A brushless DC motor fault pulse output system and method

Abstract

The present invention relates to the technical field of motor systems, and specifically discloses a brushless DC motor fault pulse output system and method, including: a fault detection module, the fault detection module is arranged on the substrate of the brushless DC motor, and is used to monitor the operating parameters of the motor's phase current, bus current, bus voltage, speed control signal, and temperature in real time, and analyzes the parameters through a built-in algorithm to determine whether the motor has a fault and the type of fault, and the built-in algorithm includes a hardware overcurrent detection standard, a software overcurrent detection standard, an over-voltage and undervoltage detection standard, a phase loss detection standard, an overtemperature judgment standard, and a speed control signal detection standard. The present invention can clearly and accurately output different fault types of the brushless DC motor to the upper control in pulses of different frequencies, thereby improving the accuracy and efficiency of fault identification, helping the upper control system to take targeted measures in a timely manner, reducing the downtime caused by motor failure, and improving the overall operating reliability and stability of the equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of motor systems, and in particular to a brushless DC motor fault pulse output system and method. Background Art

[0002] Brushless DC motors are widely used in many fields, but there are certain deficiencies in fault detection and feedback. In the existing technology, the transmission method of motor fault signals is relatively simple, and it is not possible to accurately and intuitively convey different fault types to the upper control system. This makes it difficult for the upper control system to accurately determine the type of motor fault in a timely manner during the operation of the motor, affecting the effective monitoring and maintenance of the motor. For example, when the motor has different problems such as winding phase loss and Hall sensor failure, the traditional fault signals may not be clearly distinguished, which brings difficulties to fault detection and repair. Summary of the invention

[0003] The object of the present invention is to provide a brushless DC motor fault pulse output system and method to solve the problems raised in the above-mentioned background technology, and to output various faults of the brushless DC motor to the upper control system and method in the form of pulses of different frequencies, so that the upper control system can quickly and accurately identify the motor fault type, thereby improving the reliability of the motor operation and the maintenance efficiency.

[0004] To achieve the above object, the present invention provides the following technical solution: a brushless DC motor fault pulse output system, comprising: The fault detection module is arranged on the substrate of the brushless DC motor, and is used to monitor the operating parameters of the motor's phase current, bus current, bus voltage, speed control signal, and temperature in real time, and analyze the parameters through a built-in algorithm to determine whether the motor has a fault and the type of fault. The built-in algorithm includes a hardware overcurrent detection standard, a software overcurrent detection standard, an overvoltage and undervoltage detection standard, a phase loss detection standard, an overtemperature judgment standard, and a speed control signal detection standard, wherein: The hardware overcurrent detection standard is that the bus current Ibus flows through the sampling resistor RS1, and a voltage VIshunt is formed on the sampling resistor. The voltage VIshunt is sent to the positive input terminal of the comparator, and the negative input terminal of the comparator is set to the reference voltage Vref output by the DA module in the chip. When V_Ishunt>Vref, the MCU generates a comparator interrupt to trigger the hardware overcurrent; The software overcurrent detection standard is to detect the three-phase current at a fixed interval, and calculate the W phase current according to the U and V phase currents through Kirchhoff's current law, wherein one end I_U of the U phase sampling resistor RS2 is connected to the same-phase input terminal of the internal operational amplifier, and the other end PGND of the sampling resistor is connected to the inverting input terminal of the operational amplifier. The ratio of R13 and R17 determines the amplification factor of the operational amplifier, and R14 and R15 set the voltage bias amplitude. The voltage difference across RS2 is amplified by the operational amplifier as the input of the ADC module in the MCU, and the real-time current of the U phase is calculated according to Ohm's law. Similarly, the V phase current is calculated. If the phase current is greater than the set value three times in a row within a certain period of time, it is judged as a software overcurrent; The over-voltage and under-voltage detection standard is that R9 and R10 are connected in series to divide the bus voltage, C7 is used for filtering, VBUS is directly connected to the ADC acquisition IO of the chip, and the data collected by the ADC is converted into the real-time voltage of the bus according to the voltage division ratio. The over-voltage and under-voltage thresholds are set in the code. When the real-time voltage is greater than the over-voltage threshold, it is judged as over-voltage, and when the real-time voltage is less than the under-voltage threshold, it is judged as under-voltage; The phase loss detection standard is based on the hardware of software overcurrent. If the maximum current value of one phase in the three-phase current is greater than the maximum current value of any other phase and greater than the phase loss protection current value, then a phase loss problem is determined. The over-temperature judgment standard is that the resistor R30 and the NTC R31 are connected in series to divide the 5 volts, C11 performs filtering to prevent interference, and the MCU judges the temperature based on the voltage collected by the ADC, wherein the NTC has a negatively correlated linear relationship with the temperature; The speed regulation signal detection standard is for the speed regulation signal of the brushless DC motor in the current small household appliance industry. The high level and low level of the pulse signal are captured by the timer in the MCU, and the high level maintenance time and the low level maintenance time are calculated to calculate the frequency and duty cycle of the speed regulation signal. The peripheral circuit includes a current limiting resistor and a filter capacitor. The pulse generation module is composed of the advanced timer of the MCU, which is used to generate a specific frequency pulse signal corresponding to the different fault types detected by the fault detection module, among which the pulses correspond to the phase loss fault, the pulses correspond to the overvoltage fault, the pulses correspond to the undervoltage fault, the pulses correspond to the overcurrent fault, the pulses correspond to the abnormal speed regulation signal, and the pulses correspond to the overtemperature fault. The frequency and duty cycle parameters of the pulse signal can be set and adjusted according to actual needs; The pulse output module is used to amplify and shape the pulse signal generated by the pulse generation module and then output it to the upper control system to ensure the stability and accuracy of the pulse signal during transmission so that it can be effectively received and recognized by the upper control system; The upper control system is used to receive the pulse signal from the pulse output module. It pre-stores a correspondence table between pulse frequency and fault type. It compares the correspondence table with the frequency of the received pulse signal to quickly determine the motor fault type and take corresponding measures, including alarm, shutdown, and adjustment of motor operating parameters.

