Motor driver open-phase detection method and system

Abstract

The invention discloses a motor driver open-phase detection method and system based on multi-stage PWM control and dynamic current analysis. In the power-on stage, by forcibly activating different phase line combinations step by step and dynamically adjusting the duty ratio of a driving signal, the system can actively verify the current response characteristic of each phase line, accurately capture the abnormal state under different load conditions, effectively distinguish normal fluctuation from a real open-phase fault, and improve the reliability of the system. Therefore, the possibility of misjudgment and missing detection is reduced, and the anti-interference capability is further enhanced through the electric cycle current statistics and voltage frequency dual verification mechanism in the operation stage. The electric period is divided based on the rotor angle, and the current mean value is dynamically analyzed, so that short-time noise interference can be filtered, and the long-term abnormal trend can be accurately identified. And meanwhile, in combination with cross validation of voltage output and a line current state, differential judgment logic is provided for different types of equipment such as a permanent magnet synchronous motor, and the stability of a detection result under a complex working condition is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor control, and specifically relates to a method and system for detecting phase loss of a motor driver based on multi-stage PWM control and dynamic current analysis. Background Art

[0002] In the new energy vehicle industry, as the core component of the drive system, the reliability of the motor controller is directly related to the safety, energy efficiency, and user experience of the vehicle. With the rapid development of electric vehicles (EVs) and hybrid electric vehicles (HEVs), the motor controller needs to operate efficiently under complex and variable working conditions (such as frequent start-stop, high-speed cruising, energy recovery, etc.).

[0003] However, the motor phase loss fault (disconnection or poor contact of a certain phase wire) is one of the common causes of controller failure and may lead to serious consequences. Summary of the Invention

[0004] The purpose of the invention is to provide a method and system for detecting phase loss of a motor driver based on multi-stage PWM control and dynamic current analysis to solve the above-mentioned problems.

[0005] The technical solution adopted by the present invention is as follows: A method for detecting phase loss of a motor driver, the method includes the following steps: S1: During the power-on stage, step by step forcibly activate the UV / VW / WU phase wire combinations, and dynamically adjust the duty cycle to verify the current response; S2: During the operation stage, based on the double verification of the average current value of the electrical cycle and the voltage frequency condition, accumulate the error count to trigger protection.

[0006] Among them, in step S1, the duty cycle adjustment decreases in a fixed step until the current reaches the standard or the duty cycle drops to 120 us.

[0007] Among them, in step S1, the specific steps of forcibly activating the phase wires include: step by step forcibly activate the UV, VW, and WU phase wire combinations to cover all phase wire states.

[0008] Among them, in step S1, the specific steps of dynamically adjusting the duty cycle include: set the initial duty cycle to 1 us; if the detected current is lower than the threshold, decrease the duty cycle in a fixed step. When the duty cycle drops to 120 us, it is determined that there is a phase loss, and the fault code is recorded.

[0009] Among them, in step S2, during the phase loss detection in the operation stage, the electrical cycle statistical method specifically includes: (such as Figure 4 function) Based on the rotor angle, divide the electrical cycle (each 65536 units is a cycle), accumulate the absolute value of each phase current, calculate the ratio of the average value to the maximum / minimum current. If the ratio > 10, increase the error count.

[0010] Among them, in the step S2, the voltage frequency verification in the phase loss detection process during the operation stage specifically includes: when the output of the current loop voltage is greater than the set value and the filtered line current value is less than the set value, additionally verify whether the operating frequency of the permanent magnet synchronous motor (PM) is lower than 1 / 4 of the rated frequency;

[0011] A phase loss detection system for a motor driver includes: a PWM control module for generating a forced phase line state and dynamically adjusting the duty cycle; a processing module for executing a detection method and synchronizing the detection logic through an interrupt service program; a fault recording module for saving fault codes and triggering a shutdown protection.

[0012] Among them, the main components of the PWM control module include a PWM signal generator for generating specific phase line combinations and a dynamic duty cycle adjustment unit; this module forcibly activates three phase line combinations of UV, VW, and WU step by step during the power-on stage, and verifies the current response of each phase line by adjusting the duty cycle of the PWM signal.

