CN110855188B

CN110855188B - Digital push-down type magnetic suspension device and control method thereof

Info

Publication number: CN110855188B
Application number: CN201911252096.XA
Authority: CN
Inventors: 郝凤琦; 杜明昊; 孟庆生; 赵晓杰; 李成攻; 孟庆龙
Original assignee: Shandong Computer Science Center National Super Computing Center in Jinan
Current assignee: Shandong Computer Science Center National Super Computing Center in Jinan
Priority date: 2019-12-09
Filing date: 2019-12-09
Publication date: 2021-04-06
Anticipated expiration: 2039-12-09
Also published as: CN110855188A

Abstract

A digital push-down magnetic suspension device comprises a magnetic suspension device base and a magnetic floater, wherein the device at least comprises: an electromagnetic coil device unit of a magnetic suspension device base and a magnetic flux acquisition unit of a magnet floater; the electromagnetic coil device unit is an electromagnetic coil driving device which is powered by a single circuit of a magnetic suspension device base and at least comprises an H-bridge circuit built by NMOS (N-channel metal oxide semiconductor) and PMOS (P-channel metal oxide semiconductor) field effect tubes, and an optical coupler isolation is arranged at the grid input end of the field effect tube of the H-bridge circuit; the magnetic flux collection unit includes: the voltage reference circuit comprises a voltage reference chip for providing reference voltage with low ripples for the Hall sensor, a voltage follower, a differential operational amplifier, a voltage division resistor, a filtering processing module and a separate wiring module. The control method of the invention ensures that the magnetic suspension device is more efficient and energy-saving, the suspension is more stable, and the time is longer when the magnetic suspension device runs stably.

Description

Digital push-down type magnetic suspension device and control method thereof

Technical Field

The invention discloses a digital push-down magnetic suspension device and a control method thereof, belonging to the technical field of suspension storage.

Background

With the development of magnetic suspension technology, the application field is increasingly wide. Because of strong scientific and technological sense and visual impact, the magnetic suspension type artistic work and the scientific and technological demonstration device are often applied to the fields of artistic works, scientific and technological demonstration and the like, for example, the magnetic suspension type artistic work and the. The main applications include offices, reception fronts, premium hotels, private homes, jewelry appreciation stores, school science and technology museums, etc.

However, in practical applications, the conventional magnetic levitation device has the following technical problems:

firstly, in the traditional digital push-down magnetic suspension device, low voltage, namely 5V to 24V DC four-wire coil digital push-down magnetic suspension is adopted, a suspended floater is embedded with a permanent magnet, and repulsion is provided by the principle that the opposite poles of the permanent magnets of a base repel each other. The like ends of two opposite electromagnetic coils on the base are connected in series and connected to the driving unit together to form an X axis and a Y axis, the electromagnetic coils are electrified to form electromagnets, the horizontal control floater keeps balance, at the moment, the polarities of the two electromagnetic coils on the same axis are opposite, the two electromagnetic coils are opposite relative to the suspended floater and are shown as one absorption and one repulsion, when the floater deviates from the center, for example, the two electromagnetic coils are deviated to the X negative axis, the coil of the X negative axis shows a repulsion force to the floater, and the X positive axis shows an attraction force to the floater. The traditional magnetic suspension device cannot control one electromagnetic coil independently, is not flexible enough to control, cannot realize a more complex control algorithm, and in addition, because the traditional electromagnetic coils are coaxially connected in series, the voltage at two ends of the single electromagnetic coil is reduced to one half of the total power supply source, so that the control force range of the electromagnetic coil on the magnet floater is reduced.

Secondly, in the conventional digital push-down magnetic suspension device, the magnetic flux change acquisition unit is affected by the problems of disturbance of fluctuation of an external power supply, signal coupling between the hall acquisition device and a controller in front and back, and the like, so that the accuracy and stability of the acquisition unit for acquiring the magnetic flux change quantity of the floater are reduced, and the suspension stability of the system is poor.

Thirdly, the control system algorithm in the traditional digital push-down magnetic suspension device adopts simple single close conversion PID control, cannot run for a long time (one month or more), and has poor anti-interference performance.

Disclosure of Invention

Aiming at the defects of the prior art, the invention discloses a digital push-down type magnetic suspension device.

The invention also discloses a control method of the digital push-down magnetic suspension device.

The technical scheme of the invention is as follows:

aiming at the problems in the prior art, the invention discloses a digital push-down type magnetic suspension device.

The invention also discloses a control method of the device.

The technical scheme of the invention is as follows:

a digital push-down magnetic suspension device is characterized in that the device comprises a magnetic suspension device base and a magnetic floater, wherein the device also at least comprises: an electromagnetic coil device unit of a magnetic suspension device base and a magnetic flux acquisition unit of a magnet floater;

the electromagnetic coil device unit is an electromagnetic coil driving device which is powered by a single circuit of a magnetic suspension device base and at least comprises an H-bridge circuit built by NMOS (N-channel metal oxide semiconductor) and PMOS (P-channel metal oxide semiconductor) field effect tubes, and an optical coupler isolation is arranged at the grid input end of the field effect tube of the H-bridge circuit;

the magnetic flux collection unit includes: the voltage reference circuit comprises a voltage reference chip for providing reference voltage with low ripples for the Hall sensor, a voltage follower, a differential operational amplifier, a voltage division resistor, a filtering processing module and a separate wiring module.

According to a preferred embodiment of the invention, the device further comprises a wireless power supply unit for powering an equivalent peripheral circuit inside the magnetic float. Preferably, the wireless power supply unit is based on the XKT515 chip, and a wireless power supply transmitting terminal in the wireless power supply unit comprises a resonance transmitting circuit formed by the XKT515 chip and a peripheral capacitor and an inductance copper coil thereof, and an NMOS field effect transistor used as a power-off and power-supply switch.

According to the invention, the device also comprises a Bluetooth audio playing unit arranged on the base of the magnetic suspension device.

According to a preferred embodiment of the present invention, the control method of the digital push-down magnetic levitation apparatus is a cascade control method.

According to a preferred embodiment of the present invention, the cascade control method includes:

in a single control period, the main controller outputs a small deviation correction amount relative to the given value of the inner ring, and then the original given value of the sub-controller is superposed to obtain a new value as a new variable which is then used as the given value of the sub-controller.

Specifically, the method comprises the following steps: superposing a deviation correcting value ValueDeviation on a set value Target at the balance position of a magnet floater to obtain a new set value Newtarget; wherein the correction value ValueDeviation is given by the outer loop digital PID incremental type output, and the new setting is the inner loop digital PD position type setting.

According to the invention, the specific method of the cascade control method comprises the following steps:

1) the values obtained by cumulatively counting the duty ratios of the respective electromagnetic coils are referred to as "electric power consumption" as Q1, Q2, Q3 and Q4, where Q1 represents "electric power consumption" of the first electromagnetic coil, Q2 represents "electric power consumption" of the second electromagnetic coil, Q3 represents "electric power consumption" of the third electromagnetic coil, and Q4 represents "electric power consumption" of the fourth electromagnetic coil;

2) when Q1< (Q3 ± e), where e is a dead zone value, indicates that in this time period, the "electric power consumption" of the electromagnetic coil close to the X negative axis is low, the "electric power consumption" of the electromagnetic coil close to the X positive axis is high, and the magnetic floater is biased toward the X positive axis, so that the magnetic floater moves in the X negative axis direction, and finally, Q1 is (Q3 ± e);

when Q2< (Q4 ± e), where e is a dead zone value, it means that in this time period, the "electrical power consumption" of the Y negative axis electromagnetic coil is low, the "electrical power consumption" of the Y positive axis electromagnetic coil is high, and the magnetic floater is biased to the Y positive axis, so that the magnetic floater moves in the Y positive axis direction, and finally Q2 is (Q4 ± e);

according to the above:

(Q1- (Q3 + -e)) <0, the correction value ValueDeviation _ X <0 for the X-axis indicates that the magnetic float is deflected toward the X positive axis, and the magnetic float is moved in the X negative axis direction.

