A magnetization state observation method for variable-flux memory motor based on bidirectional transient current injection

Abstract

The application discloses a variable magnetic flux memory motor magnetization state observation method based on bidirectional transient current injection, and comprises the following steps: step 1, initializing the variable magnetic flux memory motor to obtain an initialization result; step 2, determining an initial magnetization state value of the variable magnetic flux memory motor based on the initialization result of the variable magnetic flux memory motor; step 3, determining whether the variable magnetic flux memory motor needs to be magnetized based on the initial magnetization state value; step 4, if the variable magnetic flux memory motor needs to be magnetized, determining a magnetization operation and injecting an observation pulse current; if the variable magnetic flux memory motor does not need to be magnetized, turning to step 2; and step 5, sampling data of the variable magnetic flux memory motor and updating a magnetization state observation value. The application solves the defects of insufficient observation accuracy and low observation efficiency in the prior art. The technical scheme can improve the accuracy of the observation result.

Description

Technical Field

[0001] This invention belongs to the field of electrical drive technology, and in particular relates to a method for observing variable flux memory motors based on bidirectional transient current injection (BTFI). Background Technology

[0002] Variable Flux Memory Machines (VFMMs) alter the magnetization state (MS) of low-coercive force (LCF) permanent magnets by applying instantaneous demagnetizing or magnetizing pulses, achieving flexible adjustment of the air gap flux linkage with almost no loss. Due to this advantage, VFMMs are highly competitive in applications requiring a wide constant power speed range (CPSR), such as electric vehicles. Hybrid permanent magnet VFMMs employ both high- and low-coercive force permanent magnets, achieving high torque density while maintaining adjustable permanent magnet flux linkage. Their operating trajectory and the current solution at the stable operating point vary across different operating regions. Therefore, observing the magnetization state based on VFMM speed, voltage, and current values ​​is a crucial task. Current methods for observing motor magnetization states often use threshold comparisons, which are insufficient for real-time observation based on the magnetization requirements of VFMMs. Summary of the Invention

[0003] In view of the above background, in order to more accurately observe the magnetization state of a variable flux memory motor, a method for observing the magnetization state of a variable flux memory motor based on bidirectional transient current injection is proposed. This method has the advantage of accurate observation of the variable flux memory motor.

[0004] Technical Solution: To achieve the above objectives, the present invention provides a multi-mode identification and coordinated control method for a hybrid permanent magnet variable flux memory motor, comprising the following steps:

[0005] Step 1: Initialize the variable flux memory motor and obtain the initialization result;

[0006] Step 2: Based on the initialization results of the variable flux memory motor, determine the initial magnetization state value of the variable flux memory motor;

[0007] Step 3: Based on the initial magnetization state value, determine whether the variable flux memory motor needs to be magnetized;

[0008] Step 4: If the variable flux memory motor needs magnetic adjustment, determine the magnetic adjustment operation and inject the observation pulse current; if magnetic adjustment is not required, go to step 2.

[0009] Step 5: Sample the data of the variable flux memory motor and update the observed magnetization state.

[0010] Optionally, the initialization of the variable flux memory motor to obtain the initialization result includes:

[0011] The observation time of the variable flux memory motor is set as the initial time;

[0012] The initial time of the variable flux memory motor is set to 0, corresponding to the number of measurements at the measurement time.

[0013] Optionally, determining the initial magnetization state value of the variable flux memory motor based on the initialization result of the variable flux memory motor includes:

[0014] Obtain the initial magnetization state value of the variable flux memory motor and determine the rotor flux linkage value;

[0015] Based on the rotor flux linkage value, the rotor flux linkage value at the initial moment is obtained.

[0016] Optionally, determining whether the variable flux memory motor needs to be magnetically adjusted based on the initial magnetization state value includes:

[0017] Obtain the expected magnetization state value of the variable flux memory motor. If the expected magnetization state value is not equal to the initial magnetization state value, the variable flux memory motor needs to be magnetized.

[0018] Obtain the expected magnetization state value of the variable flux memory motor. If the expected magnetization state value is equal to the initial magnetization state value, then the variable flux memory motor does not need to be magnetized.

