Asynchronous motor torque current distribution method and system
By receiving the target torque Te in the asynchronous motor, obtaining the steady-state excitation current Id(s), and using the rotor time constant Tr and the adjustable gain coefficient K for dynamic compensation to generate the dynamic excitation current, the influence of the rotor time constant on the torque response speed is solved, and the torque response speed and motor performance of the asynchronous motor are improved.
Patent Information
- Application Number
- CN202510855207.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-25
- Publication Date
- 2025-09-23
AI Technical Summary
Existing technologies make it difficult to effectively consider the impact of the rotor time constant on the torque response time in asynchronous motors, resulting in a slow torque response speed that cannot meet the performance requirements of the entire vehicle.
By receiving the target torque Te, the steady-state excitation current Id(s) is obtained, and the rotor time constant Tr and the adjustable gain coefficient K are used for dynamic compensation to generate the dynamic excitation current, calculate the target torque current iq in real time, and generate a PWM drive signal to control the power inverter.
The response speed of the asynchronous motor torque is improved, ensuring that the motor operates at the expected operating point under steady-state conditions, and improving the performance of the electric drive system.
Smart Images
Figure CN120691784A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of motor control, and in particular to a method and system for distributing torque and current of an asynchronous motor. Background Art
[0002] Compared to permanent magnet synchronous motors, asynchronous motors offer a simpler structure, lower manufacturing costs, and higher reliability. They offer greater resistance to demagnetization and stability under harsh operating conditions such as high temperatures and high loads, making them more suitable for frequent start-stop or intense driving scenarios.
[0003] In the field of motor control, directional control is performed according to the rotor magnetic field, and the d-axis of the rotating coordinate system is set to be aligned with the direction of the rotor magnetic flux, so that decoupling control of the excitation current and the torque current can be achieved, which is suitable for high-performance speed regulation scenarios. The torque current distribution scheme is crucial to the performance improvement of the electric drive system. The existing technical solutions are mainly based on the calibration table lookup scheme, which obtains the distribution relationship between torque, speed, voltage and excitation current id and torque current iq through bench calibration. From the perspective of current distribution, it is difficult to consider the influence of the rotor time constant on the torque response time, resulting in a slow system torque response speed and failure to meet the performance requirements of the vehicle. The specific reasons are as follows:
[0004] The relationship between the rotor flux and the excitation current of the asynchronous motor can be expressed as: In the formula Among them, L r is the rotor inductance; R r is the rotor resistance; L m is the mutual inductance of the stator and rotor. The formula clearly shows that its dynamic characteristics are first-order inertia links, and its steady-state value is
[0005] From this relationship, we can see that when T e (i sd 、i sq ) has been determined, if a fixed torque step command is given at this time, then the corresponding excitation current command and torque current command step can be obtained. Due to the rotor time constant T r Due to the existence of , the actual rotor flux response lags behind the excitation current command, resulting in a lag in torque response. Summary of the Invention
[0006] In order to solve the technical problems existing in the background technology, the present invention proposes a method and system for distributing torque and current of an asynchronous motor.
[0007] The present invention provides an asynchronous motor torque and current distribution method, comprising the following steps:
[0008] S1, receiving target torque T e , and obtain the target torque T eThe corresponding steady-state excitation current I d (s);
[0009] S2. Get the rotor time constant T r and adjustable gain factor K, and based on the rotor time constant T r and the adjustable gain coefficient K for the steady-state excitation current I d (s) performs dynamic compensation to generate dynamic excitation current
[0010] S3, according to the dynamic excitation current and target torque T e Calculate the target torque current i in real time q ;
[0011] S4, the dynamic excitation current and target torque current i q The input current loop controller generates a PWM drive signal to control the power inverter.
[0012] Preferably, the rotor time constant T r and the adjustable gain coefficient K for the steady-state excitation current I d (s) performs dynamic compensation to generate dynamic excitation current Specifically:
[0013]
[0014] in, is the dynamic excitation current; K is the adjustable gain coefficient; T r is the rotor time constant; I d (s) is the steady-state excitation current; s is the Laplace operator.
[0015] Preferably, the dynamic excitation current and target torque T e Calculate the target torque current i in real time q , specifically:
[0016]
[0017] Among them, i q is the target torque current; T r is the rotor time constant; is the dynamic excitation current; L r is the rotor inductance; L m is the mutual inductance between stator and rotor; n p is the number of pole pairs of the motor.
[0018] Preferably, the steady-state excitation current I dThe specific method of obtaining (s) is as follows:
[0019] According to the target torque T e Query the corresponding steady-state excitation current I from the preset MTPA lookup table d (s), the MTPA table is configured with a target torque T e , motor speed ω, DC bus voltage U dc And the steady-state excitation current I d (s) have a one-to-one mapping relationship.
[0020] Preferably, the dynamic compensation in step S2 is implemented in a discrete system as follows:
[0021]
[0022] Among them, T s is the control period; k is the current time index.
[0023] Preferably, the adjustable gain coefficient K is calibrated by the following steps:
[0024] Apply step torque command in bench test;
[0025] Adjust the value of the adjustable gain coefficient K until the torque response time meets the threshold requirement;
[0026] Establish the adjustable gain coefficient K and target torque T e , and the motor speed ω two-dimensional mapping table and burn it into the controller.
[0027] The present invention proposes an asynchronous motor torque and current distribution system, comprising:
[0028] Data acquisition module, used to receive target torque T e , and obtain the target torque T e The corresponding steady-state excitation current I d (s);
[0029] Dynamic compensation module, used to obtain the rotor time constant T r and adjustable gain factor K, and based on the rotor time constant T r and the adjustable gain coefficient K for the steady-state excitation current I d (s) performs dynamic compensation to generate dynamic excitation current
[0030] Torque current solution module is used to calculate the torque current according to the dynamic excitation current and target torque T e Calculate the target torque current i in real time q ;
[0031] Current control module, used to convert the dynamic excitation current and target torque current i q The input current loop controller generates a PWM drive signal to control the power inverter.
[0032] Preferably, in the dynamic compensation module, the rotor time constant T r and the adjustable gain coefficient K for the steady-state excitation current I d (s) performs dynamic compensation to generate dynamic excitation current Specifically:
[0033]
[0034] in, is the dynamic excitation current; K is the adjustable gain coefficient; T r is the rotor time constant; I d (s) is the steady-state excitation current; s is the Laplace operator.
[0035] Preferably, in the torque current solution module, the dynamic excitation current and target torque T e Calculate the target torque current i in real time q , specifically:
[0036]
[0037] Among them, i q is the target torque current; T r is the rotor time constant; is the dynamic excitation current; L r is the rotor inductance; L m is the mutual inductance between stator and rotor; n p is the number of pole pairs of the motor.
[0038] The present invention proposes a vehicle electric drive controller, which integrates the asynchronous motor torque and current distribution system as described in any one of the above items and is connected to a power inverter to drive the asynchronous motor.
[0039] In the present invention, the proposed asynchronous motor torque current distribution method and system receive the target torque T e , and obtain the target torque T e The corresponding steady-state excitation current I d (s); Get the rotor time constant T r and adjustable gain factor K, and based on the rotor time constant T r and the adjustable gain coefficient K for the steady-state excitation current I d (s) performs dynamic compensation to generate dynamic excitation current According to the dynamic excitation current and target torque T e Calculate the target torque current i in real time q ; Dynamic excitation current and target torque current i q The input current loop controller generates a PWM drive signal to control the power inverter. Dynamic compensation increases the speed of rotor flux excitation, thereby improving the torque response speed of the asynchronous motor. At the same time, it can also ensure that the motor operates at the expected operating point under steady-state conditions. BRIEF DESCRIPTION OF THE DRAWINGS
[0040] Figure 1 A schematic diagram of the working process of a torque and current distribution method for an asynchronous motor proposed in the present invention;
[0041] Figure 2 This is a schematic diagram of the transfer function of the asynchronous motor torque and current distribution method proposed by the present invention in the time domain;
[0042] Figure 3 A schematic diagram of excitation response curves of different K values for an asynchronous motor torque and current distribution method proposed by the present invention;
[0043] Figure 4 This is a schematic diagram of the system architecture of an asynchronous motor torque and current distribution system proposed in the present invention. DETAILED DESCRIPTION
[0044] Reference Figure 1-4 The present invention proposes an asynchronous motor torque and current distribution method, comprising the following steps:
[0045] S1, receiving target torque T e , and obtain the target torque T e The corresponding steady-state excitation current I d (s).
[0046] In this embodiment, the steady-state excitation current I d The specific method of obtaining (s) is as follows:
[0047] According to the target torque T e Query the corresponding steady-state excitation current I from the preset MTPA lookup table d (s), the MTPA table is configured with the target torque T e , motor speed ω, DC bus voltage U dc And the steady-state excitation current I d (s) have a one-to-one mapping relationship.
[0048] S2. Get the rotor time constant T r and adjustable gain factor K, and based on the rotor time constant Tr and the adjustable gain coefficient K on the steady-state excitation current I d (s) performs dynamic compensation to generate dynamic excitation current .
[0049] In this embodiment, based on the rotor time constant T r and the adjustable gain coefficient K on the steady-state excitation current I d (s) performs dynamic compensation to generate dynamic excitation current Specifically:
[0050]
[0051] in, is the dynamic excitation current; K is the adjustable gain coefficient; T r is the rotor time constant; I d (s) is the steady-state excitation current; s is the Laplace operator.
[0052] Specifically, in order to improve the torque response time, it is necessary to overcome T r , to improve the response speed of rotor excitation, the original table lookup current setting solution is no longer applicable in asynchronous motors, so the excitation current setting is redesigned and the transient part of the current setting is added. As shown in the above formula, is the new excitation current given, I d (s) is the steady-state excitation current command obtained by looking up the table. K is the adjustable gain coefficient, which can be calibrated according to the actual torque response requirements. The calculation formula is specifically expressed in the time domain as follows Figure 2 shown. Figure 2 in yes After Laplace transformation, it is obtained by Figure 2 It can be seen that the new transfer function, that is, the calculation method of the excitation current, at the initial moment when the excitation current is given, the actual instruction Relatively stable target instruction i d There is a certain overshoot, the overshoot size is i d +K, when time reaches T r When the overshoot is reduced to i d +0.27K, final actual current instruction
[0053] Assume T r =5s, i under steady-state conditions d =1A, mutual inductance L m =1H, such as Figure 3 The figure shows the comparison curve of excitation response speed for different K values.
[0054] The superposition of this dynamic process increases the speed of rotor flux excitation, and at the same time ensures that the motor operates at the expected operating point under steady-state conditions.
[0055] The above calculation process has obtained the current target torque T e And the adjusted excitation current command At this time, the average torque formula of the asynchronous motor can be used Calculate the target torque current i q .
[0056] In this embodiment, the dynamic compensation in step S2 is implemented in the discrete system as follows:
[0057]
[0058] Among them, T s is the control period; k is the current time index.
[0059] In this embodiment, the adjustable gain coefficient K is calibrated by the following steps:
[0060] Apply step torque command in bench test;
[0061] Adjust the value of the adjustable gain coefficient K until the torque response time meets the threshold requirement;
[0062] Establish the adjustable gain coefficient K and target torque T e , and the motor speed ω two-dimensional mapping table and burn it into the controller.
[0063] S3, according to the dynamic excitation current and target torque T e Calculate the target torque current i in real time q .
[0064] In this embodiment, step S3 is specifically as follows:
[0065]
[0066] Among them, i q is the target torque current; T r is the rotor time constant; is the dynamic excitation current; L r is the rotor inductance; L m is the mutual inductance between stator and rotor; n p is the number of pole pairs of the motor.
[0067] S4, the dynamic excitation current and target torque current i q The input current loop controller generates a PWM drive signal to control the power inverter.
[0068] Reference Figure 1-4 The present invention proposes an asynchronous motor torque and current distribution system, comprising:
[0069] Data acquisition module, used to receive target torque T e , and obtain the target torque T e The corresponding steady-state excitation current I d (s);
[0070] Dynamic compensation module, used to obtain the rotor time constant T r and adjustable gain factor K, and based on the rotor time constant T r and the adjustable gain coefficient K on the steady-state excitation current I d (s) performs dynamic compensation to generate dynamic excitation current
[0071] Torque current solution module is used to calculate the torque current according to the dynamic excitation current and target torque T e Calculate the target torque current i in real time q ;
[0072] Current control module, used to convert the dynamic excitation current and target torque current i q The input current loop controller generates a PWM drive signal to control the power inverter.
[0073] In this embodiment, in the dynamic compensation module, based on the rotor time constant T r and the adjustable gain coefficient K on the steady-state excitation current I d (s) Perform dynamic compensation to generate dynamic excitation current Specifically:
[0074]
[0075] in, is the dynamic excitation current; K is the adjustable gain coefficient; T r is the rotor time constant; I d (s) is the steady-state excitation current; s is the Laplace operator.
[0076] In this embodiment, in the torque current solution module, according to the dynamic excitation current and target torque T e Calculate the target torque current i in real time q , specifically:
[0077]
[0078] Among them, i q is the target torque current; Tr is the rotor time constant; is the dynamic excitation current; L r is the rotor inductance; L m is the mutual inductance between stator and rotor; n p is the number of pole pairs of the motor.
[0079] Reference Figure 1-4 The present invention proposes a vehicle electric drive controller, which integrates the asynchronous motor torque and current distribution system as any of the above items and is connected to a power inverter to drive the asynchronous motor.
[0080] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.
Claims
1. A method for distributing torque and current of an asynchronous motor, characterized in that: The following steps are involved: S1, receiving target torque T e , and obtain the target torque T e The corresponding steady-state excitation current I d (s); S2. Get the rotor time constant T r and adjustable gain factor K, and based on the rotor time constant T r and the adjustable gain coefficient K for the steady-state excitation current I d (s) performs dynamic compensation to generate dynamic excitation current S3, according to the dynamic excitation current and target torque T e Calculate the target torque current i in real time q ; S4, the dynamic excitation current and target torque current i q The input current loop controller generates a PWM drive signal to control the power inverter.
2. The asynchronous motor torque and current distribution method according to claim 1, characterized in that: The rotor time constant T r and the adjustable gain coefficient K for the steady-state excitation current I d (s) performs dynamic compensation to generate dynamic excitation current Specifically: in, is the dynamic excitation current; K is the adjustable gain coefficient; T r is the rotor time constant; I d (s) is the steady-state excitation current; s is the Laplace operator.
3. The asynchronous motor torque and current distribution method according to claim 1, characterized in that: The dynamic excitation current and target torque T e Calculate the target torque current i in real time q , specifically: Among them, i q is the target torque current; T r is the rotor time constant; is the dynamic excitation current; L r is the rotor inductance; L m is the mutual inductance between stator and rotor; n p is the number of pole pairs of the motor.
4. The asynchronous motor torque and current distribution method according to claim 1, characterized in that: The steady-state excitation current I d The specific method of obtaining (s) is as follows: According to the target torque T e Query the corresponding steady-state excitation current I from the preset MTPA lookup table d (s), the MTPA table is configured with a target torque T e , motor speed ω, DC bus voltage U dc And the steady-state excitation current I d (s) have a one-to-one mapping relationship.
5. The asynchronous motor torque and current distribution method according to claim 1, characterized in that: The implementation of the dynamic compensation in the discrete system in step S2 is as follows: Among them, T s is the control period; k is the current time index.
6. The asynchronous motor torque and current distribution method according to claim 1, characterized in that: The adjustable gain coefficient K is calibrated by the following steps: Apply step torque command in bench test; Adjust the value of the adjustable gain coefficient K until the torque response time meets the threshold requirement; Establish the adjustable gain coefficient K and target torque T e , and the motor speed ω two-dimensional mapping table and burn it into the controller.
7. An asynchronous motor torque and current distribution system, characterized in that: include: Data acquisition module, used to receive target torque T e , and obtain the target torque T e The corresponding steady-state excitation current I d (s); Dynamic compensation module, used to obtain the rotor time constant T r and adjustable gain factor K, and based on the rotor time constant T r and the adjustable gain coefficient K for the steady-state excitation current I d (s) performs dynamic compensation to generate dynamic excitation current Torque current solution module is used to calculate the torque current according to the dynamic excitation current and target torque T e Calculate the target torque current i in real time q ; Current control module, used to convert the dynamic excitation current and target torque current i q The input current loop controller generates a PWM drive signal to control the power inverter.
8. The asynchronous motor torque and current distribution system according to claim 7, characterized in that: In the dynamic compensation module, the rotor time constant T r and the adjustable gain coefficient K for the steady-state excitation current I d (s) performs dynamic compensation to generate dynamic excitation current Specifically: in, is the dynamic excitation current; K is the adjustable gain coefficient; T r is the rotor time constant; I d (s) is the steady-state excitation current; s is the Laplace operator.
9. The asynchronous motor torque and current distribution system according to claim 7, characterized in that: In the torque current solution module, the dynamic excitation current and target torque T e Calculate the target torque current i in real time q , specifically: Among them, i q is the target torque current; T r is the rotor time constant; is the dynamic excitation current; L r is the rotor inductance; L m is the mutual inductance between stator and rotor; n p is the number of pole pairs of the motor.
10. A vehicle electric drive controller, characterized in that: The asynchronous motor torque and current distribution system according to any one of claims 7 to 9 is integrated and connected to a power inverter to drive the asynchronous motor.