A PWM phase difference control system and method of a dual electric drive system

Abstract

The application discloses a PWM phase difference control system and method of a double-electric-drive system. The PWM phase difference control system of the double-electric-drive system comprises a first phase difference angle calculation unit, a second phase difference angle calculation unit and a target phase difference angle confirmation unit. The first phase difference angle calculation unit is used for calculating a first phase difference angle according to an actual phase difference and a target phase difference. The second phase difference angle calculation unit is used for calculating a second phase difference angle according to a limit parameter. The limit parameter is set with reference to at least one of a dead time of a target motor, a narrow pulse width inhibition time and a safety torque threshold value. The target motor is a first motor or a second motor. The target phase difference angle confirmation unit is used for confirming a smaller one of the first phase difference angle and the second phase difference angle as a target phase difference angle. A wave generation unit is connected to the target phase difference angle confirmation unit and is used for controlling a PWM wave of the target motor according to the target phase difference angle. The technical scheme of the application realizes safe and reliable control of the phase difference of the PWM wave of the first motor and the second motor.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and in particular to a PWM phase difference control system and method for a dual-electric drive system. Background Technology

[0002] With the development and maturation of new energy vehicle technology, new energy vehicles are accounting for an increasingly larger share of the market. Dual-motor drive systems, characterized by strong power output, wide speed range, and high drive stability, are widely used in high-performance new energy vehicles. Dual-motor drive systems typically employ a single-processor centralized control architecture, where the same processor synchronously manages two drive motors, and the drive modules for both motors share a common DC bus capacitor.

[0003] Currently, the industry commonly uses Pulse Width Modulation (PWM) phase difference control technology to suppress DC bus capacitor ripple current. Specifically, by adjusting the phase difference of the PWM waveforms of the two motor drive modules, the various ripple currents generated on the DC bus capacitor can cancel each other out, effectively reducing the amplitude of the DC capacitor ripple current, reducing heat loss during capacitor operation, and thus reducing the assembly size of the DC capacitor, lowering system hardware costs and space occupation. Existing main control chips do not have phase reversal functionality; they rely on frequent reading and writing of the PWM waveform timer's counter value via software to adjust the relative phase of the two motor PWM waveforms, thereby achieving phase difference control for both motors.

[0004] However, the above technical solutions rely on the MCU's load rate and runtime, which can easily lead to control errors and cannot meet the safe operation requirements of dual-motor drive systems in new energy vehicles. Summary of the Invention

[0005] This invention provides a PWM phase difference control system and method for a dual-electric drive system, so as to achieve safe and reliable control of the phase difference of the PWM waveforms of the first motor and the second motor, thereby more reliably realizing the mutual cancellation of the ripple current of the DC bus capacitor in the vehicle drive system and reducing the ripple current in the DC bus capacitor.

[0006] According to one aspect of the present invention, a PWM phase difference control system for a dual-electric drive system is provided. The PWM phase difference control system for the dual-electric drive system of the present invention includes a first phase misalignment angle calculation unit, a second phase misalignment angle calculation unit, a target phase misalignment angle confirmation unit, and a wave generation unit. The first phase misalignment angle calculation unit is used to obtain the actual phase difference of the current PWM waveform of the first motor and the second motor, and calculate the first phase misalignment angle based on the actual phase difference and the target phase difference; The second phase reversal angle calculation unit is used to calculate the second phase reversal angle according to the limiting parameters; wherein, the limiting parameters refer to at least one of the dead time, narrow pulse width suppression time and safe torque threshold of the target motor, and the target motor is the first motor or the second motor; The target phase misalignment angle confirmation unit is connected to the first phase misalignment angle calculation unit and the second phase misalignment angle calculation unit respectively, and is used to confirm the smaller of the first phase misalignment angle and the second phase misalignment angle as the target phase misalignment angle. The wave generation unit is connected to the target phase misalignment angle confirmation unit and is used to control the PWM wave generation of the target motor according to the target phase misalignment angle.

[0007] Optionally, the first phase misalignment angle calculation unit includes a phase misalignment direction determination subunit and a first phase misalignment angle determination subunit; The phase misalignment direction determination subunit is used to determine the phase misalignment direction based on the relationship between the actual phase difference and the target phase difference; The first phase misalignment angle determination sub-unit is used to calculate the first phase misalignment angle based on the relationship between the actual phase difference and the target phase difference.

[0008] Optionally, the PWM phase difference control system of the dual electric drive system in this embodiment of the invention further includes a target motor confirmation unit; The target motor confirmation unit is connected to the first phase misalignment angle calculation unit. It is used to confirm the target motor controlled by the phase difference according to the phase misalignment direction and transmit the confirmation result of the target motor to the second phase misalignment angle calculation unit.

[0009] Optionally, the PWM phase difference control system of the dual electric drive system in this embodiment of the invention further includes an actual phase difference calculation unit; The actual phase difference calculation unit is connected to the waveform generation unit and is used to capture the starting point of the PWM waveform timer value of the first motor and the second motor, and calculate the actual phase difference based on the PWM waveform period value of the first motor and the second motor.