[0005] Preferably, in the hardware overcurrent detection of the fault detection module, the resistance value of the sampling resistor RS1 is selected according to the detection accuracy requirement of the bus current to ensure that the hardware overcurrent detection can be accurately triggered under different bus current conditions.

[0006] Preferably, in the software overcurrent detection of the fault detection module, the fixed interval time can be adjusted according to the operating characteristics of the motor and the timeliness requirements for fault detection, and the set overcurrent value is set according to the rated current and safety margin of the motor.

[0007] Preferably, in the over-voltage and under-voltage detection of the fault detection module, the resistance ratio of R9 and R10 is determined according to the range of the bus voltage and the accuracy requirement of ADC acquisition, so as to accurately convert the real-time voltage of the bus.

[0008] Preferably, in the phase loss detection of the fault detection module, the phase loss protection current value is set according to the phase current rating of the motor and the stability requirement of the motor operation.

[0009] Preferably, in the over-temperature judgment of the fault detection module, the resistance values ​​of R30 and NTC R31 are selected according to the normal operating temperature range of the motor and the accuracy requirements of temperature detection to accurately reflect the voltage changes corresponding to the temperature changes.

[0010] Preferably, the duty cycle of the pulse signal generated by the pulse generating module can be adjusted between 10-90% according to actual needs to adapt to different receiving requirements of the upper control system.

[0011] Preferably, the pulse output module uses a power amplifier to amplify the pulse signal and uses a Schmitt trigger to shape the pulse signal to ensure that the output pulse signal meets the input requirements of the upper control system.

