A single cycle delay compensation method and device for a magnetic suspension bearing switching power amplifier

Abstract

This invention belongs to the field of active magnetic levitation bearing technology, and discloses a single-cycle delay compensation method and device for a magnetic levitation bearing switching power amplifier. The method includes: establishing a unipolar single-cycle control mathematical model and calculating the duty cycle of a single cycle; setting a state switching criterion for the charging and discharging cycle and determining the charging and discharging state of a single cycle; establishing a linear duty cycle prediction model and deriving the duty cycle d linearly through calculation. t And calculate the duty cycle value d j The total duty cycle of the corresponding switching transistor within the cycle is obtained and output to the corresponding switching transistor. This invention enables the tracking of the target under static conditions without steady-state error, and under dynamic conditions, it can effectively reduce the time delay problem of traditional digital single-cycle control algorithms.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of active magnetic suspension bearings, and particularly relates to a single-cycle delay compensation method and device for a magnetic suspension bearing switching power amplifier. BACKGROUND

[0002] When the rotor deviates due to external disturbance, the power amplifier needs to switch the current polarity and adjust the amplitude within microseconds, so that the electromagnetic force direction is opposite to the displacement deviation, forming a closed loop suppression effect. This process requires the amplifier to have high bandwidth to match the adjustment frequency of the controller, while ensuring high linearity and low ripple of the current output to avoid high-frequency oscillation of the rotor caused by electromagnetic force pulsation.

[0003] The mainstream scheme of the power amplifier currently adopts a full-bridge topology structure, realizes positive and negative bus voltage output through H-bridge symmetric design, supports bidirectional continuous adjustment of current, and can shorten the dynamic response time to microseconds; has eight working modes, and can greatly reduce the current ripple through a three-level modulation strategy. In addition, compared with the multi-bridge arm parallel topology, the system has high reliability, and is particularly suitable for fields with strict requirements on failure rate. However, there are still problems such as slow response speed and slow convergence of system error.

[0004] The patent application with the Chinese patent publication number CN118157526A and the name of a permanent magnet synchronous motor control method based on an improved linear super helix establishes a two-phase stationary coordinate system, obtains a stator current equation, establishes a mechanical motion equation of the permanent magnet synchronous motor, defines a state variable of the permanent magnet synchronous motor system, establishes an integral sliding mode surface, and constructs a reaching law speed controller. An improved linear super helix sliding film observer is established for estimating the back electromotive force, and the rotor speed and rotor position of the permanent magnet synchronous motor are calculated. This method is improved on the basis of the linear super helix sliding mode observer. When the system error increases, the sliding mode gain can be adjusted with the system error, and the precise estimation of the motor speed without using a low-pass filter can be realized, and the anti-interference ability is improved. However, this patent application cannot realize fast convergence of system error and cannot solve the problem of slow response speed. SUMMARY

[0005] In order to overcome the problems in the prior art, the purpose of the present application is to provide a single-cycle delay compensation method and device for a magnetic suspension bearing switching power amplifier. The digital single-cycle control algorithm is optimized considering the coil resistance voltage drop, the mathematical model of the accurate algorithm is determined, the judgment criteria of the charging and discharging period are determined, the delay under the digital single-cycle control algorithm is estimated based on the control principle, a linear duty cycle prediction model is constructed, the duty cycle of the previous two periods is extrapolated to predict the duty cycle of the current period, and an equalization coefficient is introduced to optimize the prediction weight.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a single-cycle delay compensation method for a magnetic levitation bearing switching power amplifier, comprising the following steps:

[0008] The circuit data includes: coil current i0 at the initial moment of a single cycle and current reference value i. ref Bus voltage U dc Period T s , load R and inductance L;

[0009] Establish a mathematical model for unipolar single-cycle control and calculate the duty cycle of a single cycle;

[0010] Set the state switching criteria for the charge and discharge cycle to determine the charge and discharge state of a single cycle;

[0011] Establish a linear duty cycle prediction model and derive the duty cycle d linearly through calculation. t And calculate the duty cycle value d j The total duty cycle of the corresponding switch within the cycle is obtained, and the total duty cycle is output to the corresponding switch.