[0019] Optionally, if the variable flux memory motor requires magnetic adjustment, a magnetic adjustment operation is determined, and an observation pulse current is injected; if magnetic adjustment is not required, proceed to step 2, which includes:

[0020] Based on the initial magnetization state value of the variable flux memory motor, the magnetization method of the variable flux memory motor is selected;

[0021] The magnetic adjustment methods of the variable flux memory motor include demagnetization and magnetization operations;

[0022] An observation pulse current is injected after the magnetization operation is completed.

[0023] Optionally, the step of sampling data from the variable flux memory motor and updating the observed magnetization state includes:

[0024] Obtain the current and voltage values ​​of the variable flux memory motor within a fixed time period of the initial magnetization state;

[0025] Obtain the current and voltage values ​​of the variable flux memory motor within a fixed time period when an observation pulse current is injected; based on the observation equation of the variable flux memory motor, obtain the flux linkage state value of the variable flux memory motor;

[0026] The flux linkage state value of the variable flux memory motor is updated.

[0027] Optionally, obtaining the flux linkage state value of the variable flux memory motor based on the observation equation of the variable flux memory motor includes:

[0028] The observation equation for the variable flux memory motor is:

[0029]

[0030] in, ω r (k0) represents the q-axis voltage, current, and angular velocity of the variable flux memory motor at time k0, which are recorded and stored in the Data 0# data group. ω r (k1) represents the q-axis voltage and current, d-axis voltage and current, and angular velocity of the variable flux memory motor at time k1, which are recorded and stored in the Data 1# data group.

[0031] Optionally, it also includes compensating for observation errors in the observed magnetization state values, including:

[0032] The equation for determining the observation error value is as follows:

[0033]

[0034] in, Indicates the observed pulse current The amplitude, ω r (k1) represents the motor speed at the k1th measurement time, u nl S represents the nonlinear disturbance voltage constant. q (k n ) represents the polarity function of the current, S d (k n () represents the electrical angle function;

[0035] The nonlinear disturbance voltage is compensated to reduce the error value of the magnetization state observation.

[0036] The present invention has the following beneficial effects:

[0037] 1. More precise observation nodes. The system determines whether a magnetic adjustment operation is required for the variable flux memory motor, thus confirming whether such an operation is necessary during its current operation. Only after confirming and analyzing appropriate observation nodes can the magnetic adjustment action of the variable flux memory motor be reasonably determined.

[0038] 2. Improved accuracy of observation results. In specific observations, multiple numerical samples are taken after the input observation current, and the observed values ​​are determined based on calculation equations. This allows for confirmation based on multiple obtained values, and the combined analysis of multiple data points improves observation accuracy. (If we must summarize three beneficial effects, we will condense them into one more.) Attached Figure Description

[0039] To more clearly illustrate the technical solutions of exemplary embodiments of the present invention, the accompanying drawings used in describing the embodiments are briefly introduced below. Obviously, the accompanying drawings described are only a part of the embodiments to be described in this invention, and not all of them. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0040] Figure 1 This is a flowchart of the magnetization state observation method of a variable flux memory motor based on bidirectional transient current injection in a specific embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the magnetization state observation method of a variable flux memory motor based on bidirectional transient current injection in a specific embodiment of the present invention.

[0042] Figure 3 The following are waveforms of the permanent magnet flux linkage observation error under different observation pulse current amplitudes in a specific embodiment of the present invention;

[0043] Figure 4 This is a waveform diagram of parameter testing during the demagnetization process from MS4 to MS2 in a specific embodiment of the present invention;

[0044] Figure 5 The waveform diagrams are for parameter testing during the magnetization process from MS2 to MS4 in a specific embodiment of the present invention. Detailed Implementation

[0045] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0046] It should also be noted that, for ease of description, the accompanying drawings show only the parts relevant to the invention and not all of them. Before discussing exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the operations (or steps) as sequential processes, many of the operations can be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations can be rearranged. The process can be terminated when its operation is completed, but it may also have additional steps not included in the drawings. The process may correspond to a method, function, procedure, subroutine, subprogram, etc.

[0047] like Figure 1 The diagram shown is a flowchart of the magnetization state observation method for a variable flux memory motor based on bidirectional transient current injection in a specific embodiment of the present invention. The multi-mode identification and coordinated control method for a hybrid permanent magnet variable flux memory motor described in this invention includes the following steps:

[0048] Step 1: Initialize the variable flux memory motor and obtain the initialization result;

[0049] Step 2: Based on the initialization results of the variable flux memory motor, determine the initial magnetization state value of the variable flux memory motor;

[0050] Step 3: Based on the initial magnetization state value, determine whether the variable flux memory motor needs to be magnetized;

[0051] Step 4: If the variable flux memory motor needs magnetic adjustment, determine the magnetic adjustment operation and inject the observation pulse current; if magnetic adjustment is not required, go to step 2.