[0012] A method for outputting fault pulses of a brushless DC motor comprises the following steps: monitoring various operating parameters of the motor in real time by a fault detection module arranged on a brushless DC motor substrate: Hardware overcurrent detection: The bus current Ibus flows through the sampling resistor RS1 to generate a voltage VIshunt, which is compared with the reference voltage Vref output by the DA module inside the chip. If V_Ishunt is greater than Vref, it is determined as a hardware overcurrent. Software overcurrent detection: The three-phase current is detected at fixed time intervals, and the W-phase current is calculated from the U-phase and V-phase currents using Kirchhoff's current law. One end I_U of the U-phase sampling resistor RS2 is connected to the non-inverting input of the internal op amp, and the other end PGND is connected to the inverting input of the op amp. The amplification factor of the op amp is determined by the ratio of R13 and R17, while R14 and R15 set the voltage bias amplitude. The voltage difference across RS2 is amplified by the op amp and used as the input of the ADC module in the MCU. According to Ohm's law, the real-time current of the U-phase is calculated. Similarly, the current of the V-phase can be obtained. If the phase current exceeds the set value within the set time interval for three consecutive times, it is determined as software overcurrent; Over-voltage and under-voltage detection: The bus voltage is divided by R9 and R10 in series, and filtered by C7. VBUS is directly connected to the ADC acquisition IO of the chip. According to the voltage division ratio, the data collected by the ADC is converted into the real-time voltage of the bus. The over-voltage and under-voltage thresholds are set in the code. When the real-time voltage exceeds the over-voltage threshold, it is judged as over-voltage, and when the real-time voltage is lower than the under-voltage threshold, it is judged as under-voltage. Phase loss detection: Based on the hardware of software overcurrent detection, if the maximum current value of one phase in the three-phase current exceeds the maximum current value of any other phase, and the value is greater than the preset phase loss protection current value, it is determined that a phase loss problem occurs; Over-temperature judgment: Resistor R30 and NTC resistor R31 are connected in series to divide the 5 volts, and C11 is used for filtering to prevent interference. Since the resistance value of the NTC resistor has a negatively correlated linear relationship with the temperature, the MCU judges the current temperature based on the voltage value collected by the ADC.

[0013] Speed ​​regulation signal detection: For the speed regulation signal of the brushless DC motor commonly used in the small household appliance industry, the timer in the MCU is used to capture the high and low levels of the pulse signal, and calculate the duration of the high and low levels to obtain the frequency and duty cycle of the speed regulation signal.

[0014] The present invention provides a brushless DC motor fault pulse output system and method, which has the following beneficial effects: 1. The present invention can clearly and accurately output different fault types of the brushless DC motor to the upper control in pulses of different frequencies, thereby improving the accuracy and efficiency of fault identification.

[0015] 2. The present invention helps the upper control system to take targeted measures in a timely manner, reduce the downtime caused by motor failure, and improve the overall operating reliability and stability of the equipment.

[0016] 3. The pulse output method of the present invention is simple and intuitive, and is easy to implement and integrate into the existing motor control system without large-scale transformation of the original system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a system block diagram of the present invention; Figure 2 is a circuit diagram of a fault detection module of the present invention; Figure 3 MCU circuit diagram of the present invention; Figure 4 is a three-phase current diagram of the present invention; Figure 5 It is a temperature detection circuit diagram of the present invention; Figure 6 The bus voltage detection circuit diagram of the present invention; Figure 7 It is the U-phase current detection circuit diagram of the present invention; Figure 8 It is a V-phase current detection circuit diagram of the present invention; Fig. 9 The hardware overcurrent detection circuit diagram of the present invention; Fig.10 This is a debugging interface circuit diagram of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] For examples, see Figure 1-10 ,The present invention provides a technical solution: a brushless DC motor fault pulse output system, comprising: a fault detection module, a pulse generation module, a pulse output module and an upper control system; The fault detection module is arranged on the substrate of the brushless DC motor, and is used to monitor the operating parameters of the motor's phase current, bus current, bus voltage, speed control signal, and temperature in real time, and analyzes the parameters through a built-in algorithm to determine whether the motor has a fault and the type of fault. The built-in algorithm includes a hardware overcurrent detection standard, a software overcurrent detection standard, an over-voltage and under-voltage detection standard, a phase loss detection standard, an overtemperature judgment standard, and a speed control signal detection standard, wherein: the hardware overcurrent detection standard is that the bus current Ibus flows through the sampling resistor RS1, and a voltage VIshunt is formed on the sampling resistor. The voltage VIshunt is sent to the positive input end of the comparator, and the negative input end of the comparator is set to the reference voltage Vref output by the DA module in the chip. When V_Ishunt>Vref, the MCU generates a comparator interrupt to trigger the hardware overcurrent; the software overcurrent detection standard is to detect the three-phase current at a fixed interval, and calculate the W phase current according to the U and V phase currents through Kirchhoff's current law, wherein one end I_U of the U phase sampling resistor RS2 is connected to the same phase input end of the internal operational amplifier, and the sampling resistor The other end PGND is connected to the inverting input of the op amp. The ratio of R13 and R17 determines the amplification factor of the op amp. R14 and R15 set the voltage bias amplitude. The voltage difference across RS2 is amplified by the op amp as the input of the ADC module in the MCU. The real-time current of the U phase is calculated according to Ohm's law. Similarly, the current of the V phase is calculated. If the phase current is greater than the set value three times in a row within a certain period of time, it is judged as software overcurrent. The over-voltage and under-voltage detection standard is that R9 and R10 are connected in series to divide the bus voltage, C7 is used for filtering, and VBUS is directly connected to the core The ADC of the chip collects IO, and the data collected by the ADC is converted into the real-time voltage of the bus according to the voltage division ratio. The overvoltage and undervoltage thresholds are set in the code. When the real-time voltage is greater than the overvoltage threshold, it is judged as overvoltage, and when the real-time voltage is less than the undervoltage threshold, it is judged as undervoltage; the phase loss detection standard is based on the hardware of the software overcurrent. In the three-phase current, if the maximum current value of one phase is greater than the maximum value of any other phase current, and is greater than the phase loss protection current value (manually set in the code), it is determined that a phase loss problem occurs; the overtemperature judgment standard is the resistor R30 and NTC R31 is connected in series to divide the 5 volts, C11 performs filtering to prevent interference, and the MCU determines the temperature based on the voltage collected by the ADC, wherein the NTC has a negatively correlated linear relationship with the temperature; the speed regulation signal detection standard is for the speed regulation signal (mostly a pulse signal) of the brushless DC motor in the current small household appliance industry, and the high and low levels of the pulse signal are captured by the timer in the MCU, and the maintenance time of the high level and the maintenance time of the low level are calculated to calculate the frequency and duty cycle of the speed regulation signal, and its peripheral circuit includes a current limiting resistor and a filter capacitor.