[0013] Among them, the processing module is used to execute multi-stage phase loss detection, which is divided into two parts: the power-on stage and the operation stage; during the power-on stage, this module judges whether there is a phase loss fault by collecting current signals in real time and analyzing the corresponding relationship between them and the dynamically adjusted duty cycle; after entering the operation stage, the module divides the electrical cycle based on the rotor angle, accumulates the absolute values of the currents of each phase, calculates the mean value and the ratio of the maximum and minimum currents, and triggers an error count when this ratio exceeds a preset threshold.

[0014] Among them, the fault recording module is composed of a non-volatile storage unit and a protection trigger circuit, and is used to save the fault codes generated during the detection process and execute the shutdown protection action.

[0015] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are: 1. In the present invention, during the power-on stage, by forcibly activating different phase line combinations step by step and dynamically adjusting the duty cycle of the drive signal, the system can actively verify the current response characteristics of each phase line. This process avoids the limitations of traditional static threshold detection, can accurately capture abnormal states under different load conditions, effectively distinguish normal fluctuations from real phase loss faults, and thus reduces the possibility of misjudgment and missed detection.

[0016] 2. In the present invention, through the electrical cycle current statistics and voltage frequency double verification mechanism during the operation stage, the anti-interference ability is further enhanced. Dividing the electrical cycle based on the rotor angle and dynamically analyzing the current mean value can filter short-term noise interference and accurately identify long-term abnormal trends. At the same time, combined with the cross-verification of the voltage output and the line current state, different determination logics are provided for different types of equipment such as permanent magnet synchronous motors to ensure the stability of the detection results under complex working conditions.

[0017] 3. In the present invention, current sampling is strictly synchronized with the PWM cycle, enabling the detection logic to complete signal acquisition and processing within microseconds. This design not only significantly reduces the fault determination delay but also ensures the time consistency of critical data, avoiding error accumulation caused by asynchronous operations, thereby quickly triggering the protection mechanism at the initial stage of a fault.

[0018] 4. In the present invention, the dynamic duty cycle adjustment mechanism can automatically optimize the detection sensitivity according to actual load changes, taking into account the detection requirements of both light-load and heavy-load scenarios. The differential calibration strategies for asynchronous motors and permanent magnet synchronous motors enable the system to adapt to a variety of drive devices. The combination of the non-volatile storage unit and the hardware protection circuit not only completely retains the fault information for subsequent diagnosis but also quickly cuts off risks through multiple security mechanisms, comprehensively enhancing the safety and maintenance efficiency of equipment operation. Description of the Drawings

[0019] Figures 1, 2, and 3 are the functions for detecting phase loss during the power-on process provided by the embodiments of the present invention.

[0020] Figure 4 is the function for detecting phase loss through the three-phase current balance provided by the embodiments of the present invention.

[0021] Figure 5 is the function for detecting phase loss through the current-loop voltage and current provided by the embodiments of the present invention.

[0022] Figure 6 is the function for initializing parameters provided by the embodiments of the present invention; Figure 7 is a schematic diagram of the flow principle of the present invention. Detailed Embodiments

[0023] In order to make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] Referring to Figures 1-7, A method for detecting phase loss in a motor driver based on multi-stage PWM control and dynamic current analysis includes the following steps: S1. Initialization stage (function shown in Figure 6): Parameter configuration: Set the PWM cycle and initial duty cycle, configure the ADC sampling rate and current filtering parameters, and reset the fault counter and status flag; Module initialization: Call the initialization PWM module, configure the dead time, and enable the ADC interrupt.

[0025] S2. Detection of phase loss during the power-on stage (functions shown in Figures 1, 2, and 3): Forced phase line activation: Activate the UV, VW, and WU phase line combinations step by step. Dynamic duty cycle adjustment: The initial duty cycle is set to 1 us. If the current is lower than the threshold, it decreases in steps. When the duty cycle drops to 120 us, a phase loss is determined and the fault code is recorded.

