs a stable PWM signal, and the circuit meets the established requirements.

[0052] Example 1

[0053] In this embodiment, the current Hall sensor module 2 has a Hall sensor, and the input voltage of the current Hall sensor module 2 is ±15V. The input voltage is ±15V, and the input voltage source is a power supply module 11 connected by wires. The input signal is connected in series in the loop through wires, and the output signal is connected to the core controller 1 through a DuPont line. It can timely convert the current signal in the circuit into a voltage signal and transmit it to the single-chip microcomputer. Since the maximum input voltage of the single-chip microcomputer IO port is 3.3V, in order to prevent the single-chip microcomputer from being damaged by excessive voltage, the Hall sensor output voltage signal needs to be divided. However, the Hall sensor used in the utility model is a 10A measurement current corresponding to a 4V output signal. The current adjustment range of the power amplifier of the utility model is 0-5A, so there is no need for voltage division, and you only need to calculate the corresponding relationship and adjust the parameters in the program.

[0054] The matrix keyboard 3 is connected to the core controller 1 through a DuPont line. The first row of the matrix keyboard controls the set voltage. When the first button is pressed, the set voltage increases, when the second button is pressed, the set voltage decreases, when the third button is pressed, the set voltage increases, and when the fourth button is pressed, the set voltage decreases.

[0055] The second line is to adjust the proportional gain Kp. When the first button is pressed, the proportional gain Kp increases, when the second button is pressed, the proportional gain Kp decreases, when the third button is pressed, the proportional gain Kp increases, and when the fourth button is pressed, the proportional gain Kp decreases. The third line is to adjust the integral gain Ki, and the fourth line is the adjustment coefficient Kd, which is the same as the proportional gain Kp. In order to prevent multiple buttons from being pressed at the same time, a key detection code is added to the control algorithm of the matrix keyboard 3, and a limit function is added to the program to prevent data overflow.

[0056] Optionally, the matrix keyboard 3 uses mechanical elastic keys. When the mechanical contacts are disconnected and closed, due to the elastic effect of the mechanical contacts, a key switch will not be immediately and stably connected when closed, nor will it be disconnected all at once when disconnected. Therefore, there is a series of jitters at the moment of closing and disconnecting. In order to avoid this phenomenon, a key de-jitter program is added to the program. Since the matrix keyboard is very small, in order to prevent multiple keys from being pressed at the same time, a key detection code is added to the program.

[0057] Since the core controller 1 does not have a negative value range, when the setting parameter is mistakenly pressed to less than 0, the microcontroller will directly reach the maximum value of the data of the defined type. In order to prevent data overflow, a limiting function is added to the program.

[0058] The optical coupling module 4 has one end connected to the core controller 1 signal and the other end connected to the input end of the power amplifier module 7, so that the optical coupling module can isolate the input from the output and prevent high voltage from entering the signal input end.

[0059] The optocoupler module 4 can isolate the input from the output, prevent high voltage from entering the signal input terminal, and protect the input device. The input terminal of the optocoupler module 4 is connected to the single-chip microcomputer to connect the single-chip microcomputer output PWM signal to the power amplifier module 7 and isolate it from it. Its power supply voltage is 12-48V. The utility model adopts a power supply module 11 to provide it with a 15V power supply, which is connected to the power supply module 11 through a wire.

[0060] Optionally, the braking resistor 5 has a resistance of 5Ω and a power of 200W, consumes the energy in the circuit in the form of heat, and has good performance and is easy to calculate; the braking resistor 5 can consume the energy in the circuit in the form of heat, and the use of a metal shell can improve the heat dissipation efficiency, and has good performance and is easy to calculate. Because the resistor in the utility model needs to pass a large current and high voltage, and will generate high heat, the position needs to be far away from the core controller 1 to prevent the human body from accidentally touching it when adjusting the controller.

[0061] The current display module 6 can collect loop current, and its power supply voltage is +5V, which is connected to the step-down module 12 through a wire. The current signal collected by the current display module 6 can be compared with the current signal displayed on the single-chip screen in real time to verify whether the collected current is correct.

