Method and system for sensorless control of a hybrid excitation motor
By estimating the rotor position of the hybrid excitation motor using a series inductance model and a full-phase pulse injection method, the problems of permanent magnet demagnetization and sensor failure were solved, achieving high-precision sensorless control and reducing engineering verification costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WUHAN UNIV OF TECH
- Filing Date
- 2026-03-12
- Publication Date
- 2026-06-09
Smart Images
Figure CN122178796A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of motor control technology, and in particular to a sensorless control method and system for a hybrid excitation motor. Background Technology
[0002] With increasing emphasis on energy conservation and environmental protection worldwide, research on Integrated Starter-Generators (ISGs) for multi-electric aircraft has garnered wider attention. However, due to the risk of demagnetization or even loss of magnetism in rare-earth permanent magnet materials under short-circuit and high-temperature conditions, developing reluctance motors with no or low permanent magnet content for ISG systems in aerospace has become a hot research topic in recent years. The novel Hybrid Excited Vernier Reluctance Motor (HE-VRM), featuring double-slot permanent magnets and zero-sequence current, offers advantages such as a wide speed range and high torque density. Furthermore, since position sensors are prone to failure, sensorless control can further improve system reliability. For reluctance motors with a double salient pole structure, the air gap permeability changes periodically with rotor position, leading to changes in phase inductance. Position information can be obtained by detecting winding inductance, thus enabling sensorless control.
[0003] Therefore, a sensorless control method for a hybrid excitation motor is proposed, which can accurately estimate the rotor position without the need for faulty position sensors, thus improving system reliability. Simultaneously, field-circuit coupling simulation experiments were used to verify the feasibility of this method. Field-circuit coupling simulation overcomes the inherent limitations of "pure field simulation" and "pure circuit simulation," achieving a balance between "electromagnetic field detail accuracy" and "system dynamic response speed," thus better realizing dynamic control. This is essential. Furthermore, this invention can significantly reduce the trial-and-error costs and debugging time costs of actual engineering experiments. Summary of the Invention
[0004] In view of this, the present invention proposes a sensorless control method and system for a hybrid excitation motor that calculates the rotor position at the current moment by establishing a series inductance model, measuring the current changes of each phase using the pulse injection method to obtain the series inductance values of different phase combinations, and eliminating the need for position sensors that are prone to failure.
[0005] On one hand, the present invention provides a sensorless control method for a hybrid excitation motor, comprising the following steps: S1: Configure a hybrid excitation motor to construct a split dual three-phase inverter drive structure; S2: Based on the conduction relationship of the windings of the hybrid excitation motor, a series inductor model under instantaneous detection signal excitation is established; S3: Simplify the series inductance model by segmentation; use the full-phase pulse injection method to inject detection pulse voltage into each phase in sequence to obtain the value of the series inductance, thereby determining the current sector of the rotor, and substituting it into the series inductance model to calculate the bias electrical angle. S4: Calculate the current rotor magnetic field angle based on the bias electrical angle to achieve control of the hybrid excitation motor.
[0006] Based on the above technical solutions, preferably, the hybrid excitation motor described in step S1 adopts a double salient pole structure with 24 slots and 22 pole pairs. The rotor part includes a stacked iron core, the excitation source is located on the stator side, and two layers of permanent magnets are provided at the slot opening. The magnetization direction of the inner permanent magnet is radial, and the magnetization direction of the outer permanent magnet is tangential.
[0007] Preferably, the hybrid excitation motor includes a first sub-phase assembly, a second sub-phase assembly, a first inverter, and a second inverter. Both the first and second sub-phase assemblies are star-connected. The first sub-phase assembly includes three-phase windings Ap, Bp, and Cp, and the second sub-phase assembly includes three-phase windings An, Bn, and Cn. The neutral points of the first and second sub-phase assemblies are interconnected. The first sub-phase assembly is electrically connected to the first inverter, and the second sub-phase assembly is electrically connected to the second inverter. The first and second inverters are controlled based on space vector pulse width modulation (SVPWM). Both the first and second inverters include several switching devices.