[0010] Optionally, the PWM phase difference control system of the dual electric drive system in this embodiment of the invention further includes a target phase misalignment angle and PWM period value conversion unit; The target phase misalignment angle and PWM period value conversion unit is connected to the target phase misalignment angle confirmation unit and the wave generation unit, respectively. It is used to convert the target phase misalignment angle into the period value of the PWM wave of the target motor in the current period and output it to the wave generation unit. The wave generation unit is used to write the period value into the period register.

[0011] Optionally, the PWM phase difference control system of the dual electric drive system in this embodiment of the invention further includes a first phase misalignment angle calculation enable unit; The first phase angle calculation enable unit is connected to the first phase angle calculation unit and is used to detect the enable condition of PWM phase control. After the enable condition is met, it sends an enable signal to the first phase angle calculation unit. The enable condition includes that the difference between the PWM signal frequency of the first motor and the PWM signal frequency of the second motor is less than a first threshold.

[0012] Optionally, the wave transmitting unit includes a first wave transmitting subunit and a second wave transmitting subunit; The first PWM transmitter subunit is used to control the PWM transmitter of the first motor, and the second PWM transmitter subunit is used to control the PWM transmitter of the second motor.

[0013] According to another aspect of the present invention, a PWM phase difference control method for a dual-electric drive system is provided, applicable to the PWM phase difference control system of a dual-electric drive system in any embodiment of the present invention. The PWM phase difference control method for the dual-electric drive system includes: The first phase misalignment angle calculation unit obtains the actual phase difference of the current PWM waveform of the first motor and the second motor, and calculates the first phase misalignment angle based on the actual phase difference and the target phase difference; The second phase misalignment angle calculation unit calculates the second phase misalignment angle according to the limiting parameters; wherein, the limiting parameters refer to at least one of the dead time, narrow pulse width suppression time and safe torque threshold of the target motor, and the target motor is the first motor or the second motor; The target phase misalignment angle confirmation unit confirms the target phase misalignment angle based on the smaller of the first phase misalignment angle and the second phase misalignment angle. The wave generation unit controls the PWM wave generation of the target motor according to the target phase misalignment angle.

[0014] Optionally, before the second phase misalignment angle calculation unit calculates the second phase misalignment angle based on the limiting parameters, it further includes: The direction of phase misalignment is determined based on the relationship between the actual phase difference and the target phase difference. The target motor for phase difference control is determined based on the direction of phase misalignment.

[0015] Optionally, before the first phase misalignment angle calculation unit obtains the actual phase difference of the current PWM waveforms of the first motor and the second motor, and calculates the first phase misalignment angle based on the actual phase difference and the target phase difference, the method further includes: The first phase misalignment angle calculation enable unit detects the enable condition of PWM phase control and sends an enable signal to the first phase misalignment angle calculation unit after the enable condition is met; wherein, the enable condition includes the difference between the PWM signal frequency of the first motor and the PWM signal frequency of the second motor being less than a first threshold.

[0016] The technical solution of this invention involves a first phase misalignment angle calculation unit that calculates a first phase misalignment angle based on the actual phase difference and the target phase difference. This first phase misalignment angle represents the theoretical phase misalignment angle between the first motor and the second motor when the control requirements are to be met. A second phase misalignment angle calculation unit calculates a second phase misalignment angle based on limiting parameters. These limiting parameters are set with reference to at least one of the following: dead time of the target motor, narrow pulse width suppression time, and safe torque threshold. This ensures that the second phase misalignment angle meets the constraints of avoiding shoot-through faults in the target motor, preventing power devices from failing to respond in a timely manner, and guaranteeing the functional safety of the system. A target phase misalignment angle confirmation unit selects the smaller of the first and second phase misalignment angles as the target phase misalignment angle. This allows the phase difference between the first motor A and the second motor B to reach the target phase difference while meeting the limiting conditions. Compared to existing technologies where the main control chip without phase reversal function controls the phase difference of the PWM waveforms of the first and second motors by frequently reading and writing the PWM timer count value through software, this invention avoids the dead time insertion or malfunction of the narrow pulse width suppression function caused by errors in the MCU's reading and writing of the PWM timer count value, which can lead to PWM waveform distortion or even shoot-through risks in the upper and lower bridge arms of the power devices. In summary, this invention can achieve safe and reliable control of the phase difference of the PWM waveforms of the first and second motors based on a common MCU, thereby more reliably canceling out the ripple current of the DC bus capacitor in the vehicle drive system and reducing the ripple current in the DC bus capacitor.

[0017] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments 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.