[0020] The pulse generation module is composed of the advanced timer of the MCU, which is used to generate specific frequency pulse signals corresponding to different fault types detected by the fault detection module, among which the phase loss fault corresponds to a pulse (such as 100Hz), the overvoltage fault corresponds to a pulse (such as 200Hz), the undervoltage fault corresponds to a pulse (such as 300Hz), the overcurrent fault corresponds to a pulse (such as 400Hz), the speed regulation signal abnormality corresponds to a pulse (such as 500Hz), and the overtemperature fault corresponds to a pulse (such as 600Hz). The frequency and duty cycle parameters of the pulse signal can be set and adjusted according to actual needs.

[0021] The pulse output module is used to amplify and shape the pulse signal generated by the pulse generation module, and then output it to the upper control system, ensuring the stability and accuracy of the pulse signal during transmission so that it can be effectively received and recognized by the upper control system; through amplification and shaping, the pulse output module ensures the stability and accuracy of the pulse signal during transmission to the upper control system; stability is reflected in the fact that the amplitude, waveform and other parameters of the signal will not undergo unpredictable changes due to external interference (such as electromagnetic interference, line loss, etc.) during transmission; accuracy is reflected in the fact that the upper control system can accurately receive the pulse signal representing the type of motor fault, so as to quickly determine the fault type and take corresponding measures based on the pre-stored corresponding relationship.

[0022] The upper control system is used to receive the pulse signal from the pulse output module, and pre-stores a correspondence table between pulse frequency and fault type. By comparing the frequency of the received pulse signal with the correspondence table, the motor fault type is quickly determined, and corresponding measures are taken, including alarm, shutdown, and adjustment of motor operating parameters. By pre-storing the correspondence table between pulse frequency and fault type, the upper control system can quickly perform frequency comparison after receiving the pulse signal, thereby quickly determining the motor fault type. This quick judgment capability reduces the time for troubleshooting and improves the maintenance efficiency of the entire motor system. For example, in industrial production, if a motor fails, quickly locating the fault type allows maintenance personnel to take timely measures to reduce the downtime of the production line and reduce production losses.