[0026] S3. Phase loss detection during the operation stage: Electrical cycle statistical method (function shown in Figure 4): Divide the electrical cycle based on the rotor angle (one cycle per 65536 units), accumulate the absolute values of the phase currents, and calculate the ratio of the mean value to the maximum / minimum current.

[0027] Voltage frequency verification (function shown in Figure 5): When the voltage output of the current loop is greater than the set value and the filtered line current is less than the set value, additionally verify whether the operating frequency of the permanent magnet synchronous motor (PM) is lower than 1 / 4 of the rated frequency.

[0028] A phase loss detection system for a motor driver based on multi-stage PWM control and dynamic current analysis includes: A PWM control module for generating the forced phase line state and dynamically adjusting the duty cycle; A processing module that executes the detection method and synchronizes the detection logic through an interrupt service routine; a fault recording module that saves the fault code and triggers shutdown protection.

[0029] The main components of the PWM control module include a PWM signal generator for generating specific phase line combinations and a dynamic duty cycle adjustment unit. This module forcibly activates the three phase line combinations of UV, VW, and WU step by step during the power-on stage, and verifies the current response of each phase line by adjusting the duty cycle of the PWM signal. The initial duty cycle is set to 1 microsecond. If the detected current is lower than the preset threshold, the duty cycle is gradually decreased in fixed steps until the critical value of 120 microseconds is reached. At this time, if the current still does not meet the standard, a phase loss is determined. The module integrates precise timers and waveform generation circuits inside to ensure fast response and dynamic adjustment of the output under different load conditions, and works in coordination with the interrupt service routine to ensure real-time performance and synchronization.

[0030] The core function of the processing module is to execute a multi-stage open-phase detection algorithm, which is divided into two parts: the power-on stage and the running stage. In the power-on stage, the module judges whether there is an open-phase fault by collecting current signals in real time and analyzing the corresponding relationship between them and the dynamically adjusted duty cycle. After entering the running stage, the module divides the electrical cycle based on the rotor angle, accumulates the absolute values of the phase currents, calculates the mean value and the ratio of the maximum and minimum currents, and triggers an error count when the ratio exceeds the preset threshold. At the same time, the module performs double verification on the current-loop voltage and the filtered line current. For a permanent magnet synchronous motor, it is also necessary to additionally detect whether its operating frequency is lower than one-fourth of the rated frequency. All detection logics are implemented through high-priority interrupt service routines to ensure strict synchronization between current sampling and the PWM cycle, thereby improving real-time performance and anti-interference ability.

[0031] The fault recording module consists of a non-volatile storage unit and a protection trigger circuit, which is responsible for saving the fault codes generated during the detection process and performing a shutdown protection action. When the processing module determines an open-phase fault, the module will immediately encode the fault type, occurrence time, and related parameters and store them in the internal memory for subsequent diagnostic analysis. At the same time, the module directly cuts off the power output of the motor driver or triggers an emergency braking program through a hardware signal to prevent the equipment from being further damaged due to an open-phase fault. The storage unit is designed with high reliability and anti-electromagnetic interference characteristics to ensure that the fault information can still be completely saved under complex working conditions. The shutdown protection mechanism is linked with the system main control unit to achieve fast response and multiple safety guarantees.

[0032] In the present invention, in the power-on stage, by forcibly activating different phase line combinations step by step and dynamically adjusting the duty cycle of the drive signal, the system can actively verify the current response characteristics of each phase line. This process avoids the limitations of traditional static threshold detection, can accurately capture abnormal states under different load conditions, effectively distinguish normal fluctuations from real open-phase faults, and thus reduces the possibility of misjudgment and missed detection.

[0033] In the present invention, the anti-interference ability is further enhanced through the electrical cycle current statistics and voltage frequency double verification mechanism in the running stage. Dividing the electrical cycle based on the rotor angle and dynamically analyzing the current mean value can filter short-term noise interference and accurately identify long-term abnormal trends. At the same time, combined with the cross-verification of the voltage output and the line current state, different determination logics are provided for different types of equipment such as permanent magnet synchronous motors to ensure the stability of the detection results under complex working conditions.