[0019] Figure 1 This is a schematic diagram of the structure of a PWM phase difference control system for a dual-electric drive system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the PWM phase difference control system of another dual-electric drive system provided in an embodiment of the present invention; Figure 3 A schematic diagram of timer values ​​for a first motor and a second motor provided for an embodiment of the present invention; Figure 4 A schematic diagram of timer values ​​for another first motor and second motor provided in an embodiment of the present invention; Figure 5 A schematic diagram of the timer values ​​of the first motor and the second motor before and after phase difference control, provided for an embodiment of the present invention; Figure 6 A flowchart of a PWM phase difference control method for a dual-electric drive system provided in an embodiment of the present invention; Figure 7 A flowchart of another PWM phase difference control method for a dual-electric drive system provided in an embodiment of the present invention; Figure 8 This is a schematic diagram of a vehicle-mounted dual electric drive system provided in an embodiment of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "first," "second," etc., 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 the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] Figure 1 This is a schematic diagram of a PWM phase difference control system for a dual-electric drive system provided in an embodiment of the present invention. This embodiment is applicable to scenarios where the phase difference between two PWM waveforms is controlled. For example, it can be applied to an onboard dual-electric drive system to control the phase difference of the PWM waveforms of two motors, so that the actual phase difference between the PWM waveforms of the two motors reaches a target phase difference. Figure 1As shown, the PWM phase difference control system of the dual electric drive system in this embodiment of the invention includes a first phase misalignment angle calculation unit 1, a second phase misalignment angle calculation unit 2, a target phase misalignment angle confirmation unit 3, and a wave generation unit 4. The first phase misalignment angle calculation unit 1 is used to obtain the actual phase difference of the current PWM waveform of the first motor A and the second motor B. And based on the actual phase difference Phase difference with target Calculate the first phase misalignment angle The second phase misalignment angle calculation unit 2 is used to calculate the second phase misalignment angle based on the limiting parameters. The limiting parameters refer to at least one of the following settings: dead time, narrow pulse width suppression time, and safe torque threshold of the target motor. The target motor is either the first motor A or the second motor B. The target phase misalignment angle confirmation unit 3 is connected to the first phase misalignment angle calculation unit 1 and the second phase misalignment angle calculation unit 2, respectively, and is used to calculate the first phase misalignment angle. Second phase angle The smaller one in the middle is confirmed as the target phase misalignment angle. The wave-emitting unit 4 is connected to the target phase misalignment angle confirmation unit 3, and is used to determine the target phase misalignment angle. Control the PWM wave generation of the target motor.

[0023] In this embodiment of the invention, the first motor A and the second motor B are two controlled drive motors. By controlling the phase difference of the PWM waveforms of the first motor A and the second motor B, the ripple current of the DC bus capacitor in the vehicle drive system can be reduced. Actual phase difference This could be the phase offset angle between the PWM waveforms of the first motor A and the second motor B. Target phase difference. It can be the ideal phase offset angle of the PWM waveform of the first motor A and the second motor B, which can be set by the user according to process or control requirements.

[0024] The first phase misalignment angle calculation unit 1 can use the threshold method, based on the actual phase difference. Phase difference with target Calculate the first phase misalignment angle According to the first phase misalignment angle The actual phase difference can be adjusted by controlling the PWM waveform of the first motor A or the second motor B. This makes the adjusted actual phase difference Approaching or reaching the target phase difference For example, the first phase difference calculation unit 1 calculates the target phase difference. and actual phase difference The difference between Difference If the absolute value exceeds a preset threshold, then the actual phase difference needs to be adjusted. Compensation is performed, and the compensation value can be the first phase misalignment angle. There can be several preset thresholds, and there can also be several compensation values. There is a one-to-one correspondence between the preset thresholds and the compensation values.

[0025] The first phase misalignment angle calculation unit 1 can also use a threshold method with hysteresis, based on the actual phase difference. Phase difference with target Calculate the first phase misalignment angle For example, the first phase difference calculation unit 1 calculates the target phase difference. and actual phase difference The difference between If the difference If the absolute value exceeds the upper preset threshold or falls below the lower preset threshold, then the actual phase difference needs to be adjusted. Compensation is performed, and the compensation value can be the first phase misalignment angle. The upper and lower preset thresholds can include several groups, with each group forming a hysteresis interval. Compensation values ​​can also include several, with a one-to-one correspondence between each hysteresis interval and each compensation value.

[0026] The dead time of the target motor is a time interval set to prevent simultaneous action of the upper and lower bridge arms of the same phase of the target motor, thus avoiding shoot-through. The phase reversal angle corresponding to meeting the dead time constraint of the target motor can be set with reference to the hardware parameters of the power devices. Narrow pulse width suppression time is a time set to prevent the power devices in the bridge circuit from failing to respond in time due to the pulse time being lower than the minimum response time of the power devices. For example, the pulse time can be the low-level time between two high levels of the PWM waveform, or the high-level time between two low levels of the PWM waveform. A narrow pulse width event is an event where the pulse time is lower than the minimum response time of the power devices. The narrow pulse width suppression time can be determined by comparing the duty cycle of the preceding and following cycles of the PWM waveform to determine whether a narrow pulse width event has occurred in the current cycle, or whether a narrow pulse width event is caused by the switching of the duty cycle between preceding and following cycles. If a narrow pulse width event occurs, the phase reversal condition is not met. The phase reversal angle corresponding to meeting the narrow pulse width suppression time constraint can be set with reference to the duty cycle threshold of the preceding and following cycles of the PWM waveform. The safe torque threshold, in motor drive functional safety management, indirectly represents the motor output torque through the duty cycle of the PWM waveform. It represents the upper limit of the allowable deviation between the duty cycle of the input PWM waveform and the duty cycle of the executed PWM waveform. If the difference between the input and executed PWM waveforms exceeds the safe torque threshold, the software will determine the input PWM waveform instruction as an erroneous instruction, thus indicating a system functional safety anomaly. The corresponding phase misalignment angle can be obtained by referring to the safe torque threshold limitation.