[0023] In the hardware overcurrent detection of the fault detection module, the resistance value of the sampling resistor RS1 is selected according to the detection accuracy requirement of the bus current to ensure that the hardware overcurrent detection can be accurately triggered under different bus current conditions; the resistance value of the sampling resistor RS1 is selected according to the detection accuracy requirement of the bus current, which can ensure that accurate detection can be achieved under bus currents of different sizes. Whether it is a low current or a high current working condition, a suitable sampling resistor resistance value can enable the hardware overcurrent detection to accurately reflect the current state. For example, when the bus current is low, selecting a suitable small resistance sampling resistor can make the generated voltage signal within the detectable range, avoiding the inability to accurately detect the voltage signal due to excessive resistance. When the bus current is high, selecting a suitable large resistance sampling resistor (under other conditions) can prevent the voltage on the sampling resistor from being too high and exceeding the detection range or damaging the detection circuit due to excessive current.

[0024] In the software overcurrent detection of the fault detection module, the fixed interval time can be adjusted according to the operating characteristics of the motor and the timeliness requirements of fault detection, and the set overcurrent value is set according to the rated current and safety margin of the motor. In the software overcurrent detection of the fault detection module, the fixed interval time is adjusted according to the operating characteristics of the motor and the timeliness requirements of fault detection, and the overcurrent value is set according to the rated current and safety margin of the motor, so as to achieve the effect of precise adaptation to the motor working conditions and timely and accurate detection of software overcurrent.

[0025] In the over-voltage and under-voltage detection of the fault detection module, the resistance ratio of R9 and R10 is determined according to the range of the bus voltage and the accuracy requirements of ADC acquisition to accurately convert the real-time voltage of the bus; the resistance ratio of R9 and R10 is determined according to the range of the bus voltage, so that the voltage divider circuit can work normally under different bus voltage conditions; whether it is a higher bus voltage or a lower bus voltage, the voltage can be adjusted to a range suitable for ADC acquisition through a suitable resistance ratio. For example, for a higher bus voltage, selecting a suitable resistance ratio can prevent the voltage after voltage division from exceeding the upper limit of ADC acquisition; for a lower bus voltage, it can also ensure that the voltage after voltage division is within the range that ADC can accurately acquire, and the acquisition error will not be too large due to the voltage being too low. Determining the resistance ratio of R9 and R10 according to the accuracy requirements of ADC acquisition helps to improve the accuracy of bus voltage conversion. A suitable resistance ratio can make the voltage signal after voltage division better match the quantization accuracy of ADC, reducing the quantization error caused by the voltage divider circuit. This ensures that the final converted bus real-time voltage has a higher accuracy, so that it can more accurately determine whether the bus voltage is in an overvoltage or undervoltage state, thereby improving the reliability of overvoltage and undervoltage detection.

[0026] In the phase loss detection of the fault detection module, the phase loss protection current value is set according to the phase current rating of the motor and the stability requirements of the motor operation; setting the phase loss protection current value according to the phase current rating of the motor can match the phase loss detection with the basic electrical characteristics of the motor. The phase current rating reflects the current level of the motor during normal operation. Setting the protection current value based on this can ensure that the phase loss fault is accurately judged within the normal operating range of the motor. For example, motors of different powers and designs have different phase current ratings. Setting the phase loss protection current value according to their respective ratings avoids misjudging a phase loss fault when the normal operating current fluctuates. Setting the phase loss protection current value in combination with the stability requirements of the motor operation helps to detect phase loss in a timely manner while ensuring the stable operation of the motor. During the operation of the motor, a stable three-phase current supply is the key to its normal operation. Reasonable protection current value setting can quickly detect phase loss problems that may affect stability without affecting the stability of the motor's normal operation. In the over-temperature judgment of the fault detection module, the resistance values ​​of R30 and NTC R31 are selected according to the normal operating temperature range of the motor and the accuracy requirements of temperature detection to accurately reflect the voltage change corresponding to the temperature change; the resistance values ​​of R30 and NTC R31 are selected according to the normal operating temperature range of the motor to ensure that the voltage divider circuit can work normally in the entire temperature range. Different motors have different normal operating temperature ranges due to factors such as working environment and heat dissipation conditions. The appropriate resistance selection can enable the voltage divider circuit to accurately convert temperature changes into voltage changes within this temperature range, avoiding conversion anomalies at the boundaries of the temperature range or at special temperature points. For example, for motors running at high temperatures, the selected resistance value can ensure that the voltage change caused by the resistance change of the NTC at high temperatures is still within the detectable and accurately convertible range; for motors running at low temperatures, it can also ensure that the voltage change will not accurately reflect the temperature change due to resistance mismatch at low temperatures. Selecting the resistance value according to the accuracy requirements of temperature detection helps to improve the accuracy of temperature detection. Temperature detection accuracy is crucial for motor protection and performance monitoring. Appropriate resistance values ​​of R30 and NTC R31 can match the voltage change caused by temperature change with the accuracy of the detection circuit (such as ADC). This enables the MCU to more accurately judge the temperature based on the voltage collected by the ADC, thereby accurately judging over-temperature and improving the reliability of over-temperature detection.