(Q1- (Q3 + -e)) >0, the deviation correction value ValueDeviation _ X >0 for the X-axis indicates that the magnetic float is deflected toward the X negative axis, so that the magnetic float moves in the X positive axis direction.

(Q2- (Q4 + -e)) <0, the correction value ValueDeviation _ Y <0 for the Y-axis indicates that the magnetic float is biased toward the positive Y-axis and is moved in the negative Y-axis direction.

(Q2- (Q4 + -e)) >0, the deviation correction value ValueDeviation _ Y >0 of the Y axis indicates that the magnetic floater deviates to the Y negative axis at the moment, so that the magnetic floater moves along the Y positive axis direction;

3) outer ring digital PID incremental control:

calculating the difference of the 'electric power consumption' of the two electromagnetic coils on the X axis in a certain current time period:

NowPowerError_X＝Power_Q1–(Power_Q3±e)；

power _ Q1 represents the accumulated electric Power consumption value of the first solenoid coil at the end of the current time period;

power _ Q3 represents the accumulated electric Power consumption value of the electromagnetic coil No. three at the end of the current time period;

e represents, dead zone value;

NowPowerError _ X represents the difference between the "power consumption" of the "one" and "three" solenoids at the end of the current time period in the dead band.

Calculating the difference between the "electrical power consumption" of the two solenoids on the X-axis during the last time period:

PrePowerError_X＝PrePower_Q1–(PrePower_Q3±e)；

PrePower _ Q1 represents the accumulated electric power consumption value of the first solenoid coil at the end of the last time period;

PrePower _ Q3 represents the accumulated electric power consumption value of the electromagnetic coil No. three at the end of the last time period;

PrePowerError _ X represents the difference between the 'electric power consumption' of the 'one' solenoid coil and the 'three' solenoid coil under the dead zone at the end of the last time period;

calculate the difference between the "electrical power consumption" of the two solenoids on the X-axis in the last time period:

PrePrePowerError_X＝PrePrePower_Q1–(PrePrePower_Q3±e)；

PrePrePower _ Q1, which represents the accumulated electric power consumption value of the first solenoid coil at the end of the last time period;

PrePrePower _ Q3, representing the accumulated 'electric power consumption' value of the 'three' electromagnetic coil at the end of the last time period;

e represents, dead zone value;

PrePrePowerError _ X, which represents the difference between the 'electric power consumption' of the 'one' electromagnetic coil and the 'three' electromagnetic coil at the end of the last time period in the dead zone;

calculating the deviation correcting value variation quantity ValueDeviation _ X of the X axis through a digital PID incremental algorithm:

ValueDeviation_X＝Kp_X*(NowPowerError_X-PrePowerError_X)+Ki_X*NowP owerError_X+Kd_X*(NowPowerError_X–2*PrePowerError_X+PrePrePowerError_X)；

kp _ X, which represents the proportionality coefficient in the PID outer ring of the X-axis;

ki _ X, which represents the integral coefficient in the PID outer ring of the X axis;

kd _ X, which represents the differential coefficient in the PID outer ring of the X-axis;

NowPowerError _ X, which represents the difference between the electric power consumption of the electromagnetic coils of the number one and the number three on the X axis under the dead zone at the end of the current time period;

PrePowerError _ X, which represents the difference between the "power consumption" of the "one" and "three" electromagnetic coils in the dead zone at the end of the last time period on the X axis. (ii) a

PrePrePowerError _ X, which represents the difference between the 'electric power consumption' of the 'one' electromagnetic coil and the 'three' electromagnetic coil on the X axis under the dead zone at the end of the last time period;

calculating the deviation correcting value variation _ Y of the Y axis by a digital PID incremental algorithm:

ValueDeviation_Y＝Kp_Y*(NowPowerError_Y-PrePowerError_Y)+Ki_Y*NowP owerError_Y+Kd_Y*(NowPowerError_Y–2*PrePowerError_Y+PrePrePowerError_Y)；

kp _ Y, which represents the proportionality coefficient in the PID outer ring of the Y-axis;

ki _ Y, which represents the integral coefficient in the PID outer ring of the Y axis;

kd _ Y, which represents the differential coefficient in the PID outer ring of the Y-axis;

NowPowerError _ Y, which represents the difference between the electric power consumption of the electromagnetic coils with numbers two and four on the Y axis under the dead zone at the end of the current time period;

PrePowerError _ Y, which represents the difference between the electric power consumption of the electromagnetic coils with the numbers of two and four on the Y axis under the dead zone at the end of the last time period;

PrePrePowerError _ Y, which represents the difference between the 'electric power consumption' of the 'second' electromagnetic coil and the 'fourth' electromagnetic coil under the dead zone at the end of the last time period on the Y axis;

after the PID calculation, the deviation correction value output amplitude limit of the X axis is processed as follows:

when the deviation correcting value ValueDeviation _ X of the X axis is smaller than 0, the deviation correcting value ValueDeviation _ X is inverted to be positive, if the deviation correcting value ValueDeviation _ X is larger than the maximum value DeviationMax _ X of the macro definition in the program, the value of the deviation correcting value ValueDeviation _ X is changed to be the value of the macro definition DeviationMax _ X, and finally, the deviation correcting value ValueDeviation _ X is inverted again to restore the deviation correcting value;

when the deviation correcting value ValueDeviation _ X of the X axis is larger than 0, if the deviation correcting value ValueDeviation _ X is larger than the maximum value DeviationMax _ X of the macro definition in the program, the value of the deviation correcting value ValueDeviation _ X is changed into the value of the macro definition DeviationMax _ X;

after the PID calculation, the deviation correction value output amplitude limit of the Y axis is processed as follows:

when the deviation correcting value ValueDeviation _ Y of the Y axis is smaller than 0, the deviation correcting value ValueDeviation _ Y is inverted to be positive, if the deviation correcting value ValueDeviation _ Y is larger than the macro definition maximum value DeviationMax _ Y in the program, the value of the deviation correcting value ValueDeviation _ Y is changed to be the macro definition DeviationMax _ Y, and finally, the deviation correcting value ValueDeviation _ Y is inverted again to restore the self;

indicating that when the deviation correcting value valuevariation _ Y of the Y axis is greater than 0, if the deviation correcting value valuevariation _ Y is greater than the macro definition maximum value deviatonmax _ Y in the program, the value of the deviation correcting value valuevariation _ Y becomes the value of the macro definition deviatonmax _ Y;

4) inner loop digital PD position type control

Taking an output value of the variation of the central position of the magnetic floater of the outer ring as a deviation correction value of the inner ring, wherein the output value contains a positive sign and is then superposed with a set value of the inner ring;

become the new set point:

NewTarget_X＝Target_X+ValueDeviation_X

NewTarget_Y＝Target_Y+ValueDeviation_Y

calculating a new deviation value of this time:

NewError_X＝NowValue_X-Newarget_X；

NewError_Y＝NowValue_Y-NewTarget_Y；

calculating a new last deviation value:

PreNewError_X＝PreValue_X-NewTarget_X；

PreNewError_Y＝PreValue_Y-NewTarget_Y；

digital PD position type control output:

an X axis:

PWM_OUT_X＝InKp_X*NewError_X+InKd_X*(NewError_X-PreNewError_X)

y-axis:

PWM_OUT_Y＝InKp_Y*NewError_Y+InKd_Y*(NewError_Y-PreNewError_Y)

judging the result PWM _ OUT _ X and PWM _ OUT _ Y of PID calculation, if the PWM _ OUT _ X is larger than 0, enabling the electromagnetic force of the electromagnetic coil No. III on the X axis and the repulsive force relative to the magnetic suspension floater to enable the electromagnetic coil No. I on the X axis not to work; if the PWM _ OUT _ X is smaller than 0, the first electromagnetic coil of the X axis has electromagnetic force and has repulsive force relative to the magnetic suspension floater, and the third electromagnetic coil of the X axis does not work; when the PWM _ OUT _ Y is larger than 0, the 'four' electromagnetic coil of the Y axis has electromagnetic force and has repulsive force relative to the magnetic suspension floater, so that the 'two' electromagnetic coil of the Y axis does not work; if the PWM _ OUT _ Y is smaller than 0, the electromagnetic force is exerted on the second electromagnetic coil of the X axis, and the repulsive force is exerted on the magnetic suspension floater, so that the fourth electromagnetic coil of the X axis does not work; then, taking the absolute value of PWM _ OUT _ X and PWM _ OUT _ Y, the controller controls the electromagnetic coil to perform corresponding actions through the driving unit by the two PWM signals.

