Full-speed-domain efficient control method suitable for electro-magnetic motor
By determining the speed range and calculating the weighted coefficients of the electrically excited motor, and combining the current/voltage model, efficient control of the electrically excited motor in the full speed range was achieved, solving the problems of copper loss and voltage limitation, and realizing efficient operation of the electrically excited motor in the full speed range.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI AUTO EDRIVE CO LTD
- Filing Date
- 2026-01-30
- Publication Date
- 2026-05-01
AI Technical Summary
Existing control algorithms for electrically excited motors suffer from problems such as non-negligible copper losses, low efficiency, low-speed multi-variable limitations, and high-speed voltage limitations across the entire speed range, making it difficult to achieve efficient control across the entire speed range.
By collecting the current actual power of the electrically excited motor and combining it with preset speed range judgment conditions, the operating range is divided. The weighting coefficients are calculated using the offline torque-current distribution table, current model and voltage model to achieve shock-free switching of the optimal dq axis current and excitation current. Combined with adaptive weighting and feedforward design, the load angle of the current model and voltage model is smoothly switched to ensure efficient control across the entire speed range.
It achieves optimal copper loss control and shock-free switching of unity power factor control for electrically excited motors across the entire speed range, balancing the speed and accuracy of the motor, solving the problems of low efficiency and voltage limitation in traditional modes, and fully leveraging the speed regulation advantages of electrically excited motors.
Smart Images
Figure CN121966384A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of motor control technology, and in particular to a high-efficiency control method for the entire speed range of electrically excited motors. Background Technology
[0002] Due to their high efficiency across the entire operating range, electrically excited motors offer advantages in functional safety and provide additional degrees of freedom through rotor current, making them ideal for axle drive requirements in automotive applications. Currently, mass-produced models such as the BMW iX3, Renault Kangoo, and Nissan ARIYA all use electrically excited motors as their automotive motors, and manufacturers like Valeo and ZF have already mass-produced electrically excited motor systems. It can be said that electrically excited motors, as automotive motors, possess significant potential advantages, not only in their performance and control freedom, but also in reducing reliance on rare earth elements, which helps lower costs and ensure supply chain security. When combined with appropriate control algorithms, they can accommodate both peak performance and high-speed continuous performance, thereby expanding the performance boundaries of electric platforms.
[0003] However, there is still a lack of research on control algorithms for electrically excited motors, especially considering the operating conditions of automotive motors. Traditional control algorithms for electrically excited motors have the following main drawbacks: 1) Many scholars have studied the problem of non-negligible copper loss caused by electrically excited motors and proposed the optimal copper loss control theory to enable the motor to achieve the best control performance. However, they usually fail to consider the voltage limit loop constraint caused by the motor running at high speed and high torque. 2) In engineering, if the global calibration is performed according to the optimal copper loss theory, it not only has the problems mentioned in 1), but also the problems of being time-consuming, labor-intensive, and inefficient. 3) In practical applications of unity power factor control, the low torque region deviates significantly from the optimal efficiency point. Optimal power factor control usually relies on the accuracy of simulation data to ensure the feasibility of the control algorithm.
[0004] In summary, if an electrically excited motor is used in a vehicle, in order to achieve the required driving range with a limited battery capacity, it is necessary to minimize the motor's losses and fully utilize the inherent advantage of the electrically excited motor's wide speed range in automotive motors. However, existing control algorithms face problems such as low-speed multivariable limitations, efficiency issues caused by non-negligible losses, and high-speed voltage limitations that prevent the electrically excited motor from fully utilizing its inherent advantages, which are not conducive to achieving efficient control across the entire speed range. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a full-speed-range high-efficiency control method for electrically excited motors, which can take into account both optimal copper loss control and unity power factor control, and perform shock-free switching between the two control modes to achieve full-speed-range high-efficiency control.