[0052] Step 5: Sample the data of the variable flux memory motor and update the observed magnetization state.

[0053] Optionally, the initialization of the variable flux memory motor to obtain the initialization result includes:

[0054] The observation time of the variable flux memory motor is set as the initial time;

[0055] The initial time of the variable flux memory motor is set to 0, corresponding to the number of measurements at the measurement time.

[0056] Optionally, determining the initial magnetization state value of the variable flux memory motor based on the initialization result of the variable flux memory motor includes:

[0057] Obtain the initial magnetization state value of the variable flux memory motor and determine the rotor flux linkage value;

[0058] Based on the rotor flux linkage value, the rotor flux linkage value at the initial moment is obtained.

[0059] Optionally, determining whether the variable flux memory motor needs to be magnetically adjusted based on the initial magnetization state value includes:

[0060] Obtain the expected magnetization state value of the variable flux memory motor. If the expected magnetization state value is not equal to the initial magnetization state value, the variable flux memory motor needs to be magnetized.

[0061] Obtain the expected magnetization state value of the variable flux memory motor. If the expected magnetization state value is equal to the initial magnetization state value, then the variable flux memory motor does not need to be magnetized.

[0062] Optionally, if the variable flux memory motor requires magnetic adjustment, a magnetic adjustment operation is determined, and an observation pulse current is injected; if magnetic adjustment is not required, proceed to step 2, which includes:

[0063] Based on the initial magnetization state value of the variable flux memory motor, the magnetization method of the variable flux memory motor is selected;

[0064] The magnetic adjustment methods of the variable flux memory motor include demagnetization and magnetization operations;

[0065] An observation pulse current is injected after the magnetization operation is completed.

[0066] Optionally, the step of sampling data from the variable flux memory motor and updating the observed magnetization state includes:

[0067] Obtain the current and voltage values ​​of the variable flux memory motor within a fixed time period of the initial magnetization state;

[0068] Obtain the current and voltage values ​​of the variable flux memory motor within a fixed time period when the observation pulse current is injected;

[0069] Based on the observation equation of the variable flux memory motor, the flux linkage state value of the variable flux memory motor is obtained;

[0070] The flux linkage state value of the variable flux memory motor is updated.

[0071] Optionally, obtaining the flux linkage state value of the variable flux memory motor based on the observation equation of the variable flux memory motor includes:

[0072] The observation equation for the variable flux memory motor is:

[0073]

[0074] in, ω r(k0) represents the q-axis voltage, current, and angular velocity of the variable flux memory motor at time k0, which are recorded and stored in the Data 0# data group. ω r (k1) represents the q-axis voltage and current, d-axis voltage and current, and angular velocity of the variable flux memory motor at time k1, which are recorded and stored in the Data 1# data group.

[0075] Optionally, it also includes compensating for observation errors in the observed magnetization state values, including:

[0076] The equation for determining the observation error value is as follows:

[0077]

[0078] in, Indicates the observed pulse current The amplitude, ω r (k1) represents the motor speed at the k1th measurement time, u nl S represents the nonlinear disturbance voltage constant. q (k n ) represents the polarity function of the current, S d (k n () represents the electrical angle function;

[0079] The nonlinear disturbance voltage is compensated to reduce the error value of the magnetization state observation.

[0080] As can be seen, the most critical technical content of the present invention is the establishment of the magnetization state observation model, which includes the following:

[0081] Without considering factors such as cross-coupling magnetic saturation, iron loss, and permanent magnet eddy current loss, when the VFMM is in an untuned magnetic operation state, its d / q axis mathematical model can be expressed by the following equation:

[0082]

[0083] In steady state, the above model can be simplified to:

[0084]

[0085] In the formula, k is the index of the discrete sampling time of the driving system.