According to a preferred embodiment of the present invention, the single repulsion method included in the control method includes:

when the magnetic floater deflects to the X axis, a third electromagnetic coil is needed to provide repulsion;

when the magnetic floater deflects to the-X axis, a first electromagnetic coil is needed to provide repulsive force;

when the magnetic floater deflects to the Y axis, a fourth electromagnetic coil is needed to provide repulsive force;

when the magnet float is biased to the-Y axis, a second electromagnetic coil is required to provide the repulsive force.

Technical advantages of the invention

1. The invention uses a new cascade control method, uses the power consumed by the electromagnetic coil as an outer ring measurement feedback value, calculates the deviation correction variable quantity of the more suitable horizontal center position of the magnetic floater through a PID unit, then superposes the deviation correction quantity with the original set value to obtain a new set value, and then measures the position of the magnetic floater at the current moment through a Hall device as an inner ring feedback value. Therefore, under the change of external disturbance, the control method of the invention ensures that the magnetic suspension device is more efficient and energy-saving, the suspension is more stable, and the time for stable operation is longer. When the magnetic floater is arranged in a debugging way, the central set value of the magnetic floater can be roughly found out, and after a period of time, the central set value of the magnetic floater can be automatically adjusted to a proper position by an algorithm.

2. The magnetic suspension device has the functions of wireless power supply and Bluetooth audio playing, and can greatly improve the ornamental value in the field of artware.

3. The electromagnetic coil in the magnetic suspension device has single-path driving capability, the MCU with low cost is used, the driving control mode is flexible and variable, the driving capability is strong, and the driving mode of the electromagnetic coil can be defined by using a software program, so that the electromagnetic coil can be quickly, simply and conveniently changed into different driving control modes, more software algorithms are changed, hardware does not need to be replaced in later upgrading, and only a software defined driving scheme needs to be changed, thereby shortening the development period.

Drawings

FIG. 1 is a technical schematic diagram of a magnetic levitation apparatus base according to the present invention;

in fig. 1, the arabic numeral circle represents a permanent magnet, the chinese character circle represents an electromagnetic coil, and the two transverse lines h1, h2 are two identical hall sensors.

FIG. 2 is an H-bridge drive circuit for a solenoid of the present invention;

FIG. 3 is an H-bridge drive circuit for four solenoids;

FIG. 4 is a schematic circuit diagram of a magnetic flux collection unit;

FIG. 5 is a block diagram of a wireless power transmitting, receiving, motherboard signal control unit;

fig. 6 is a block diagram of a bluetooth audio playback unit.

Detailed Description

The following detailed description is made with reference to the embodiments and the accompanying drawings, but not limited thereto.

Examples 1,

the technical advantages of the design here are: the invention abandons the simple coaxial series connection mode of the traditional coil, designs the electromagnetic coil driving device of the suspension system base into single-path power supply, thereby improving the voltage at two ends of the original coil by 2 times; the single-path drive uses NMOS and PMOS field effect transistors with low cost to build an H-bridge circuit, uses a Schottky freewheeling diode with large redundancy, and enhances the capability of releasing back electromotive force when a coil is turned off and turned on at high frequency, thereby prolonging the service life of circuit elements; in addition, an optical coupler isolation is designed at the grid input end of the field effect transistor of the H bridge, so that the electric isolation between the MCU and the driving device is realized, and the IO port of the controller is prevented from being punctured by reverse voltage when the driving device is interfered by electromagnetism; because two electromagnetic coils are not simply connected in series any more, each electromagnetic coil can be controlled independently, the control is more flexible at the moment, the electromagnetic coils can be expressed in three modes of 'one absorption and one repulsion', 'single absorption' and 'single repulsion', and different driving modes can be defined and switched in a software program.

The term "one-to-one attraction/repulsion" refers to that two electromagnetic coils on the same shaft are opposite to the magnetic floater in the same control period, wherein one electromagnetic coil represents attraction force (attraction force) to the magnetic floater, and the other electromagnetic coil represents repulsion force to the magnetic floater.

The term "single repulsion" means that, in the same control period, two electromagnetic coils on the same shaft are opposite to the magnetic floater, only one electromagnetic coil represents electromagnetic force, and the opposite magnetic floater represents repulsion force.

The "single attraction" means that two electromagnetic coils on the same shaft are opposite to the magnetic floater in the same control period, only one electromagnetic coil represents electromagnetic force, and the attraction force (attraction force) is represented opposite to the magnetic floater.

When the position of the magnetic floater changes, the linear Hall sensor device of the base can effectively detect the change of the magnetic field, so that the position of the magnetic floater is determined. The stability and accuracy of the output value of the Hall device are crucial to the whole magnetic suspension device, therefore, the invention also designs a magnetic flux collecting unit:

the magnetic flux collection unit includes: the voltage reference chip is used for providing reference voltage with low ripples for the Hall sensor, and comprises a voltage follower, a differential operational amplifier, a voltage division resistor, a filtering processing module and a separation wiring module;

the technical advantages of the design here are: the accuracy and the stability of collecting the float magnetic flux variation quantity by the Hall sensor in the magnetic suspension device are improved in the following mode, and the method specifically comprises the following steps:

(1) the voltage reference chip is used for providing reference voltage with low ripples for the Hall sensor, so that the influence of power supply fluctuation on the Hall sensor is reduced;

(2) the voltage follower with high input impedance and low output impedance is used, the isolation Hall device is coupled with the front circuit and the rear circuit of the acquisition amplifying unit, and then the output value of the voltage follower is amplified through the differential operational amplifier, so that the sensitivity of the Hall device is indirectly improved;

(3) and dividing the amplified voltage value of the Hall sensor through a precision resistor, so that the highest output voltage value is less than or equal to the logic high level of 3.3V of the controller. Then the voltage follower with low output impedance is connected to an AD peripheral IO port of the controller, so that high impedance influence caused by front end resistor voltage division is eliminated, and the AD sampling precision of the controller is improved;

(4) filtering the amplified Hall signal by using a hardware RC filtering algorithm and a software sliding filtering algorithm;

(5) the analog ground of the Hall device and the analog ground of the control chip are digitally separated from the system and are finally connected with the analog ground through a 0 ohm resistor at the entrance of the digital power supply general ground.

The device also comprises a wireless power supply unit for supplying power to the equivalent peripheral circuit in the magnetic floater. Preferably, the wireless power supply unit is based on the XKT515 chip, and a wireless power supply transmitting terminal in the wireless power supply unit comprises a resonance transmitting circuit formed by the XKT515 chip and a peripheral capacitor and an inductance copper coil thereof, and an NMOS field effect transistor used as a power-off and power-supply switch. The wireless power supply unit in the base generates an alternating magnetic field, the receiving end inductor copper coil is coupled in the magnetic field to generate electric potential, and then rectification and filtering are carried out, so that non-contact physical power supply for the equivalent peripheral circuit control board is realized.

