A current reconstruction method, a current fault-tolerant processing method and device of an electric drive system

Abstract

The application provides a current reconstruction method and a current fault-tolerant processing method and device of an electric drive system, and relates to the technical field of electric drive system control, and comprises the following steps: acquiring any phase current signal, taking the phase current signal as an alpha-axis current in a predetermined coordinate system, and obtaining a beta-axis current estimation value by using space vector projection; adopting a Luenberger observer to acquire a d-axis voltage and a q-axis voltage as input, and performing current reconstruction by taking the alpha-axis current and the beta-axis current estimation value as feedback, and outputting a d-axis current reconstruction value and a q-axis current reconstruction value, wherein a gain matrix of the observer is generated in advance by pole configuration, and speed and angle information for the observer is collected by a position sensor; and the problem that, when the electric drive system is running, the safety of the electric drive system control is affected by any phase sensor fault due to the dependence on multiple phase sensors is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric drive system control, and particularly relates to a current reconstruction method of an electric drive system, and a phase current sensor fault processing method and device. BACKGROUND

[0002] With the rapid development of new energy vehicles and energy storage systems, high reliability of electric drive systems has become a core requirement. In the control process, accurate phase current feedback information is often required, and phase current sensors are usually used to monitor phase current. Therefore, the phase current sensor is a key component of motor control, which monitors three-phase current in real time to convert into current components required for electric drive system control.

[0003] However, during the operation of the phase current sensor, device failure may occur due to hardware problems or interference factors such as current impact. When any phase current sensor fails, the feedback phase current signal is unbalanced or distorted, which will affect the motor control in the electric drive system, especially during operation, which may even cause loss of control risk. Therefore, in the arrangement scenario of three-phase sensors, when one of the sensors fails, motor control can be performed according to the calculation of three-phase current. In the arrangement scenario of two-phase current sensors, when one of the sensors fails or only one sensor is normal, three-phase current calculation cannot be performed, and a current reconstruction method needs to be provided to reduce the risk of loss of control of the electric drive system due to partial phase sensor failure. SUMMARY

[0004] In order to overcome the above technical defects, the purpose of the present application is to provide a current reconstruction method, a current fault-tolerant processing method and device of an electric drive system to solve the problem that any phase sensor failure will affect the safety of electric drive system control when the electric drive system is running.

[0005] The present application discloses a current reconstruction method of an electric drive system, comprising:

[0006] Obtaining any phase current signal, using the phase current signal as an alpha-axis current in a predetermined coordinate system, and obtaining a beta-axis current estimation value by using space vector projection;

[0007] Using a Luenberger observer to obtain d-axis voltage and q-axis voltage as input, and using the alpha-axis current and the beta-axis current estimation value as feedback to perform current reconstruction, and outputting a d-axis current reconstruction value and a q-axis current reconstruction value, wherein a gain matrix of the observer is generated in advance by pole placement, and speed and angle information for the observer is collected by a position sensor.

[0008] Preferably, using the phase current signal as an alpha-axis current in a predetermined coordinate system, and obtaining a beta-axis current estimation value by using space vector projection, comprises:

[0009] The predetermined coordinate system integrates the three-phase coordinate system and the αβ-axis coordinate system, and makes the phase current signal coincide with the axis corresponding to the α-axis current.

[0010] Based on the α-axis current and current vector angle, a trigonometric transformation is performed, and then the estimated value of the β-axis current is output through filtering and PI control.

[0011] Preferably, the α-axis current and β-axis current estimates are converted into d-axis current estimates and q-axis current estimates and input to the observer as feedback;

[0012] The state equations of the observer include: ,in , , For the system matrix, This is the gain matrix; For reconstruction quantity, For feedback volume, , , , These represent the disturbances of the d-axis current and the q-axis current, respectively. For input quantity, , , These are the d-axis voltage and the q-axis voltage, respectively. For speed, It is a magnetic flux.

[0013] Preferably, the The matrix poles are positioned at preset fixed locations, such that...

[0014] , The damping ratio of the system; The natural frequency of the system is used to generate the gain matrix.

[0015] Preferably, the gain matrix is:

[0016] ;in , For d-axis and q-axis inductance; The damping ratio of the system; is the natural frequency of the system.