[0062] The power amplifier module 7 has a signal input terminal, a power input terminal and a control voltage output terminal, wherein the signal input terminal is connected to the optical coupling module 4 , the power input terminal is connected to the high-voltage switching power supply, and the control voltage output terminal is connected to the braking resistor 5 .

[0063] The power amplifier module 7 adjusts the voltage at the control voltage output terminal through the input PWM signal, thereby indirectly adjusting the current in the loop. The current in the loop is collected by the current Hall sensor module 2 and transmitted to the single-chip microcomputer to form a control loop.

[0064] The brake resistor power switch 8 is used to turn on and off the high-voltage switch power supply, thereby supplying power to the load or cutting off power.

[0065] The low-voltage power switch 10 is used to turn on and off the power supply to the step-down module 12. The low-voltage power switch 10 is arranged between the step-down module 12 and the low-voltage power supply.

[0066] The power module 11 has an input voltage of 220V and an output voltage of ±15V DC voltage, and can supply power to the step-down module 12 , the current Hall sensor module 2 , and the optocoupler module 4 .

[0067] The step-down module 12 can convert the input 15V DC power into 5V DC power and 3.3V DC power respectively; the 3.3V DC power is used to power the core controller 1 ; and the 5V DC power is used to power the current display module 6 .

[0068] Optionally, the screen 15 is a thin film transistor screen.

[0069] The interface type of the screen 15 is a 16-bit parallel port with a 37-pin pin header, which is plugged into the 37-pin female header of the core controller 1. Various information can be intuitively seen through the screen. The first row is the set voltage, the second row is the current current, the third row is the proportional gain Kp, and the integral gain Ki and Kd are respectively. The set voltage is adjusted through the keyboard, and the current current is collected in real time by the Hall sensor. The effect to be achieved by adjusting the size of the PID proportional gain Kp, the integral gain Ki, and the Kd is that the difference between the set voltage and the current current is zero. The adjusted PID parameters proportional gain Kp, integral gain Ki, and Kd can be displayed on the screen in real time for easy recording, because the load can also be replaced with resistors of other resistance values ​​in addition to the resistor, and can also be made into a resistive-inductive load, etc. The PID parameters of different loads are also different, and by adjusting the PID parameters, an oscilloscope can be used to observe the PWM waveform output by the core controller 1.

[0070] Specifically, the core controller 1 , the current Hall sensor module 2 , the optical coupling module 4 , the braking resistor 5 , the power amplifier module 7 and the buck module 12 are all mounted on the base plate 14 via studs 13 .

[0071] Example 2

[0072] In order to verify the feasibility of the utility model and the reliability of the experimental device, a large number of experiments and simulations were carried out, and the collected data were plotted. The curves of the set voltage and current current changing with the PID parameters are shown in the figure below. Figure 5 shown.

[0073] By observing the above figure, we can verify the regulatory role of PID parameters in the experiment. During the experiment, we can continuously adjust the PID parameters to find the most suitable parameters. From the above figure, we can find that when the proportional gain Kp = 2.6 and the integral gain Ki, Kd = 0, it best meets the requirements. In this case, the set voltage is approximately the same as the current current, so the slope of the curve drawn when the proportional gain Kp = 2.6 is close to 45°.

[0074] Example 3

[0075] The influence of different PID parameters on PWM output duty cycle under the same set voltage is as follows: Figures 6 to 17 As shown;

[0076] according to Figures 6 to 9 When the proportional gain Kp=2.5, the optocoupler output PWM duty cycle is 3.16% when the voltage is set to 0.5V; the optocoupler output PWM duty cycle is 7.16% when the voltage is set to 1V; the optocoupler output PWM duty cycle is 20.15% when the voltage is set to 2.5V; the optocoupler output PWM duty cycle is 32.15% when the voltage is set to 4V.

[0077] according to Figures 10 to 13 When the proportional gain Kp=2.6, when the set voltage is 0.5V, the PWM duty cycle of the optocoupler output is 3.16%; when the set voltage is 1V, the PWM duty cycle of the optocoupler output is 7.15%; when the set voltage is 2.5V, the PWM duty cycle of the optocoupler output is 20.15%; when the set voltage is 4V, the PWM duty cycle of the optocoupler output is 33.15%.