[0012] Optionally, the unipolar single-cycle control mathematical model is: when i0 < iref, d = When i0 ≥ iref, d = Where: L is the inductance of the magnetic levitation bearing coil; R is the resistance of the magnetic levitation bearing coil; i ref i0 is the current reference value; i0 is the initial value of the single-cycle coil feedback current; T s It is the duration of a single cycle, U dc It is the bus voltage.

[0013] Optionally, the state switching criterion of the charge / discharge cycle is: when i0 < When i0 ≥ 1, the coil should be in a charging state during this cycle; when i0 ≥ 1, the coil should be in a charging state during this cycle. At this time, the coil should be in a discharging state during this cycle; where i0 is the initial value of the single-cycle coil feedback current; i ref is the current reference value; L is the inductance of the magnetic levitation bearing coil; R is the resistance of the magnetic levitation bearing coil; T is the sampling period.

[0014] Optionally, the linear duty cycle prediction model is: In the formula: This refers to the predicted duty cycle; the equilibrium coefficient a is 0.05. <a<0.4;d t The duty cycle is derived linearly; d j It calculates the duty cycle value.

[0015] Optionally, the linear derivation of the duty cycle dt The calculation formula is: ; in the formula: is the n-period linear derivation duty ratio; is the predicted duty ratio of the (n-1)th period; is the predicted duty ratio of the (n-2)th period.

[0016] Optionally, the calculation duty ratio value d j The formula is:

[0017] When i0< i , dj= ;

[0018] When i0>= i , dj= ;

[0019] In the formula, i0 is the single-period coil feedback current initial value; i ref is the current given reference value; L is the magnetic suspension bearing coil inductance; R is the magnetic suspension bearing coil resistance; and T is the sampling period.

[0020] In a second aspect, the present application provides a single-period delay compensation system of a magnetic suspension bearing switching power amplifier, comprising:

[0021] A data acquisition module is configured to acquire circuit data, wherein the circuit data comprises: a single-period initial time coil current i0, a current reference value i ref , a bus voltage U dc , a period T s , a load R and an inductance L.

[0022] A model establishment module is configured to establish a single-polarity single-period control mathematical model and calculate a single-period duty ratio.

[0023] A rule setting module is configured to set a state switching criterion of a charging and discharging period and judge a charging and discharging state of a single period.

[0024] A prediction module is configured to establish a linear duty ratio prediction model, obtain a total duty ratio of a corresponding switch tube in a period by calculating a linear derivation duty ratio d t and a calculation duty ratio value d j .

[0025] An output module is configured to output the total duty ratio to the corresponding switch tube.

[0026] In a third aspect, the present application provides an electronic device, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the single-period delay compensation method of the magnetic suspension bearing switching power amplifier when executing the computer program.

[0027] In a fourth aspect, the present application provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the single-cycle delay compensation method of the magnetic suspension bearing switching power amplifier.

[0028] In a fifth aspect, the present application provides a computer program product comprising a computer readable medium, and the computer readable medium comprises computer readable program code, and the program code implements the single-cycle delay compensation method of the magnetic suspension bearing switching power amplifier.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] The present application optimizes the digital single-cycle control algorithm by considering the coil resistance voltage drop, accurately the mathematical model of the algorithm, and clearly the judgment criteria of the charging and discharging cycle, estimates the delay of the digital single-cycle control algorithm based on the control principle, constructs a linear duty cycle prediction model, extrapolates and predicts the current cycle duty cycle using the first two cycle duty cycles, and introduces a balance coefficient to optimize the prediction weight.

[0031] The present application can track the target under static conditions without steady-state error, and under dynamic conditions, the improved algorithm can effectively reduce the time delay problem of the traditional digital single-cycle control algorithm. BRIEF DESCRIPTION OF DRAWINGS

[0032] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present application in any way.

[0033] In the drawings:

[0034] Figure 1 is a single-degree-of-freedom magnetic suspension bearing switching power amplifier control system block diagram.