[0017] The present invention also provides a current reconfiguration device for an electric drive system, which performs the above-described current reconfiguration method, including:

[0018] A calculation module is configured to acquire a phase current signal, construct a coordinate system based on the phase current signal as an alpha-axis current, and calculate a beta-axis current estimation value by using a space vector projection;

[0019] An observer is configured to output a d-axis current reconstruction value and a q-axis current reconstruction value based on the alpha-axis current and the beta-axis current estimation value, wherein a gain matrix of the observer is generated in advance by pole placement;

[0020] A position sensor is configured to acquire speed and angle information fed back to the observer.

[0021] The application further provides a current fault-tolerant processing device of an electric drive system, comprising the current reconstruction device of the electric drive system, and further comprising:

[0022] The phase current sensors are arranged in at least two to provide at least two phase currents;

[0023] A fault diagnosis module is configured to monitor whether any phase current sensor is faulty;

[0024] A current selection module is configured to receive outputs of the phase current sensors and the observer, and select the d-axis current and the q-axis current acquired by the phase current sensors or the d-axis current reconstruction value and the q-axis current reconstruction value output by the observer for motor control according to the monitoring of the fault diagnosis module.

[0025] The application further provides a current fault-tolerant processing method of an electric drive system, which applies the current reconstruction method and comprises:

[0026] The d-axis current and the q-axis current are acquired for motor control according to the phase current sensors;

[0027] The fault diagnosis module is used to monitor each phase current sensor, and when any phase current sensor is found to be faulty, the current selection module is used to perform motor control according to the d-axis current reconstruction value and the q-axis current reconstruction value output by the observer.

[0028] Preferably, when the fault diagnosis module finds that a phase current sensor is faulty, an instruction is sent to the observer;

[0029] The observer sends a response signal to the current selection module in synchronization with the d-axis current reconstruction value and the q-axis current reconstruction value according to the instruction;

[0030] The current selection module selects to perform motor control according to the d-axis current reconstruction value and the q-axis current reconstruction value according to the response signal.

[0031] After the above technical solutions are adopted, the following beneficial effects are achieved compared with the prior art:

[0032] The current reconstruction method, current fault-tolerant processing method and device of the electric drive system provided by the application utilize a phase current signal to provide accurate phase current, obtain alpha-axis current and beta-axis current estimation values based on space vector projection, input the alpha-axis current and the beta-axis current estimation values to an observer, and utilize the observer to add a disturbance phase to the reconstruction values under the condition of parameter disturbance, thereby outputting d-axis current reconstruction values and q-axis current reconstruction values, the reconstruction results of which have high matching degrees with actual currents, and the current reconstruction method, current fault-tolerant processing method and device can be applied to a scene in which only a unique phase current sensor is arranged, thereby reducing sensor arrangement, and can also be applied to a scene in which any phase of two-phase current sensors fails, so as to solve the problem that any phase sensor failure will affect the control safety of the electric drive system when the electric drive system is running. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The method flowchart of the current reconstruction method, current fault-tolerant processing method and device of the electric drive system according to the first embodiment of the application;

[0034] Figure 2 The schematic diagram of the coordinate constructed in the current reconstruction method, current fault-tolerant processing method and device of the electric drive system according to the first embodiment of the application;

[0035] Figure 3 The control logic schematic diagram of space vector projection in the current reconstruction method, current fault-tolerant processing method and device of the electric drive system according to the first embodiment of the application;

[0036] Figure 4 The control logic schematic diagram of the current reconstruction method, current fault-tolerant processing method and device of the electric drive system according to the first and second embodiments of the application, taken as an example of the current reconstruction of the a-phase current sensor with the b-phase current sensor failure;

[0037] Figure 5 The method flowchart of the current reconstruction method, current fault-tolerant processing method and device of the electric drive system according to the second embodiment of the application;

[0038] Figure 6 The module schematic diagram of the device in the current reconstruction method, current fault-tolerant processing method and device of the electric drive system according to the first and second embodiments of the application;

[0039] Figure 7a The result diagram of the simulation experiment under the first working condition in the current reconstruction method, current fault-tolerant processing method and device of the electric drive system according to the second embodiment of the application;

[0040] Figure 7b The result diagram of the simulation experiment under the second working condition in the current reconstruction method, current fault-tolerant processing method and device of the electric drive system according to the second embodiment of the application;

[0041] Figure 7c Figure 6 is a result diagram of a simulation experiment under a third working condition of the second embodiment of the current reconstruction method, the current fault-tolerant processing method and the device of the electric drive system according to the present application;

[0042] Figure 7d Figure 7 is a result diagram of a simulation experiment under a fourth working condition of the second embodiment of the current reconstruction method, the current fault-tolerant processing method and the device of the electric drive system according to the present application.