[0086] Combining equations (4) and (5), we can see that the rank of this mathematical model is 2, but the equation contains the d / q axis inductance L. d and L q Stator resistance R s Permanent magnet flux ψ pmWith four parameters, the VFMM mathematical model described above is an underranked model. It is not feasible to simultaneously solve for the values ​​of all four parameters using this model; therefore, when directly using this mathematical model for magnetization state observation, it cannot be guaranteed that the observed flux linkage will accurately converge to the actual value. Solving equations (4) and (5) simultaneously yields the permanent magnet flux linkage ψ. pm The expression is:

[0087]

[0088] It can be seen that when the sampling accuracy of voltage, current, and speed meets the requirements, the observation error of permanent magnet flux linkage is closely related to the error of inductance parameters. At this time, the observed value of permanent magnet flux linkage... It can be represented as:

[0089]

[0090] In the formula, ΔL d ΔL q This represents the error between the actual and calculated values ​​of the d / q axis inductance, i.e. Equation (7) can be rearranged as follows:

[0091]

[0092] It can be seen that the observed values ​​of permanent magnet flux It can be decomposed into the actual value ψ of the permanent magnet flux. pm and permanent magnet flux linkage observation error Δψ pm Two parts, the latter can be represented as:

[0093]

[0094] When the motor is in a steady-state operation with constant speed and torque, the d / q axis current... and inductance error ΔL d ΔL q All are constant values. Therefore, ignoring the sampling errors of voltage, current, and speed, it can be seen from equation (9) that the error of the motor during steady-state operation under fixed magnetization is mainly determined by the inductance error. Usually, the measured no-load d / q-axis inductance value is used as the calculated value. As the current increases, the deviation of its actual value becomes larger, and the inductance value error ΔL increases. d ΔL q The larger the value, the greater the inductance. There is a three-dimensional coupling relationship between the motor's d / q-axis inductance, d / q-axis current, and magnetization state. Under the same current conditions but different magnetization states, the motor's inductance parameters will change. Therefore, the inductance error is expressed as:

[0095]

[0096] It can be seen that the range of VFMM inductance variation is larger and more complex, which increases the difficulty of determining the accurate magnetization state using the above model. In addition, the magnetization state adjustment of the VFMM studied in this invention is achieved by applying a d-axis pulse current. During the magnetization process, the transient current peak is relatively large, which also significantly disturbs the dynamic performance of flux linkage observation.

[0097] For the full-rank observation process of the bidirectional transient current injection method, such as Figure 2 The diagram shown illustrates the principle of the magnetization state observation method for a variable flux memory motor based on bidirectional transient current injection in a specific embodiment of the present invention. The demagnetizing and magnetizing current trajectories are illustrated using trapezoidal waves as an example, and the injected observation pulse current uses a square wave signal. Magnetization state observation is performed after the demagnetizing and magnetizing processes are completed; that is, the observation pulse current is injected after the demagnetizing and magnetizing processes. The polarity of this current signal is the same as that of the previous magnetizing current, but its amplitude is lower than that of the previous magnetizing current, in order to distinguish the magnetizing current from... To prevent erroneous magnetization state adjustments during the observation process, and to simplify simulation and experimental procedures, the magnetization state flags DMM_Flag or RMM_Flag can be used in the program to determine the magnetization state. polarity, and will The amplitude is set to be lower than the previous magnetizing current amplitude. For example, 1 / 2. Figure 2 The delays Delay 1# and Delay 3# set in the configuration are used to complete the transient adjustment process of demagnetization and magnetization, preventing errors in parameter measurement due to transient changes during magnetization. After the system re-enters steady state, the VFMM operating voltage and current are measured and the data are recorded as Data 0# and Data 2#. After data recording is completed, an observation pulse current is applied. After delays of Delay2# and Delay4# to ensure the elimination of the step transient of the observed pulse, the measurement of the motor's operating voltage and current is restarted, and data Data1# and Data3# are recorded. It should be noted that the time widths of Data0# and Data1#, and Data2# and Data3# are equal; if the current changes smoothly during the magnetization process, then Delay2# and Delay4# can be 0.

[0098] The magnetization state observation process was conducted under constant load torque conditions. Taking the magnetization state observation process after demagnetization as an example, the permanent magnet flux linkage at this time is ψ. pm_DM The steady-state equation of the motor after demagnetization and delay 1# is:

[0099]

[0100] In the formula, variables with and without "0" in their subscripts correspond to... and The parameters are as follows. “k0” and “k1” represent the measurement times of Data 0# and Data 1# at the k0 and k1 times, respectively.