[0035] Figure 2 is a single-phase full-bridge switching power amplifier topology schematic diagram;

[0036] Figure 3 is a single-polarity control forward charging cycle schematic diagram;

[0037] Figure 4 is a single-polarity control forward discharging cycle schematic diagram;

[0038] Figure 5 is a single-polarity control full-continuation cycle schematic diagram;

[0039] Figure 6 is a delay schematic diagram of the tracking current;

[0040] Figure 7 This is a schematic diagram of an ideal case for current tracking;

[0041] Figure 8 This is a schematic diagram of duty cycle prediction;

[0042] Figure 9 This is a schematic diagram of actual current oscillation;

[0043] Figure 10 This is a schematic diagram of the actual current i of the single-cycle digital control algorithm based on duty cycle prediction and the actual current i0 of the traditional algorithm, which tracks a step signal with an amplitude of 3A.

[0044] Figure 11 This is a schematic diagram of the actual current i of the single-cycle digital control algorithm based on duty cycle prediction and the actual current i0 of the traditional algorithm, which tracks a step signal with an amplitude of 3A. Detailed Implementation

[0045] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0047] It should be noted that any reference signs placed between parentheses in the claims should not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. This application can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

[0048] In addition, the terms "first", "second", etc. are used only for descriptive purposes and should not be construed as implying or suggesting relative importance or an indicated number of the technical features. Therefore, the features defined as "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0049] The application will be described in detail below with reference to the accompanying drawings.

[0050] The single cycle delay compensation method of the magnetic suspension bearing switching power amplifier of the application comprises the following steps:

[0051] The circuit data is collected, and the circuit data includes: single cycle initial time coil current i0, current reference value i ref , bus voltage U dc , period T s , load R and inductance L;

[0052] A unipolar single cycle control mathematical model is established, and the duty cycle of the single cycle is calculated;

[0053] The state switching criterion of the charge and discharge cycle is set, and the charge and discharge state of the single cycle is judged;

[0054] A linear duty cycle prediction model is established, the linear derived duty cycle d t is calculated, and the duty cycle value d j is calculated to obtain the total duty cycle of the corresponding switch tube in the cycle, and the total duty cycle is output to the corresponding switch tube.

[0055] Specifically, the actual current i in the coil is detected and sampled by the current sensor, the result is subtracted from the reference current and input to the controller, the controller calculates the conduction state and duty cycle of the four switch tubes according to the difference using the single cycle control principle, generates the PWM wave of the corresponding switch tube, and then outputs to the switch tube in the magnetic bearing switching power amplifier.

[0056] The application optimizes the digital single cycle control algorithm by considering the coil resistance voltage drop, accurately the mathematical model of the algorithm, and clearly the judgment criterion of the charge and discharge cycle. Based on the control principle, the delay of the digital single cycle control algorithm is estimated, a linear duty cycle prediction model is constructed, the current cycle duty cycle is extrapolated and predicted, and an equalization coefficient is introduced to optimize the prediction weight.

[0057] The application can track the target under static conditions without steady-state error, and under dynamic conditions, the improved algorithm can effectively reduce the time delay problem existing in the traditional digital single-cycle control algorithm.

[0058] Embodiment 1

[0059] Figure 1 To be a single degree of freedom magnetic bearing switching power amplifier control system block diagram, the system is mainly composed of a controller, a switching power amplifier and a current sensor. Among them, the current sensor is responsible for detecting and sampling the actual current in the coil, and the result is subtracted from the reference current and input to the controller. The controller calculates the on-off timing and time of the four switching tubes according to the interpolation using the single-cycle control principle, and then generates the corresponding switching signal. The switching power amplifier as the main circuit will control the corresponding switching tube according to the switching signal, so as to achieve dynamic regulation of the magnetic suspension bearing coil current.

[0060] The topology structure of the main power is a single-phase full-bridge switching power amplifier topology. The full-bridge topology can realize three-level control of the electromagnetic bearing, has small output ripple and good tracking performance, and its specific topology structure is shown in Figure 2 The single-cycle control of the magnetic suspension bearing switching power amplifier is divided into two modes of bipolar control and unipolar control. The bipolar control has no freewheeling process, the algorithm is relatively simple, the program execution efficiency is higher, but the output current ripple is larger. The unipolar control has a freewheeling process, the switching loss of the system is smaller, and the output current ripple is also smaller.