[0027] The duty cycle of the pulse signal generated by the pulse generation module can be adjusted between 10-90% according to actual needs to adapt to the reception requirements of different upper control systems; the duty cycle of the pulse signal of the pulse generation module can be adjusted between 10-90%, and this feature can adapt to the reception requirements of different upper control systems. Different upper control systems may have different requirements for the duty cycle of the pulse signal due to factors such as their internal circuit design, signal processing algorithms, or compatibility with other devices. For example, some upper control systems may be able to achieve optimal signal recognition and processing under a pulse signal with a duty cycle of 30%, while others may be more suitable for a pulse signal with a duty cycle of 60%. Through the adjustable duty cycle, it can be ensured that the pulse signal is well adapted to various upper control systems.

[0028] The pulse output module uses a power amplifier to amplify the pulse signal and a Schmitt trigger to shape the pulse signal to ensure that the output pulse signal meets the input requirements of the upper control system; the power amplifier amplifies the pulse signal and increases the strength of the pulse signal. This helps to overcome the attenuation problem during signal transmission and ensures that the pulse signal has sufficient amplitude when it reaches the upper control system so that it can be accurately identified by the upper control system. For example, in the case of long-distance transmission or signal interference, the original pulse signal may become weak. After amplification by the power amplifier, the signal strength is enhanced, reducing the risk of misjudgment due to weak signals.

[0029] A method for outputting fault pulses of a brushless DC motor comprises the following steps: monitoring various operating parameters of the motor in real time by a fault detection module arranged on a brushless DC motor substrate: Hardware overcurrent detection: The bus current Ibus flows through the sampling resistor RS1 to generate a voltage VIshunt, which is compared with the reference voltage Vref output by the DA module inside the chip. If V_Ishunt is greater than Vref, it is determined as a hardware overcurrent. Software overcurrent detection: The three-phase current is detected at fixed time intervals, and the W-phase current is calculated from the U-phase and V-phase currents using Kirchhoff's current law. One end I_U of the U-phase sampling resistor RS2 is connected to the non-inverting input of the internal op amp, and the other end PGND is connected to the inverting input of the op amp. The amplification factor of the op amp is determined by the ratio of R13 and R17, while R14 and R15 set the voltage bias amplitude. The voltage difference across RS2 is amplified by the op amp and used as the input of the ADC module in the MCU. According to Ohm's law, the real-time current of the U-phase is calculated. Similarly, the current of the V-phase can be obtained. If the phase current exceeds the set value within the set time interval for three consecutive times, it is determined as software overcurrent; Over-voltage and under-voltage detection: The bus voltage is divided by R9 and R10 in series, and filtered by C7. VBUS is directly connected to the ADC acquisition IO of the chip. According to the voltage division ratio, the data collected by the ADC is converted into the real-time voltage of the bus. The over-voltage and under-voltage thresholds are set in the code. When the real-time voltage exceeds the over-voltage threshold, it is judged as over-voltage, and when the real-time voltage is lower than the under-voltage threshold, it is judged as under-voltage. Phase loss detection: Based on the hardware of software overcurrent detection, if the maximum current value of one phase in the three-phase current exceeds the maximum current value of any other phase, and the value is greater than the preset phase loss protection current value, it is determined that a phase loss problem occurs; Over-temperature judgment: Resistor R30 and NTC resistor R31 are connected in series to divide the 5 volts, and C11 is used for filtering to prevent interference. Since the resistance value of the NTC resistor has a negatively correlated linear relationship with the temperature, the MCU judges the current temperature based on the voltage value collected by the ADC.