[0101] To minimize the impact on output torque, the pulse current was observed. The width is limited to a very short time. Because the mechanical and temperature time constants are much larger than the electrical constants, the rotor speed and stator winding resistance are almost constant during the observation process, i.e., ω. r (k0)=ω r (k1), R s0 =R s Based on this, it can be assumed that under constant load torque, the motor... and The electromagnetic torque is equal under both control conditions, that is:

[0102]

[0103] The injection can be obtained by solving equation (15). The rotor flux linkage after the rotor:

[0104]

[0105] Substituting equation (16) into equation (14), we get:

[0106]

[0107] Multiply both sides of equation (17) by We can obtain:

[0108]

[0109] Multiply both sides of equation (13) by We can obtain:

[0110]

[0111] Adding equation (18) to equation (19) yields:

[0112]

[0113] Combining equations (20) and (12), we get:

[0114]

[0115] From equation (21), it can be seen that the rank of this equation is 2, that is, only 2 rank is present in the equation. Permanent magnet flux linkage ψ under certain conditions pm_DM and stator winding resistance R s Two variables, and all d / q axis inductance Ld0 L q0 L d L q and in Permanent magnet flux ψ during the process pm_ep All of these are canceled out after the above derivation. Therefore, ψ after the demagnetization process pm_DM and R s The observed values ​​can be calculated using equation (21) and converge to the accurate values. Let ω r (k0)=ω r (k1), R s0 =R s Substituting into equation (3.21) yields:

[0116]

[0117] In the formula, ω r (k0) is recorded and stored in the Data 0# data group. ω r (k1) Record and store the data in Data 1#. Iterative calculations are performed using the recorded Data0# and Data 1# data until the observation results converge to the final value. The observation process for the magnetization state after magnetization is similar; the permanent magnet flux linkage after magnetization can be obtained using the recorded Data 2# and Data 3# data. The flow of the above observation method is as follows: Figure 1 As shown in the figure, ψ pm_m This indicates the permanent magnet linkage after the magnetization operation is completed.

[0118] This magnetization state observation method is based on a full-rank motor model. The solution process does not require the introduction of d / q-axis inductance, avoiding errors caused by inaccurate inductance estimation. Furthermore, it is unaffected by transient changes in d / q-axis inductance caused by magnetization and observation processes. In addition, optimizing the injected transient current sequence ensures that the observation process does not change the motor's magnetization state and avoids the influence of transient permanent magnet flux linkages on the observation results. Therefore, theoretically, this method is well-suited for VFMMs. The observed magnetization state value remains constant after the magnetization process ends until the next magnetization action is performed, at which point the magnetization state value is updated again.

[0119] During observation, the nonlinearity of the conventional voltage source inverter (VSI) can also affect the observation results. Therefore, it is necessary to suppress the errors generated during the observation process.

[0120] The specific error influence principle is that the inherent dead time of VSI, switching delay and conduction voltage drop and other factors cause voltage distortion, which affects the observation results obtained in equation (22). Therefore, it is necessary to deal with this influence.

[0121] The perturbation equation for the VSI nonlinearity factor is as follows:

[0122]

[0123] in, Indicates the observed pulse current The amplitude, ω r (k1) represents the motor speed at the k1th measurement time, u nl S represents the voltage constant. q (k n ) represents the polarity function of the current, S d (k n ) represents the electrical angle function, which is:

[0124]

[0125]

[0126] Among them, t dead t on t off T s These are dead time, switch turn-on delay time, switch turn-off delay time, and switching cycle, respectively. dc u ds u d0 These represent the DC bus voltage, the on-state voltage drop of the switching transistor, and the on-state voltage drop of the freewheeling diode, respectively. θ is the electrical angle. e =θ+π / 2, where sign(i a，b，c The equation is:

[0127]

[0128] Based on the Δψ in equation (23) pm_DM about After differentiation, we can see that Δψ pm_DM yes It is a monotonically decreasing function, therefore it can be improved by increasing... The value of u is used to weaken the effect of u nl1 u nl0 The resulting observation error Δψ pm_DM Therefore, pulse current was observed. The amplitude needs to be increased as much as possible without changing the current magnetization state, that is, it must satisfy... Under the given conditions, maximize its amplitude. To make Δψpm_DM If the value is close to 0, then the nonlinear disturbance voltage constant u can be... nl Compensation is performed to bring the value close to 0. The above analysis considers only the absolute values ​​of each parameter; therefore, the conclusions for the magnetization and demagnetization processes are the same. Regarding the resulting errors, such as... Figure 3 The figure shown is a waveform diagram of the permanent magnet flux linkage observation error under different observation pulse current amplitudes in a specific embodiment of the present invention.