The magnetic suspension device has the advantages that the magnetic suspension device is suitable for being used in a plurality of fields such as art and craft appreciation. In order to improve the appreciation of the magnetic levitation handicrafts, the levitated handicrafts usually require light conversion or other circuits. The invention sticks the equivalent peripheral circuit control board on the front of the magnet floater, then embeds the magnet floater and the equivalent peripheral circuit control board into the handicraft, or directly supports the handicraft at the bottom without embedding the magnet floater and the equivalent peripheral circuit control board into the handicraft. The magnetic floater and the equivalent peripheral circuit control board are suspended in the air, and non-contact physical power supply is needed to provide energy for the magnetic floater and the equivalent peripheral circuit control board, so that the magnetic floater and the equivalent peripheral circuit control board are designed and drawn with a PCB (printed Circuit Board) at a receiving end, namely the end of the magnetic floater and the equivalent peripheral circuit control board, mainly using an inductance copper coil and a chip capacitor to form an LC (inductance-capacitance) resonance receiving circuit, then converting alternating voltage into pulsating direct current through bridge rectification, finally converting the pulsating direct current into direct current through capacitor filtering, and using an LDO (low dropout regulator) chip to stabilize the voltage so as to provide a direct current power supply for. The inductance copper coil is drawn on the PCB only through two wiring terminals, and other parts are separated from the PCB without physical connection, so that the coil is convenient to mount according to actual conditions. The transmitting end of the wireless power supply unit is positioned in the base of the magnetic suspension device, and the weight problem does not need to be considered, so that the PCB of the wireless power supply transmitting end is additionally designed, the wireless power supply transmitting end is not integrated with the PCB control board of the base, the wireless power supply transmitting end and the PCB control board of the base are connected through the contact pin, the wireless power supply transmitting end and the base can be conveniently plugged and unplugged, and the main PCB control board of the base can enable the PCB control board of the wireless power supply transmitting end to be in a power-off and power-supply state through a high-level signal and a low-level signal, so.

The device also comprises a Bluetooth audio playing unit arranged on the magnetic suspension device base.

The technical advantage of the design is that the Bluetooth music playing circuit is designed in the base of the magnetic suspension device, and the loudspeaker is arranged in one side of the base. This bluetooth music broadcast circuit and base PCB circuit board are integrated integrative, receive equipment audio information such as cell-phone through bluetooth low energy chip on the circuit board, through the analytic processing back of bluetooth chip, carry out the difference wiring with audio signal, reach and give power amplifier chip input pin, and then play the music through power amplifier chip drive speaker. Except that the Bluetooth music playing circuit can be connected with devices such as a mobile phone, the Bluetooth music playing circuit can identify the audio frequency of the TF card, play the audio frequency in sequence, play the audio frequency in the video and the like. The power supply part of the Bluetooth audio playing unit comprises a DC-DC power supply voltage stabilizing chip which can input wide voltage and output low ripple waves and a solid-state capacitor with low ESR. Therefore, when the DC12V or the DC24 is supplied with power, the positive voltage conversion efficiency can be kept above 85%.

The control method of the digital push-down magnetic suspension device is characterized in that the control method is a cascade control method.

The cascade control is explained as follows: compared with a simple single-loop control system, cascade control forms two closed loops on the structure, wherein one closed loop is positioned inside and is called an inner loop (inner loop) or a secondary loop; the other closed loop is outside and is called the outer loop (outer loop) or main loop. The controllers in the inner ring are referred to as secondary controllers and the controllers in the outer ring are referred to as primary controllers. The inner loop is in charge of coarse adjustment in the control process, the outer loop is in charge of fine adjustment, cascade control is that the control effect which is difficult to achieve by a common single-loop control system is achieved through the matching control of the two loops, the control quality of the system is improved, and the system has certain self-adaptive capacity. The main controller has its own independent set value, the output of which is used as the set value of the sub-controller, and the output signal of the sub-controller is sent to the control mechanism to control the production process.

Examples 2,

The cascade control method of the apparatus according to embodiment 1 includes:

The technical advantages of this design are: an optimized deformation is carried out on a place in the definition of the cascade control principle, namely, in a control period, the output of the main controller has a small deviation correction quantity relative to the given value of the inner ring, then the original given value of the secondary controller is superposed to obtain a new value, and the new variable value is used as the given value of the secondary controller. In the invention, the outer ring is fed back according to 'electric power consumption' of two coaxial electromagnetic coils, the outer ring calculates once every several minutes or tens of minutes and controls the output deviation correction amount, the inner ring controls the driving unit in a negative feedback manner every tens of milliseconds, if the output correction amount of the outer loop is directly given as the inner loop, this would result in the given value being much smaller than the feedback value of the inner loop, in addition, in the first few minutes after the system is powered on and initialized, the output deviation correction quantity of the outer ring is always 0, only the inner ring can be used for rough adjustment in the period, therefore, a given value of the two hall sensors when the magnetic floater is in the horizontal center of the magnetic field must be given in advance, since errors can be caused by hall sensors, AD acquisition, power supply fluctuations, etc., this given value is in error from the theoretically true value.

In the cascade stage, the outer ring carries out negative feedback output deviation correction quantity through 'electric power consumption' of the coaxial electromagnetic coil, and the preset given value of the original inner ring is corrected to approach the real theoretical value. In addition, when the system works for a long time (one day or more), or in different seasons of summer and winter, the internal Hall magnetic flux collecting unit can generate temperature drift, and the obtained Hall feedback value of the inner ring can change at the moment, so that the deviation between the feedback value and the given value changes, the PD calculation result changes, and further the electromagnetic coil executes action to cause the instability of the system.

The specific method of the cascade control method comprises the following steps:

1) when the magnet floater is closer to the balance point, the duty ratio signal of the driving electromagnetic coil is smaller, so that the power consumption of the electromagnetic coil is lower, and the coaxial electromagnetic coil only works in one driving control period, so that the duty ratio of each electromagnetic coil is accumulated and counted at regular intervals, and the 'electric power consumption' of the coaxial electromagnetic coil can be calculated. The invention notices that the actual power consumption of the electromagnetic coil and the accumulated and counted duty ratio of each electromagnetic coil are not equal in value, but are approximately in direct proportion, and has no influence on the following algorithm, therefore, the invention makes technical improvement: the values obtained by cumulatively counting the duty ratios of the respective electromagnetic coils are referred to as "electric power consumption" as Q1, Q2, Q3 and Q4, where Q1 represents "electric power consumption" of the first electromagnetic coil, Q2 represents "electric power consumption" of the second electromagnetic coil, Q3 represents "electric power consumption" of the third electromagnetic coil, and Q4 represents "electric power consumption" of the fourth electromagnetic coil;

according to the above:

as above, the larger the absolute value of the difference between the "electrical power consumption" of the two coaxial electromagnetic coils, the larger the absolute value of the deviation correction value;

3) outer ring digital PID incremental control:

wherein, the time period can be set to 5 minutes in the initial debugging, and needs to be set to 10 minutes, 30 minutes and the like according to the actual situation of the field stability;

NowPowerError_X＝Power_Q1–(Power_Q3±e)；

e represents, dead zone value;

PrePowerError_X＝PrePower_Q1–(PrePower_Q3±e)；

PrePrePowerError_X＝PrePrePower_Q1–(PrePrePower_Q3±e)；

e represents, dead zone value;

and when the program finishes the last step after a control period, assigning and storing the variable (physical quantity) with the Now prefix to the variable with the prefix before. And then, when the next period is nearly finished, the last variable reassignment is stored to the last variable with the PrePrePreprefix, and the variable with the Now Now prefix is reassigned to the last variable with the PrePreprefix. One control cycle is about 10Ms-20Ms, and the control cycle is repeated;

ValueDeviation_Y＝Kp_Y*(NowPowerError_Y-PrePowerError_Y)+Ki_Y*NowP owerError_Y+Kd_Y*(NowPowerError_Y–

2*PrePowerError_Y+PrePrePowerError_Y)；

if(ValueDeviation_X<0){

ValueDeviation_X＝-ValueDeviation_X；

if(ValueDeviation_X>DeviationMax_X){

ValueDeviation_X＝DeviationMax_X；}

ValueDeviation_X＝-ValueDeviation_X；}

the above procedure shows that when the deviation correction value ValueDeviation _ X of the X-axis is less than 0, the deviation correction value

ValueDeviation _ X itself is inverted to positive if it is larger than the macro definition maximum in the program

If DeviationMax _ X is large, the value of the deviation correction value ValueDeviation _ X is changed to the macro definition

