A method for overmodulation of a hydrogen fuel hybrid electric vehicle motor control system

Abstract

The application provides a method for overmodulation of a hydrogen fuel hybrid electric vehicle motor control system, comprising: collecting three-phase currents of the control system and calculating an amplitude of a stator voltage vector according to a rotor position electrical angle of the control system; determining a stator voltage vector modulation degree according to the amplitude of the stator voltage vector; collecting a floating ground capacitor voltage of the control system to calculate an active component of an auxiliary inverter reference voltage, combining the three-phase currents to calculate an active component of a main inverter reference voltage, and determining an active voltage modulation degree according to the active component of the main inverter reference voltage; defining an overmodulation area based on the stator voltage vector modulation degree and the active voltage modulation degree; and determining an overmodulation correction strategy of the active voltage and a reactive voltage of the main inverter according to the overmodulation area. The application realizes the definition of the overmodulation area of the hydrogen fuel hybrid electric vehicle motor control system, improves the critical speed of the motor in the control system, and thus improves the voltage utilization rate of the hydrogen fuel cell.

Description

Technical Field

[0001] This invention belongs to the field of motor control technology, and particularly relates to an overmodulation method for a motor control system of a hydrogen fuel cell hybrid electric vehicle. Background Technology

[0002] Hydrogen fuel cells offer advantages such as high energy density, high energy conversion efficiency, and short charging time, making them a recognized preferred battery solution for new energy vehicles with long driving ranges and high power requirements. However, systems powered solely by a hydrogen fuel cell suffer from a limitation in energy form, making it difficult to meet the actual power demands of the vehicle's electric motor system. To fundamentally address this issue, current new energy vehicles typically employ a hybrid electric vehicle motor control system that combines fuel cells with energy storage components such as floating capacitors to power the motor. For this type of control system, a reasonable power distribution strategy needs to be designed to ensure efficient power transfer between the hydrogen fuel cell and the energy storage components.

[0003] However, traditional power distribution strategies only apply to the linear modulation region, which limits the degree of freedom of inverter modulation strategies in the power system. In particular, when the inverter operates in the over-modulation region, the power balance under the original strategy will be disrupted, resulting in low voltage utilization of hydrogen fuel cells in this type of control system. Summary of the Invention

[0004] To address the problem of low hydrogen fuel cell voltage utilization caused by power distribution in existing hydrogen fuel cell hybrid electric vehicle motor control systems, this invention proposes an overmodulation method for such a system. The hydrogen fuel cell hybrid electric vehicle motor control system employs a main inverter powered by a hydrogen fuel cell and an auxiliary inverter powered by a floating capacitor to jointly power the electric vehicle's motor. The overmodulation method includes:

[0005] The amplitude of the stator voltage vector is calculated by collecting the three-phase current of the control system and the electrical angle of the motor rotor position, and the stator voltage vector modulation degree is determined based on the amplitude of the stator voltage vector.

[0006] The active component of the auxiliary inverter reference voltage is calculated by collecting the floating ground capacitor voltage of the control system, and the active component of the main inverter reference voltage is calculated by combining the three-phase current. The active voltage modulation is determined based on the active component of the main inverter reference voltage.

[0007] The overmodulation region is defined based on the stator voltage vector modulation and active voltage modulation, and the overmodulation correction strategy for the active and reactive voltages of the main inverter is determined according to the overmodulation region.

[0008] Optionally, the amplitude of the stator voltage vector is calculated by collecting the three-phase current of the control system and the electrical angle of the motor rotor position, including:

[0009] The three-phase current i a i b i c Transform to the αβ coordinate system and perform arctangent calculation to obtain the current position angle θ. i The current position angle θ i Transform to the dq coordinate system to obtain the motor d-axis current i d With motor q-axis current i q ;

[0010] Collect the electrical angle θ of the motor rotor position e The motor speed ω is obtained by differentiation. e Set the preset rotation speed ω e ref and ω e After subtraction and PI control, the reference current i of the motor's q-axis is obtained. q ref Based on whether the motor requires field weakening control, set the motor d-axis reference current i. d ref ;

[0011] will i d ref i q ref respectively with the corresponding i d i q After subtraction and PI control, the reference voltage of the motor's d-axis is obtained. and motor q-axis reference voltage

[0012] Will and Transforming to the power coordinate system, we obtain the active component of the motor stator voltage vector. and reactive components Then, the amplitude is calculated to obtain the amplitude of the stator voltage vector.