[0043] Reference signs:

[0044] 3 - current reconstruction device of the electric drive system; 31 - calculation module; 32 - observer; 33 - position sensor; 34 - first phase current sensor; 4 - current fault-tolerant processing device of the electric drive system; 41 - second phase current sensor; 42 - fault diagnosis module; 43 - current selection module. DETAILED DESCRIPTION

[0045] The advantages of the present application are further described below in conjunction with the accompanying drawings and specific embodiments.

[0046] Hereinafter, exemplary embodiments will be described in detail with reference to accompanying drawings. In the following description, unless otherwise expressly specified and limited, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments are not representative of all embodiments consistent with the present disclosure. Rather, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0047] The terms used in the present disclosure are merely for the purpose of describing particular embodiments and are not intended to limit the present disclosure. As used in the present disclosure and the appended claims, singular forms "a," "an" and "the" are intended to include plural forms, unless the context clearly indicates otherwise. It will be further understood that the term "and / or" as used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0048] In the description of the present application, unless otherwise specified and limited, it should be noted that the terms "mounting", "connecting", "connection" should be understood in a broad sense, for example, it can be mechanical connection or electrical connection, or the communication between the internal elements, or direct connection, or indirect connection through intermediate medium, and the specific meaning of the above terms can be understood according to the specific circumstances by those skilled in the art.

[0049] In the subsequent description, the suffix such as "module", "component" or "unit" used to represent elements is only for the convenience of the description of the present application, and has no specific meaning in itself. Therefore, "module" and "component" can be used interchangeably.

[0050] Embodiment one: the embodiment provides a current reconstruction method of an electric drive system, which can reconstruct current according to any phase current signal, can be applied to a scenario where only a unique phase current sensor is arranged, reduces sensor arrangement, and can be applied to a scenario where any phase current sensor of two-phase current sensors described in embodiment two fails (this scenario limits the following phase current as normal phase current / healthy phase current, non-fault phase current), reduces safety risks caused by current sensor failure. Specifically, refer to Figure 1 , which comprises:

[0051] S11: obtaining any phase current signal, using space vector projection to obtain an estimated value of the β-axis current in the predetermined coordinate system with the phase current signal as the α-axis current;

[0052] Specifically, in this step, the space vector projection is used to obtain the α-axis current and the estimated value of the β-axis current according to the phase current signal. Specifically, in the predetermined coordinate system, the three-phase coordinate system and the αβ-axis coordinate system are integrated, so that the phase current signal coincides with the corresponding axis of the α-axis current. Specifically, the phase current and the α-axis current are coincided to construct the predetermined coordinate system (coordinate system I below), or the stationary coordinate system (dq-axis coordinate system) is rotated, the phase current and the rotated α' axis are coincided to construct the predetermined coordinate system (coordinate system II below), the β' current is reconstructed by the α' current, and then the α'β' is rotated to the standard stationary coordinate system to obtain the estimated value of the β-axis current, which can be used as the feedback quantity in the observer .

[0053] As an example, refer to Figure 2 , taking the arrangement of a-phase and b-phase sensors as an example, if the normal phase current is the a-phase current (b-phase current sensor failure), the constructed coordinate system is as shown in coordinate system I, and if the normal phase current is the b-phase current (a-phase current sensor failure), the constructed coordinate system is as shown in coordinate system II.

[0054] Specifically, in the predetermined coordinate system, the space vector projection is used to obtain the estimated value of the β-axis current with the phase current signal as the α-axis current, which comprises:

[0055] The phase current signal is used as the α-axis current, a trigonometric transformation is performed on the α-axis current and the current vector angle γ, and then a β-axis current estimated value is output through filtering and PI control.