The value of Devalion Max _ X, which is finally inverted to restore itself again;

else if(ValueDeviation_X>0){if(ValueDeviation_X>DeviationMax_X)；ValueDeviation_X＝DeviationMax_X；}

the above-mentioned procedure shows that when the deviation correcting value valuevariation _ X of the X-axis is greater than 0, if the deviation correcting value valuevariation _ X is greater than the macro definition maximum value deviatonmax _ X in the procedure, the value of the deviation correcting value valuevariation _ X becomes the value of the macro definition deviatonmax _ X;

else ValueDeviation_X＝0；

if(ValueDeviation_Y<0){

ValueDeviation_Y＝-ValueDeviation_Y；

if(ValueDeviation_Y>DeviationMax_Y){

ValueDeviation_Y＝DeviationMax_Y；}

ValueDeviation_Y＝-ValueDeviation_Y；}

the above procedure shows that when the deviation correction value ValueDeviation _ Y of the Y-axis is less than 0, the deviation correction value

ValueDeviation _ Y is inverted to positive if compared with the macro definition maximum in the program

If DeviationMax _ Y is large, the value of the deviation correction value ValueDeviation _ Y becomes the macro definition

The value of Devalion Max _ Y, which is finally inverted again to restore itself;

else if(ValueDeviation_Y>0){if(ValueDeviation_Y>DeviationMax_Y)；

ValueDeviation_Y＝DeviationMax_Y；}

the above procedure shows that when the correction value ValueDeviation _ Y of the Y-axis is greater than 0, if the correction value is greater than 0

If the value development _ Y is larger than the maximum value development max _ Y defined by the macro in the program, the deviation correction value is larger

The value of ValueDeviation _ Y becomes the value of macro definition DeviationMax _ Y;

else ValueDeviation_Y＝0；

4) inner loop digital PD position type control

Taking an output value of the variation of the central position of the magnetic floater of the outer ring as a deviation correction value of the inner ring, wherein the output value contains a positive sign and is then superposed with a set value of the inner ring; the setting steps of the inner ring are as follows: the magnetic floater is placed at the center balance position of a permanent magnetic field in the base by the aid of the force of an assistant, the voltage values of the Hall sensor h1 and the Hall sensor h2 at the moment are read by an AD (analog-digital) peripheral of the controller, and after sliding filtering, the two voltage values are respectively marked as global variables Target _ X and Target _ Y in a program, namely, the global variables are represented as the center positions in the horizontal plane of the magnetic floater, and the Target _ X and the Target _ Y are respectively set values of an X axis and a Y axis of an inner ring.

Become the new set point:

NewTarget_X＝Target_X+ValueDeviation_X

NewTarget_Y＝Target_Y+ValueDeviation_Y

calculating a new deviation value of this time:

NewError_X＝NowValue_X-Newarget_X；

NewError_Y＝NowValue_Y-NewTarget_Y；

the NowValue _ X and NowValue _ Y are obtained in such a way that in the magnetic flux acquisition stage of a control period, the voltage values of the Hall sensor h1 and the Hall sensor h2 at the moment are read out by the AD external of the controller for a plurality of times, and are respectively marked as global variables NowValue _ X and NowValue _ Y in a program after being processed by a sliding filter program;

calculating a new last deviation value:

PreNewError_X＝PreValue_X-NewTarget_X；

PreNewError_Y＝PreValue_Y-NewTarget_Y；

digital PD position type control output:

an X axis:

PWM_OUT_X＝InKp_X*NewError_X+InKd_X*(NewError_X-PreNewError_X)

y-axis:

PWM_OUT_Y＝InKp_Y*NewError_Y+InKd_Y*(NewError_Y-PreNewError_Y)

The above physical variables have the following meanings:

target _ X, represents the X-axis set value of the inner ring. The magnetic floater is placed at the center balance position of a permanent magnetic field in the base by the aid of the force of an assistant, the voltage value of the Hall sensor h1 at the moment is read through the AD external equipment of the controller, and after sliding filtering, the voltage value is marked as a global variable Target _ X in a program, namely the central position in the horizontal plane of the magnetic floater, and the Target _ X is a set value of the X axis of the inner ring.

Value development _ X, which represents the correction value of the output X-axis direction of the outer loop.

And the NewTarget _ X represents a new set value obtained by superposing the X-axis set value of the inner ring and the output X-axis deviation correction value of the outer ring.

NowValue _ X, which represents the voltage of the Hall sensor h1 obtained by the current controller through the AD peripheral reading magnetic flux unit and the software filtering processing

NewError _ X, which represents the current magnet float deviation from the origin in the X-axis direction.

And PreValue _ X, which represents the voltage value of the Hall sensor h1 obtained by the controller through the AD peripheral equipment reading magnetic flux unit and software filtering processing in the last control cycle acquisition stage.

PreNewError _ X, which represents the deviation of the magnet float from the origin in the X-axis direction for the last control cycle.

And InKp _ X represents a proportionality coefficient in the X-axis direction of the inner ring.

InKd _ X represents a differential coefficient in the X-axis direction of the inner ring.

Target _ Y, represents the Y-axis set value of the inner loop. Indicating the Y-axis setting of the inner ring. The magnetic floater is placed at the center balance position of a permanent magnetic field in the base by the aid of the force of an assistant, the voltage value of the Hall sensor h2 at the moment is read through the AD external equipment of the controller, and after sliding filtering, the voltage value is recorded as a global variable Target _ Y in a program, namely the central position in the horizontal plane of the magnetic floater, and the Target _ Y is a set value of the Y axis of the inner ring.

Value development _ Y, which represents the correction value in the output Y-axis direction of the outer loop.

And NewTarget _ Y, which represents a new set value obtained by superposing the Y-axis set value of the inner ring and the output X-axis deviation correction value of the outer ring.

NowValue _ Y, which represents the voltage value of the Hall sensor h2 obtained by the current controller through the AD peripheral reading magnetic flux unit and the software filtering processing.

NewError _ Y, which represents the current magnet float deviation from the origin in the Y-axis direction.

And PreValue _ Y, which represents the voltage value of the Hall sensor h2 obtained by the controller through the AD peripheral equipment reading magnetic flux unit and software filtering processing in the last control cycle acquisition stage.

PreNewError _ Y, which represents the deviation of the magnet float in the Y-axis direction from the origin in the last control cycle.

And InKp _ Y represents a proportionality coefficient in the Y-axis direction of the inner ring.

InKd _ Y represents a differential coefficient in the Y-axis direction of the inner ring.

The suspended magnetic floater is positioned 1 cm to 5 cm above the center of the figure;

when the magnet floater moves in a small range in a horizontal plane at the center of the figure (the range which can be collected by the AD peripheral equipment of the controller in the base), the magnetic field of the magnet floater also changes, the output voltage value changes of the h1 Hall sensor and the h2 Hall sensor correspond to the magnetic flux change of the magnet floater, and the magnetic flux change of the magnet floater and the output voltage value of the Hall sensor are in a linear relation in a certain range (the range which can be collected by the AD peripheral equipment of the controller in the base when the magnet floater floats);

the value of the h1 output voltage decreases as the magnetic float is deflected toward the-X axis, and then the value of the h1 output voltage increases as the magnetic float is deflected toward the X axis. The h2 output voltage value decreased when the magnetic float was biased toward-Y, and the h2 voltage value increased when the magnetic float was biased toward the Y axis.

According to the principle that the electromagnetic coil becomes an electromagnet when electrified, and the N \ S poles of the electromagnetic coil are different if the current flows in different directions, the invention uses the scheme that only one coaxial coil works in each control period and is expressed as repulsion, namely 'single repulsion'.

The single repulsion method included in the control method includes: the microcontroller outputs PWM signals to the driving unit, and the driving unit controls the on and off states of the DC main power supply and the electromagnetic coil; when the duty ratio is larger, the conducting time of the electromagnetic coil and the direct current main power supply is larger than the relative turn-off time in one period, and the repulsion force displayed by the electromagnetic coil is larger;

The traditional magnetic suspension device has a single drive control form, cannot change a drive mode, is difficult to meet various drive conditions, and has a single adaptive scene. However, the present invention can satisfy various driving conditions, and the following explains "one-suction-one-repulsion", "one-suction" and "one-suction-one-repulsion" according to the circuit schematic diagram of fig. 1 and the technical schematic diagram of the magnetic suspension device base of fig. 3.