[0027] The second phase misalignment angle calculation unit 2 calculates the second phase misalignment angle by combining the limiting parameters. This makes it possible to determine the second phase shift angle. Adjusted actual phase difference The system can meet the constraints, which can include preventing shoot-through faults in the target motor, preventing power devices from failing to respond in a timely manner, and ensuring the functional safety of the system. When the constraint parameters include at least one of the target motor's dead time, narrow pulse width suppression time, and safe torque threshold, the second phase reversal angle calculated for each constraint condition is... The smallest one is taken as the second phase misalignment angle for calculation. For example, the second phase misalignment angle is calculated while satisfying the dead time constraint of the target motor. for The second phase misalignment angle calculated to meet the narrow pulse width suppression time constraint. for The second phase misalignment angle calculated to meet the safety torque threshold limit condition. for Then the final second phase misalignment angle for The above values ​​are only used to explain how the second phase misalignment angle is calculated by the second phase misalignment angle calculation unit 2 in combination with the limiting parameters. This is not intended to limit the specific implementation of this invention.

[0028] Target phase misalignment angle confirmation unit 3 can determine the first phase misalignment angle based on the target phase misalignment angle. Second phase angle The smaller of the two values ​​is chosen as the target phase shift angle. If the first phase misalignment angle The smaller value indicates the actual phase difference. Phase difference with target The difference between them is very small, according to the first phase misalignment angle Adjustments can satisfy the constraints and directly achieve the target phase difference between the first motor A and the second motor B. If the second phase misalignment angle The smaller value indicates the actual phase difference. Phase difference with target The difference between them is large; if we follow the first phase misalignment angle... Adjustments may result in a shoot-through fault in the target motor, delayed response of power devices, and abnormal system functional safety issues. Therefore, at the first phase misalignment angle... If it is too large, it needs to be adjusted according to the second phase shift angle. Adjusting the actual phase difference This makes the actual phase difference Gradually approaching the target phase difference .

[0029] Wave-generating unit 4 can adjust the phase shift angle of the target. The corresponding PWM waveform is output, which then drives either the first motor A or the second motor B. Specifically, the first phase misalignment angle calculation unit 1 can calculate the phase difference based on the actual phase difference. Phase difference with target Calculate the first phase misalignment angle The second phase misalignment angle calculation unit 2 can calculate the second phase misalignment angle according to the limiting parameters. The target phase misalignment angle confirmation unit 3 selects the first phase misalignment angle. Second phase angle The smaller one in the middle is used as the target misalignment angle. The output is sent to beamforming unit 4. Beamforming unit 4 outputs the signal based on the target phase misalignment angle. By controlling the PWM waveform of either the first motor A or the second motor B, the actual phase difference can be made possible under certain constraints. Approaching or reaching the target phase difference This enables phase difference control.

[0030] According to the technical solution of this invention, a first phase misalignment angle is calculated by a first phase misalignment angle calculation unit based on the actual phase difference and the target phase difference. The first phase misalignment angle represents the theoretical phase misalignment angle between the first motor and the second motor when the control requirements are to be met. A second phase misalignment angle is calculated by a second phase misalignment angle calculation unit based on limiting parameters. The limiting parameters are set with reference to at least one of the following: dead time of the target motor, narrow pulse width suppression time, and safe torque threshold. This ensures that the second phase misalignment angle meets the limiting conditions of avoiding shoot-through faults in the target motor, avoiding problems with the power devices not responding in time, and ensuring the functional safety of the system. The target phase misalignment angle is selected by a target phase misalignment angle confirmation unit, which selects the smaller of the first phase misalignment angle and the second phase misalignment angle as the target phase misalignment angle. Under the condition of meeting the limiting conditions, the phase difference between the first motor A and the second motor B can be controlled to reach the target phase difference. Compared with the prior art, which uses frequent reading and writing of the PWM timer count value by software to control the PWM waveform phase difference between the first motor and the second motor, this method avoids the dead time insertion or abnormal pulse width suppression function caused by errors in the MCU reading and writing the PWM timer count value, resulting in PWM waveform distortion or even the risk of shoot-through between the upper and lower bridge arms of the power devices. In summary, the embodiments of the present invention can achieve safe and reliable control of the phase difference of the PWM waveforms of the first motor and the second motor based on a common MCU, thereby more reliably achieving mutual cancellation of the ripple current of the DC bus capacitor in the vehicle drive system and reducing the ripple current in the DC bus capacitor.