[0006] The objective of this invention can be achieved through the following technical solution: a high-efficiency control method for the entire speed range of an electrically excited motor, comprising: Collect the current actual power of the electrically excited motor Based on preset speed range judgment conditions, the working state of the electrically excited motor and its current operating zone are determined, and the corresponding weighting coefficients are calculated. The working state includes motor state and generator state; the operating zone includes zone I, switching zone and zone II. Zone I is the base speed or high speed low torque operating zone, and zone II is the high speed high torque operating zone. If the electrically excited motor is determined to be in zone I, the optimal dq axis current and excitation current under the base speed condition can be determined using the torque-current distribution table obtained offline. If the electrically excited motor is determined to be in the switching zone, the first air gap flux linkage and the first load angle, the second air gap flux linkage and the second load angle are calculated using the pre-built current model and voltage model, respectively. Then, based on the first load angle and the second load angle, the transition between the two load angles is realized by combining weighting coefficients, thereby determining the optimal dq axis current in the switching zone. Based on the first air gap flux linkage and the second air gap flux linkage, the optimal excitation current in the switching zone is determined by the air gap flux linkage control module. If the electrically excited motor is determined to be in Zone II, the second air gap flux and the second load angle are calculated using the pre-built voltage model to determine the optimal dq axis current and excitation current under high speed conditions. The system adopts a current-command-free switching method, selecting the optimal dq-axis current and excitation current based on the actual operating conditions of the electrically excited motor, such as the output base speed, switching zone, or high-speed condition, as reference values for the control current, thereby achieving control of the electrically excited motor.
[0007] Furthermore, the weighting coefficients include a first weighting coefficient. Second weighting coefficient The first weighting coefficient Used to control the smooth switching between the first load angle and the second load angle; Second weighting coefficient Used for shockless switching of the control loop current setpoint.
[0008] Furthermore, the preset speed range determination conditions include: When the electrically excited motor is in motor mode and in zone I, the corresponding speed range judgment condition is: , The power threshold for region I is used, where the first weighting coefficient is... The calculation formula is: ,in At minimum power, at this time The output load angle is biased towards the current model; When the electrically excited magneto is in generator mode and in zone I, the corresponding judgment conditions and The calculation formulas all use absolute values; When the electrically excited motor is in motor mode and in the switching zone, the corresponding judgment condition is: At this point, the first weighting coefficient The calculation formula is: ,in P 2 represents the power threshold for Region II. The output load angle is biased towards the voltage model; When the electrically excited magnetizer is in generator mode and in the switching zone, the corresponding judgment conditions and The calculation formulas all use absolute values; Second weighting coefficient The calculation design principle and the first weighting coefficient The computational design principles are the same.
[0009] Furthermore, the process of determining the optimal dq-axis current and excitation current under the base velocity condition includes: Based on the optimal copper loss control theory, the current / torque gridded calibration of the electrically excited motor at its base speed is performed, and a torque-current allocation table is constructed. Based on the torque-current allocation table, and according to the base speed operating requirements of the electrically excited motor, the optimal dq-axis current required by the output control loop at the base speed is determined. and the excitation circuit given current .
[0010] Furthermore, the current model is specifically constructed based on the torque-current distribution table by calculating the inductor current mapping table. The first air gap flux linkage calculated by the current model is specifically as follows: in, For the first d-axis air gap flux linkage, For d-axis inductance, For stator side leakage, For d-axis current, For excitation current, For mutual inductance between stator and rotor; For the first q-axis air gap flux linkage, It is the q-axis inductance. For stator side leakage, This is the q-axis current; The first load angle calculated by the current model is as follows: .
[0011] Furthermore, the voltage model calculates the second air gap flux linkage as follows: Where x = α and β correspond to the α-axis and β-axis respectively, the α-axis direction is the direction of the axis of the A-phase stator AC winding, and the β-axis direction leads the α-axis by 90° electrical angle. Stator flux linkage along the α-axis or β-axis, This refers to the stator current along the α-axis or β-axis. The voltage model calculates the second load angle as follows: in, For rotor angle, For the air gap angle, For the α-axis air gap flux linkage, It represents the β-axis air gap flux linkage.
[0012] Furthermore, the process of determining the optimal dq-axis current and excitation current in the switching region includes: Based on the first air gap flux linkage, a reference value for the air gap flux linkage is calculated. This value is used to calculate the torque current setpoint. Furthermore, in conjunction with the second air gap flux linkage, the air gap flux linkage control module determines the excitation circuit setpoint current required for the control circuit of the electrically excited motor under high-speed operation conditions. ; Using the first weighting coefficient This is used to smoothly switch between the first and second load angles. Combined with the torque current setpoint, the dq-axis current required by the control circuit of the electrically excited motor under high-speed operation is obtained through coordinate transformation. .