[0061] The waveform under the control of the single-cycle unipolar algorithm is shown in Figure 3 From top to bottom, the trigger pulse of the switching period, the overlapping triangular wave, the conduction duty cycle waveform, and the current waveform in the coil are shown. In the figure, T M is the switching period of the digital single-cycle control, T on is the time duration of the forward conduction state of each period, d is the duty cycle of the coil conduction state, cnt is the peak value of the overlapping triangular wave, and i is the current in the magnetic suspension bearing control coil.

[0062] In the forward charging period of the single-cycle unipolar control, M4 is always on, and M1 and M2 are complementary on. When M1 is on, the voltage across the coil is a forward voltage, and the current rises. When M2 is on, the voltage across the coil is 0, and the current slowly decreases due to the existence of the coil resistance.

[0063] When t0 1, M3 is off. The state equation of the coil current is

[0064] Equation 1

[0065] Where, L is the magnetic suspension bearing coil inductance; R is the magnetic suspension bearing coil resistance; i is the magnetic suspension bearing coil current.

[0066] Substitute , The coil current expression is obtained

[0067] Equation 2

[0068] According to Taylor formula, equation 2 can be changed into

[0069] Equation 3

[0070] From Figure 3 It can be known that

[0071] Equation 4

[0072] The current change amount from t0 to t1 is

[0073] Equation 5

[0074] Substitute equation 3 and equation 4 into equation 5, the coil current expression is obtained

[0075] Equation 6

[0076] When t1 < t < t2, the duty ratio waveform is 1, the coil is in the positive conduction state, and the switch tubes M1 and M4 are turned on, and M2 and M3 are turned off. The state equation of the coil current is

[0077] Equation 7

[0078] Where, U dc is the DC bus voltage.

[0079] Substitute i(t1) = i1 and i(t2) = i2, the time domain expression of the coil current is obtained

[0080] Equation 8

[0081] According to Taylor formula, equation 8 can be changed into

[0082] Equation 9

[0083] From Figure 3 It can be known that

[0084] Equation 10

[0085] The current change amount from t1 to t2 is

[0086] Equation 11

[0087] Substitute formula 9 and formula 10 into formula 11, we can get

[0088] Formula 12

[0089] When t2 < t < t3, the duty ratio waveform is 0, the coil is in the freewheeling state, the switch tube M2 and M4 are on, M1 and M3 are off, the working state is the same as the initial freewheeling stage, and the current change amount from t2 to t3 is

[0090] Formula 13

[0091] The total current change amount in the forward charging period of the single-cycle unipolar control is

[0092] Formula 14

[0093] If the current i3 at the end of each period is selected to track the reference value i ref , the current change amount in one period is

[0094] Formula 15

[0095] Substitute formula 14 and formula 15, we can get

[0096] Formula 16

[0097] The switching frequency in the switching power amplifier system is high, and the current change amount in each period is relatively small, and the current change in the freewheeling state is almost 0, so i0 and i1 can be considered approximately equal, i2 and i3 are approximately equal, that is

[0098] Formula 17

[0099] Formula 18

[0100] Substitute formula 17 and formula 18 into formula 16, we can get

[0101] Formula 19

[0102] In the forward discharging period of the single-cycle unipolar control, M2 is always on, and M3 and M4 are complementary on. When M4 is on, the voltage across the coil is 0, and the current slowly decreases due to the existence of the coil resistance. When M3 is on, the voltage across the coil is a reverse voltage, and the current decreases. The waveform under the control of the single-cycle unipolar algorithm is shown in Figure 4 . From top to bottom, they are the trigger pulse of the switching period, the overlapping triangular wave, the conduction duty ratio waveform, and the current waveform in the coil. In the figure, T s , T ond, cnt, i are consistent with the definition of the charging cycle.