[0008] More preferably, step S2 involves driving the inverter to make two different three-phase windings p and q Conductive, p , q ∈{Ap, Bp, Cp, An, Bn, Cn}, and inject instantaneous detection signals, at which point the three-phase windings are instantaneously turned on. p and q In series configuration, obtain the current three-phase winding configuration. p and q The voltage equation for the series state, neglecting back electromotive force, rotor angular velocity and winding voltage drop, yields a simplified voltage equation, which describes the relationship between the inductance of the winding in the series state and the voltage of the instantaneous detection signal and the current of the winding in the series state; a total of six sets of series inductance models with the same expression and a phase difference of 60° are formed.
[0009] More preferably, the piecewise function simplification of the series inductor model in step S3 is performed by removing the peak and trough regions from the waveform of the series inductor model as the rotor angle changes, mirroring the sampling points of the non-peak and trough sectors to the same side of the waveform peak, and fitting the simplified equivalent series inductor model; the bias angle is calculated by setting feature points and substituting them into the equivalent series inductor model.
[0010] In a further preferred embodiment, step S3 involves sequentially injecting detection pulse voltages into each phase using the full-phase pulse injection method to obtain the value of the series inductance, thereby determining the current sector of the rotor and obtaining the winding corresponding to the series inductance. The bias angle is then calculated by substituting this value into the series inductance model. This involves configuring several detection pulses and acceleration pulses. Starting from the first time interval (t1, t2), detection pulses are injected into each of the three-phase windings, with each pulse having the same width. The generated current signal is recorded. After detecting the current signals of all three-phase windings, after a first time interval, acceleration pulses are injected again in the second time interval (t3, t4). After another second time interval, a new round of detection pulses is injected in the third time interval starting from time t5. This alternating injection process of detection pulses and acceleration pulses is repeated to obtain six sets of series inductance values. The current sector of the rotor is determined based on the series inductance values. Based on the obtained sector of the rotor, the series inductance values are matched one-to-one with the windings in the series inductance model under instantaneous detection signal excitation to calculate the rotor's electrical angle.
[0011] Preferably, in each round of injection in the whole-phase pulse injection method, the interval between adjacent detection pulses is (t2-t1-6△t) / 5, where △t is the width of the detection pulse.
[0012] Preferably, the first time interval and the second time interval are used to release the magnetic flux remaining in the winding after the injection of the detection pulse, and the first time interval is shorter than the second time interval.
[0013] Preferably, step S4 involves: calculating the rotor electrical angle based on the bias electrical angle; converting the reference current in the three-phase stationary coordinate system to the reference current in the dq coordinate system using the field-oriented control (FOC) method; comparing the error between the reference current in the dq coordinate system and the actual sampled current, inputting the error into the proportional-integral controller; outputting the voltage reference value; combining it with the rotor electrical angle; determining the sector and size of the voltage space vector corresponding to the voltage reference value; and providing PWM signals to the first and second inverters based on the sector and size of the voltage space vector to control the conduction time and conduction sequence of the switching devices, so that the actual current on the three-phase windings follows the reference current in the three-phase stationary coordinate system.
[0014] On the other hand, the present invention provides a sensorless control system for a hybrid excitation motor, for implementing the above-mentioned method, comprising: The hybrid excitation motor adopts a split dual three-phase inverter drive structure, and a zero-sequence current excitation circuit is built inside. The series inductor model building unit injects an instantaneous detection signal into the windings of the hybrid excitation motor, causing two different three-phase windings to be instantaneously turned on. p and q In series configuration, obtain the current three-phase winding configuration. p and q The voltage equation for the series state, neglecting back electromotive force, rotor angular velocity and winding voltage drop, yields a simplified voltage equation, which describes the relationship between the inductance of the winding in the series state and the voltage of the instantaneous detection signal and the current of the winding in the series state. The full-phase pulse injection detection unit sequentially injects detection pulses and acceleration pulses into each of the three-phase windings; The bias electrical angle calculation unit, based on the waveform of the series inductor model as the rotor angle changes, removes the peak and trough regions, mirrors the sampling points of the non-peak and trough sectors to the same side of the waveform peak, and fits to obtain an equivalent series inductor model. The bias electrical angle is then calculated using the equivalent series inductor model. The control drive unit calculates the electrical angle of the rotor magnetic field at the current moment based on the bias electrical angle, thereby controlling the hybrid excitation motor.