[0013] Furthermore, the process of calculating the air gap flux reference value includes: combining the rotational speed... n DC bus voltage And the first air gap flux linkage, which is output as a limited air gap flux linkage through the air gap flux linkage limiting module. Then, after weakening the magnetic field, the air gap flux reference value is output. .
[0014] Furthermore, the torque current setpoint Specifically, it involves combining the torque reference value. T refand air gap flux reference value This can be calculated.
[0015] Furthermore, the calculation yields the torque current setpoint. The process is as follows: set the torque reference value. T ref and air gap flux reference value Substituting the corresponding formulas into the relationship between torque and air gap flux... To calculate the torque current setpoint .
[0016] Compared with the prior art, the present invention has the following advantages: This invention first collects the current actual power of the electrically excited motor, then combines it with preset speed range judgment conditions to determine the working state and current operating zone of the electrically excited motor, and calculates the corresponding weighting coefficients. Next, based on the operating zone judgment results of the electrically excited motor, using the offline torque-current distribution table and pre-built current and voltage models, combined with the weighting coefficients and air gap flux linkage control module, the optimal dq-axis current and excitation current are determined for the base speed, switching zone, and high-speed conditions. Finally, using a current-command-free switching method, the optimal dq-axis current and excitation current for the base speed, switching zone, or high-speed conditions are selected according to the actual operating conditions of the electrically excited motor, serving as a reference value for the control current. This enables shockless switching of optimal copper loss control and unity power factor control, achieving efficient full-speed range control of the electrically excited motor.
[0017] This invention divides the motor operating region into three zones: Zone I (base speed or high speed with low torque), Zone II (switching zone), and Zone III (high speed with high torque). A first weighting coefficient is calculated accordingly to select the load angle for the control loop. In the initial stage of the base speed zone or during high speed with low torque, the voltage model signal is weak, making the current model more stable, and the output load angle is biased towards the current model. In the middle to late stages of the base speed zone, during high speed with high torque, the back electromotive force is strong, making the voltage model more accurate, and the output load angle is biased towards the voltage model. This invention considers the torque setpoint, speed, and DC bus voltage, and uses this design approach to design an adaptive weighting calculation to output the first weighting coefficient. The load angle calculated using the voltage and current models is used to smoothly switch between them, along with the corresponding weighting coefficients. By implementing a load angle feedforward design, the load angle used in the control loop can be balanced. This invention, based on adaptive weighting and a feedforward load angle calculation method, can effectively balance the speed and accuracy of torque control.
[0018] In this invention, the second weighting coefficient is calculated and output. It is used for shockless switching of the control loop current setpoint. It can select the corresponding dq axis current and excitation current as the current reference value of the control loop according to the actual operation of the motor, thereby achieving optimal control.
[0019] This invention aims to minimize the losses of the electrically excited motor while fully leveraging its inherent advantage of a wide speed range. Therefore, based on optimal copper loss control theory, a torque-current distribution table is obtained through gridded calibration of the current / torque. An inductor current mapping table is then calculated from this table, allowing the construction of a current model for calculating the first air gap flux linkage and the first load angle. Additionally, a voltage model is constructed to calculate the second air gap flux linkage and the second load angle. Subsequently, based on the torque-current distribution table, the optimal dq-axis current and excitation current for the control loop at base speed are determined. Furthermore, adaptive weight adjustment facilitates the transition between the load angle outputs of the current and voltage models, thereby determining the optimal dq-axis current in the switching zone. The optimal excitation current in the switching zone is then determined through the air gap flux linkage control module. This ensures accurate and reliable control of the electrically excited motor in the switching zone. Attached Figure Description
[0020] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is the control current distribution logic diagram under the base speed calibration in the embodiment; Figure 3 This is the logic diagram of the torque-current mapping table in the embodiment; Figure 4 This is a schematic diagram of the shaft system definition in the embodiment; Figure 5 This is the full-speed-domain control framework for the electrically excited motor constructed in the embodiment; Figure 6 This is a schematic diagram of the motor operating area division used for weighting coefficient calculation in the embodiment; Figure 7 This is a block diagram of the load angle feedforward design structure in the embodiment. Detailed Implementation
[0021] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.