Wherein, in fig. 1 and 2:

PWM1_ NMOS _ A1, which indicates the gate of the low side NMOS transistor to the left of the H-bridge of solenoid "one" from which the MCU outputs the PWM signal.

PWM2_ NMOS _ A2, which indicates the gate of the low side NMOS transistor on the left side of the H-bridge of solenoid number "two" from which the MCU outputs the PWM signal.

PWM3_ NMOS _ A3, which indicates the gate of the low side NMOS transistor on the left side of the H-bridge of solenoid "three" output PWM signal from MCU.

PWM4_ NMOS _ A4, which represents the gate of the low side NMOS transistor to the left of the H-bridge of solenoid "four" from which the MCU outputs the PWM signal.

And the PWM1_ NMOS _ B1 represents that the MCU outputs a PWM signal to the grid electrode of the low-end NMOS tube on the right side of the H bridge of the first electromagnetic coil.

And the PWM2_ NMOS _ B2 represents that the MCU outputs a PWM signal to the grid electrode of the low-end NMOS tube on the right side of the H bridge of the electromagnetic coil II.

And the PWM3_ NMOS _ B3 represents that the MCU outputs a PWM signal to the grid electrode of the low-end NMOS tube on the right side of the H bridge of the electromagnetic coil No. three.

And the PWM4_ NMOS _ B4 represents that the MCU outputs a PWM signal to the grid electrode of the low-end NMOS tube on the right side of the H bridge of the electromagnetic coil with the number of 'four'.

D1_ PMOS _ A1 shows that the MCU outputs common high-low level signals to the grid of the high-end PMOS tube on the left side of the H bridge of the solenoid coil I.

D2_ PMOS _ A2 shows that the MCU outputs common high-low level signals to the grid of the high-end PMOS tube on the left side of the H bridge of the solenoid coil II.

D3_ PMOS _ A3 shows that the MCU outputs common high-low level signals to the grid of the high-end PMOS tube on the left side of the H bridge of the solenoid coil No. three.

D4_ PMOS _ A4 shows that the MCU outputs common high-low level signals to the grid of the high-end PMOS tube on the left side of the H bridge of the solenoid coil of the 'four' number.

D1_ PMOS _ B1 shows that the MCU outputs a common high-low level signal to the grid of the high-end PMOS tube on the right side of the H bridge of the first electromagnetic coil.

D2_ PMOS _ B2 shows that the MCU outputs a common high-low level signal to the grid of the high-end PMOS tube on the right side of the H bridge of the solenoid coil II.

D3_ PMOS _ B3 shows that the MCU outputs a common high-low level signal to the grid of the high-end PMOS tube on the right side of the H bridge of the solenoid coil No. III.

D4_ PMOS _ B4 shows that the MCU outputs common high-low level signals to the grid of the high-end PMOS tube on the right side of the H bridge of the electromagnetic coil with the number of 'four'.

(1) "one suction and one repulsion" condition

According to the illustration in fig. 3, two electromagnetic coils on the same axis, namely, the electromagnetic coils with the numbers of "one" and "three" on the X axis and the electromagnetic coils with the numbers of "two" and "four" on the Y axis are represented in the same control period (the MCU starts to collect the magnetic flux of the float and then outputs the collected magnetic flux through the program algorithm to control the driving unit to perform the action, and the process is a control period), and the two electromagnetic coils on the same axis are opposite to the magnetic float, wherein one of the electromagnetic coils represents attraction force (attraction force) to the magnetic float, and the other electromagnetic coil represents repulsion force to the magnetic float.

When the first electromagnetic coil of the X axis shows repulsive force and the third electromagnetic coil shows attractive force, the controller outputs a low level signal D1_ PMOS _ A1 to enable the PMOS _ A1 tube to be conducted; the controller outputs PWM signals to PWM1_ NMOS _ B1 after cascade PID calculation so as to control the on-off state of an NMOS _ B1 tube; the controller outputs a high level signal D1_ PMOS _ B1 to turn off the PMOS _ B1; the controller outputs a 0% duty cycle PWM signal to the PWM1_ NMOS _ a1 to turn off the NMOS _ a1 transistor. The controller outputs a low level signal D3_ PMOS _ B3 to enable the PMOS _ B3 tube to be conducted; the controller outputs PWM signals to PWM3_ NMOS _ A3 after cascade PID calculation to control the on-off state of an NMOS _ A3 tube; the controller outputs a high level signal D3_ PMOS _ A3 to turn off the PMOS _ A3 tube; the controller outputs a 0% duty cycle PWM signal to the PWM3_ NMOS _ B3 to turn off the NMOS _ B3 transistor.

When the first electromagnetic coil of the X axis shows suction and the third electromagnetic coil shows repulsion, the controller outputs a low level signal D1_ PMOS _ B1 to enable the PMOS _ B1 tube to be conducted; the controller outputs PWM signals to PWM1_ NMOS _ A1 after cascade PID calculation to control the on-off state of an NMOS _ A1 tube; the controller outputs a high level signal D1_ PMOS _ A1 to turn off the PMOS _ A1 tube; the controller outputs a 0% duty cycle PWM signal to the PWM1_ NMOS _ B1 to turn off the NMOS _ B1 transistor. The controller outputs a low level signal D3_ PMOS _ A3 to enable the PMOS _ A3 tube to be conducted; the controller outputs PWM signals to PWM3_ NMOS _ B3 after cascade PID calculation so as to control the on-off state of an NMOS _ B3 tube; the controller outputs a high level signal D3_ PMOS _ B3 to turn off the PMOS _ B3; the controller outputs a 0% duty cycle PWM signal to the PWM3_ NMOS _ A3 to turn off the NMOS _ A3 transistor.

When the electromagnetic coil No. two of the Y axis shows repulsion and the electromagnetic coil No. four of the Y axis shows attraction, the controller outputs a low level signal D2_ PMOS _ A2 to enable the PMOS _ A2 tube to be conducted; the controller outputs PWM signals to PWM2_ NMOS _ B2 after cascade PID calculation so as to control the on-off state of an NMOS _ B2 tube; the controller outputs a high level signal D2_ PMOS _ B2 to turn off the PMOS _ B2; the controller outputs a 0% duty cycle PWM signal to the PWM2_ NMOS _ a2 to turn off the NMOS _ a2 transistor. The controller outputs a low level signal D4_ PMOS _ B4 to enable the PMOS _ B4 tube to be conducted; the controller outputs PWM signals to PWM4_ NMOS _ A4 after cascade PID calculation to control the on-off state of an NMOS _ A4 tube; the controller outputs a high level signal D4_ PMOS _ A4 to turn off the PMOS _ A4 tube; the controller outputs a 0% duty cycle PWM signal to the PWM4_ NMOS _ B4 to turn off the NMOS _ B4 transistor.

When the electromagnetic coil No. two of the Y axis shows suction and the electromagnetic coil No. four shows repulsion, the controller outputs a low level signal D2_ PMOS _ B2 to enable the PMOS _ B2 tube to be conducted if necessary; the controller outputs PWM signals to PWM2_ NMOS _ A2 after cascade PID calculation to control the on-off state of an NMOS _ A2 tube; the controller outputs a high level signal D2_ PMOS _ A2 to turn off the PMOS _ A2 tube; the controller outputs a 0% duty cycle PWM signal to the PWM2_ NMOS _ B2 to turn off the NMOS _ B2 transistor. The controller outputs a low level signal D4_ PMOS _ A4 to enable the PMOS _ A4 tube to be conducted; the controller outputs PWM signals to PWM4_ NMOS _ B4 after cascade PID calculation so as to control the on-off state of an NMOS _ B4 tube; the controller outputs a high level signal D4_ PMOS _ B4 to turn off the PMOS _ B4; the controller outputs a 0% duty cycle PWM signal to the PWM4_ NMOS _ a4 to turn off the NMOS _ a4 transistor.