[0015] The sensorless control method and system for hybrid excitation motors provided by this invention have the following advantages compared to the prior art: 1. The hybrid excitation motor selected in this invention is HE-VRM, which is a novel hybrid vernier reluctance motor with double-slot permanent magnets and zero-sequence current. Its zero-sequence current is adjustable and the DC winding and AC winding are combined into one winding, also known as DC / AC concentrated winding. This motor has the advantages of wide speed range and high torque density. The radially magnetized inner slot permanent magnet can improve the effective torque through the magnetic flux modulation effect, while the tangentially magnetized outer slot permanent magnet can improve the torque density by eliminating DC saturation in the stator core.
[0016] 2. By establishing a series inductor model under instantaneous detection signals and sequentially exciting each phase using the full-phase pulse injection method, inductance information is systematically collected, providing a sufficient data foundation for angle calculation. Strongly nonlinear peak / trough regions in the inductance waveform are removed, and the remaining sectors are mirrored to the same side, constructing a linearly varying equivalent inductance model. This significantly reduces the impact of inductance nonlinearity on angle calculation, improving estimation accuracy and algorithm robustness. The full-phase pulse injection method employs an alternating injection pattern of detection and acceleration pulses, with a flux release interval set between pulses. This design effectively suppresses residual current and reduces torque ripple while ensuring sufficient sampling information, thus improving position accuracy.
[0017] 3. The estimated rotor electrical angle is seamlessly integrated into the FOC control loop to achieve high dynamic performance torque and speed control, giving the entire system good closed-loop control performance. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 This is a schematic diagram of the motor structure of the sensorless control method and system for the hybrid excitation motor of the present invention. Figure 2 This is a schematic diagram of the drive system of the hybrid excitation motor in the sensorless control method and system for the hybrid excitation motor of the present invention. Figure 3 This is a schematic diagram of the sensorless control method and system for the hybrid excitation motor of the present invention using the all-phase pulse injection method. Figure 4 This is a schematic diagram of the series inductor model of the sensorless control method and system for the hybrid excitation motor of the present invention; Figure 5 This is a schematic diagram of the main circuit model of the sensorless control method and system for the hybrid excitation motor of the present invention, built in Ansys's Simplier. Figure 6 This is a comparative schematic diagram of the series inductance and series inductance model of the motor built by Maxwell for the sensorless control method and system of the hybrid excitation motor of the present invention. Figure 7 This invention relates to the sensorless control method and system for a hybrid excitation motor, detailing the driving process and position estimation error as the motor accelerates to a given speed under no-load and 1N load conditions. Detailed Implementation
[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0021] The permanent magnets of hybrid excitation motors are at risk of demagnetization or even loss of magnetism in harsh environments, and position sensors often malfunction. Moreover, current verification experiments are conducted directly on prototypes, which incurs high costs for trial and error and debugging time. Furthermore, "pure field simulation" and "pure circuit simulation" only reflect the results of the motor in steady state and cannot accurately represent the simulation results of the motor's dynamic operation.
[0022] In view of this, such as Figure 1 As shown, in one aspect, the present invention provides a sensorless control method for a hybrid excitation motor, comprising the following steps: S1: Configure a hybrid excitation motor to construct a split dual three-phase inverter drive structure.
[0023] like Figure 1 As shown, the hybrid excitation motor in this embodiment adopts HE-VRM and has a double salient pole structure with 24 slots and 22 pole pairs. The rotor part includes a stacked iron core, the excitation source is located on the stator side, and two layers of permanent magnets are provided at the slot opening. The magnetization direction of the inner permanent magnet is radial, and the magnetization direction of the outer permanent magnet is tangential.
[0024] Figure 2 (a) shows the hybrid excitation motor HE-VRM and its drive system. The content within the dashed box is the hybrid excitation motor HE-VRM. The figure shows the first sub-phase assembly, the second sub-phase assembly, the first inverter, and the second inverter. Both the first and second sub-phase assemblies are connected in a star configuration. The first sub-phase assembly includes three-phase windings Ap, Bp, and Cp, and the second sub-phase assembly includes three-phase windings An, Bn, and Cn. The neutral points of the first and second sub-phase assemblies are interconnected. The first sub-phase assembly is electrically connected to the first inverter, and the second sub-phase assembly is electrically connected to the second inverter. The first and second inverters are controlled based on space vector pulse width modulation (SVPWM). Both the first and second inverters include several switching devices. The hybrid excitation motor HE-VRM is a structure with DC and AC windings combined. In this embodiment, the switching devices can be IGBTs, or other switching devices, which will not be elaborated further here.