[0022] Example like Figure 1 As shown, a high-efficiency control method for the entire speed range of an electrically excited motor includes: Collect the current actual power of the electrically excited motor Based on preset speed range judgment conditions, the working state of the electrically excited motor and its current operating zone are determined, and the corresponding weighting coefficients are calculated. The working state includes motor state and generator state; the operating zone includes zone I, switching zone and zone II. Zone I is the base speed or high speed low torque operating zone, and zone II is the high speed high torque operating zone. If the electrically excited motor is determined to be in zone I, the optimal dq axis current and excitation current under the base speed condition can be determined using the torque-current distribution table obtained offline. If the electrically excited motor is determined to be in the switching zone, the first air gap flux linkage and the first load angle, the second air gap flux linkage and the second load angle are calculated using the pre-built current model and voltage model, respectively. Then, based on the first load angle and the second load angle, the transition between the two load angles is realized by combining weighting coefficients, thereby determining the optimal dq axis current in the switching zone. Based on the first air gap flux linkage and the second air gap flux linkage, the optimal excitation current in the switching zone is determined by the air gap flux linkage control module. If the electrically excited motor is determined to be in Zone II, the second air gap flux and the second load angle are calculated using the pre-built voltage model to determine the optimal dq axis current and excitation current under high speed conditions. The system adopts a current-command-free switching method, selecting the optimal dq-axis current and excitation current based on the actual operating conditions of the electrically excited motor, such as the output base speed, switching zone, or high-speed condition, as reference values for the control current, thereby achieving control of the electrically excited motor.
[0023] This embodiment applies the above solution, and the specific process is as follows: (1) Figure 2 The diagram shows the control current setpoint allocation logic (base speed). First, a test bench is built, and the required host computer is designed. Based on the optimal copper loss control theory at base speed, the current / torque gridded calibration is performed at base speed. Using MATLAB / Simulink, code is written to process the data, resulting in a torque-current allocation table and an inductor current mapping table that conform to the optimal copper loss control curve. Figure 3 As shown.
[0024] To better utilize the performance of the electrically excited motor, this scheme theoretically analyzes the performance curve of the electrically excited motor. Since the electrically excited motor has more complex coupling and nonlinear characteristics than the permanent magnet synchronous motor, considering losses, the optimal torque-copper loss ratio point can be found to derive the motor's operating trajectory. This allows for the determination of the control variable setpoints that meet the control requirements of the electrically excited motor. This method is called the optimal copper loss control algorithm for the electrically excited motor. The torque equation of an electrically excited motor is given by: According to the current limiting circle equation and the total copper loss equation of the electrically excited motor By using MATLAB / Simulink to set constraints and plot the graphs, we can obtain the distribution curves of total copper loss, torque, current limit, and voltage limit for different speed and current ranges. It can be seen that under different excitation currents and different speeds, there is an optimal motor control trajectory.
[0025] Therefore, this scheme, based on optimal copper loss control theory and combined with bench calibration of current / torque using a gridded method, obtains a torque-current distribution table that conforms to the actual operating trajectory of the base-speed optimal copper loss control algorithm after data processing. This table is also a key data table for subsequent control—it can control the required dq-axis current of the output control loop according to the base-speed operating requirements. and the excitation circuit setpoint To take control.
[0026] (2) Figure 4 The diagram shown is a schematic of the axis system relationship involved in this embodiment. The d-axis direction is the direction of the rotor DC winding axis, and the q-axis direction leads the d-axis by 90° electrical angle; the α-axis direction is the direction of the A-phase stator AC winding axis, and the β-axis direction leads the α-axis by 90° electrical angle. The axial direction is the direction of the air gap flux linkage. The axial direction leads the axial direction by an electrical angle of 90°, which is the direction of torque current; assuming the d-axis leads the α-axis. Angle, among which Let the rotor angle be ; assuming d-axis ahead of d-axis Angle, among which Let the load angle be ; assuming Axis ahead of α axis Angle, among which This is the air gap angle.