[0013] Optionally, the will and Transforming to the power coordinate system, we obtain the active component of the motor stator voltage vector. and reactive components The formula is:

[0014]

[0015] Optionally, determining the stator voltage vector modulation based on the amplitude of the stator voltage vector includes:

[0016] The stator voltage vector modulation is calculated as follows:

[0017]

[0018] Where M is the voltage vector modulation index, V is the magnitude of the stator voltage vector. dc The voltage is supplied to the main inverter of the hydrogen fuel cell.

[0019] Optionally, the active component of the auxiliary inverter reference voltage is calculated by collecting the floating ground capacitor voltage of the control system, and the active component of the main inverter reference voltage is calculated by combining the three-phase current and the electrical angle of the motor rotor position, including:

[0020] The voltage V of the floating capacitor cap Reference value for floating capacitor After subtraction, the active component of the auxiliary inverter reference voltage is obtained through a PI regulator.

[0021] The three-phase current i a i b i c Transform to the αβ coordinate system and perform arctangent calculation to obtain the current position angle O. i The current position angle O i Transform to the dq coordinate system to obtain the motor d-axis current i d ;

[0022] Based on whether the motor requires field weakening control, set the motor d-axis reference current i. d ref , change i d ref with i d After subtraction and PI control, the reference voltage of the motor's d-axis is obtained. Will Transforming to the power coordinate system, we obtain the active component of the motor stator voltage vector.

[0023] Will and The active component of the main inverter reference voltage is obtained by subtraction.

[0024] Optionally, the active voltage modulation scheme is determined based on the active component of the main inverter reference voltage, including:

[0025] The active voltage regulation is calculated as follows:

[0026]

[0027] Among them, M MIact For active voltage regulation, The active component of the main inverter reference voltage, V dcThe voltage is supplied to the main inverter of the hydrogen fuel cell.

[0028] Optionally, defining the overmodulation region based on stator voltage vector modulation and active voltage modulation includes:

[0029] The overmodulation region S, considering power distribution, is defined as follows:

[0030]

[0031] Where S = I represents entering the linear modulation region, S = II represents entering the stator voltage over-modulation region, S = III represents entering the active voltage over-modulation region, and M is the voltage vector modulation degree. MIact This refers to the active voltage regulation system.

[0032] Optionally, the overmodulation correction strategy for determining the active and reactive voltages of the main inverter based on the overmodulation region includes:

[0033] When S=II, only the reactive voltage of the main inverter is corrected, and the correction formula is:

[0034]

[0035] Where, φ MI The power factor angle of the main inverter. The active component of the main inverter reference voltage. V represents the reactive component of the corrected main inverter reference voltage. dc The voltage is supplied to the main inverter of the hydrogen fuel cell.

[0036] Optionally, the overmodulation correction strategy for determining the active and reactive voltages of the main inverter based on the overmodulation region includes:

[0037] When S=III, the active voltage and reactive voltage of the main inverter are corrected simultaneously. The correction process is as follows:

[0038] First, the modulation critical angle was calculated to be 0. g :

[0039]

[0040] Among them, O g For the over-modulation critical angle, V dc To supply voltage to the main inverter of the hydrogen fuel cell, The active component of the main inverter reference voltage;

[0041] Based on the overmodulation critical angle, the voltage vector phase angle of the corrected main inverter is:

[0042]

[0043] O MI O is the voltage vector phase angle of the corrected main inverter. i To convert the three-phase current i a i b i c The current position angle is obtained by transforming to the αβ coordinate system and performing an arctangent operation.

[0044] According to O MI The active and reactive components of the main inverter voltage vector are corrected as follows:

[0045]

[0046] In the formula, This represents the active component of the main inverter voltage vector after correction.

[0047]

[0048] In the formula, This represents the reactive component of the main inverter voltage vector after correction.