[0056] Specifically, as shown in Figure 3 , the current vector angle ; the heterodyne method is used to calculate:

[0057] : wherein , is the stator current, is a stator current estimation value, which can be understood as a stator current error, is angle information (rotor angle) collected by a position sensor, after obtaining the above operation result signal, the current component of the operation result signal is extracted through a low-pass filter (LPF), and a proportional integral (PI) controller is used to adjust the error, and output the amplitude of the stator current estimation value projection is performed, specifically , and output the β-axis current estimation value The β-axis current estimation value will return to the above heterodyne method operation, so as to obtain the α-axis current output the β-axis current estimation value .

[0058] S12: The d-axis voltage and the q-axis voltage are obtained by using the Lyapunov observer, the α-axis current and the β-axis current estimation value are used as feedback for current reconstruction, and the d-axis current reconstruction value and the q-axis current reconstruction value are output, wherein the gain matrix of the observer is generated in advance by pole placement, and the speed and angle information for the observer are collected by a position sensor.

[0059] Specifically, the Lyapunov observer reconstructs the internal state variable that cannot be directly measured through a system input matrix and an output matrix, in this embodiment, the internal state variable is the d-axis current reconstruction value and the q-axis current reconstruction value, and the reconstruction amount The α-axis current and the β-axis current estimation value are converted (by inverse Park transformation) into the d-axis current estimation value and the q-axis current estimation value are input to the observer as feedback, and the following ;

[0060] The state equation of the observer includes: , , , is a system matrix, determines the state matrix , the system input matrix , the system output matrix , is a gain matrix ; , is a reconstruction amount, is an (reconstruction amount) estimation value, , is a feedback amount, is an output error feedback, used to correct the estimation value, , respectively a disturbance of the d-axis current, a disturbance of the q-axis current; is an input quantity, , , respectively a d-axis voltage, a q-axis voltage, is a rotational speed (obtained by a position sensor), is a flux linkage.

[0061] Each value in each system matrix in the above state equation can be directly obtained. Specifically, it is fed back by a position sensor or an electric drive system control module.

[0062] Specifically, the gain matrix in the observer affects the observation balance convergence, thereby affecting the accuracy of the observation output quantity, i.e., the accuracy of the reconstructed values of the d-axis current and the q-axis current. In the embodiment, the eigenvalues (poles) of the observer error dynamic equation are located at a specific position (a pre-set fixed position) in the left half of the complex plane by reasonably selecting the gain matrix of the observer, so that the gain matrix is configured at the pre-set fixed position in the embodiment. , is a damping ratio of the system; is a natural frequency of the system, thereby generating the gain matrix.

[0063] Specifically, the gain matrix is: ; wherein , is a d-axis inductance, a q-axis inductance; is a damping ratio of the system; is a natural frequency of the system. It can be understood that the above gain parameters are an example of the above poles being configured at the pre-set fixed position. In fact, it can also be other gain matrices formed by satisfying the above pole configuration condition, so that the reconstructed values of the d-axis current and the q-axis current output by the observer are more accurate.

[0064] Based on the above, in the embodiment, an accurate phase current is provided by using a phase current signal. Based on this, the α-axis current and the β-axis current estimation values are obtained by using the space vector projection method, which are input into the observer. The feedback quantity contains the normal phase current signal and does not contain the fault phase current signal. The observer considers the parameter disturbance, adds the disturbance phase to the vector, thereby outputting the reconstructed values of the d-axis current and the q-axis current. The reconstructed results have a high matching degree with the actual currents, and the process is simple and suitable for most working conditions.

[0065] Based on the above current reconstruction method, the embodiment further provides a current reconstruction device of an electric drive system, which executes the above current reconstruction method, such as Figure 4 and Figure 6 , comprising:​

[0066] Phase current sensor (first phase current sensor in the middle) Figure 6 The current reconstruction method only relies on a phase current sensor, and can be applied to a scene in which one of two phase current sensors fails, and can also be applied to a scene in which a unique phase sensor is separately arranged to reduce sensor arrangement. The phase current sensor is consistent with the phase current sensor of the current fault-tolerant device in Embodiment Two, two or three of which can be arranged in the current fault-tolerant device in Embodiment Two, and only one is required here.

[0067] The calculation module is configured to obtain a phase current signal, construct a coordinate system based on the phase current signal as an alpha-axis current, and calculate a beta-axis current estimation value by using space vector projection; based on the above, a specific operation is performed to obtain 、 .

[0068] The observer is configured to output a d-axis current reconstruction value and a q-axis current reconstruction value based on the alpha-axis current and the beta-axis current estimation value, wherein a gain matrix of the observer is generated in advance by pole placement; the gain matrix and the observer are each matrix or operation, and reference is made to the above method.

[0069] The position sensor is configured to collect speed and angle information fed back to the observer.

[0070] Therefore, the current reconstruction device can be arranged in an electric drive system having one or more phase current sensors for current reconstruction, and can be integrated or connected with other modules / devices for cooperation, or further carry other control logic in the calculation module and / or the observer to meet different use requirements.

[0071] Embodiment Two: The application further provides a current fault-tolerant processing method of an electric drive system, which applies the above-mentioned current reconstruction method, and can be specifically applied to a scene in which two phase current sensors are applied but one of the current sensors fails, so as to realize fault-tolerant processing of the current. Here, the "fault-tolerant processing" is for the case of current error caused by the failure of one of the sensors, as shown in Figure 5 , comprising:

[0072] S21: obtaining d-axis current and q-axis current for motor control according to the phase current sensor acquisition calculation;

[0073] When the current sensor does not fail, no processing is required, and the three-phase current is obtained directly from the phase current sensor acquisition result, and the d-axis current and the q-axis current are obtained by using Clark transformation and Park transformation and fed back to a PI controller for motor control.

[0074] S22: monitoring each phase current sensor by using a fault diagnosis module (S22-1), when monitoring any phase current sensor failure, using a current selection module to reconstruct the d-axis current and q-axis current according to the observer output (S22-3).

[0075] Specifically, a fault diagnosis module is configured, which can judge whether the phase current sensor is normal or faulty by monitoring the signals output by each phase current sensor, such as directly monitoring whether the current value exceeds the preset range, or zero drift detection, etc., or through current consistency verification, such as according to the relationship of three-phase current, or spectrum analysis, etc. The existing general monitoring method can be applied without limitation, and can be selected according to different application scenarios.

[0076] In the embodiment, a current selection module is also configured to select according to whether the phase current sensor fails, and the reconstructed value obtained by the current reconstruction method based on the value of a certain phase current sensor or the result directly output by the phase current sensor is used for motor control.

[0077] It can be understood that the current reconstruction method is integrated into the normal motor control process, and when the phase current sensor failure is monitored, the execution of the current reconstruction method is triggered, and the fault tolerance module directly applies the reconstructed value, which responds quickly; The current reconstruction can also be executed synchronously to provide fault tolerance space for current changes, i.e. the reconstructed value is used as an alternative, and even further as a verification application, thereby improving the accuracy of each phase current obtained in the electric control system, thereby improving the control accuracy of the entire system.

[0078] Specifically, to improve the response of the current selection module, the observer outputs a corresponding flag signal (flag bit), which is sent to the current selection module synchronously with the d-axis current reconstruction value and the q-axis current reconstruction value. When the phase current sensor is monitored to be abnormal, the d-axis current reconstruction value and the q-axis current reconstruction value with the flag signal are sent, and the current selection module directly applies the reconstructed value after receiving the flag signal.

[0079] Therefore, in the embodiment, when the fault diagnosis module monitors the phase current sensor failure, an instruction is sent to the observer (S22-3); the observer triggers a response signal (i.e. the above-mentioned flag signal / flag bit trigger is 1) according to the instruction, and synchronously sends the response signal with the d-axis current reconstruction value and the q-axis current reconstruction value to the current selection module; the current selection module selects the d-axis current reconstruction value and the q-axis current reconstruction value according to the response signal for motor control.

[0080] In this embodiment, as a specific example, the fault diagnosis module provides d-axis voltage and q-axis voltage to the observer and sends a command to the observer (to perform current reconstruction) without sending a signal to the current selection module. The current selection module receives the d-axis current reconstruction value and q-axis current reconstruction value with response signals and then applies the reconstruction value to control the motor.

[0081] Understandably, during the operation of the electric drive system, current reconstruction can be performed based on any phase current signal. When a phase current sensor is detected to be damaged, current reconstruction is performed based on the output of the normal phase current sensor, and motor control is performed based on the reconstructed value.

[0082] Based on this, the current fault-tolerant processing method provided in this embodiment arranges two phase current sensors (or three). When the electric control system is running, the output of the phase current sensors is directly used for motor control under normal conditions. When any phase current sensor fails, a response signal is triggered to the observer for current reconstruction and fed back to the fault-tolerant module for motor control. This greatly reduces the risk of the electric drive system going out of control due to phase sensor failure. The fault diagnosis speed and implementation requirements are low, and the implementation process is simple.

[0083] Based on the above, this embodiment also provides a current fault-tolerant processing device for an electric drive system, including the current reconstruction device for the electric drive system in Embodiment 1, which can be used to execute the above-described current fault-tolerant processing method, such as... Figure 4 and Figure 6 It also includes:

[0084] Phase current sensor ( Figure 6 The second phase current sensor is arranged in at least two configurations to provide at least two phase currents, and one of the two configurations includes the phase current sensor in the aforementioned current reconstruction device. Figure 6 The designations "first phase current sensor" and "second phase current sensor" are used only to distinguish between normal phase current sensors and faulty phase current sensors.

[0085] The fault diagnosis module is used to monitor whether any phase current sensor is faulty; for specific monitoring methods, please refer to the general monitoring methods used in the above applications.

[0086] The current selection module is used to receive the outputs of the phase current sensor and the observer, and select the d-axis current and q-axis current obtained by the phase current sensor or the d-axis current reconstruction value and q-axis current reconstruction value output by the observer for motor control based on the monitoring of the fault diagnosis module.

[0087] In the embodiment, the current fault-tolerant processing device can be used in different electric drive systems. The device outputs the d-axis current and q-axis current obtained by the phase current sensor or the d-axis current reconstruction value and q-axis current reconstruction value output by the observer to the PI controller and SVPWM control circuit in the electric drive system to realize motor control. The device can also be connected or integrated with other modules / devices to further optimize the collection and / or fault tolerance of the current or further apply phase current to achieve more control.

[0088] In addition to the above, to embody the application effect of the current fault-tolerant processing method and device in the embodiment, simulation verification is performed, and specific verification results are shown in Figures 7a-7d , wherein Figures 7a-7d are simulation results under different working conditions.

[0089] Specifically, as shown in Figure 7a , working condition 1: q-axis command current 200 A, speed 955 rpm, A-phase failure fault occurs at 0.2 s; as shown in Figure 7b , working condition 2: q-axis command current 200 A, speed is accelerated from 239 rpm to 1000 rpm / s, A-phase failure fault occurs at 0.2 s; as shown in Figure 7c , working condition 3: q-axis command current 200 A, speed 5730 rpm, A-phase failure fault occurs at 0.2 s; as shown in Figure 7d , working condition 4: q-axis command current 50 A, speed 95 rpm, B-phase failure fault occurs at 0.2 s.

[0090] According to the above Figures 7a-7d , it can be known that the current fault-tolerant processing device and the current reconstruction method and device of embodiment one are applied in the embodiment. When a phase current sensor fails, only a sharp current change occurs (at about 0.2 s), and the current reconstruction is quickly realized after the failure occurs. The reconstructed current has a high matching degree with the actual phase current sensor output current, and the reconstructed current has no obvious lag. Therefore, the above embodiments one and two of the present application provide an accurate and efficient current reconstruction method, which can be applied to any phase current sensor failure scene and / or other electric drive system control scenes that need to realize current fault tolerance.

[0091] It can be understood that the current reconstruction device in embodiment one and the current fault-tolerant processing device in embodiment two can be separately applied to different electric drive systems. The current reconstruction method and the current fault-tolerant processing method can also be similar to the existing other control modules / systems, and can be integrated with the existing other control modules / systems to optimize the control of the electric drive system.