[0129] Based on Figure 3 Further analysis reveals that due to the VSI disturbance voltage constant u nl The resulting Δψ pm_e / ψ pm It is the amplitude of the injected observation pulse current. The monotonically decreasing function, as The increase of Δψ pm_e / ψ pm The decreasing slope becomes gentler, when The amplitude of the modulated magnetocurrent is greater than that under this magnetization state. In half of the cases, the percentage of permanent magnet flux linkage observation error is close to 5%, and the reduction in error is not significant. Therefore, this invention will... Set to the current magnetization state 1 / 2 of.

[0130] After determining the overall observation method, it is also necessary to analyze the observation performance achievable by the observation method disclosed in this application, specifically:

[0131] In T L =0.75Nm operating condition The performance of the observation method after magnetization was tested during the control phase. A trapezoidal demagnetizing pulse current with an amplitude of -5.1A and a width of 30ms was injected at 10s, thus achieving the demagnetization process from MS4 to MS2. A square wave observation pulse current with an amplitude of -3A and a width of 10ms was injected at 10.2s. The waveforms of each parameter test are shown below. Figure 4 As shown in the figure, the parameters marked with an asterisk (*) represent their given values.

[0132] Depend on Figure 4(a) It can be seen that under MS4 light load conditions without demagnetizing pulse current, the motor's steady-state performance is good, and both d / q axis currents meet the rated specifications with minimal fluctuations. After applying the trapezoidal wave d-axis demagnetizing pulse current command at 10s, the measured d-axis current response is good, and the q-axis current amplitude remains basically unchanged during demagnetization. After 10.03s, the magnetization process ends, and the magnetization state decreases to MS2. Various parameters fluctuate and reach a steady state under MS2 after about 50ms of dynamic adjustment. At this time, because the permanent magnet flux decreases while the motor torque remains constant, the q-axis current amplitude increases compared to that under MS4. After applying the observation pulse current at 10.2s, various parameters fluctuate and return to the steady-state value under MS2 after 11ms of dynamic adjustment. During the observation process, the measured d-axis current follows the given DC command well, and the measured q-axis current remains basically unchanged.

[0133] The actual given value before the demagnetization operation is performed. Set to the theoretical value given by the permanent magnet flux linkage. Equal, i.e., 0.126 Wb. After the demagnetization operation is performed at 10 s... The value decreased to 0.072 Wb, and demagnetization was completed at 10.03 s. The value was reduced to 0.072 Wb. After performing a 10 ms BTFI observation at 10.2 s, the transient observation value ψ of the permanent magnet flux was calculated. pm_et After iterative calculation to ψ pm_et When it reaches a stable state, its fluctuation error is about 4%. Let ψ pm_et The average value of 0.072 Wb is used as the steady-state observation value of the permanent magnet flux linkage ψ. pm_e To prevent severe jitter during demagnetization and observation of the HPM-VFMM, the actual setpoint for the permanent magnet flux linkage is... In ψp m_et Always with before reaching steady state Maintain consistency until it reaches a steady state. Updated to ψ pm_e ,like Figure 4 As shown in (b). After the demagnetization process, the BTFI method can obtain relatively accurate magnetization state observations without changing the magnetization state adjustment, but there is an observation delay.

[0134] A trapezoidal wave magnetizing pulse current with an amplitude of 38A and a width of 70ms was injected at 20s, thus realizing the magnetization process from MS2 to MS4. A square wave observation pulse current with an amplitude of 20A and a width of 10ms was injected at 20.2s. The waveforms of each parameter test are as follows: Figure 5As shown in the figure, parameters marked with an asterisk (*) represent their given values. Compared to the magnetization state observation process after demagnetization, the changes in various parameters during the magnetization state observation process after magnetization show opposite trends, and the fluctuations in d / q axis current and stator flux linkage trajectory parameters are more drastic. After magnetization, the BTFI method can obtain relatively accurate permanent magnet flux linkage observation values, but it also suffers from observation delay.