[0049] Optionally, after determining the overmodulation correction strategy, based on the active and reactive components of the corrected main inverter voltage vector determined by the modulation correction strategy, and in conjunction with SVPWM, drive signals for the main inverter and auxiliary inverter are generated, including:

[0050] Active component of the corrected main inverter voltage vector and reactive components After transformation to the αβ coordinate system, the reference voltage of the main inverter in the stationary frame is obtained. Will The reactive component of the auxiliary inverter voltage vector is obtained by combining the reactive component of the motor reference voltage with the reactive component of the motor reference voltage. After transformation to the αβ coordinate system, the reference voltage of the auxiliary inverter in the stationary frame is obtained. Will The switching signal S of the main inverter is obtained through SVPWM modulation. MI ,Will The switching signal S of the auxiliary inverter is obtained through SVPWM modulation. CI .

[0051] The beneficial effects of the technical solution provided by this invention are:

[0052] This invention, considering the power distribution stage, defines the overmodulation zone of the motor control system for a hydrogen fuel cell hybrid electric vehicle. It then designs a stator voltage vector overmodulation method and an active voltage overmodulation method for the motor control system of a hybrid electric vehicle powered by both a hydrogen fuel cell and a floating capacitor. This improves the critical speed of the motor in the control system, thereby increasing the voltage utilization rate of the hydrogen fuel cell. Attached Figure Description

[0053] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This is a schematic diagram of the overall structure of the hydrogen fuel cell electric vehicle motor control system proposed in this embodiment of the invention;

[0055] Figure 2 This is a flowchart illustrating an overmodulation method for a hydrogen fuel cell hybrid electric vehicle motor control system according to an embodiment of the present invention.

[0056] Figure 3 This is a schematic diagram of the specific structure of the overmodulation system according to an embodiment of the present invention;

[0057] Figure 4 The steady-state response waveform of the vector control method in the traditional linear modulation region is shown.

[0058] Figure 5 The steady-state response waveform diagram is shown using the overmodulation technique proposed in the embodiments of the present invention. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein.

[0061] It should be understood that in the various embodiments of the present invention, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0062] It should be understood that in this invention, "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0063] It should be understood that in this invention, "multiple" refers to two or more. "And / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, "and / or B" can represent: A existing alone, A and B existing simultaneously, and B existing alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "Contains A, B, and C", "Contains A, B, and C" means that all three A, B, and C are contained; "Contains A, B, or C" means that one of A, B, and C is contained; "Contains A, B, and / or C" means that any one, two, or three of A, B, and C are contained.

[0064] It should be understood that in this invention, "B corresponding to A", "B corresponding to A", "A and B correspond", or "B and A correspond" means that B is associated with A, and B can be determined based on A. Determining B based on A does not mean determining B solely based on A; B can also be determined based on A and / or other information. Matching A and B is defined as a similarity between A and B that is greater than or equal to a preset threshold.

[0065] Depending on the context, "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection."

[0066] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0067] Example

[0068] This embodiment proposes an overmodulation method for a hydrogen fuel cell hybrid electric vehicle motor control system. The hydrogen fuel cell hybrid electric vehicle motor control system described in this embodiment is as follows: Figure 1As shown, the power system structure that uses a hydrogen fuel cell and a floating capacitor to jointly power the motor includes a hydrogen fuel cell, a main inverter powered by the hydrogen fuel cell, an on-board drive motor, an auxiliary inverter powered by the floating capacitor, and a floating capacitor.

[0069] The overmodulation method is as follows: Figure 2 As shown, it includes:

[0070] S1: Collect the three-phase current of the control system and the electrical angle of the motor rotor position to calculate the amplitude of the stator voltage vector, and determine the stator voltage vector modulation based on the amplitude of the stator voltage vector;

[0071] S2: Collect the floating ground capacitor voltage of the control system to calculate the active component of the auxiliary inverter reference voltage, combine it with the three-phase current to calculate the active component of the main inverter reference voltage, and determine the active voltage modulation based on the active component of the main inverter reference voltage.

[0072] S3: Define the overmodulation region based on the stator voltage vector modulation and active voltage modulation, and determine the overmodulation correction strategy for the active and reactive voltages of the main inverter based on the overmodulation region.

[0073] This embodiment, considering the power distribution stage, defines the overmodulation zone of the hydrogen fuel cell hybrid electric vehicle motor control system. It then designs a stator voltage vector overmodulation method and an active voltage overmodulation method for the hybrid electric vehicle motor control system powered by both a hydrogen fuel cell and a floating capacitor, thereby increasing the critical speed of the motor in the control system and improving the voltage utilization rate of the hydrogen fuel cell.