[0103] The waveform under single-cycle unipolar algorithm control is as follows: Figure 3 As shown, from top to bottom, the waveforms represent the trigger pulse of the switching cycle, the overlapping triangular wave, the duty cycle waveform, and the current waveform in the coil. In the figure, T... M For the switching cycle of digital single-cycle control, T on d is the duration of the forward conduction state in each cycle, cnt is the duty cycle of the coil conduction state, i is the peak value of the overlapping triangular wave, and i is the current in the magnetic levitation bearing control coil.

[0104] When t0 < t < t1, the duty cycle waveform is 0, the coil is in freewheeling mode, and switching transistors M2 and M4 are on, while M1 and M3 are off. The freewheeling state is the same as the freewheeling phase of the forward charging cycle, therefore the current change from t0 to t1 is:

[0105] Formula 20

[0106] When t1 < t < t2, the duty cycle waveform is 1, the coil is in reverse conduction, switching transistors M2 and M3 are on, and M1 and M4 are off. The state equation for the coil current is:

[0107] Formula 21

[0108] Substituting i(t1) = i1 and i(t2) = i2, we can obtain the time-domain expression for the coil current.

[0109] Formula 22

[0110] According to Taylor's formula, equation 22 can be transformed into...

[0111] Formula 23

[0112] Depend on Figure 4 It can be known

[0113] Formula 24

[0114] The change in current from t1 to t2 is

[0115] Formula 25

[0116] Substituting equations 23 and 24 into equation 25, we get

[0117] Formula 26

[0118] When t2 < t < t3, the duty cycle waveform is 0, the coil is in freewheeling state, switching transistors M2 and M4 are on, and M1 and M3 are off. The operating state is the same as the initial freewheeling stage. Therefore, the current change from t2 to t3 is:

[0119] Formula 27

[0120] The total current change during a single-cycle unipolar control forward charging cycle is:

[0121] Formula 28

[0122] If we choose to track the reference value i3 at the end of each cycle... ref By combining equations 28 and 15, we can obtain...

[0123] Formula 29

[0124] Considering the high switching frequency in the switching power amplifier system, the current change within each cycle is relatively small, and the freewheeling current change is almost zero. Substituting equations 17 and 18 into equation 29, we can obtain...

[0125] Formula 30

[0126] As can be seen from equations (19) and (30), at the beginning of each cycle, only the initial value of the feedback current, the bus voltage value and the reference current value need to be sampled to directly calculate the duty cycle of that cycle, so that the actual current tracks the reference current at the end of each cycle.

[0127] Under the single-cycle digital control algorithm, i at the start of each cycle ref i0 determines whether this cycle is in a charging or discharging state, and then the control algorithm determines the state based on i0. ref The duty cycle is calculated using i0 to control the switching transistor's on and off states. Traditional calculation methods directly compare i0 with the duty cycle. ref The state of the cycle is determined by the magnitude of i0. However, due to the coil resistance, when the duty cycle is 0, the current in the coil will freewheel from i0 to a fixed value i0 within one cycle. * ,as follows Figure 5 As shown, the condition for determining the charge / discharge cycle is related to this fixed value i0. * related.

[0128] When t0 < t < t1, the duty cycle waveform is 0, the coil is in freewheeling state, and the state equation of the coil current is:

[0129] Formula 31

[0130] Depend on Figure 5 Know

[0131] Equation 32

[0132] Substitute , , combined with Taylor formula, the calculation of

[0133] Equation 33

[0134] When i0 * < i ref , that is

[0135] Equation 34

[0136] The coil should be in the charging state in this period;

[0137] When i0 * > i ref , that is

[0138] Equation 35

[0139] The coil should be in the discharging state in this period.

[0140] The mathematical model of the single-cycle single-polarity control algorithm is updated to