[0031] In some embodiments, the first phase misalignment angle calculation unit 1 includes a phase misalignment direction determination subunit and a first phase misalignment angle determination subunit. The phase misalignment direction determination subunit is used to determine the first phase misalignment angle based on the actual phase difference. Phase difference with target The magnitude relationship between the values ​​determines the phase difference direction (Dir). The first phase difference angle determination sub-unit is used to determine the actual phase difference. Phase difference with target Calculate the first phase misalignment angle based on the size relationship between them. .

[0032] Among them, the actual phase difference It may be less than or greater than the target phase difference. When performing phase difference control, the actual phase difference is considered. Less than the target phase difference Phase difference between situation and actual Greater than the target phase difference The situation can be used to determine the phase difference control's out-of-phase direction, Dir. For example, the difference... for: , The phase-shifting direction Dir is the positive direction. The phase misalignment direction Dir is negative. Determining the phase misalignment direction Dir through the phase misalignment direction determination subunit helps in selecting a suitable motor as the target motor for control.

[0033] Figure 2 This is a schematic diagram of the PWM phase difference control system of another dual-electric drive system provided in an embodiment of the present invention. Figure 2 As shown, in some embodiments, the PWM phase difference control system of the dual electric drive system of this invention further includes a target motor confirmation unit 5. The target motor confirmation unit 5 is connected to the first phase misalignment angle calculation unit 1, and is used to confirm the target motor for phase difference control according to the phase misalignment direction Dir, and transmit the confirmation result of the target motor to the second phase misalignment angle calculation unit 2.

[0034] In this system, the PWM phase difference control system of the dual-electric drive system includes a first motor A and a second motor B. When performing phase difference control, a motor A can be selected based on the misalignment direction Dir to achieve the fastest possible phase misalignment angle of the target. The motor that is affected is the target motor.

[0035] The target motor confirmation unit 5 can select either the first motor A or the second motor B as the target motor based on the phase misalignment direction Dir. For example, At that time, select the first motor A as the target motor. When selecting a target motor, the second motor B is chosen. The algorithm for selecting the target motor can be designed according to the actual situation, with the final selection based on whether the chosen target motor can achieve phase difference control at a relatively fast speed.

[0036] in, Figure 3 This is a schematic diagram of timer values ​​for a first motor and a second motor provided in an embodiment of the present invention. Figure 4 This is a schematic diagram of timer values ​​for another first motor and second motor provided in an embodiment of the present invention. (See diagram below.) Figure 3 As shown, CN0 represents the timer value of the second motor B, and CN1 represents the timer value of the first motor A. The phase-shifting direction Dir is the positive direction, and the first motor A is the target motor. For example... Figure 4 As shown, CN0 represents the timer value of the second motor B, and CN1 represents the timer value of the first motor A. The phase-shifting direction Dir is the negative direction, and the second motor B is the target motor.

[0037] In some embodiments, the wave transmitting unit includes a first wave transmitting subunit 41 and a second wave transmitting subunit 42; The first PWM transmitting subunit 41 is used to control the PWM transmitting of the first motor A, and the second PWM transmitting subunit 42 is used to control the PWM transmitting of the second motor B.

[0038] When the first motor A is the target motor, the first wave-emitting subunit 41 determines the phase misalignment angle based on the target. Configure timer value CN1 to output the PWM waveform controlling the first motor A. When the second motor B is the target motor, the second waveform generator subunit 42 outputs the PWM waveform according to the target phase misalignment angle. Configure timer value CN0 to output the PWM waveform for controlling the second motor B.

[0039] Continue to refer to Figure 2 In some embodiments, the PWM phase difference control system of the dual-electric drive system further includes an actual phase difference calculation unit 6. The actual phase difference calculation unit 6 is connected to the waveform generation unit and is used to capture the starting point of the PWM waveform timer value of the first motor A and the second motor B, and calculate the actual phase difference based on the PWM waveform period values ​​of the first motor A and the second motor B. .

[0040] The actual phase difference calculation unit 6 can be simultaneously connected to the first wave-generating subunit 41 and the second wave-generating subunit 42. It determines the start point of the PWM waveform period for the first motor A and the second motor B based on timer values ​​CN1 and CN0, respectively. Before performing phase control, it is necessary to ensure that the difference in period values ​​between the PWM waveforms of the first motor A and the second motor B is less than a first threshold. Therefore, the difference between the end times of the PWM waveform periods of the first motor A and the second motor B can be used as the actual phase difference. The difference at the end of the cycle can be obtained from the difference at the beginning of the cycle. In summary, the actual phase difference calculation unit 6 can determine the actual phase difference based on the difference between the end times of the PWM waveforms of the first motor A and the second motor B. .