[0074] In this embodiment, the amplitude of the stator voltage vector is calculated by collecting the three-phase current of the control system and the electrical angle of the motor rotor position, including:

[0075] The three-phase current i a i b i c Transform to the αβ coordinate system and perform arctangent calculation to obtain the current position angle θ. i The current position angle θ i Transform to the dq coordinate system to obtain the motor d-axis current i d With motor q-axis current i q ;

[0076] Collect the electrical angle of the motor rotor position O e The motor speed ω is obtained by differentiation. e Set the preset rotation speed ω e ref and ω e After subtraction and PI control, the reference current i of the motor's q-axis is obtained. q refBased on whether the motor requires field weakening control, set the motor d-axis reference current i. d ref ;

[0077] will i d ref i q ref respectively with the corresponding i d i q After subtraction and PI control, the reference voltage of the motor's d-axis is obtained. and motor q-axis reference voltage

[0078] Will and Transforming to the power coordinate system, we obtain the active component of the motor stator voltage vector. and reactive components Then, the amplitude is calculated to obtain the amplitude of the stator voltage vector.

[0079] Among them, and Transforming to the power coordinate system, we obtain the active component of the motor stator voltage vector. and reactive components The formula is:

[0080]

[0081] The active component of the auxiliary inverter reference voltage is calculated by collecting the floating ground capacitor voltage of the control system, and the active component of the main inverter reference voltage is calculated by combining the three-phase current and the electrical angle of the motor rotor position, including:

[0082] The voltage V of the floating capacitor cap Reference value for floating capacitor After subtraction, the active component of the auxiliary inverter reference voltage is obtained through a PI regulator.

[0083] The three-phase current i a i b i c Transform to the αβ coordinate system and perform arctangent calculation to obtain the current position angle θ. i The current position angle θ i Transform to the dq coordinate system to obtain the motor d-axis current i d ;

[0084] Based on whether the motor requires field weakening control, set the motor d-axis reference current i. d ref , change i d ref with id After subtraction and PI control, the reference voltage of the motor's d-axis is obtained. Will Transforming to the power coordinate system, we obtain the active component of the motor stator voltage vector.

[0085] Will and The active component of the main inverter reference voltage is obtained by subtraction.

[0086] Combination Figure 3 The overmodulation system shown above, the specific process is as follows:

[0087] The rotor position electrical angle θ of motor 2 is sampled using position encoder 1. e and the rotor position angle θ e The motor speed ω is obtained by performing differential calculation 3. e ; give the rotational speed ω e ref and ω e The difference is used to obtain the q-axis reference current i through PI regulator 4. q ref The three-phase current i of the system is sampled using current sensor 5. a i b i c i is obtained by transforming to the αβ coordinate system using Clarke coordinate transformation 6. α i β , change i α i β Performing arctangent operation 7 yields the current position angle θ. i ;change i α i β i is obtained by transforming the coordinates from Park coordinates to the dq coordinate system using the Park coordinate transformation 8. d i q The voltage V of the floating capacitor is sampled by voltage sensor 9. cap .

[0088] According to the above embodiments of the present invention, PI regulation is performed on the speed, current, and capacitor voltage to obtain the dq-axis component of the motor-side reference voltage and the active component of the auxiliary inverter-side reference voltage, as detailed below:

[0089] The difference between the dq-axis reference current and the feedback current is passed through PI regulators 10 and 11 to obtain the motor's dq-axis reference voltage. and The voltage of the floating capacitor is compared with its reference value. The active component of the auxiliary inverter reference voltage is obtained by the difference through PI regulator 12.

[0090] According to the above embodiments of the present invention, considering the power distribution stage, the stator voltage vector modulation system and the active voltage modulation system are defined as follows:

[0091] Through coordinate transformation 13 and Transforming to the power coordinate system, we obtain the active component of the motor stator voltage vector. and reactive components

[0092]

[0093] Simultaneously, the amplitude of the stator voltage vector is obtained through amplitude calculation 14.

[0094]

[0095] The active component of the motor stator voltage vector The active component of the auxiliary inverter reference voltage The active component of the main inverter reference voltage is obtained by subtraction.