[0027] (3) Figure 5 The diagram shown is the control block diagram of the full-speed domain high-efficiency control algorithm for electrically excited motors established in this application. According to step (1), the dq-axis current that meets the optimal copper loss control trajectory under the base speed condition can be obtained. and excitation current .
[0028] (4) such as Figure 5 As shown, based on the inductor current mapping table calculated in step (1), a current model is built, and the relationship between air gap flux linkage and current is established. , And the formula relating load angle and current The air gap flux linkage under the current model was calculated. and load angle .
[0029] (5) such as Figure 5 As shown, considering the speed limitation caused by back electromotive force at high speeds, an air gap flux limiting module is built to output the limited air gap flux. Then, after weakening the magnetic field, the air gap flux reference value is output. Among the variables that need to be considered when setting the amplitude limit is the rotational speed. n DC bus voltage ; Specifically, for air gap flux limiting, the real-time rotational speed and DC bus voltage are adjusted accordingly. By limiting the amplitude and then using traditional field weakening control, the reference value of the air gap flux under this operating condition can be obtained. .
[0030] (6) For example Figure 5 As shown, based on the air gap flux reference value calculated in step (5) Combined with the torque reference value According to the formula relating torque and air gap flux linkage: By building a torque and current calculation module based on air gap flux linkage, the torque and current reference values for the control loop can be obtained. ; (7) For example Figure 5 As shown, considering high-speed conditions, the current response does not take voltage limiting into account, resulting in a calculated load angle that does not meet the requirements for safe and accurate operation. This highlights the instability in load angle calculation caused by an excessively fast current response. This solution constructs air-gap flux linkage and load angle calculation modules based on a voltage model, taking into account the relationship between air-gap flux linkage and voltage. , (where x = α, β), and based on the formula relating air gap flux linkage and load angle. , (in (where the rotor angle is used) to calculate the air gap flux under the voltage model. and load angle ; It should be noted that the input of the voltage model is a feedback quantity, and the engineering processing to prevent integral drift usually includes a filter. There is a certain lag in the calculation of flux linkage and load angle during the dynamic process. Therefore, the voltage model needs to be processed in an engineering manner to avoid the integral drift problem in the model. On the other hand, the input of the current model in this scheme is a given value and there is no filtering stage. Therefore, the calculation of flux linkage and load angle based on the current model will be faster, which will be reflected in the torque dynamic performance.
[0031] (8) Figure 6The diagram shows the motor operating region division used for weighted coefficient calculation. Based on power, the motor operating region is divided into Zone I (base speed or high speed with low torque), the switching zone, and Zone II (high speed with high torque). Weighted coefficients are designed accordingly to select the load angle of the control loop: In the initial stage of the base speed zone or at high speed with low torque, the voltage model signal is weak, and the current model is more stable, so the output load angle is biased towards the current model; in the middle to late stages of the base speed zone, at high speed with high torque, the back EMF is strong, and the voltage model is more accurate, so the output load angle is biased towards the voltage model. The diagram considers the torque setpoint, speed, and DC bus voltage, and an adaptive weighting calculation module is designed accordingly, which outputs the first weighted coefficient. The load angle calculated by the voltage model and the current model is used to smoothly switch between them, and on the one hand, the second weighting coefficient is output. Used for shockless switching of the control loop current setpoint.
[0032] (9) First weighting coefficient The calculation method is as follows: When the electrically excited motor is in motor mode and in zone I, the corresponding judgment condition is: ,in, This represents the current real-time power of the electrically excited motor. This is the power threshold for region I, at which point... The calculation formula is: ,in At minimum power, at this time The output load angle is biased towards the current model; When the electrically excited magneto is in generator mode and in zone I, the corresponding judgment conditions and The calculation formulas all use absolute values; When the electrically excited motor is in motor mode and in the switching zone, the corresponding judgment condition is: ,at this time The calculation formula is: ,in P 2 represents the power threshold for Region II. The output load angle is biased towards the voltage model; When the electrically excited magnetizer is in generator mode and in the switching zone, the corresponding judgment conditions and All calculation formulas are treated as absolute values.
[0033] This is also the second weighting coefficient. The computational design approach differs from the previous one, but this solution... The design also takes into account the impact of torque change rate on switching.