[0041] Continue to refer to Figure 2 In some embodiments, the PWM phase difference control system of the dual-electric drive system further includes a target phase misalignment angle to PWM period value conversion unit 7. The target phase misalignment angle to PWM period value conversion unit 7 is connected to the target phase misalignment angle confirmation unit 3 and the wave generation unit, respectively, and is used to convert the target phase misalignment angle... The value is converted into the period value of the PWM wave of the target motor in the current cycle and output to the wave generation unit. The wave generation unit is used to write the period value into the period register.

[0042] Among them, the target phase misalignment angle and PWM period value conversion unit 7 converts the target phase misalignment angle... Convert to the period value of the PWM wave in the current period If the first motor A is the target motor, then the period value is... The output is sent to the first wave transmitting subunit 41, which then transmits the period value. The data is stored in the period register and then automatically updated. The PWM waveform of the first motor A is adjusted according to the target phase misalignment angle. Phase shifting is performed. Similarly, if the second motor B is the target motor, then the period value... The output is sent to the second wave transmitting subunit 42, which then transmits the period value. The data is stored in the period register and then automatically updated. The PWM waveform of the second motor B is adjusted according to the target phase misalignment angle. Perform phase misalignment.

[0043] Figure 5 This is a schematic diagram showing the timer values ​​of the first and second motors before and after phase difference control, provided as an embodiment of the present invention. Figure 5 The diagram shows the first phase shift angle with the first motor A as the target motor. Greater than the second phase misalignment angle For example, a schematic diagram showing the period values ​​of the first motor A and the second motor B before and after phase difference control. Due to the first phase misalignment angle... Greater than the second phase misalignment angle Therefore, the target phase angle With the second phase angle Equal. P represents the period value of the PWM waveform before phase misalignment in the current cycle. The first waveform generation subunit 41 sets the target phase misalignment angle. Convert to the period value of the PWM wave in the current period and the period value The PWM waveform of the first motor A is stored in the period register and automatically updated in the current period, according to the target phase misalignment angle. Perform a phase shift. If the actual phase difference after the phase shift is... Target phase difference not achieved After completing this phase misalignment, phase difference control can be performed again until the final actual phase difference is reached. Achieving the target phase difference .

[0044] It is understandable that if the first phase misalignment angle Less than the second phase misalignment angle Target phase misalignment angle Angle of first phase misalignment Equal, actual phase difference after phase misalignment The target phase difference can be achieved .

[0045] Continue to refer to Figure 2In some embodiments, the PWM phase difference control system of the dual-electric drive system further includes a first phase misalignment angle calculation enable unit 8. The first phase misalignment angle calculation enable unit 8 is connected to the first phase misalignment angle calculation unit 1 and is used to detect the enable condition of PWM phase control, and send an enable signal "Enable" to the first phase misalignment angle calculation unit after the enable condition is met. The enable condition includes that the difference between the PWM signal frequency of the first motor A and the PWM signal frequency of the second motor B is less than a first threshold.

[0046] The PWM signal frequencies of the first motor A and the second motor B can be calculated from the period values ​​of the PWM signals. The degree of difference in PWM signal frequencies can be the degree of deviation between the PWM signal frequencies of the first motor A and the second motor B, which can be calculated using at least one of the difference, variance, and square difference of the period values ​​of the PWM signals of the first motor A and the second motor B. The first threshold can be a set value for determining whether the first motor A and the second motor B meet the synchronization requirements. For example, if the difference between the PWM signal frequencies of the first motor A and the second motor B is less than the first threshold, the PWM signal frequencies of the two motors are considered to be synchronized.

[0047] Specifically, the first phase angle calculation enable unit 8 can be connected to the first wave transmitting subunit 41 and the second wave transmitting subunit 42 at the same time. The period values ​​of the PWM waveforms of the first motor A and the second motor B are determined according to the timer value CN1 and the timer value CN0, respectively. If the difference in the period values ​​is less than the first threshold, it is considered that the difference in the PWM signal frequencies of the first motor A and the second motor B is less than the first threshold.

[0048] Optionally, the enabling condition may also include that the first motor A and the second motor B are not faulty. Whether the first motor A and the second motor B are faulty can be determined based on whether the rotor position decoding of the two motors is faulty, whether the speeds of the two motors are the same, etc. In practical applications, the enabling condition for phase difference control can be set according to the actual situation.

[0049] Figure 6 This is a flowchart illustrating a PWM phase difference control method for a dual-electric drive system provided in an embodiment of the present invention. The PWM phase difference control method for a dual-electric drive system provided in this embodiment of the present invention can be applied to the PWM phase difference control system of a dual-electric drive system in any embodiment of the present invention. Figure 6 As shown, the PWM phase difference control method for a dual-electric drive system includes: S101, the first phase misalignment angle calculation unit obtains the actual phase difference of the current PWM waveform of the first motor and the second motor, and calculates the first phase misalignment angle based on the actual phase difference and the target phase difference.