[0096] In this embodiment, the stator voltage vector modulation degree is determined based on the amplitude of the stator voltage vector, and the active voltage modulation degree is determined based on the active component of the main inverter reference voltage, including:

[0097] The stator voltage vector modulation is calculated as follows:

[0098]

[0099] Where M is the voltage vector modulation index, V is the magnitude of the stator voltage vector. dc To supply voltage to the main inverter of the hydrogen fuel cell;

[0100] The active voltage regulation is calculated as follows:

[0101]

[0102] Among them, M MIact For active voltage regulation, The active component of the main inverter reference voltage, V dc The voltage is supplied to the main inverter of the hydrogen fuel cell.

[0103] According to the above embodiments of the present invention, based on the defined stator voltage vector modulation and active voltage modulation, the overmodulation region considering power distribution is redefined, specifically the overmodulation region S considering power distribution is defined as follows:

[0104]

[0105] Where S = I indicates entering the linear modulation region 16, S = II indicates entering the stator voltage over-modulation region 17, S = III indicates entering the active voltage over-modulation region 18, and M is the voltage vector modulation degree, M MIact This refers to the active voltage regulation system.

[0106] Based on the above embodiments, it can be seen that when S = I, since the linear modulation region 16 is entered, overmodulation correction is not required.

[0107] According to the above embodiments of the present invention, for the redefined stator voltage vector overmodulation region, a stator voltage vector overmodulation method for a hybrid power supply system of hydrogen fuel cell and floating capacitor is designed as follows:

[0108] When S=II, the stator voltage enters the over-modulation region 17. At this time, the active voltage of the main inverter is still within the linear modulation region (M). MIact Since the reactive voltage is less than 0.9069, only the reactive voltage of the main inverter needs to be corrected. The correction method is as follows:

[0109]

[0110] Where, φ MI The power factor angle of the main inverter. The active component of the main inverter reference voltage. V represents the reactive component of the corrected main inverter reference voltage. dc The voltage is supplied to the main inverter of the hydrogen fuel cell.

[0111] According to the above embodiments of the present invention, for the redefined active voltage over-modulation region, an active voltage over-modulation method is designed for a hybrid power supply system of hydrogen fuel cells and floating capacitors, as follows:

[0112] When S=III, the stator voltage over-modulation 18 is entered, and the active and reactive voltages of the main inverter need to be corrected simultaneously. The correction method is as follows:

[0113] First, the modulation critical angle θ was calculated. g :

[0114]

[0115] Where, θ g For the over-modulation critical angle, V dc To supply voltage to the main inverter of the hydrogen fuel cell, The active component of the main inverter reference voltage;

[0116] Based on the overmodulation critical angle, the voltage vector phase angle of the corrected main inverter is:

[0117]

[0118] O MI O is the voltage vector phase angle of the corrected main inverter. i To convert the three-phase current i a i b i c The current position angle is obtained by transforming to the αβ coordinate system and performing an arctangent operation.

[0119] According to O MI The active and reactive components of the main inverter voltage vector are corrected as follows:

[0120]

[0121] In the formula, This represents the active component of the main inverter voltage vector after correction.

[0122]

[0123] In the formula, This represents the reactive component of the main inverter voltage vector after correction.

[0124] In this embodiment, to achieve the control of the overmodulation method described above, after determining the overmodulation correction strategy, based on the active and reactive components of the corrected main inverter voltage vector determined by the modulation correction strategy, and in conjunction with SVPWM, drive signals for the main inverter and auxiliary inverter are generated, including:

[0125] Active component of the corrected main inverter voltage vector and reactive components After coordinate transformation 19 to the αβ coordinate system, the reference voltage of the main inverter in the stationary frame is obtained. Will The reactive component of the auxiliary inverter voltage vector is obtained by combining the reactive component of the motor reference voltage with the reactive component of the motor reference voltage. The reference voltage of the auxiliary inverter in the stationary frame is obtained after coordinate transformation 20 to the αβ coordinate system. Will The switching signal S of the main inverter 22 is obtained by SVPWM modulation 21. MI ,Will The switching signal S of the auxiliary inverter 24 is obtained by SVPWM modulation 23. CI .