[0141] Equation 36

[0142] According to the principle of single-cycle control, the coil current of the magnetic suspension bearing is consistent with the given value at the end and the beginning of the period, which leads to the actual current lagging behind the given current, indicating that there is a delay in the control system of the switching power amplifier under digital single-cycle control. This delay seriously affects the performance of the power amplifier, causing time deviation in signal transmission, reducing bandwidth, gain, and other indicators. Especially in high-frequency signal processing, the output signal is distorted, the frequency response is poor, and it is difficult to meet the high-precision requirements. In the face of rapidly changing input signals, the system response is slow, the dynamic performance is poor, and overshoot and oscillation are prone to occur, affecting stability and reliability. Moreover, due to the delay, the power amplifier's energy consumption increases, and its efficiency decreases, which may also cause heating, threatening the stability and life of the system. When the delay is deepened, the system stability is severely damaged, the phase lag and gain change weaken the stability margin, causing the system to oscillate and lose control, ultimately leading to the instability of the magnetic suspension bearing control system. To solve these problems and expand the stability domain and enhance reliability, it is necessary to study the delay existing in the system. On the one hand, the control algorithm needs to be analyzed to find out the key delay factors; on the other hand, an accurate compensation model needs to be established to achieve efficient and stable operation.

[0143] In single-cycle control of a magnetic levitation switching power amplifier, the primary task for compensating for the delay in the control system of the magnetic levitation bearing switching power amplifier is to identify the existing delays in the system. In the case of digital single-cycle control, the system delay mainly includes the delay of AD conversion, the delay of algorithm calculation, the delay caused by the control algorithm, and the delay of the circuit. Among these, the delay T caused by the control algorithm is the most significant. c Far exceeding the other three parts. This is because the current is set to track the reference value i at the end of each cycle. ref Therefore, the delay caused by the control algorithm is equal to the switching period, i.e., T. c =T s .

[0144] The delay caused by the single-cycle control algorithm is equal to the switching period, i.e., T. c =T s The diagram is as follows: Figure 6 As shown in the figure, the current waveform of a single-cycle control tracking sinusoidal signal is i. ref Let i represent the given current waveform, i represent the actual current waveform, and i1 represent the fundamental wave of the actual current waveform i.

[0145] Duty cycle predictive control uses the coil conduction duty cycle of the previous two cycles to linearly derive the duty cycle d of the current cycle. t This is to compensate for the delay in the control loop. However, the predicted duty cycle cannot be completely consistent with the ideal duty cycle of the current cycle. Therefore, the duty cycle d calculated using the reference current and the actual current of the current cycle should also be added. j This is to compensate for the insufficient accuracy of the predicted duty cycle. Thus, the overall predicted duty cycle... for

[0146] Formula 37

[0147] Thus, the predicted duty cycle consists of two parts: one part is d, which is linearly derived from the duty cycles of the previous two cycles. t It is mainly used to compensate for delay, and another part uses the difference between the reference current and the actual current. Calculated duty cycle value d j This is mainly used to compensate for the forecast discrepancy from the previous cycle. In ideal forecasting, the calculated duty cycle value d... j It should be as small as possible, which explains the derivation of the duty cycle d. t It's quite accurate. Therefore, if we're predicting the duty cycle... If the duty cycle is equal to the ideal duty cycle, the system control loop delay can be completely compensated. The ideal schematic diagram is as follows: Figure 7 As shown.

[0148] d tis linearly derived from the duty cycles of the previous two periods, but the coil conduction duty cycle in the discharge period or the charging period is between 0 and 1, and the value of the duty cycle cannot distinguish whether the coil is in the charging period or the discharge period, and the positive and negative conversion of the conduction duty cycle is needed to distinguish the charging and discharging states of the coil. Definition is the coil linear conduction duty cycle, and in the positive charging state is a positive value from 0 to 1; in the positive discharging state is a negative value from -1 to 0. In this way, The expression of d

[0149] Equation 38

[0150] When the coil linear conduction duty cycle in the period is -1, the coil is in the full discharge state; when the coil linear conduction duty cycle in the period is greater than -1 and less than 0, the coil is in the partial discharge state in this period, and the current change decreases as d decreases; when the coil linear conduction duty cycle in the period is 0, the coil is in the full freewheeling state; when the coil linear conduction duty cycle in the period is greater than 0 and less than 1, the coil is in the partial charging state in this period, and the current change increases as d increases; when the coil linear conduction duty cycle in the period is 1, the coil is in the full charging state. Since the coil freewheeling state current change is small in each period, it can be ignored compared with the charging and discharging current change, so it can be considered that the coil current change is proportional to the linear conduction duty cycle.