[0025] When zero-sequence current is injected into the hybrid excitation motor (HE-VRM), it is equivalent to injecting DC current into each sub-phase component, which can then act as a virtual DC excitation winding to generate electromagnetic torque. The first sub-phase component is powered by the first inverter on the left, and similarly, the second sub-phase component is powered by the second inverter on the right. The neutral points of the two sub-phase components are connected together, providing a return path for the zero-sequence current excitation.
[0026] refer to Figure 2 In (a), to establish a module magnetic field with zero-sequence current excitation, the armature current of each sub-phase component is: , formula 1; The current output by the first inverter is respectively i Ap , i Bp and i Cp The output currents of the second inverter are respectively i An , i Bn and i Cn , i dc The DC component, i ac For the purpose of exchanging quantities, i 0 This refers to the current on the neutral line connecting the neutral points of the two sub-phase components.
[0027] S2: Based on the conduction relationship of the windings of the hybrid excitation motor, a series inductor model under instantaneous detection signal excitation is established.
[0028] Step S2 involves driving the inverter to make two different three-phase windings p and q Conductive, p , q ∈{Ap, Bp, Cp, An, Bn, Cn}, and inject instantaneous detection signals, at which point the three-phase windings are instantaneously turned on. p and q In series configuration, obtain the current three-phase winding configuration. p and q The voltage equation for the series state, neglecting back electromotive force, rotor angular velocity and winding voltage drop, yields a simplified voltage equation, which describes the relationship between the inductance of the winding in the series state and the voltage of the instantaneous detection signal and the current of the winding in the series state; a total of six sets of series inductance models with the same expression and a phase difference of 60° are formed.
[0029] like Figure 2As shown in (b), each phase winding can be equivalent to an inductor, a resistor, and a back electromotive force source. For example, the Ap winding is equivalent to an inductor. L a ,resistance R and back EMF source e a Similarly, the Cp winding is equivalent to an inductor. L c ,resistance R and back EMF source e c The branches Ap, Bp, Cp, An, Bn, and Cn corresponding to the six windings of the three-phase system can be labeled as a, b, c, d, e, and g, respectively.
[0030] When switching devices S1 and S6 are turned on and a momentary detection signal is injected, the momentary conduction loop is a series structure with mutual inductive coupling between windings Ap and Cp. The voltage equation can be expressed as: , formula 2; in U dc This is the DC bus voltage. L a+c Let the total equivalent inductance of the series path between windings Ap and Cp be denoted as . i a This represents the instantaneous current value of winding Ap. ω This refers to the rotor angular velocity. In the zero-speed or low-speed range, the rotor angular velocity is zero or very small, and the back electromotive force can be ignored. Furthermore, the instantaneous detection signal results in a small response current, and therefore the winding voltage drop can also be neglected. The voltage equation can be further simplified as follows:
[0031] , formula 3; Let the width of the instantaneous detection signal, i.e., its duration, be Δt. Taking the series structure with inductive coupling between windings Ap and Cp as an example, the series inductance is: , formula 4, in L ac For mutual intuition, I a+c This represents the effective current value of the series inductor model during the duration of the instantaneous detection signal.
[0032] Similarly, when any two different three-phase windings are turned on... p and q When connected in series, the inductance of its series state L p+q It can be written as , in For mutual intuition, This represents the effective current value of the series inductor model during the duration of the instantaneous detection signal.
[0033] S3: Simplify the series inductance model by segmentation; use the full-phase pulse injection method to inject detection pulse voltage into each phase in sequence to obtain the value of the series inductance, thereby determining the current sector of the rotor, and substituting it into the series inductance model to calculate the bias electrical angle.
[0034] The piecewise simplification of the series inductor model involves removing peak and trough regions from the waveform of the series inductor model as the rotor angle changes, mirroring the sampling points of non-peak and trough sectors to the same side of the waveform peak, and fitting the simplified equivalent series inductor model. The bias angle is then calculated by setting feature points and substituting them into the equivalent series inductor model.
[0035] The variation of the series inductor model with electrical angle can be expressed as follows: Figure 4 (a) The formation of a double three-phase winding is a series inductor model with six phases differing by 60°. L ( θ ):
[0036] , formula 5; in L 0 is the electrical angle θ The offset when it is 0 k 1 represents the slope of the six piecewise functions, and the six expressions correspond to the piecewise functions of the series inductor model of the six sectors.