[0126] Figure 4The steady-state response waveforms of the vector control algorithm within the traditional linear modulation region are presented. From top to bottom, these waveforms represent the motor speed, motor phase a current, motor output torque, and floating ground capacitor voltage. In Figures (a) and (b), the motor carries a 3 Nm load and operates at reference speeds of 1075 and 1100 r / min, respectively. It can be observed that significant torque pulsation occurs at 1075 r / min; when the speed is slightly increased to 1100 r / min, significant torque instability occurs, indicating that the motor is insufficient to support the rated torque at this speed. This demonstrates that when using the traditional over-modulation method, the critical speed of the motor is between 1075 and 1100 rpm.

[0127] Based on the above embodiments, Figure 5 The steady-state response waveforms of a hydrogen fuel cell electric vehicle motor control system using the overmodulation technique of this embodiment are presented. In waveforms (a) and (b), the motor is carrying a 3 Nm load and operating at reference speeds of 1225 and 1250 r / min, respectively. The motor only begins to destabilize at 1250 r / min, indicating that the critical speed of the motor using the proposed overmodulation method is between 1225 and 1250 rpm. Compared to the conventional method without overmodulation, the critical speed of the proposed method is increased by approximately 14%, verifying the superiority of the proposed overmodulation method in improving the critical speed of the motor in the control system and the voltage utilization rate of the hydrogen fuel cell.

[0128] The serial numbers in the above embodiments are for descriptive purposes only and do not represent the order in which the components are assembled or used.

[0129] The above description is merely an embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An overmodulation method for a hydrogen fuel cell hybrid electric vehicle motor control system, characterized in that, The hydrogen fuel cell hybrid electric vehicle motor control system uses a main inverter powered by a hydrogen fuel cell and an auxiliary inverter powered by a floating capacitor to jointly power the electric vehicle motor. The overmodulation method includes: The amplitude of the stator voltage vector is calculated by collecting the three-phase current of the control system and the electrical angle of the motor rotor position, and the stator voltage vector modulation degree is determined based on the amplitude of the stator voltage vector. The active component of the auxiliary inverter reference voltage is calculated by collecting the floating ground capacitor voltage of the control system, and the active component of the main inverter reference voltage is calculated by combining the three-phase current. The active voltage modulation is determined based on the active component of the main inverter reference voltage. The overmodulation region is defined based on the stator voltage vector modulation and active voltage modulation, and the overmodulation correction strategy for the active and reactive voltages of the main inverter is determined according to the overmodulation region.

2. The overmodulation method for a hydrogen fuel cell hybrid electric vehicle motor control system according to claim 1, characterized in that, The amplitude of the stator voltage vector is calculated by collecting the three-phase current of the control system and the electrical angle of the motor rotor position, including: The three-phase current i a i b i c Transform to the αβ coordinate system and perform arctangent calculation to obtain the current position angle θ. i The current position angle θ i Transform to the dq coordinate system to obtain the motor d-axis current i d With motor q-axis current i q ; Collect the electrical angle θ of the motor rotor position e The motor speed ω is obtained by differentiation. e Set the preset rotation speed ω e ref and ω e After subtraction and PI control, the reference current i of the motor's q-axis is obtained. q ref Based on whether the motor requires field weakening control, set the motor d-axis reference current i. d ref ; will i d ref i q ref respectively with the corresponding i d i q After subtraction and PI control, the reference voltage of the motor's d-axis is obtained. and motor q-axis reference voltage Will and Transforming to the power coordinate system, we obtain the active component of the motor stator voltage vector. and reactive components Then, the amplitude is calculated to obtain the amplitude of the stator voltage vector.

3. The overmodulation method for a hydrogen fuel cell hybrid electric vehicle motor control system according to claim 2, characterized in that, The and Transforming to the power coordinate system, we obtain the active component of the motor stator voltage vector. and reactive components The formula is:

4. The overmodulation method for a hydrogen fuel cell hybrid electric vehicle motor control system according to claim 1, characterized in that, Determining the stator voltage vector modulation based on the amplitude of the stator voltage vector includes: The stator voltage vector modulation is calculated as follows: Where M is the voltage vector modulation index, V is the magnitude of the stator voltage vector. dc The voltage is supplied to the main inverter of the hydrogen fuel cell.