(2) "Single repulsion" situation

According to the illustration in fig. 3, two electromagnetic coils on the same axis, namely, the "first" and "third" electromagnetic coils on the X axis and the "second" and "fourth" electromagnetic coils on the Y axis, are represented in the same control period (the MCU starts to collect the magnetic flux of the float and then outputs the collected magnetic flux to control the driving unit to perform the action, and the process is a control period), and only one electromagnetic coil represents the electromagnetic force relative to the magnetic float, and the two electromagnetic coils on the same axis represent the repulsive force relative to the magnetic float.

When the coil I of the X axis shows repulsive force, the controller outputs a low level signal D1_ PMOS _ A1 to enable the PMOS _ A1 tube to be conducted if necessary; the controller outputs PWM signals to PWM1_ NMOS _ B1 after cascade PID calculation so as to control the on-off state of an NMOS _ B1 tube; the controller outputs a high level signal D1_ PMOS _ B1 to turn off the PMOS _ B1; the controller outputs a 0% duty cycle PWM signal to the PWM1_ NMOS _ a1 to turn off the NMOS _ a1 transistor. When the solenoid coil No. III stops working, the controller outputs a high-level signal D3_ PMOS _ B3 to turn off the PMOS _ B3 tube; the controller outputs a PWM signal with 0% duty ratio to PWM3_ NMOS _ A3 to turn off an NMOS _ A3 tube; the controller outputs a high level signal D3_ PMOS _ A3 to turn off the PMOS _ A3 tube; the controller outputs a 0% duty cycle PWM signal to the PWM3_ NMOS _ B3 to turn off the NMOS _ B3 transistor.

When the coil No. three of the X axis shows repulsive force, the controller outputs a low level signal D3_ PMOS _ A3 to enable the PMOS _ A3 tube to be conducted if necessary; the controller outputs PWM signals to PWM3_ NMOS _ B3 after cascade PID calculation so as to control the on-off state of an NMOS _ B3 tube; the controller outputs a high level signal D3_ PMOS _ B3 to turn off the PMOS _ B3; the controller outputs a 0% duty cycle PWM signal to the PWM3_ NMOS _ A3 to turn off the NMOS _ A3 transistor. When the first solenoid coil stops working, the controller outputs a high-level signal D1_ PMOS _ B1 to turn off the PMOS _ B1 tube; the controller outputs a PWM signal with 0% duty ratio to PWM1_ NMOS _ A1 to turn off an NMOS _ A1 tube; the controller outputs a high level signal D1_ PMOS _ A1 to turn off the PMOS _ A1 tube; the controller outputs a 0% duty cycle PWM signal to the PWM1_ NMOS _ B1 to turn off the NMOS _ B1 transistor.

When the coil No. two of the Y axis shows repulsive force, the controller outputs a low level signal D2_ PMOS _ A2 to enable the PMOS _ A2 tube to be conducted if necessary; the controller outputs PWM signals to PWM2_ NMOS _ B2 after cascade PID calculation so as to control the on-off state of an NMOS _ B2 tube; the controller outputs a high level signal D2_ PMOS _ B2 to turn off the PMOS _ B2; the controller outputs a 0% duty cycle PWM signal to the PWM2_ NMOS _ a2 to turn off the NMOS _ a2 transistor. When the four solenoid coil stops working, the controller outputs a high-level signal D4_ PMOS _ B4 to turn off the PMOS _ B4 tube; the controller outputs a PWM signal with 0% duty ratio to PWM4_ NMOS _ A4 to turn off an NMOS _ A4 tube; the controller outputs a high level signal D4_ PMOS _ A4 to turn off the PMOS _ A4 tube; the controller outputs a 0% duty cycle PWM signal to the PWM4_ NMOS _ B4 to turn off the NMOS _ B4 transistor.

When the 'four' coil of the Y axis represents repulsive force, the controller outputs a low level signal D4_ PMOS _ A4 to enable the PMOS _ A4 tube to be conducted if necessary; the controller outputs PWM signals to PWM4_ NMOS _ B4 after cascade PID calculation so as to control the on-off state of an NMOS _ B4 tube; the controller outputs a high level signal D4_ PMOS _ B4 to turn off the PMOS _ B4; the controller outputs a 0% duty cycle PWM signal to the PWM4_ NMOS _ a4 to turn off the NMOS _ a4 transistor. When the second solenoid coil stops working, the controller outputs a high-level signal D2_ PMOS _ B2 to turn off the PMOS _ B2 tube; the controller outputs a PWM signal with 0% duty ratio to PWM2_ NMOS _ A2 to turn off an NMOS _ A2 tube; the controller outputs a high level signal D2_ PMOS _ A2 to turn off the PMOS _ A2 tube; the controller outputs a 0% duty cycle PWM signal to the PWM2_ NMOS _ B2 to turn off the NMOS _ B2 transistor.

(3) "Single suck" situation

According to the illustration in fig. 3, two electromagnetic coils on the same axis, namely, the electromagnetic coils with the numbers of "one" and "three" on the X axis and the electromagnetic coils with the numbers of "two" and "four" on the Y axis, are represented in the same control period (the MCU starts to collect the magnetic flux of the float and then outputs the collected magnetic flux through the program algorithm to control the driving unit to perform the action, and the process is a control period), and only one electromagnetic coil is represented as an electromagnetic force relative to the magnetic float and is represented as an attractive force (attraction force) relative to the magnetic float.

When the first electromagnetic coil of the X axis shows suction force, the controller outputs a low level signal D1_ PMOS _ B1 to enable a PMOS _ B1 tube to be conducted if necessary; the controller outputs PWM signals to PWM1_ NMOS _ A1 after cascade PID calculation to control the on-off state of an NMOS _ A1 tube; the controller outputs a high level signal D1_ PMOS _ A1 to turn off the PMOS _ A1 tube; the controller outputs a 0% duty cycle PWM signal to the PWM1_ NMOS _ B1 to turn off the NMOS _ B1 transistor. When the three-position electromagnetic coil is required to stop working, the controller outputs a high-level signal D3_ PMOS _ A3 to turn off a PMOS _ A3 tube; the controller outputs a PWM signal with 0% duty ratio to PWM3_ NMOS _ B3 to turn off an NMOS _ B3 tube; the controller outputs a high level signal D3_ PMOS _ B3 to turn off the PMOS _ B3; the controller outputs a 0% duty cycle PWM signal to the PWM3_ NMOS _ A3 to turn off the NMOS _ A3 transistor.

When the electromagnetic coil of No. three on the X axis shows suction, the controller outputs a low level signal D3_ PMOS _ B3 to enable the PMOS _ B3 tube to be conducted if necessary; the controller outputs PWM signals to PWM3_ NMOS _ A3 after cascade PID calculation to control the on-off state of an NMOS _ A3 tube; the controller outputs a high level signal D3_ PMOS _ A3 to turn off the PMOS _ A3 tube; the controller outputs a 0% duty cycle PWM signal to the PWM3_ NMOS _ B3 to turn off the NMOS _ B3 transistor. When the 'one' solenoid coil is required to stop working, the controller outputs a high-level signal D1_ PMOS _ A1 to turn off a PMOS _ A1 tube; the controller outputs a PWM signal with 0% duty ratio to PWM1_ NMOS _ B1 to turn off an NMOS _ B1 tube; the controller outputs a high level signal D1_ PMOS _ B1 to turn off the PMOS _ B1; the controller outputs a 0% duty cycle PWM signal to the PWM1_ NMOS _ a1 to turn off the NMOS _ a1 transistor.