[0037] The six-phase-differentiated series inductor model can be further equivalent to performing six discrete samplings at 60° intervals on a single series inductor model. As shown in the figure, discrete sampling points P1, P3, P4, and P6 are located in the linear variation region, while discrete sampling points P2 and P5 are located in the saturation region, where the inductance does not change significantly with the electrical angle. Therefore, discrete sampling points P2 and P5 are only used for sector estimation in the hexagonal plane. Based on the symmetry of the curve, the discrete sampling points P1 and P6 are mirrored to obtain symmetrical points P1* and P6*, thus placing the four discrete sampling points within the same linear region.
[0038] Then, using the full-phase pulse injection method, detection pulse voltages are injected sequentially into each phase to obtain the value of the series inductance, thereby determining the current sector of the rotor and obtaining the winding corresponding to the series inductance. The bias angle is calculated by substituting the series inductance model. Several detection pulses and acceleration pulses are configured. Starting from the first time segment (t1, t2), detection pulses are injected into each of the three-phase windings. The width of each detection pulse is the same, and the generated current signal is recorded. After detecting the current signals of all three-phase windings, after the first time interval, acceleration pulses are injected in the second time segment (t3, t4). After the second time interval, a new round of detection pulses is injected in the third time segment starting from time t5. The above alternating injection process of detection pulses and acceleration pulses is repeated to obtain the values of six sets of series inductance. The current sector of the rotor is determined based on the value of the series inductance. Based on the obtained sector of the rotor, the value of the series inductance is matched one-to-one with the winding in the series inductance model under the excitation of the instantaneous detection signal to calculate the rotor electrical angle.
[0039] Specifically, such as Figure 3 As shown, the full-phase pulse injection method involves configuring several detection pulses and acceleration pulses. Starting from the first time segment (t1, t2), detection pulses are injected into each of the three-phase windings. The width of each detection pulse is the same, and the generated current signal is recorded. After detecting the current signals of all three-phase windings, after the first time interval, acceleration pulses are injected in the second time segment (t3, t4). After the second time interval, a new round of detection pulses from the full-phase pulse injection method is injected in the third time segment starting from time t5. The above alternating injection process of detection pulses and acceleration pulses is repeated to obtain the magnitudes of six sets of series inductance values. The current sector of the rotor is determined based on the magnitude of the series inductance values. Based on the obtained sector of the rotor, the magnitude of the series inductance values is matched one-to-one with the windings in the series inductance model under the excitation of the instantaneous detection signal, and the rotor electrical angle is calculated. Figure 3 The figure below shows the timing diagram of several detection pulses and acceleration pulses. Figure 3 The image above shows the current signals of the corresponding detection pulse and acceleration pulse.
[0040] In the full-phase pulse injection method, the interval between adjacent detection pulses in each injection round is (t2-t1-6Δt) / 5, where Δt is the width of the detection pulse. As a preferred embodiment, the width of the detection pulse here is the same as the width of the instantaneous detection signal in step S2.
[0041] The first time interval and the second time interval are used to release the magnetic flux remaining in the winding after the injection of the detection pulse. The first time interval is shorter than the second time interval.
[0042] Figure 4(b) in the figure redefines the piecewise linear interval region of the series inductor in an orthogonal coordinate system. l 1 and l 2. To achieve accurate position estimation, discrete sampling points P2 and P5, which have limited location-related information, are not introduced. (Electrical angle) θ It is expressed as follows:
[0043] , Formula 6; in s For sectors, △ θ The bias angle is shown in Table 1.
[0044] Table 1
[0045] Combination Figure 2 As shown in (b), taking the first row as an example, it indicates that in the first sector corresponding to 0-60°, when detecting six different inductor combinations under six different combinations at the current moment, the inductance value of the series combination of Bp and Bn windings is the largest. Based on this maximum inductance value Max( L p+q This allows us to determine which sector the rotor is located in. As can be seen, Table 1 establishes a mapping relationship between the combination corresponding to the maximum value of a series inductor and the sector of the rotor position.