[0078] according to Figures 14 to 17 When the proportional gain Kp=2.7, when the set voltage is 0.5V, the PWM duty cycle of the optocoupler output is 3.16%; when the set voltage is 1V, the PWM duty cycle of the optocoupler output is 8.15%; when the set voltage is 2.5V, the PWM duty cycle of the optocoupler output is 21.15%; when the set voltage is 4V, the PWM duty cycle of the optocoupler output is 34.15%.

[0079] It can be seen that there is a difference in PWM under the same set voltage, which means that the PID parameters affect the output PWM, which in turn affects the power amplifier module 7, and finally causes a deviation in the loop current.

[0080] The above conclusions are verified through experimental analysis: the core controller has a regulating effect in the loop; different PID parameters have different output results; when the proportional gain Kp is 2.6, it is the optimal PID parameter.

[0081] Example 4

[0082] The PWM duty cycle and current simulation waveform of this embodiment are as follows: Figures 18 to 21 As shown, the red line is the PWM waveform, and the cyan line is the current waveform. The grid value is 6V / div. The loop current waveform is recorded under the conditions of PWM duty cycle of 10%, 30%, 60%, and 90%. The formula is:

[0083] Grid value × 6V = maximum current

[0084] Grid value × 6V × PWM duty cycle = current current

[0085] Calculate the current value that should be in the loop when the duty cycle is 10%, 30%, 60%, and 90%. Because this simulation is an open-loop simulation experiment, the control effect of STM32F103ZET6 on the loop can be observed by comparing it with the actual object (digital closed loop).

[0086] Unless otherwise specified, the device elements involved in the above embodiments are all conventional device elements, and the structural settings, working modes or control modes involved are all conventional settings, working modes or control modes in the art unless otherwise specified.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the utility model by ordinary technicians in this field should be included in the scope of the claims of the utility model as long as they do not depart from the spirit and scope of the technical solution of the utility model.

Claims

1. A digital control device for a magnetic levitation power amplifier, characterized in that: include: A core controller (1), a current Hall sensor module (2), an optical coupling module (4), a current display module (6), a power amplifier module (7), a power supply module (11) and a step-down module (12); wherein the core controller (1) is connected to the output signal end of the current Hall sensor module (2), and the current Hall sensor module (2) is connected to the power supply module (11); the core controller (1) is connected to a matrix keyboard (3); the core controller (1) is connected to the input end of the optical coupling module (4); the power amplifier module (7) has a signal input end, a power input end and a control voltage output end, the signal input end is connected to the output end of the optical coupling module (4), the power input end is connected to a high-voltage switching power supply, and the control voltage output end is connected to a braking resistor (5); the core controller (1) is also connected to a screen (15); the output end of the power module (11) is respectively connected to a step-down module (12), a current Hall sensor module (2) and an optical coupling module (4), and the output end of the step-down module (12) is respectively connected to the core controller (1) and a current display module (6).

2. A magnetic levitation power amplifier digital control device according to claim 1, characterized in that: The model of the core controller (1) is STM32F103ZET6.

3. The digital control device for a magnetic levitation power amplifier according to claim 1, characterized in that: The matrix keyboard (3) has four rows and four columns, with a total of sixteen keys.

4. The digital control device for a magnetic levitation power amplifier according to claim 1, characterized in that: The voltage of the power module (11) is 15V.

5. The digital control device for a magnetic levitation power amplifier according to claim 1, characterized in that: The power module (11) has a power switch (9).

6. The digital control device for a magnetic levitation power amplifier according to claim 1, characterized in that: The voltage of the high-voltage switching power supply is 80V.

7. The digital control device for a magnetic levitation power amplifier according to claim 1, characterized in that: The screen (15) is a thin film transistor screen.

8. The digital control device for a magnetic levitation power amplifier according to claim 1, characterized in that: The interface type of the screen (15) is a 16-bit parallel port, which is plugged into the 37-pin female header of the core controller (1) via a 37-pin header.

9. The digital control device for a magnetic levitation power amplifier according to claim 1, characterized in that: The high-voltage switching power supply has a braking resistor power switch (8).

10. A digital control device for a magnetic levitation power amplifier according to claim 9, characterized in that: The braking resistor (5) is connected to the braking resistor power switch (8) via a base plate (14).

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