When the second electromagnetic coil of the Y axis shows suction force, the controller outputs a low level signal D2_ PMOS _ B2 to enable a PMOS _ B2 tube to be conducted if necessary; the controller outputs PWM signals to PWM2_ NMOS _ A2 after cascade PID calculation to control the on-off state of an NMOS _ A2 tube; the controller outputs a high level signal D2_ PMOS _ A2 to turn off the PMOS _2 tube; the controller outputs a 0% duty cycle PWM signal to the PWM2_ NMOS _ B2 to turn off the NMOS _ B2 transistor. When the four solenoid coil is required to stop working, the controller outputs a high-level signal D4_ PMOS _ A4 to turn off the PMOS _ A4 tube; the controller outputs a PWM signal with 0% duty ratio to PWM4_ NMOS _ B4 to turn off an NMOS _ B4 tube; the controller outputs a high level signal D4_ PMOS _ B4 to turn off the PMOS _ B4; the controller outputs a 0% duty cycle PWM signal to the PWM4_ NMOS _ a4 to turn off the NMOS _ a4 transistor.

When the 'four' electromagnetic coil of the Y axis shows suction force, the controller outputs a low level signal D4_ PMOS _ B4 to enable a PMOS _ B4 tube to be conducted if necessary; the controller outputs PWM signals to PWM4_ NMOS _ A4 after cascade PID calculation to control the on-off state of an NMOS _ A4 tube; the controller outputs a high level signal D4_ PMOS _ A4 to turn off the PMOS _4 tube; the controller outputs a 0% duty cycle PWM signal to the PWM4_ NMOS _ B4 to turn off the NMOS _ B4 transistor. When the second electromagnetic coil is required to stop working, the controller outputs a high-level signal D2_ PMOS _ A2 to turn off a PMOS _ A2 tube; the controller outputs a PWM signal with 0% duty ratio to PWM2_ NMOS _ B2 to turn off an NMOS _ B2 tube; the controller outputs a high level signal D2_ PMOS _ B2 to turn off the PMOS _ B2; the controller outputs a 0% duty cycle PWM signal to the PWM2_ NMOS _ a2 to turn off the NMOS _ a2 transistor.

The device adopts a single electromagnetic coil independent driving mode, is 2 times of the traditional serial connection mode, and has wider control force range. The 'single repulsion' and 'single attraction' in the device are similar to those of the traditional series connection type in the aspect of controlling the floater capacity, but the device is driven by a single way, so that the device is more flexible in programming algorithm design, can realize complex algorithm and enables the system to suspend more stably. The "single attraction" in the device of the present invention is slightly stronger in the control force of the magnetic floater than the "single repulsion", but the "single attraction" is thought in reverse at the time of program design and the "single repulsion" is thought in forward at the time of program design, so it is preferable to use the "single repulsion" for the convenience of designing and developing the algorithm program.

Compared with the two modes of 'single repulsion' or 'single attraction', the 'one attraction and repulsion' in the device of the invention is that two coils simultaneously generate force and one more electromagnetic coil generates force, so that the device has stronger capability of controlling the floater, but the power consumption is close to twice of the 'single repulsion' or 'single attraction'. Therefore, the 'one-suction-one-repulsion' type electromagnetic coil and the 'single-repulsion' type electromagnetic coil have no advantages or disadvantages, the 'one-suction-one-repulsion' type electromagnetic coil has strong control force but large power consumption, and the 'single-repulsion' type electromagnetic coil and the 'single-suction' type electromagnetic coil have little power consumption and relatively weak control force, but the three modes are superior to the traditional series mode in the aspect of control effect. The three modes of the device can be selected according to actual scenes, if the scene requires high suspension degree, the electromagnetic coil also has strong control force, and the device can be switched by software, so that the 'one-absorption-one-repulsion' mode of the device is used. If the scene does not have great requirements on the suspension height of the magnetic floater, and the requirements on the control force of the electromagnetic coil are relatively low, the magnetic floater can be switched by software, and the 'single-attraction' or 'single-repulsion' mode of the device can be used.

In the device actually developed by the invention, no very high requirement is made on the suspension height, so that a 'single repulsion' scheme is selected and used by software, the scheme is superior to the traditional series connection type in terms of control algorithm, and is superior to a 'one repulsion and one attraction' mode in the device in terms of power consumption.

Claims

1. A control method of a digital push-down magnetic suspension device comprises the digital push-down magnetic suspension device, wherein the device comprises a magnetic suspension device base and a magnetic floater, and the control method at least comprises the following steps: an electromagnetic coil device unit of a magnetic suspension device base and a magnetic flux acquisition unit of a magnet floater;

the device also comprises a wireless power supply unit for supplying power to an equivalent peripheral circuit in the magnetic floater; the wireless power supply unit is based on an XKT515 chip, wherein a wireless power supply transmitting end in the wireless power supply unit comprises an XKT515 chip, a resonant transmitting circuit formed by a peripheral capacitor and an inductance copper coil of the XKT515 chip and an NMOS field effect tube serving as a power-off and power-supply switch;

the device also comprises a Bluetooth audio playing unit arranged on the magnetic suspension device base;

the electromagnetic coil unit includes four electromagnetic coils: the electromagnetic coil is provided with a first electromagnetic coil, a second electromagnetic coil, a third electromagnetic coil and a fourth electromagnetic coil in a counterclockwise way; a second permanent magnet (2) is arranged between the first electromagnetic coil and the second electromagnetic coil; a third permanent magnet (3) is arranged between the second electromagnetic coil and the third electromagnetic coil; a fourth permanent magnet (4) is arranged between the 'three' electromagnetic coil and the 'four' electromagnetic coil; a first permanent magnet (1) is arranged between the four electromagnetic coils and the one electromagnetic coil; a first Hall sensor h1 is arranged at the connecting line position between the second electromagnetic coil and the fourth electromagnetic coil, and a first Hall sensor h2 is arranged at the connecting line position between the first electromagnetic coil and the third electromagnetic coil;

the method is characterized in that the control method is a cascade control method;

the cascade control method comprises the following steps:

in a single control period, the main controller outputs the deviation correction amount, then the original initial given value of the sub-controller is superposed to obtain a new value as a new variable, and the new variable is used as the given value of the sub-controller;

according to the above:

(Q1- (Q3 + -e)) <0, the deviation correction value ValueDeviation _ X <0 of the X-axis indicates that the magnetic floater is deflected to the X positive axis at this time, so that the magnetic floater moves along the X negative axis direction;

(Q1- (Q3 + -e)) >0, the deviation correction value ValueDeviation _ X >0 of the X axis indicates that the magnetic floater deviates to the X negative axis at the moment, so that the magnetic floater moves along the X positive axis direction;

(Q2- (Q4 ± e)) <0, the Y-axis deviation correction value valuevariation _ Y <0, indicating that the magnetic float is deflected to the Y-positive axis at this time, so that the magnetic float moves in the Y-negative axis direction;

3) outer ring digital PID incremental control:

NowPowerError_X＝Power_Q1–(Power_Q3±e)；

e represents, dead zone value;

NowPowerError _ X represents the difference between the "power consumption" of the "first" and "third" electromagnetic coils in the dead zone at the end of the current time period;

PrePowerError_X＝PrePower_Q1–(PrePower_Q3±e)；

PrePrePowerError_X＝PrePrePower_Q1–(PrePrePower_Q3±e)；

e represents, dead zone value;

PrePowerError _ X, which represents the difference between the 'electric power consumption' of the 'one' electromagnetic coil and the 'three' electromagnetic coil in the dead zone at the end of the last time period on the X axis;

4) inner loop digital PD position type control

become the new set point:

NewTarget_X＝Target_X+ValueDeviation_X

NewTarget_Y＝Target_Y+ValueDeviation_Y

calculating a new deviation value of this time:

NewError_X＝NowValue_X-Newarget_X；

NewError_Y＝NowValue_Y-NewTarget_Y；

calculating a new last deviation value:

PreNewError_X＝PreValue_X-NewTarget_X；

PreNewError_Y＝PreValue_Y-NewTarget_Y；

digital PD position type control output:

an X axis:

PWM_OUT_X＝InKp_X*NewError_X+InKd_X*(NewError_X-PreNewError_X)

y-axis:

PWM_OUT_Y＝InKp_Y*NewError_Y+InKd_Y*(NewError_Y-PreNewError_Y)

2. The control method of a digital push-down magnetic levitation apparatus as recited in claim 1, wherein the single repulsion method included in the control method comprises: