Double permanent magnet synchronous motor deadbeat speed synchronization control method

Abstract

This invention discloses a deadbeat speed synchronization control method for a dual permanent magnet synchronous motor. It employs a full-order deadbeat current tracking controller for dynamic voltage vector calculation; the deadbeat speed synchronization controller calculates the inverter voltage difference vector required for synchronization control based on the deadbeat speed synchronization condition; and distributes the difference vector to two sets of voltage vectors calculated by the current tracking controller, causing the two inverters to generate corresponding desired differences, thus achieving current tracking and speed synchronization control of the dual permanent magnet synchronous motor under various unbalanced operating conditions. This invention enables the system to maintain high synchronization consistency and rapid response capability even when subjected to external disturbances or changes in operating conditions.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and in particular to a method for zero-delay speed synchronization control of a dual permanent magnet synchronous motor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in aerospace, electric vehicles, industrial equipment, and robotics—applications requiring high dynamic performance and control precision—due to their high power density, high efficiency, and fast response. In multi-motor cooperative drive systems, to enhance system redundancy, output capacity, and operational safety, a structure of two PMSMs connected in parallel or in cooperative drive is often employed. This allows the two motors to share the load, achieving high-performance power output.

[0003] However, dual-motor systems commonly face problems such as inconsistent motor parameters, unbalanced load distribution, and asynchronous changes in motor operating states during operation. Motor parameters are affected by factors such as manufacturing errors, temperature rise characteristics, and magnetic saturation. Even motors of the same model may have parameters such as resistance, inductance, and permanent magnet flux that are difficult to keep completely consistent. In addition, disturbances on the load side or asymmetry in the mechanical structure often cause dynamic imbalances in the load borne by the two motors, resulting in deviations in current response and speed.

[0004] To address the synchronous operation requirements of dual motors, existing technologies primarily employ a collaborative control structure based on PI control of the current and speed loops or feedforward compensation. Synchronization performance is improved by increasing the current loop bandwidth or adding speed difference suppression components. However, due to the significant coupling characteristics inherent in permanent magnet synchronous motors, traditional control methods often suffer from limited response speed, insufficient predictive capability, and difficulties in multi-loop coordination under rapid dynamic conditions, such as sudden load increases, speed command jumps, or rapid parameter changes.

[0005] In recent years, deadbeat control has been increasingly applied to high-performance current control scenarios due to its ability to eliminate prediction errors within a single sampling period. Deadbeat current control can significantly improve current tracking accuracy and dynamic response capabilities. However, existing deadbeat controllers mostly focus on current tracking of a single motor, lacking a systematic mechanism for handling synchronization constraints, dynamic voltage distribution, and speed difference suppression issues in multi-motor systems, and thus cannot guarantee rapid speed synchronization of two motors under unbalanced loads.

[0006] In summary, existing technologies for the coordinated control of dual permanent magnet synchronous motors still suffer from problems such as insufficient response speed, limited synchronization accuracy, and difficulty in simultaneously achieving current tracking and speed synchronization. There is an urgent need for a control method that can effectively eliminate speed deviation and improve system synchronization performance under dynamic operating conditions. Summary of the Invention

[0007] Purpose of the invention: This invention provides a deadbeat speed synchronization control method for dual permanent magnet synchronous motors, enabling the system to maintain high synchronization consistency and rapid response capability even when subjected to external disturbances or changes in operating conditions.

[0008] Technical solution: The present invention provides a method for deadbeat-free speed synchronization control of a dual permanent magnet synchronous motor, comprising the following steps:

[0009] Dynamic voltage vector calculation is performed using a full-order deadbeat current tracking controller.

[0010] The deadbeat speed synchronization controller calculates the inverter voltage difference vector required for synchronization control based on the deadbeat speed synchronization condition.

[0011] The difference vector is distributed to the two sets of voltage vectors calculated by the current tracking controller, so that the two inverters generate the corresponding expected difference value, thereby realizing the current tracking and speed synchronization control of the dual permanent magnet synchronous motor under various unbalanced operating conditions.

[0012] Furthermore, a full-order deadbeat current tracking controller is used for dynamic voltage vector calculation, expressed as:

[0013]

[0014] In the formula, the superscript Representing the The state quantity at the start of the control cycle is given by the formula. , , , These are the motor stator resistance, stator inductance, electric angular velocity, and control cycle duration, respectively. , .

[0015] Furthermore, the voltage difference along the q-axis is used as the control variable for speed synchronization planning in vector space, utilizing the deadbeat condition for dual-motor speed synchronization. The inverter voltage difference vector required for synchronous control is predicted and calculated.

[0016] Furthermore, the desired voltage difference vector is expressed as:

[0017]

[0018] In the formula, , , These are the permanent magnet flux linkage, moment of inertia, and number of pole pairs of the motor, respectively. The deviation operator is defined as follows: , representing the deviation between the two motors, the increment operator is defined as , which represents the amount by which a state variable increases during a control cycle.

[0019] Furthermore, the desired voltage difference vector is dynamically allocated to the output vector of the full-order deadbeat current tracking controller, so that the allocated voltage vector has the ability to synchronize speed.

[0020] Furthermore, the desired voltage difference vector is evenly distributed to the output vectors of the two sets of full-order deadbeat current tracking controllers to achieve speed synchronization while minimizing the impact on the current tracking target. Voltage limiting also needs to be considered, where the unallocated desired voltage difference considering limiting saturation is expressed as:

[0021]

[0022] In the formula, the voltage limiting saturation operator is defined as follows: The saturation indicator is represented as:

[0023]

[0024] In the formula, It is a step function. , The dynamically allocated q-axis reference voltage is then expressed as:

[0025]

[0026] By dynamically allocating the desired voltage difference, the output of the desired voltage difference can be satisfied as much as possible while ensuring the amplitude limit of each motor, thus taking into account both the safety of motor operation and synchronization performance.

[0027] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) It adopts a full-order deadbeat current tracking controller to accurately model the speed coupling term in the current loop and predict the desired voltage vector within the control cycle, so that the system can achieve high-precision current tracking under rapid dynamic conditions such as load change, and significantly reduce the accumulation of transient errors; (2) It calculates the desired voltage difference vector based on the speed synchronization deadbeat condition and dynamically superimposes the difference vector onto the current control output, effectively compensating for the instantaneous speed deviation caused by load disturbance, so that the two motors can recover the synchronization state in a short time and improve the consistency of operation; (3) It adds the synchronization voltage difference to the reference voltage of the two inverters in a dynamic allocation manner, realizes speed synchronization control without significantly affecting the current tracking target, and considers the saturation limit of the two control channels to ensure that the output voltage does not exceed the safety range of the inverter, thereby improving the stability and safety of the system operation; (4) The control logic of the present invention is based on the deadbeat control model, and the algorithm structure is clear and concise. It can be directly embedded into the existing permanent magnet synchronous motor digital control platform without additional hardware or complex optimization calculations, and has high engineering feasibility and promotion application value. Attached Figure Description

[0028] Figure 1 This is a block diagram of the deadbeat speed synchronization control of the dual permanent magnet synchronous motor in this invention.

[0029] Figure 2 This is a schematic diagram of the voltage vector dynamic allocation strategy in this invention.

[0030] Figure 3 The figure shows the simulation results of the three-phase current, q-axis current, speed and speed deviation of the dual permanent magnet synchronous motor system under unbalanced load in the method of the present invention. Detailed Implementation

[0031] like Figure 1 As shown, a method for deadbeat-free speed synchronization control of a dual permanent magnet synchronous motor includes the following steps:

[0032] Dynamic voltage vector calculation is performed using a full-order deadbeat current tracking controller.

[0033] The deadbeat speed synchronization controller calculates the inverter voltage difference vector required for synchronization control based on the deadbeat speed synchronization condition.

[0034] The difference vector is distributed to the two sets of voltage vectors calculated by the current tracking controller, so that the two inverters generate the corresponding expected difference value, thereby realizing the current tracking and speed synchronization control of the dual permanent magnet synchronous motor under various unbalanced operating conditions.

[0035] The system architecture comprises two permanent magnet synchronous motors (PMSMs), two sets of three-phase bridge inverters, an outer speed tracking loop, an inner speed synchronization loop, and an inner current synchronization loop. The two sets of three-phase bridge inverters supply power to the two PMSMs respectively, allowing the two PMSMs to operate independently without mechanical connection. The controller uses the motor stator current and motor speed as feedback signals, and through the coordinated control of the current loop and speed synchronization loop, calculates the reference voltage vectors of the two inverters in real time, enabling the system to achieve deadbeat current tracking and speed synchronization control under various operating conditions.