[0151] In this way, the duty cycle value d j and the coil linear conduction duty cycle d should be

[0152] Equation 39

[0153] Next, the duty cycle of the n-th period is predicted by linear extrapolation, and the method is shown in the schematic diagram of Figure 8 .

[0154] Ts is the system switching period and the sampling period, let the coil linear conduction duty cycle in the n-2-th period be d , let the coil linear conduction duty cycle in the n-1-th period be d , and the coil conduction duty cycle d t n in the n-th period is predicted by linear extrapolation.

[0155] Equation 40

[0156] that is,

[0157] Formula 41

[0158] In practice, if the duty cycle is predicted... The prediction part d t Without restrictions, the actual current will oscillate around the reference current, as shown above. Figure 9 As shown.

[0159] This phenomenon occurs because unconstrained dt may lead to overcompensation or undercompensation in the control loop, thereby causing instability and oscillating behavior during current tracking.

[0160] To alleviate this problem, the predicted duty cycle d t Imposing appropriate constraints is crucial to ensure they remain within reasonable limits and meet system stability requirements. This approach helps maintain smooth current tracking and prevents undesirable oscillations. An equalization coefficient 'a' is introduced to address the predicted duty cycle. For the derivation part d t To avoid over-reliance on [the system / mechanism], multiple simulations have verified that an equilibrium coefficient α of 0.05-0.4 is generally suitable. (Updated prediction duty cycle) The formula is

[0161] Formula 42

[0162] Example 2

[0163] A simulation analysis was performed on a single-cycle control delay compensation method of the present invention. Table 1 shows the specific parameters of the power amplifier.

[0164] Table 1

[0165]

[0166] To verify the superiority of the single-cycle digital control algorithm based on duty cycle prediction, a step signal with an amplitude of 3A was simulated, and the results are as follows: Figure 10 In the figure, iref represents the given current, i represents the actual current of the single-cycle digital control algorithm based on duty cycle prediction, and i0 represents the actual current of the traditional algorithm.

[0167] A tracking simulation analysis was performed on a sinusoidal signal with an amplitude of 3A and a frequency of 500Hz. Figure 11 As shown in the figure, iref represents the given current, i represents the actual current of the single-cycle digital control algorithm based on duty cycle prediction, and i0 represents the actual current of the traditional algorithm.

[0168] Compared with the traditional single-cycle digital control algorithm, the improved single-cycle algorithm has the following advantages:

[0169] 1) Static conditions can achieve tracking targets without steady-state error.

[0170] 2) Under dynamic conditions, the improved algorithm can effectively reduce the time delay problem existing in the traditional digital single-cycle control algorithm.

[0171] Embodiment 3

[0172] Based on the method of embodiment 1, a single-cycle delay compensation system for a magnetic suspension bearing switching power amplifier is disclosed, comprising:

[0173] A data acquisition module is configured to acquire circuit data, including: single-cycle initial time coil current i0, current reference value i ref , bus voltage U dc , period T s , load R and inductance L;

[0174] A model establishment module is configured to establish a single-polarity single-cycle control mathematical model and calculate the duty cycle of the single cycle;

[0175] A rule setting module is configured to set the state switching criterion of the charging and discharging period and determine the charging and discharging state of the single cycle;

[0176] A prediction module is configured to establish a linear duty cycle prediction model, calculate the linearly derived duty cycle d t , and calculate the duty cycle value d j to obtain the total duty cycle of the corresponding switch tube in the period;

[0177] An output module is configured to output the total duty cycle to the corresponding switch tube.

[0178] Embodiment 4

[0179] The purpose of this embodiment is to provide an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the single-cycle delay compensation method for the magnetic suspension bearing switching power amplifier when executing the computer program.

[0180] Embodiment 5

[0181] The purpose of this embodiment is to provide a computer-readable storage medium storing a computer program, wherein the computer program is executed by a processor to implement the single-cycle delay compensation method for the magnetic suspension bearing switching power amplifier.

[0182] Embodiment 6

[0183] The embodiment is to provide a computer program product including a computer readable medium, and computer readable program code is included on the computer readable medium, and the program code performs the single cycle delay compensation method of the magnetic suspension bearing switch power amplifier.