[0046] exist Figure 4 In the orthogonal coordinate system of (b), based on the obtained discrete sampling point P1* (△ θ -60, L 1) P3 (-△) θ , L 3) P6* (△) θ , L 6) P4 (60-△) θ , L 4) The coordinates of the piecewise linear interval region of the series inductor. l 1 and l The expression for 2 is: , Formula 7; Due to piecewise linear interval regions l 1 and l 2 are collinear, therefore the slope is - k 1. Same, the angle here. θ 1 and θ 2 is the offset angle of the rotor position relative to the current sector center point at -60° and 0°. L 1. L 3. L 4 and LPoints 6 represent the inductance detected at discrete sampling points P1, P3, P4, and P6, respectively. A linear interval region is defined. l 1 and l The coordinates of the midpoint of 2 are M1[-30, 0.5( L 1+ L 3)] and M2[30, 0.5( L 4+ L 3) Substitute M1 and M2 into the linearly spaced region. l 1 and l In the expression for 2, the bias electrical angle Δ θ Solve using the following formula:
[0047] , Formula 8.
[0048] Since the six-phase series inductor model is the same, except that the phases are spaced 60° apart, therefore L 1. L 2. L 3. L 4. L 5. L The value corresponding to 6 can be represented by different series inductance values in different sectors, as detailed in Table 2. In different rotor sectors, the physically fixed combination of six series inductors will periodically change. Table 2 establishes the correspondence between physical inductances and model parameters, that is, the inductance combinations detected at each discrete sampling point P1, P2, P3, P4, P5, and P6 in different sectors. L 1. L 2. L 3. L 4. L 5. L What is 6? After obtaining the sector where the rotor is located from Table 1, assign the corresponding parameters to the inductance information in Table 2. L 1. L 2. L 3. L 4. L 5. L 6. Then, the bias electrical angle Δ is calculated according to Formula 8 and Formula 6. θ With electrical angle θ .
[0049] Table 2
[0050] S4: Calculate the current rotor magnetic field angle based on the bias electrical angle to achieve control of the hybrid excitation motor.
[0051] Step S4 involves calculating the rotor electrical angle based on the bias electrical angle; using the field-oriented control (FOC) method, converting the reference current in the three-phase stationary coordinate system to the reference current in the dq coordinate system; comparing the error between the reference current in the dq coordinate system and the actual sampled current, and inputting the error into the proportional-integral controller; outputting the voltage reference value and combining it with the rotor electrical angle to determine the sector and size of the voltage space vector corresponding to the voltage reference value; and providing PWM signals to the first and second inverters based on the sector and size of the voltage space vector to control the on-time and on-sequence of the inverter's switching devices, so that the actual current on the three-phase windings follows the reference current in the three-phase stationary coordinate system.
[0052] On the other hand, the present invention provides a sensorless control system for a hybrid excitation motor, for implementing the above-mentioned method, comprising: The hybrid excitation motor adopts a split dual three-phase inverter drive structure, and a zero-sequence current excitation circuit is built inside. The series inductor model building unit injects an instantaneous detection signal into the windings of the hybrid excitation motor, causing two different three-phase windings to be instantaneously turned on. p and q In series configuration, obtain the current three-phase winding configuration. p and q The voltage equation for the series state, neglecting back electromotive force, rotor angular velocity and winding voltage drop, yields a simplified voltage equation, which describes the relationship between the inductance of the winding in the series state and the voltage of the instantaneous detection signal and the current of the winding in the series state. The full-phase pulse injection detection unit sequentially injects detection pulses and acceleration pulses into each of the three-phase windings; The bias electrical angle calculation unit, based on the waveform of the series inductor model as the rotor angle changes, removes the peak and trough regions, mirrors the sampling points of the non-peak and trough sectors to the same side of the waveform peak, and fits to obtain an equivalent series inductor model. The bias electrical angle is then calculated using the equivalent series inductor model. The control drive unit calculates the electrical angle of the rotor magnetic field at the current moment based on the bias electrical angle, thereby controlling the hybrid excitation motor.
[0053] The following is an implementation scheme for field-circuit coupling simulation, used to verify the feasibility of the control method of this application.
[0054] First, a HE-VRM motor model was built in the Maxwell platform of Ansys, and electromagnetic simulation was performed to verify the correctness of the electromagnetic design. Then, a split dual three-phase inverter drive structure was built in Simplier within Ansys, and the motor model from Maxwell was imported. Finally, the control algorithm was implemented in Simulink. Simplier and Simulink are connected through a data exchange module. Simplier transmits current sampling signals and actual position information to Simulink, which uses this information to generate PWM switching signals that are then sent back to Simplier to control the inverter's switching devices, such as the IGBT switches. Essentially, Maxwell simulates the actual motor, Simplier simulates the actual power supply and inverter circuit, and Simulink simulates the real-time control platform.
[0055] like Figure 5 The diagram shows a schematic of the simulation main circuit model built in Ansys's Simulator. Figure 6 The pink broken line in the figure shows the series inductance of the motor built by Maxwell, which is basically consistent with the proposed series inductance model, i.e., the black solid line.
[0056] Figure 7 Figure (a) shows the sensorless control method for the hybrid excitation motor of this application, accelerating to a set speed of 50 rpm under no-load conditions. The system stabilizes in approximately 0.3 s. As can be seen from the figure, the estimated rotor position tracks the actual position well. The error between the actual and estimated positions is between 0 and 20° throughout the entire operation. This is because the estimated position is used throughout the acceleration cycle, and a new position is estimated only when a new cycle begins. In this experiment, the acceleration cycle was 0.0024 s. When the speed stabilized at 50 rpm, the accumulated error was approximately 16°. Therefore, the actual position estimation error should be within 5°. This is also evident from the magnified position estimation graph, where the error was within 5° before accumulation.
[0057] Figure 7 (b) shows the result of the sensorless control method of the hybrid excitation motor of this application accelerating to a speed setpoint of 50 rpm with a 1N load. It can be seen that it can still start well and run stably in the low-speed range with a light load. The position estimation and error are not significantly different from those when unloaded.
[0058] This embodiment uses field-circuit coupling simulation for experimental verification, which can provide more reliable simulation reference results before actual application on the prototype. It retains the high-precision calculation capability of finite element simulation for electromagnetic details, and also has the dynamic closed-loop analysis capability of circuit control system simulation, which can greatly reduce the trial and error cost and debugging time cost of actual engineering tests.
[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A sensorless control method for a hybrid excitation motor, characterized in that, Includes the following steps: S1: Configure a hybrid excitation motor to construct a split dual three-phase inverter drive structure; S2: Based on the conduction relationship of the windings of the hybrid excitation motor, a series inductor model under instantaneous detection signal excitation is established; S3: Simplify the series inductance model by segmentation; use the full-phase pulse injection method to inject detection pulse voltage into each phase in sequence to obtain the value of the series inductance, thereby determining the current sector of the rotor, and substituting it into the series inductance model to calculate the bias electrical angle. S4: Calculate the current rotor magnetic field angle based on the bias electrical angle to achieve control of the hybrid excitation motor.
2. The sensorless control method for a hybrid excitation motor according to claim 1, characterized in that, The hybrid excitation motor described in step S1 adopts a double salient pole structure with 24 slots and 22 pole pairs. The rotor part includes a stacked iron core, the excitation source is located on the stator side, and two layers of permanent magnets are provided at the slot opening. The magnetization direction of the inner permanent magnet is radial, and the magnetization direction of the outer permanent magnet is tangential.
3. The sensorless control method for a hybrid excitation motor according to claim 2, characterized in that, The hybrid excitation motor includes a first sub-phase assembly, a second sub-phase assembly, a first inverter, and a second inverter. Both the first and second sub-phase assemblies are star-connected. The first sub-phase assembly includes three-phase windings Ap, Bp, and Cp, and the second sub-phase assembly includes three-phase windings An, Bn, and Cn. The neutral points of the first and second sub-phase assemblies are interconnected. The first sub-phase assembly is electrically connected to the first inverter, and the second sub-phase assembly is electrically connected to the second inverter. The first and second inverters are controlled based on space vector pulse width modulation (SVPWM). Both the first and second inverters include several switching devices.
4. The sensorless control method for a hybrid excitation motor according to claim 3, characterized in that, Step S2 involves driving the inverter to make two different three-phase windings p and q Conductive, p , q ∈{Ap, Bp, Cp, An, Bn, Cn}, and inject instantaneous detection signals, at which point the three-phase windings are instantaneously turned on. p and q In series configuration, obtain the current three-phase winding configuration. p and q The voltage equation for the series state, neglecting back electromotive force, rotor angular velocity and winding voltage drop, yields a simplified voltage equation, which describes the relationship between the inductance of the winding in the series state and the voltage of the instantaneous detection signal and the current of the winding in the series state; a total of six sets of series inductance models with the same expression and a phase difference of 60° are formed.