[0135] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any transformations or substitutions that can be conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for observing the magnetization state of a variable flux memory motor based on bidirectional transient current injection, characterized in that, The method includes the following steps: Step 1: Initialize the variable flux memory motor and obtain the initialization result; Step 2: Based on the initialization results of the variable flux memory motor, determine the initial magnetization state value of the variable flux memory motor; Step 3: Based on the initial magnetization state value, determine whether the variable flux memory motor needs to be magnetized; Step 4: If the variable flux memory motor needs magnetic adjustment, determine the magnetic adjustment operation and inject the observation pulse current; if magnetic adjustment is not required, go to step 2. Step 5: Sample the data of the variable flux memory motor and update the observed magnetization state.

2. The method for observing the magnetization state of a variable flux memory motor based on bidirectional transient current injection according to claim 1, characterized in that, The initialization of the variable flux memory motor, to obtain the initialization result, includes: The observation time of the variable flux memory motor is set as the initial time; The initial time of the variable flux memory motor is set to 0, corresponding to the number of measurements at the measurement time.

3. The method for observing the magnetization state of a variable flux memory motor based on bidirectional transient current injection according to claim 1, characterized in that, The determination of the initial magnetization state value of the variable flux memory motor based on the initialization result of the variable flux memory motor includes: Obtain the initial magnetization state value of the variable flux memory motor and determine the rotor flux linkage value; Based on the rotor flux linkage value, the rotor flux linkage value at the initial moment is obtained.

4. The method for observing the magnetization state of a variable flux memory motor based on bidirectional transient current injection according to claim 1, characterized in that, The step of determining whether the variable flux memory motor needs to be magnetically adjusted based on the initial magnetization state value includes: Obtain the expected magnetization state value of the variable flux memory motor. If the expected magnetization state value is not equal to the initial magnetization state value, the variable flux memory motor needs to be magnetized. Obtain the expected magnetization state value of the variable flux memory motor. If the expected magnetization state value is equal to the initial magnetization state value, then the variable flux memory motor does not need to be magnetized.

5. The method for observing the magnetization state of a variable flux memory motor based on bidirectional transient current injection according to claim 1, characterized in that, If the variable flux memory motor requires magnetic adjustment, a magnetic adjustment operation is determined, and an observation pulse current is injected; if magnetic adjustment is not required, proceed to step 2, which includes: Based on the initial magnetization state value of the variable flux memory motor, the magnetization method of the variable flux memory motor is selected; The magnetic adjustment methods of the variable flux memory motor include demagnetization and magnetization operations; An observation pulse current is injected after the magnetization operation is completed.

6. The method for observing the magnetization state of a variable flux memory motor based on bidirectional transient current injection according to claim 1, characterized in that, The step of sampling data from the variable flux memory motor and updating the observed magnetization state includes: Obtain the current and voltage values ​​of the variable flux memory motor within a fixed time period of the initial magnetization state; Obtain the current and voltage values ​​of the variable flux memory motor within a fixed time period when the observation pulse current is injected; Based on the observation equation of the variable flux memory motor, the flux linkage state value of the variable flux memory motor is obtained; The flux linkage state value of the variable flux memory motor is updated.

7. The method for observing the magnetization state of a variable flux memory motor based on bidirectional transient current injection according to claim 6, characterized in that, The process of obtaining the flux linkage state value of the variable flux memory motor based on the observation equation of the variable flux memory motor includes: The observation equation for the variable flux memory motor is: in, ω r (k0) represents the q-axis voltage, current, and angular velocity of the variable flux memory motor at time k0, which are recorded and stored in the Data 0# data group. ω r (k1) represents the q-axis voltage and current, d-axis voltage and current, and angular velocity of the variable flux memory motor at time k1, which are recorded and stored in the Data 1# data group.

8. The method for observing the magnetization state of a variable flux memory motor based on bidirectional transient current injection according to claim 1, characterized in that, It also includes compensation for observation error values ​​of the observed magnetization state, including: The equation for determining the observation error value is as follows: in, Indicates the observed pulse current The amplitude, ω r (k1) represents the motor speed at the k1th measurement time, u nl S represents the nonlinear disturbance voltage constant. q (k n ) represents the polarity function of the current, S d (k n () represents the electrical angle function; The nonlinear disturbance voltage is compensated to reduce the error value of the magnetization state observation.

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