[0034] (10) Figure 7 The diagram shown is a block diagram of the load angle feedforward design structure, corresponding to the weighting coefficients obtained in step (9). The main purpose of load angle feedforward design is to balance the load angle used in the control loop. Used for coordinate transformation.
[0035] (11) such as Figure 5 As shown, the load angle obtained in step (10) is... Combined with the torque current obtained in step (6) By using the constructed coordinate transformation module, the dq-axis currents that meet the optimal control operation under switching zone and high-speed conditions are obtained. , .
[0036] (12) such as Figure 5 As shown, combined with the voltage model calculated in step (7), The result calculated in step (5) By constructing the air gap flux linkage control module, the excitation current that meets the optimal control operation in the switching zone and at high speed is obtained. , .
[0037] (13) such as Figure 5 As shown, this scheme ultimately uses a current-setpoint-without-impact switching module to select the dq-axis current and excitation current calculated in steps (3), (11), and (12) based on the actual operation of the motor, using them as the current reference values for the control loop to achieve optimal control. The current-setpoint-without-impact switching module is used to analyze the control commands and combine them with the second weighting coefficient. It can output the corresponding adapted dq axis current and excitation current for loop control, thereby realizing the smooth switching of the optimal control adaptation variables of the electric excitation motor in the full speed domain.
[0038] In summary, this scheme divides the operating area of the electrically excited motor into Zone I, the switching zone, and Zone II. First, when the electrically excited motor is running in Zone I, the data obtained from bench calibration based on the optimal copper loss control theory algorithm is used for base speed operation control. Second, considering the voltage limitation problem of optimal copper loss control at high speeds, unity power factor control is smoothly switched in the switching zone to ensure operating performance in Zone II. Furthermore, considering the back electromotive force signal strength phenomenon caused by different speed domains in the switching zone, the load angle is calculated simultaneously using the current model and the voltage model, and an adaptive weight and load angle feedforward module is designed to complete the smooth switching of speed domain control.
[0039] The above-mentioned load angle calculation method based on adaptive weights and feedforward balances the speed and accuracy of torque control. Furthermore, this scheme combines the advantages of optimal copper loss control and unity power factor control, enabling seamless switching between the two modes and achieving efficient control across the entire speed domain. This effectively solves the problems of low-speed multivariable limitations, efficiency issues caused by non-negligible losses, and the inability of the electric excitation motor to fully utilize its inherent advantages due to high-speed voltage limitations in traditional electric motor control algorithms.
Claims
1. A high-efficiency control method for the entire speed range of an electrically excited motor, characterized in that, include: Collect the current actual power of the electrically excited motor Based on preset speed range judgment conditions, the working state of the electrically excited motor and its current operating zone are determined, and the corresponding weighting coefficients are calculated. The working state includes motor state and generator state; the operating zone includes zone I, switching zone and zone II. Zone I is the base speed or high speed low torque operating zone, and zone II is the high speed high torque operating zone. If the electrically excited motor is determined to be in zone I, the optimal dq axis current and excitation current under the base speed condition can be determined using the torque-current distribution table obtained offline. If the electrically excited motor is determined to be in the switching zone, the first air gap flux linkage and the first load angle, the second air gap flux linkage and the second load angle are calculated using the pre-built current model and voltage model, respectively. Then, based on the first load angle and the second load angle, the transition between the two load angles is realized by combining weighting coefficients, thereby determining the optimal dq axis current in the switching zone. Based on the first air gap flux linkage and the second air gap flux linkage, the optimal excitation current in the switching zone is determined by the air gap flux linkage control module. If the electrically excited motor is determined to be in Zone II, the second air gap flux and the second load angle are calculated using the pre-built voltage model to determine the optimal dq axis current and excitation current under high speed conditions. The system adopts a current-command-free switching method, selecting the optimal dq-axis current and excitation current based on the actual operating conditions of the electrically excited motor, such as the output base speed, switching zone, or high-speed condition, as reference values for the control current, thereby achieving control of the electrically excited motor.
2. The method for efficient full-speed-range control of an electrically excited motor according to claim 1, characterized in that, The weighting coefficients include a first weighting coefficient. Second weighting coefficient The first weighting coefficient Used to control the smooth switching between the first load angle and the second load angle; Second weighting coefficient Used for shockless switching of the control loop current setpoint.