[0036] This invention simultaneously achieves current tracking for each of the two motors and speed synchronization for the dual-motor system. It mainly calculates two types of vectors: the first is a vector for current tracking (one for each motor, two in total), and the second is a difference vector for speed synchronization (one for the dual-motor system). In order to achieve both current tracking and speed synchronization simultaneously, the difference vector for speed synchronization is dynamically allocated to the current tracking vector of each motor, so that the two vectors acting on the two motors ultimately generate the desired speed synchronization difference vector based on the current tracking vector.

[0037] Traditional deadbeat current controllers do not consider the coupled electromotive force caused by motor speed. When motor speed changes rapidly, prediction errors easily accumulate, affecting current tracking accuracy and even speed control accuracy, making them unsuitable for the speed synchronization control scenario in this invention. Therefore, a full-order deadbeat current tracking controller is used as the main controller for the current tracking target. In each control cycle, this controller calculates the desired voltage required for current tracking in both control channels without deadbeat based on the difference between the dq-axis currents of the two motors and the target current, the speeds of the two motors, and the parameters of the two motors. The desired voltage can be expressed as:

[0038]

[0039] In the formula, the superscript Representing the The state quantity at the start of the control cycle is given by the formula. , , , These are the motor stator resistance, stator inductance, electric angular velocity, and control cycle duration, respectively. , .

[0040] The predictive control objective of a full-order deadbeat current tracking controller Similarly, a deadbeat-free speed synchronization controller is applied, using the voltage difference along the q-axis as the control variable for speed synchronization planning in vector space, utilizing the deadbeat condition for dual-motor speed synchronization. The inverter voltage difference vector required for synchronous control is predicted and calculated. The desired voltage difference vector can be expressed as:

[0041]

[0042] In the formula, , , These are the permanent magnet flux linkage, moment of inertia, and number of pole pairs of the motor, respectively. The deviation operator is defined as follows: This represents the deviation between the two motors. The increment operator is defined as follows: This represents the amount by which the state variable increases within a control cycle. Deadbeat elimination of speed deviation corresponds to deadbeat elimination of current error, simultaneously achieving both current tracking and speed synchronization at the start of the next control cycle. However, when calculating the deadbeat voltage for fusing and outputting these two objectives, the voltage limits that the two inverters can output must be considered to ensure the control system can effectively realize its calculated control quantities and prevent control dead zones and accumulated errors.

[0043] To minimize the impact of the speed synchronization vector on the current tracking vector, if there is no voltage limiting in the two control channels, the desired voltage difference vector is evenly distributed across the current tracking vectors of the two channels. That is:

[0044]

[0045] However, the actual control system has voltage limiting, and it is necessary to consider the situation where the q-axis voltage exceeds the limit after voltage distribution. After the speed synchronization vector is evenly distributed, the voltage of the two channels is saturated and limited. Then, the speed synchronization vector that is not successfully distributed can be expressed as:

[0046]

[0047] In the formula, the voltage limiting saturation operator is defined as follows: It is also necessary to determine the saturation status of each channel in order to further allocate unsuccessfully assigned vectors. The saturation flag can be represented as:

[0048]

[0049] In the formula, It is a step function. , The unallocated speed synchronization vector is further distributed to unsaturated channels. If both channels are already saturated, they are treated according to the saturation limit value, and the target speed synchronization vector is not forcibly allocated. The dynamically allocated q-axis reference voltage can then be expressed as:

[0050]

[0051] like Figure 2 As shown, the voltage vector dynamic allocation strategy in this invention can be divided into three cases: First, when neither channel saturates after allocation, the expected voltage difference is evenly distributed; second, when one channel is saturated and the other is not, the former is allocated according to saturation, and the unallocated expected voltage difference is allocated to the latter; third, when the latter is also saturated according to case two, the saturation allocation of the two channels is maintained. Dynamic allocation of the expected voltage difference can ensure the limiting of each motor while maximizing the output of the expected voltage difference, balancing motor operation safety and synchronization performance. The dynamic allocation strategy simultaneously ensures the control effect of the current tracking vector and the speed synchronization vector, minimizing the control conflict between the two control objectives and achieving stable and rapid speed synchronization control of the dual permanent magnet synchronous motor system.