[0184] The steps involved in the devices of embodiments 3, 4, 5 and 6 above correspond to method embodiment 1, and the specific implementation can refer to the relevant description part of embodiment 1.

[0185] Those skilled in the art of the present technology should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage, etc.) containing computer-usable program code.

[0186] The present application is described with reference to flowcharts and / or block diagrams according to the method, device (system), and computer program product of the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The device that implements the functions specified in one or more flows and / or blocks.

[0187] These computer program instructions can also be stored in a computer readable storage medium that can guide the computer or other programmable data processing apparatus to work in a specific way, so that the instructions stored in the computer readable storage medium produce a product including instruction devices that implement the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The device that implements the functions specified in one or more flows and / or blocks.

[0188] These computer program instructions can also be loaded into a computer or other programmable data processing apparatus, so that a series of operation steps are performed on the computer or other programmable data processing apparatus to produce a computer-implemented process, so that the instructions executed on the computer or other programmable data processing apparatus provide a process for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The device that implements the functions specified in one or more flows and / or blocks.

[0189] The working mode or control mode involved in the above embodiments is the conventional working mode or control mode in the art unless otherwise specified.

[0190] Although the preferred embodiments of the present application have been described, those skilled in the art who once know the basic creative concept can make additional changes and modifications to the embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0191] Finally, it is stated that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit, and other modifications or equivalent replacements made by those skilled in the art to the technical solutions of the present application, as long as they do not deviate from the spirit and scope of the technical solutions of the present application, should be covered in the scope of the claims of the present application.

Claims

1. A single cycle delay compensation method for a magnetic bearing switching power amplifier, characterized in that, The method comprises the following steps: Collecting circuit data, the circuit data including: single cycle coil feedback current initial value i0, current given reference value i ref , bus voltage U dc , sampling period T, magnetic suspension bearing coil resistance R and magnetic suspension bearing coil inductance L; establishing a single-polarity single-cycle control mathematical model, and calculating the duty cycle of a single cycle; setting a state switching criterion of the charging and discharging cycle, and judging the charging and discharging state of a single cycle; A linear duty cycle prediction model is established, and the linear derived duty cycle d t and the calculated duty cycle value d j The total duty cycle corresponding to the switch tube in the period is obtained, and the total duty cycle is output to the corresponding switch tube; the linear duty cycle prediction model is: ; In the formula: is the predicted duty cycle; the equalization coefficient a is 0.05 t d is the linear derived duty cycle; d j is the calculated duty cycle value; The state switching criterion for the charging and discharging cycle is: when i0 < When i0 ≥ 1, the coil should be in a charging state during this cycle; when i0 ≥ 1, the coil should be in a charging state during this cycle. During this period, the coil should be in a discharging state. The linear derivation duty cycle d t The calculation formula is: ; in the formula: is the n-period linear derivation duty cycle; is the predicted duty cycle of the n-1 period; is the predicted duty cycle of the n-2 period; The calculated duty cycle value d j The formula is: when i0< 0 dj= 0 ; when i0≥ dj= .

2. A single-cycle delay compensation system for a magnetic bearing switching power amplifier based on the single-cycle delay compensation method of claim 1, characterized in that, The method comprises the following steps: a data acquisition module for acquiring circuit data; a model establishment module for establishing a single-polarity single-cycle control mathematical model; a rule setting module for setting a state switching criterion of the charging and discharging cycle; a prediction module for establishing a linear duty cycle prediction model; an output module for outputting the total duty cycle to the corresponding switch tube.

3. An electronic device, comprising: The computer readable storage medium stores a computer program, and the computer program is executed by the processor to realize the single-cycle delay compensation method of the magnetic suspension bearing switching power amplifier.

4. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program is executed by the processor to realize the single-cycle delay compensation method of the magnetic suspension bearing switching power amplifier.

5. A computer program product comprising a computer readable medium, characterized in that, The computer readable medium comprises computer readable program code, and the program code executes the single-cycle delay compensation method of the magnetic suspension bearing switching power amplifier.

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