[0034] In the present invention, current sampling and the PWM cycle are strictly synchronized, enabling the detection logic to complete signal acquisition and processing within microseconds. This design not only greatly shortens the fault determination delay but also ensures the time consistency of key data, avoiding error accumulation caused by asynchronous operations, and thus quickly triggering the protection mechanism at the initial stage of a fault.

[0035] In the present invention, the dynamic duty cycle adjustment mechanism can automatically optimize the detection sensitivity according to the actual load change, taking into account the detection requirements in both light load and heavy load scenarios. The differential verification strategy for asynchronous motors and permanent magnet synchronous motors enables the system to adapt to a variety of drive devices. The combination of the non-volatile storage unit and the hardware protection circuit not only completely retains the fault information for subsequent diagnosis, but also quickly cuts off the risks through multiple security mechanisms, comprehensively improving the safety and maintenance efficiency of the device operation.

[0036] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0037] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for detecting phase loss of a motor driver, characterized in that, It includes the following steps: S1: During the power-on stage, the UV / VW / WU phase line combinations are forcibly activated step by step, and the duty cycle is dynamically adjusted to verify the current response; S2: During the operation stage, based on the double verification of the average current of the electrical cycle and the voltage frequency condition, the cumulative error count triggers protection.

2. The motor driver open-phase detection method according to claim 1, characterized in that: In the step S1, the duty cycle adjustment decreases in a fixed step until the current meets the standard or the duty cycle drops to 120 us.

3. The motor driver open-phase detection method according to claim 1, characterized in that: In the step S1, the specific steps of forcibly activating the phase lines include: forcibly activating the UV, VW, and WU phase line combinations step by step to cover all phase line states.

4. The method for detecting phase loss of a motor driver according to claim 1, characterized in that: In the step S1, the specific steps of dynamically adjusting the duty cycle include: the initial duty cycle is set to 1 us; if the detected current is lower than the threshold, the duty cycle is decreased in a fixed step. When the duty cycle drops to 120 us, a phase loss is determined and the fault code is recorded.

5. The motor driver open-phase detection method according to claim 1, characterized in that: In the step S2, during the phase loss detection in the operation stage, the electrical cycle statistical method specifically includes: based on the rotor angle, the electrical cycle is divided, the absolute values of the currents of each phase are accumulated, the mean value and the ratio of the maximum / minimum current are calculated. If the ratio > 10, the error count is increased.

6. The method for detecting the open phase of a motor driver according to claim 1, wherein: In the step S2, during the phase loss detection in the operation stage, the voltage frequency verification specifically includes: when the voltage output of the current loop is greater than the set value and the filtered line current value is less than the set value, it is additionally verified whether the operating frequency of the permanent magnet synchronous motor is lower than 1 / 4 of the rated frequency.

7. A phase loss detection system for a motor driver according to any one of claims 1 to 6, characterized in that: The system includes: a PWM control module for generating the forced phase line state and dynamically adjusting the duty cycle; a processing module for executing the detection method and synchronizing the detection logic through an interrupt service program; a fault recording module for saving the fault code and triggering shutdown protection.

8. The motor driver open-phase detection system according to claim 7, characterized in that: The main components of the PWM control module include a PWM signal generator for generating specific phase line combinations and a dynamic duty cycle adjustment unit; this module forcibly activates the UV, VW, and WU phase line combinations step by step during the power-on stage, and verifies the current response of each phase line by adjusting the duty cycle of the PWM signal.

9. The motor driver open-phase detection system according to claim 7, wherein: The processing module is used to execute the phase loss detection in multiple stages, which is divided into two parts: the power-on stage and the operation stage; during the power-on stage, this module judges whether there is a phase loss fault by collecting the current signal in real time and analyzing the corresponding relationship between it and the dynamically adjusted duty cycle; After entering the operation stage, the module divides the electrical cycle based on the rotor angle, accumulates the absolute values of the currents of each phase and calculates the mean value and the ratio of the maximum and minimum currents. When this ratio exceeds the preset threshold, the error count is triggered.

10. The motor driver open-phase detection system according to claim 7, characterized in that: The fault recording module consists of a non-volatile storage unit and a protection trigger circuit, and is used to save the fault code generated during the detection process and execute the shutdown protection action.

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