[0050] Optionally, the actual phase difference calculation unit captures the starting point of the PWM waveform timer value of the first motor and the second motor, and calculates the actual phase difference based on the PWM waveform period value of the first motor and the second motor.

[0051] S102, The second phase misalignment angle calculation unit calculates the second phase misalignment angle according to the limiting parameters.

[0052] The limiting parameters refer to at least one of the following settings: dead time of the target motor, narrow pulse width suppression time, and safe torque threshold. The target motor is either the first motor or the second motor.

[0053] S103, The target phase misalignment angle confirmation unit confirms the target phase misalignment angle based on the smaller of the first phase misalignment angle and the second phase misalignment angle.

[0054] S104, the wave generation unit controls the PWM wave generation of the target motor according to the target phase misalignment angle.

[0055] Optionally, the wave transmitting unit includes a first wave transmitting subunit and a second wave transmitting subunit.

[0056] The first wave-generating subunit controls the PWM wave generation of the first motor, and the second wave-generating subunit controls the PWM wave generation of the second motor.

[0057] Optionally, the target phase misalignment angle to PWM period value conversion unit converts the target phase misalignment angle into the period value of the PWM wave of the target motor in the current period, and outputs it to the wave generation unit. The wave generation unit writes the period value into the period register, so that the PWM wave of the target motor can be controlled in the current period.

[0058] Optionally, before the first phase misalignment angle calculation unit obtains the actual phase difference of the current PWM waveforms of the first motor and the second motor, and calculates the first phase misalignment angle based on the actual phase difference and the target phase difference, the method further includes: The first phase misalignment angle calculation detects the enable condition of PWM phase control and sends an enable signal to the first phase misalignment angle calculation unit after the enable condition is met. The enable condition includes the difference between the PWM signal frequency of the first motor and the PWM signal frequency of the second motor being less than a first threshold. The first phase misalignment angle calculation unit starts working after receiving the enable signal.

[0059] Figure 7 A flowchart of another PWM phase difference control method for a dual-electric drive system provided in an embodiment of the present invention is shown below. Figure 7 As shown, another PWM phase difference control method for a dual-electric drive system provided in this embodiment of the invention includes: S201, the first phase misalignment angle calculation unit obtains the actual phase difference of the current PWM waveform of the first motor and the second motor, and calculates the first phase misalignment angle based on the actual phase difference and the target phase difference.

[0060] Optionally, the first phase misalignment angle determination subunit calculates the first phase misalignment angle based on the relationship between the actual phase difference and the target phase difference.

[0061] S202. Determine the direction of phase misalignment based on the relationship between the actual phase difference and the target phase difference.

[0062] Optionally, the phase misalignment direction determination subunit determines the phase misalignment direction based on the magnitude relationship between the actual phase difference and the target phase difference.

[0063] S203. Confirm the target motor for phase difference control based on the phase misalignment direction.

[0064] Optionally, the target motor confirmation unit confirms the target motor controlled by the phase difference according to the phase misalignment direction, and transmits the confirmation result of the target motor to the second phase misalignment angle calculation unit.

[0065] S204, The second phase misalignment angle calculation unit calculates the second phase misalignment angle according to the limiting parameters.

[0066] The limiting parameters refer to at least one of the following settings: dead time of the target motor, narrow pulse width suppression time, and safe torque threshold. The target motor is either the first motor or the second motor.

[0067] S205, The target phase misalignment angle confirmation unit confirms the target phase misalignment angle based on the smaller of the first phase misalignment angle and the second phase misalignment angle.

[0068] S206, the wave generation unit controls the PWM wave generation of the target motor according to the target phase misalignment angle.

[0069] Figure 8 This is a schematic diagram of a vehicle-mounted dual-electric drive system provided in an embodiment of the present invention. Figure 8 As shown, this embodiment of the invention also provides an on-board dual electric drive system, including a PWM phase difference control system 10 for the dual electric drive system of any embodiment of the invention.

[0070] The first phase difference angle calculation unit, the second phase difference angle calculation unit, the target phase difference angle confirmation unit, the wave generation unit, the target motor confirmation unit, the actual phase difference calculation unit, the target phase difference angle to PWM period value conversion unit, and the first phase difference angle calculation enable unit can be integrated into the MCU of the PWM phase difference control system 10 of the dual-electric drive system. The first motor drive module and the second motor drive module can increase the driving capability of the PWM signal, and thus can drive the first motor A and the second motor B respectively.