[0030] Speed ​​regulation signal detection: For the speed regulation signal of the brushless DC motor commonly used in the small household appliance industry, the timer in the MCU is used to capture the high and low levels of the pulse signal, and calculate the duration of the high and low levels to obtain the frequency and duty cycle of the speed regulation signal.

[0031] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A brushless DC motor fault pulse output system, characterized in that: include: The fault detection module is arranged on the substrate of the brushless DC motor, and is used to monitor the operating parameters of the motor's phase current, bus current, bus voltage, speed control signal, and temperature in real time, and analyze the parameters through a built-in algorithm to determine whether the motor has a fault and the type of fault. The built-in algorithm includes a hardware overcurrent detection standard, a software overcurrent detection standard, an overvoltage and undervoltage detection standard, a phase loss detection standard, an overtemperature judgment standard, and a speed control signal detection standard, wherein: The hardware overcurrent detection standard is that the bus current flows through the sampling resistor, a voltage is formed on the sampling resistor, and the voltage is sent to the positive input terminal of the comparator. The negative input terminal of the comparator is set to the reference voltage output by the module in the chip. At this time, a comparator interrupt is generated to trigger the hardware overcurrent; The software overcurrent detection standard is to detect the three-phase current at a fixed interval, and calculate the phase current according to the phase current and the phase current through Kirchhoff's current law, wherein one end of the phase sampling resistor is connected to the same-phase input terminal of the internal operational amplifier, and the other end of the sampling resistor is connected to the inverting input terminal of the operational amplifier. The ratio of and determines the amplification factor of the operational amplifier, and sets the voltage bias amplitude. The voltage difference at both ends is amplified by the operational amplifier as the input of the internal module, and the real-time current of the phase is calculated according to Ohm's law. Similarly, the phase current is calculated. If the phase current is detected to be greater than the set value three times in a row within a certain period of time, it is judged as software overcurrent; The over-voltage and under-voltage detection standard is to divide the bus voltage in series, filter it, and directly connect it to the chip for collection. The collected data is converted into the real-time voltage of the bus according to the voltage division ratio. The over-voltage and under-voltage thresholds are set in the code. When the real-time voltage is greater than the over-voltage threshold, it is judged as over-voltage, and when the real-time voltage is less than the under-voltage threshold, it is judged as under-voltage; The phase loss detection standard is based on the hardware of software overcurrent. If the maximum current value of one phase in the three-phase current is greater than the maximum current value of any other phase and greater than the phase loss protection current value, then a phase loss problem is determined. The over-temperature judgment standard is to divide the voltage of the resistor and the series connection, filter to prevent interference, and judge the temperature according to the collected voltage, wherein there is a negatively correlated linear relationship with the temperature; The speed regulation signal detection standard is for the speed regulation signal of the brushless DC motor in the current small household appliance industry. The timer is used to capture the high level and low level of the pulse signal, and the high level maintenance time and the low level maintenance time are calculated to calculate the frequency and duty cycle of the speed regulation signal. The peripheral circuit includes a current limiting resistor and a filter capacitor. The pulse generation module is composed of an advanced timer, which is used to generate a specific frequency pulse signal corresponding to the different fault types detected by the fault detection module, wherein the pulse corresponds to the phase loss fault, the pulse corresponds to the overvoltage fault, the pulse corresponds to the undervoltage fault, the pulse corresponds to the overcurrent fault, the pulse corresponds to the abnormal speed regulation signal, and the pulse corresponds to the overtemperature fault. The frequency and duty cycle parameters of the pulse signal can be set and adjusted according to actual needs; The pulse output module is used to amplify and shape the pulse signal generated by the pulse generation module and then output it to the upper control system to ensure the stability and accuracy of the pulse signal during transmission so that it can be effectively received and recognized by the upper control system; The upper control system is used to receive the pulse signal from the pulse output module. It pre-stores a correspondence table between pulse frequency and fault type. It compares the correspondence table with the frequency of the received pulse signal to quickly determine the motor fault type and take corresponding measures, including alarm, shutdown, and adjustment of motor operating parameters.