5. The sensorless control method for a hybrid excitation motor according to claim 4, characterized in that, The piecewise simplification of the series inductor model described in step S3 is to remove the peak and trough regions according to the waveform of the series inductor model as the rotor angle changes, and then mirror the sampling points of the non-peak and trough sectors to the same side of the waveform peak to obtain the simplified equivalent series inductor model. The bias electric angle is calculated by setting feature points and substituting them into the equivalent series inductor model.
6. The sensorless control method for a hybrid excitation motor according to claim 5, characterized in that, In step S3, the detection pulse voltage is injected sequentially into each phase using the full-phase pulse injection method to obtain the value of the series inductance, thereby determining the current sector of the rotor and obtaining the winding corresponding to the series inductance. The bias angle is calculated by substituting it into the series inductance model. Several detection pulses and acceleration pulses are configured, and detection pulses are injected into each three-phase winding starting from the first time segment (t1, t2). The width of each detection pulse is the same, and the generated current signal is recorded. After detecting the current signals of all three-phase windings, an acceleration pulse is injected during the second time interval (t3, t4) after the first time interval. After the second time interval, a new round of detection pulses is injected during the third time interval starting from time t5. The above process of alternating injection of detection pulses and acceleration pulses is repeated to obtain the magnitudes of six sets of series inductance values. The current sector of the rotor is determined based on the magnitude of the series inductance values. Based on the obtained sector of the rotor, the magnitude of the series inductance values is matched one-to-one with the windings in the series inductance model under the excitation of the instantaneous detection signal to calculate the rotor electrical angle.
7. The sensorless control method for a hybrid excitation motor according to claim 6, characterized in that, In each round of injection using the full-phase pulse injection method, the interval between adjacent detection pulses is (t2-t1-6Δt) / 5, where Δt is the width of the detection pulse.
8. A sensorless control method for a hybrid excitation motor according to claim 6, characterized in that, The first time interval and the second time interval are used to release the magnetic flux remaining in the winding after the injection of the detection pulse. The first time interval is shorter than the second time interval.
9. A sensorless control method for a hybrid excitation motor according to claim 6, characterized in that, Step S4 involves calculating the rotor electrical angle based on the bias electrical angle; using the field-oriented control (FOC) method, converting the reference current in the three-phase stationary coordinate system into the reference current in the dq coordinate system; comparing the error between the reference current in the dq coordinate system and the actual sampled current, and inputting the error into the proportional-integral controller; outputting the voltage reference value and combining it with the rotor electrical angle to determine the sector and size of the voltage space vector corresponding to the voltage reference value; and providing PWM signals to the first and second inverters based on the sector and size of the voltage space vector to control the conduction time and conduction sequence of the switching devices, so that the actual current on the three-phase windings follows the reference current in the three-phase stationary coordinate system.
10. A sensorless control system for a hybrid excitation motor, used to implement the method according to any one of claims 1-9, characterized in that, include: The hybrid excitation motor adopts a split dual three-phase inverter drive structure, and a zero-sequence current excitation circuit is built inside. The series inductor model building unit injects an instantaneous detection signal into the windings of the hybrid excitation motor, causing two different three-phase windings to be instantaneously turned on. p and q In series configuration, obtain the current three-phase winding configuration. p and q The voltage equation for the series state, neglecting back electromotive force, rotor angular velocity and winding voltage drop, yields a simplified voltage equation, which describes the relationship between the inductance of the winding in the series state and the voltage of the instantaneous detection signal and the current of the winding in the series state. The full-phase pulse injection detection unit sequentially injects detection pulses and acceleration pulses into each of the three-phase windings; The bias electrical angle calculation unit, based on the waveform of the series inductor model as the rotor angle changes, removes the peak and trough regions, mirrors the sampling points of the non-peak and trough sectors to the same side of the waveform peak, and fits to obtain an equivalent series inductor model. The bias electrical angle is then calculated using the equivalent series inductor model. The control drive unit calculates the electrical angle of the rotor magnetic field at the current moment based on the bias electrical angle, thereby controlling the hybrid excitation motor.