[0071] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0072] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A PWM phase difference control system for a dual-electric drive system, characterized in that, It includes a first phase misalignment angle calculation unit, a second phase misalignment angle calculation unit, a target phase misalignment angle confirmation unit, and a wave generation unit; The first phase misalignment angle calculation unit is used to obtain the actual phase difference of the current PWM waveform of the first motor and the second motor, and calculate the first phase misalignment angle based on the actual phase difference and the target phase difference; The second phase reversal angle calculation unit is used to calculate the second phase reversal angle according to the limiting parameters; wherein, the limiting parameters are set with reference to at least one of the dead time, narrow pulse width suppression time and safe torque threshold of the target motor, and the target motor is the first motor or the second motor; The target phase misalignment angle confirmation unit is connected to the first phase misalignment angle calculation unit and the second phase misalignment angle calculation unit respectively, and is used to confirm the smaller of the first phase misalignment angle and the second phase misalignment angle as the target phase misalignment angle; The wave generation unit is connected to the target phase misalignment angle confirmation unit and is used to control the PWM wave generation of the target motor according to the target phase misalignment angle.

2. The PWM phase difference control system for the dual-electric drive system according to claim 1, characterized in that, The first phase misalignment angle calculation unit includes a phase misalignment direction determination subunit and a first phase misalignment angle determination subunit; The phase misalignment direction determination subunit is used to determine the phase misalignment direction based on the magnitude relationship between the actual phase difference and the target phase difference; The first phase misalignment angle determination subunit is used to calculate the first phase misalignment angle based on the relationship between the actual phase difference and the target phase difference.

3. The PWM phase difference control system for the dual-electric drive system according to claim 2, characterized in that, It also includes a target motor verification unit; The target motor confirmation unit is connected to the first phase misalignment angle calculation unit and is used to confirm the target motor controlled by the phase difference according to the phase misalignment direction, and transmit the confirmation result of the target motor to the second phase misalignment angle calculation unit.

4. The PWM phase difference control system for the dual-electric drive system according to claim 1, characterized in that, It also includes an actual phase difference calculation unit; The actual phase difference calculation unit is connected to the wave generation unit and is used to capture the starting point of the PWM waveform timer value of the first motor and the second motor, and calculate the actual phase difference based on the PWM waveform period value of the first motor and the second motor.

5. The PWM phase difference control system for the dual-electric drive system according to claim 1, characterized in that, It also includes a target phase misalignment angle to PWM period value conversion unit; The target phase misalignment angle to PWM period value conversion unit is connected to the target phase misalignment angle confirmation unit and the wave generation unit, respectively. It is used to convert the target phase misalignment angle into the period value of the PWM wave generation of the target motor in the current period and output it to the wave generation unit. The wave generation unit is used to write the period value into the period register.

6. The PWM phase difference control system for the dual-electric drive system according to claim 1, characterized in that, It also includes the first phase angle calculation enable unit; The first phase misalignment angle calculation enable unit is connected to the first phase misalignment angle calculation unit and is used to detect the enable condition of PWM phase control, and send an enable signal to the first phase misalignment angle calculation unit after the enable condition is met; wherein, the enable condition includes the difference between the PWM signal frequency of the first motor and the PWM signal of the second motor being less than a first threshold.

7. The PWM phase difference control system for the dual-electric drive system according to claim 1, characterized in that, The wave-emitting unit includes a first wave-emitting subunit and a second wave-emitting subunit; The first PWM generation subunit is used to control the PWM generation of the first motor, and the second PWM generation subunit is used to control the PWM generation of the second motor.

8. A PWM phase difference control method for a dual-electric drive system, characterized in that, The PWM phase difference control system applied to the dual-electric drive system according to any one of claims 1-7, wherein the PWM phase difference control method of the dual-electric drive system includes: The first phase misalignment angle calculation unit obtains the actual phase difference of the current PWM waveforms of the first motor and the second motor, and calculates the first phase misalignment angle based on the actual phase difference and the target phase difference; The second phase misalignment angle calculation unit calculates the second phase misalignment angle according to the limiting parameters; wherein, the limiting parameters are set with reference to at least one of the target motor's dead time, narrow pulse width suppression time, and safe torque threshold, and the target motor is the first motor or the second motor; The target phase misalignment angle confirmation unit confirms the target phase misalignment angle based on the smaller of the first phase misalignment angle and the second phase misalignment angle. The PWM generation unit controls the PWM generation of the target motor according to the target phase misalignment angle.

9. The PWM phase difference control method for a dual-electric drive system according to claim 8, characterized in that, Before the second phase misalignment angle calculation unit calculates the second phase misalignment angle based on the limiting parameters, the following steps are also included: The direction of phase misalignment is determined based on the relationship between the actual phase difference and the target phase difference; The target motor for phase difference control is confirmed based on the phase misalignment direction.

10. The PWM phase difference control method for a dual-electric drive system according to claim 8, characterized in that, Before the first phase misalignment angle calculation unit obtains the actual phase difference of the current PWM waveforms of the first motor and the second motor, and calculates the first phase misalignment angle based on the actual phase difference and the target phase difference, the method further includes: The first phase misalignment angle calculation enable unit detects the enable condition of PWM phase control and sends an enable signal to the first phase misalignment angle calculation unit after the enable condition is met; wherein, the enable condition includes the difference between the PWM signal frequency of the first motor and the PWM signal frequency of the second motor being less than a first threshold.

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