3. The method for efficient full-speed-range control of an electrically excited motor according to claim 2, characterized in that, The preset velocity range determination conditions include: When the electrically excited motor is in motor mode and in zone I, the corresponding speed range judgment condition is: , The power threshold for region I is used, where the first weighting coefficient is... The calculation formula is: ,in At minimum power, at this time The output load angle is biased towards the current model; When the electrically excited magneto is in generator mode and in zone I, the corresponding judgment conditions and The calculation formulas all use absolute values; When the electrically excited motor is in motor mode and in the switching zone, the corresponding judgment condition is: At this point, the first weighting coefficient The calculation formula is: ,in P 2 represents the power threshold for Region II. The output load angle is biased towards the voltage model; When the electrically excited magnetizer is in generator mode and in the switching zone, the corresponding judgment conditions and The calculation formulas all use absolute values; Second weighting coefficient The calculation design principle and the first weighting coefficient The computational design principles are the same.
4. The method for efficient full-speed-range control of an electrically excited motor according to claim 1, characterized in that, The process of determining the optimal dq-axis current and excitation current under the base velocity condition includes: Based on the optimal copper loss control theory, the current / torque gridded calibration of the electrically excited motor at its base speed is performed, and a torque-current allocation table is constructed. Based on the torque-current allocation table, and according to the base speed operating requirements of the electrically excited motor, the optimal dq-axis current required by the output control loop at the base speed is determined. and the excitation circuit given current .
5. The method for efficient full-speed-range control of an electrically excited motor according to claim 1, characterized in that, The current model is specifically constructed based on the torque-current distribution table and by calculating the inductor current mapping table. The first air gap flux linkage calculated by the current model is as follows: in, For the first d-axis air gap flux linkage, For d-axis inductance, For stator side leakage, For d-axis current, For excitation current, For mutual inductance between stator and rotor; For the first q-axis air gap flux linkage, It is the q-axis inductance. For stator side leakage, This is the q-axis current; The first load angle calculated by the current model is as follows: 。 6. The method for efficient full-speed-range control of an electrically excited motor according to claim 1, characterized in that, The voltage model calculates the second air gap flux linkage as follows: Where x = α and β correspond to the α-axis and β-axis respectively, the α-axis direction is the direction of the axis of the A-phase stator AC winding, and the β-axis direction leads the α-axis by 90° electrical angle. Stator flux linkage along the α-axis or β-axis, This refers to the stator current along the α-axis or β-axis. The voltage model calculates the second load angle as follows: in, For rotor angle, For the air gap angle, For the α-axis air gap flux linkage, It represents the β-axis air gap flux linkage.
7. The method for efficient full-speed-range control of an electrically excited motor according to claim 2, characterized in that, The process of determining the optimal dq-axis current and excitation current in the switching region includes: Based on the first air gap flux linkage, a reference value for the air gap flux linkage is calculated. This value is used to calculate the torque current setpoint. Furthermore, in conjunction with the second air gap flux linkage, the air gap flux linkage control module determines the excitation circuit setpoint current required for the control circuit of the electrically excited motor under high-speed operation conditions. ; Using the first weighting coefficient This is used to smoothly switch between the first and second load angles. Combined with the torque current setpoint, the dq-axis current required by the control circuit of the electrically excited motor under high-speed operation is obtained through coordinate transformation. .
8. The method for efficient full-speed-range control of an electrically excited motor according to claim 7, characterized in that, The process of calculating the air gap flux reference value includes: combining the rotational speed... n DC bus voltage And the first air gap flux linkage, which is output as a limited air gap flux linkage through the air gap flux linkage limiting module. Then, after weakening the magnetic field, the air gap flux reference value is output. .
9. A high-efficiency full-speed-range control method for electrically excited motors according to claim 8, characterized in that, The torque current given value Specifically, it involves combining the torque reference value. T ref and air gap flux reference value This can be calculated.
10. A high-efficiency full-speed-range control method for electrically excited motors according to claim 9, characterized in that, The calculated torque current setpoint is obtained. The process is as follows: set the torque reference value. T ref and air gap flux reference value Substituting the corresponding formulas into the relationship between torque and air gap flux... To calculate the torque current setpoint .