[0092] It should be noted that the embodiments of the present application have better implementation, and do not limit the present application in any form, any skilled person in the art can change or modify the above disclosed technical content into equivalent effective embodiments, as long as it does not deviate from the content of the technical scheme of the present application, any modification or equivalent change and modification of the above embodiments according to the technical essence of the present application, still belongs to the scope of the technical scheme of the present application.

Claims

1. A current reconstruction method of an electric drive system, characterized in that, The method comprises: acquiring a phase current signal, using the phase current signal as an α-axis current in a predetermined coordinate system, and obtaining a β-axis current estimation value by space vector projection; using a Luenberger observer to acquire a d-axis voltage and a q-axis voltage as input, using the α-axis current and the β-axis current estimation value as feedback to perform current reconstruction, and outputting a d-axis current reconstruction value and a q-axis current reconstruction value, wherein a gain matrix of the observer is generated in advance by pole placement, and a speed and an angle of the observer are collected by a position sensor; the gain matrix is: ; wherein , is the d-axis, q-axis inductance; is the damping ratio of the system; is the natural frequency of the system; is the rotational speed; is the stator resistance.

2. The current reconstruction method of claim 1, wherein, in a predetermined coordinate system, using the phase current signal as an α-axis current, and obtaining a β-axis current estimation value by space vector projection, comprising: the predetermined coordinate system integrates a three-phase coordinate system and an αβ-axis coordinate system, and the phase current signal and the α-axis current correspond to the same axis line; performing a trigonometric transformation on the α-axis current and a current vector angle, and then outputting a β-axis current estimation value by filtering and PI control.

3. The current reconstruction method of claim 1, wherein: the α-axis current and the β-axis current estimation value are converted into a d-axis current estimation value and a q-axis current estimation value, which are input into the observer as feedback; The state equation of the observer comprises: wherein , , is a system matrix, is a gain matrix; is a reconstruction quantity, is a feedback quantity, , , , are respectively a disturbance of a d-axis current, a disturbance of a q-axis current; is an input quantity, , , are respectively a d-axis voltage, a q-axis voltage, is a rotational speed, is a flux linkage.

4. The current reconstruction method of claim 3, wherein: Will The matrix poles are positioned at preset fixed locations, such that... , is the damping ratio of the system; is the natural frequency of the system, thereby generating a gain matrix.

5. A current reconfiguration device for an electric drive system, characterized by the current reconstruction method of any one of claims 1-4 is performed, comprising: a calculation module configured to acquire a phase current signal, construct a coordinate system based on the phase current signal as an α-axis current, and calculate a β-axis current estimation value by space vector projection; an observer configured to output a d-axis current reconstruction value and a q-axis current reconstruction value based on the α-axis current and the β-axis current estimation value, wherein a gain matrix of the observer is generated in advance by pole placement; a position sensor configured to collect a speed and an angle of the observer for feedback.

6. A current fault tolerant processing device of an electric drive system, characterized by, The current reconstruction device of the electric drive system of claim 5 further comprises: a phase current sensor arranged with at least two phase current sensors to provide at least two phase currents; a fault diagnosis module configured to monitor whether any phase current sensor is faulty; a current selection module configured to receive an output of the phase current sensor and the observer, and select a d-axis current and a q-axis current acquired by the phase current sensor or a d-axis current reconstruction value and a q-axis current reconstruction value output by the observer for motor control according to a monitoring result of the fault diagnosis module.

7. A current fault-tolerant processing method of an electric drive system, characterized by, The current reconstruction method of any one of claims 1-4 is applied, comprising: a d-axis current and a q-axis current acquired by calculation of the phase current sensor are used for motor control; a fault diagnosis module is used to monitor each phase current sensor, and when it is monitored that any phase current sensor is faulty, a current selection module is used to perform motor control according to a d-axis current reconstruction value and a q-axis current reconstruction value output by the observer.

8. The current fault-tolerant processing method of claim 7, wherein: when the fault diagnosis module monitors that a phase current sensor is faulty, an instruction is sent to the observer; the observer triggers a response signal according to the instruction, and synchronously sends the response signal, the d-axis current reconstruction value and the q-axis current reconstruction value to the current selection module. The current selection module selects, according to the response signal, to perform motor control according to the d-axis current reconstruction value and the q-axis current reconstruction value.

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