[0052] To verify this method, a model was built for simulation verification. The simulation conditions were as follows: two permanent magnet synchronous motors were running stably under no-load conditions. At 0.02s, a load of 0.1Nm was suddenly applied to motor 1. At 0.03s and 0.06s, a load of 0.15Nm was suddenly applied to and removed from motor 2, respectively. At all three time points, an unbalanced load was formed on the dual-motor system. The simulation results are as follows. Figure 3 As shown, during the entire simulation, the three-phase current exhibits high sinusoidal strength, and the q-axis current can quickly track the target value, enabling the system to achieve current tracking. After the speeds of the two motors stabilize, a sudden application of an unbalanced load causes the speed of the corresponding motor to drop or increase. Under the action of the deviation vector of the speed synchronization controller, the speed of the other motor, which currently has a stable load, also drops or increases accordingly, effectively suppressing the speed deviation between the two motors, and the system can achieve speed synchronization. This demonstrates that the deadbeat-free speed synchronization control method can simultaneously achieve current tracking and speed synchronization in a dual permanent magnet synchronous motor system, indicating the feasibility of this invention.

Claims

1. A deadbeat rotational speed synchronous control method for dual permanent magnet synchronous motors, characterized by, Includes the following steps: Dynamic voltage vector calculation is performed using a full-order deadbeat current tracking controller. The deadbeat speed synchronization controller calculates the inverter voltage difference vector required for synchronization control based on the deadbeat speed synchronization condition. The difference vector is distributed to the two sets of voltage vectors calculated by the current tracking controller, so that the two inverters generate the corresponding expected difference value, thereby realizing the current tracking and speed synchronization control of the dual permanent magnet synchronous motor under various unbalanced operating conditions.

2. The dead-beat rotational speed synchronous control method of dual permanent magnet synchronous machines according to claim 1, characterized by, Dynamic voltage vector calculation is performed using a full-order deadbeat current tracking controller, expressed as: In the formula, the superscript Representing the The state quantity at the start of the control cycle is given by the formula. , , , These are the motor stator resistance, stator inductance, electric angular velocity, and control cycle duration, respectively. , .

3. The method for zero-delay speed synchronization control of a dual permanent magnet synchronous motor as described in claim 1, characterized in that, In vector space, the voltage difference along the q-axis is used as the control variable for speed synchronization planning, utilizing the deadbeat condition for dual-motor speed synchronization. The inverter voltage difference vector required for synchronous control is predicted and calculated.

4. The method for deadbeat-free speed synchronization control of a dual permanent magnet synchronous motor as described in claim 3, characterized in that, The desired voltage difference vector is expressed as: In the formula, , , These are the permanent magnet flux linkage, moment of inertia, and number of pole pairs of the motor, respectively. The deviation operator is defined as follows: , representing the deviation between the two motors, the increment operator is defined as , which represents the amount by which a state variable increases during a control cycle.

5. The method for deadbeat speed synchronization control of a dual permanent magnet synchronous motor as described in claim 1, characterized in that, The desired voltage difference vector is dynamically allocated to the output vector of the full-order deadbeat current tracking controller, so that the allocated voltage vector has the ability to synchronize speed.

6. The method for deadbeat-free speed synchronization control of a dual permanent magnet synchronous motor as described in claim 5, characterized in that, The desired voltage difference vector is evenly distributed to the output vectors of the two sets of full-order deadbeat current tracking controllers to achieve speed synchronization while minimizing the impact on the current tracking target. Voltage limiting also needs to be considered, where the unallocated desired voltage difference considering limiting saturation is expressed as: In the formula, the voltage limiting saturation operator is defined as follows: The saturation indicator is represented as: In the formula, It is a step function. , The dynamically allocated q-axis reference voltage is then expressed as: By dynamically allocating the desired voltage difference, the output of the desired voltage difference can be satisfied as much as possible while ensuring the amplitude limit of each motor, thus taking into account both the safety of motor operation and synchronization performance.

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