2. A brushless DC motor fault pulse output system according to claim 1, characterized in that: In the hardware overcurrent detection of the fault detection module, the resistance value of the sampling resistor is selected according to the detection accuracy requirement of the bus current to ensure that the hardware overcurrent detection can be accurately triggered under different bus current conditions.

3. A brushless DC motor fault pulse output system according to claim 2, characterized in that: In the software overcurrent detection of the fault detection module, the fixed interval time can be adjusted according to the operating characteristics of the motor and the timeliness requirements for fault detection, and the set overcurrent value is set according to the rated current and safety margin of the motor.

4. A brushless DC motor fault pulse output system according to claim 3, characterized in that: In the over-voltage and under-voltage detection of the fault detection module, the resistance ratio of and is determined according to the range of the bus voltage and the accuracy requirement of the acquisition, so as to accurately convert the real-time voltage of the bus.

5. A brushless DC motor fault pulse output system according to claim 4, characterized in that: In the phase loss detection of the fault detection module, the phase loss protection current value is set according to the phase current rating of the motor and the stability requirement of the motor operation.

6. A brushless DC motor fault pulse output system according to claim 5, characterized in that: In the over-temperature judgment of the fault detection module, the resistance values ​​of and are selected according to the normal operating temperature range of the motor and the accuracy requirement of temperature detection to accurately reflect the voltage change corresponding to the temperature change.

7. A brushless DC motor fault pulse output system according to claim 6, characterized in that: The duty cycle of the pulse signal generated by the pulse generation module can be adjusted between 10-90% according to actual needs to adapt to different receiving requirements of the upper control system.

8. A brushless DC motor fault pulse output system according to claim 7, characterized in that: The pulse output module adopts a power amplifier to amplify the pulse signal and adopts a Schmitt trigger to shape the pulse signal to ensure that the output pulse signal meets the input requirement of the upper control system.

9. A method for outputting fault pulses of a brushless DC motor, applied to a brushless DC motor fault pulse output system as claimed in claim 8, characterized in that: The following steps are involved: Through the fault detection module set on the brushless DC motor substrate, various operating parameters of the motor are monitored in real time: Hardware overcurrent detection: The bus current flows through the sampling resistor to generate a voltage, which is compared with the reference voltage output by the chip's internal module. If it is greater, it is determined to be a hardware overcurrent. Software overcurrent detection: The three-phase current is detected at fixed time intervals, and the phase current is calculated by the phase and phase currents using Kirchhoff's current law; One end of the phase sampling resistor is connected to the non-inverting input of the internal operational amplifier, and the other end is connected to the inverting input of the operational amplifier. The amplification factor of the operational amplifier is determined by the ratio of and, and and set the voltage bias amplitude. The voltage difference between the two ends is amplified by the operational amplifier and used as the input of the middle module. According to Ohm's law, the real-time current of the phase is calculated. Similarly, the phase current can be obtained. If the phase current exceeds the set value for three consecutive times within the set time interval, it is determined as software overcurrent; Over-voltage and under-voltage detection: divide the bus voltage by connecting in series and use filtering, directly connect to the chip acquisition, convert the acquired data into the real-time voltage of the bus according to the voltage division ratio, set the over-voltage and under-voltage thresholds in the code, and judge it as over-voltage when the real-time voltage exceeds the over-voltage threshold, and judge it as under-voltage when the real-time voltage is lower than the under-voltage threshold; Phase loss detection: Based on the hardware of software overcurrent detection, if the maximum current value of one phase in the three-phase current exceeds the maximum current value of any other phase, and the value is greater than the preset phase loss protection current value, it is determined that a phase loss problem occurs; Over-temperature judgment: Resistors are connected in series to divide the 5 volts and filter to prevent interference. Since the resistance value of the resistor has a negatively correlated linear relationship with the temperature, the current temperature is judged based on the collected voltage value; Speed ​​regulation signal detection: For the speed regulation signal of the brushless DC motor commonly used in the small household appliance industry, the timer is used to capture the high and low levels of the pulse signal, and calculate the duration of the high and low levels, so as to obtain the frequency and duty cycle of the speed regulation signal.

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