5. The overmodulation method for a hydrogen fuel cell hybrid electric vehicle motor control system according to claim 1, characterized in that, The active component of the auxiliary inverter reference voltage is calculated by collecting the floating ground capacitor voltage of the control system, and the active component of the main inverter reference voltage is calculated by combining the three-phase current and the electrical angle of the motor rotor position, including: The voltage V of the floating capacitor cap Reference value for floating capacitor After subtraction, the active component of the auxiliary inverter reference voltage is obtained through a PI regulator. The three-phase current i a i b i c Transform to the αβ coordinate system and perform arctangent calculation to obtain the current position angle θ. i The current position angle θ i Transform to the dq coordinate system to obtain the motor d-axis current i d ; Based on whether the motor requires field weakening control, set the motor d-axis reference current i. d ref , change i d ref with i d After subtraction and PI control, the reference voltage of the motor's d-axis is obtained. Will Transforming to the power coordinate system, we obtain the active component of the motor stator voltage vector. Will and The active component of the main inverter reference voltage is obtained by subtraction.

6. The overmodulation method for a hydrogen fuel cell hybrid electric vehicle motor control system according to claim 1, characterized in that, Determining the active voltage modulation based on the active component of the main inverter reference voltage includes: The active voltage regulation is calculated as follows: Among them, M MIact For active voltage regulation, The active component of the main inverter reference voltage, V dc The voltage is supplied to the main inverter of the hydrogen fuel cell.

7. The overmodulation method for a hydrogen fuel cell hybrid electric vehicle motor control system according to claim 1, characterized in that, The definition of the overmodulation region based on stator voltage vector modulation and active voltage modulation includes: The overmodulation region S, considering power distribution, is defined as follows: Where S = I represents entering the linear modulation region, S = II represents entering the stator voltage over-modulation region, S = III represents entering the active voltage over-modulation region, and M is the voltage vector modulation degree. MIact This refers to the active voltage regulation system.

8. The overmodulation method for a hydrogen fuel cell hybrid electric vehicle motor control system according to claim 7, characterized in that, The overmodulation correction strategy for determining the active and reactive voltages of the main inverter based on the overmodulation region includes: When S=II, only the reactive voltage of the main inverter is corrected, and the correction formula is: in, The power factor angle of the main inverter. The active component of the main inverter reference voltage. V represents the reactive component of the corrected main inverter reference voltage. dc The voltage is supplied to the main inverter of the hydrogen fuel cell.

9. The overmodulation method for a hydrogen fuel cell hybrid electric vehicle motor control system according to claim 7, characterized in that, The overmodulation correction strategy for determining the active and reactive voltages of the main inverter based on the overmodulation region includes: When S=III, the active voltage and reactive voltage of the main inverter are corrected simultaneously. The correction process is as follows: First, the modulation critical angle θ was calculated. g : Where, θ g For the over-modulation critical angle, V dc To supply voltage to the main inverter of the hydrogen fuel cell, The active component of the main inverter reference voltage; Based on the overmodulation critical angle, the voltage vector phase angle of the corrected main inverter is: θ MI θ is the voltage vector phase angle of the corrected main inverter. i To convert the three-phase current i a i b i c The current position angle is obtained by transforming to the αβ coordinate system and performing an arctangent operation. According to θ MI The active and reactive components of the main inverter voltage vector are corrected as follows: In the formula, This represents the active component of the main inverter voltage vector after correction. In the formula, This represents the reactive component of the main inverter voltage vector after correction.

10. The overmodulation method for a hydrogen fuel cell hybrid electric vehicle motor control system according to claim 1, characterized in that, After determining the overmodulation correction strategy, based on the active and reactive components of the corrected main inverter voltage vector determined by the modulation correction strategy, and in conjunction with SVPWM, drive signals for the main inverter and auxiliary inverter are generated, including: the active component of the corrected main inverter voltage vector. and reactive components After transformation to the αβ coordinate system, the reference voltage of the main inverter in the stationary frame is obtained. Will The reactive component of the auxiliary inverter voltage vector is obtained by combining the reactive component of the motor reference voltage with the reactive component of the motor reference voltage. After transformation to the αβ coordinate system, the reference voltage of the auxiliary inverter in the stationary frame is obtained. Will The switching signal S of the main inverter is obtained through SVPWM modulation. MI ,Will The switching signal S of the auxiliary inverter is obtained through SVPWM modulation. CI .

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