PWM signal conditioning circuit and overcurrent protection system

Abstract

The invention relates to a PWM signal conditioning circuit, an overcurrent protection system, an overcurrent protection method and a vehicle, and relates to the technical field of circuits, the PWM signal conditioning circuit comprises a filtering module, a comparison module and a shaping module; the first end of the filtering module is connected with the first end of the microcontroller circuit, the second end of the filtering module is connected with the first end of the comparison module, the third end of the filtering module is connected with the first end of the driving circuit and the first end of the signal amplification circuit, and the fourth end of the filtering module is grounded; the second end of the comparison module is connected with the first end of the shaping module, the third end and the fourth end of the comparison module are respectively externally connected with a power supply, the fifth end and the sixth end of the comparison module are respectively grounded, the second end of the shaping module is connected with the first end of the motor pre-drive chip circuit, the third end of the shaping module is externally connected with a power supply, and the fourth end of the shaping module is grounded. Compared with the prior art, the over-current protection circuit can stably and efficiently realize an over-current protection function.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit, in particular to a PWM signal conditioning circuit, an overcurrent protection system and method, and a vehicle. BACKGROUND

[0002] A large number of DC motors are used in the body domain of an electric vehicle, such as seats, windows, tailgates, etc., which are controlled by a body control module (BCM). When the motor is locked, its current will be much larger than the normal working current, thereby generating a large amount of heat in the coil. Since the heat dissipation effect of the motor in the vehicle is poor, too much heat accumulation may damage the motor and cause functional failure, thereby affecting the normal operation of the vehicle.

[0003] Currently, overcurrent protection is mainly performed on the motor using a Hall sensor in the DC motor. Specifically, the number of waveform transition times of the Hall sensor collected per second is determined by software. When the waveform transition frequency is too low, it is considered that the motor is in a locked state, and the pulse width modulation (PWM) driving signal of the switching device is cut off, so that the motor stops working, thereby protecting the motor.

[0004] However, using this overcurrent protection method requires connecting a Hall sensor in the DC motor and determining whether to protect by software, which increases the cost of the overcurrent protection circuit. In the case of software running errors or preset parameter errors, the DC motor cannot be protected. SUMMARY

[0005] Therefore, the present application provides a PWM signal conditioning circuit, an overcurrent protection system and method, and a vehicle, which mainly aims to solve the technical problem that the prior art needs to connect a Hall sensor in the DC motor and determine whether to protect by software, which increases the cost of the overcurrent protection circuit, and in the case of software running errors or preset parameter errors, the DC motor cannot be protected.

[0006] In a first aspect, the present application provides a PWM signal conditioning circuit, characterized in that it comprises a filtering module, a comparison module and a shaping module.

[0007] The first end of the filtering module is connected to the first end of the microcontroller circuit, the second end of the filtering module is connected to the first end of the comparison module, the third end of the filtering module is connected to the first end of the driving circuit and the first end of the signal amplification circuit, and the fourth end of the filtering module is grounded.

[0008] The second end of the comparison module is connected with the first end of the shaping module, the third end and the fourth end of the comparison module are respectively connected with an external power supply, the fifth end and the sixth end of the comparison module are respectively grounded, the second end of the shaping module is connected with the first end of the motor pre-driving chip circuit, the third end of the shaping module is connected with an external power supply, and the fourth end of the shaping module is grounded.

[0009] The filter module is used for inputting the first output voltage of the microcontroller circuit and the direct current voltage component of the driving circuit into the comparison module for processing, and the comparison module is used for judging the total voltage of the first output voltage and the direct current voltage component, and adjusting the duty cycle of the first output voltage to be less than a preset duty cycle threshold when it is judged that the total voltage is greater than a preset voltage threshold.

[0010] The shaping module is used for shaping the adjusted first output voltage to obtain the second output voltage of the PWM signal conditioning circuit, and inputting the second output voltage into the driving circuit through the motor pre-driving chip circuit.

[0011] The driving circuit is used for controlling the driving motor in the driving circuit to be inoperable according to the second output voltage, and performing overcurrent protection on the driving motor, wherein the electromagnetic torque generated by the output current corresponding to the second output voltage is less than the load torque of the driving motor, so that the driving motor in the driving circuit is inoperable.

[0012] Optionally, the filter module comprises a first capacitor, a first resistor and a second resistor.

[0013] The first end of the first capacitor is connected with the first end of the microcontroller circuit and the first end of the first resistor, and the second end of the first capacitor is connected with the first end of the comparison module and the first end of the second resistor.

[0014] The second end of the first resistor is grounded, and the second end of the second resistor is connected with the first end of the driving circuit and the first end of the signal amplification circuit.

[0015] The first capacitor and the second resistor are used for composing a high-pass filter, filtering the first output voltage to obtain the high-frequency part of the first output voltage, and inputting the direct current voltage component of the driving circuit and the high-frequency part of the first output voltage into the comparison module.

[0016] Optionally, the comparison module comprises a comparator, a second capacitor, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor.

[0017] The positive input end of the comparator is connected with the second end of the filtering module and the first end of the third resistor, the negative input end of the comparator is connected with the first end of the second capacitor, the first end of the fourth resistor and the first end of the fifth resistor, and the output end of the comparator is connected with the second end of the third resistor, the first end of the sixth resistor and the first end of the shaping module;

[0018] The second end of the second capacitor is grounded, the second end of the fourth resistor is connected with an external power supply, and the second end of the fifth resistor is grounded, and the second end of the sixth resistor is connected with an external power supply.

[0019] Optionally, the fourth resistor and the fifth resistor are used to determine the preset voltage threshold.

[0020] The comparator is used to compare the total voltage of the first output voltage and the direct current voltage component with a preset voltage threshold, and in the case that the total voltage is greater than the preset voltage threshold, the duty cycle of the high-frequency part of the first output voltage is adjusted to be less than a preset duty cycle threshold, and the high-frequency part of the first output voltage is input to the shaping module.

[0021] The comparator is also used to input the high-frequency part of the first output voltage to the shaping module in the case that the total voltage is less than or equal to the preset voltage threshold.

[0022] Optionally, the shaping module comprises an inverter and a seventh resistor.

[0023] The input end of the inverter is connected with the second end of the comparison module, the output end of the inverter is connected with the first end of the motor pre-drive chip circuit, the positive power supply end of the inverter is connected with the first end of the seventh resistor, the ground end of the inverter is grounded, and the second end of the seventh resistor is connected with an external power supply.

[0024] The inverter is used to perform reverse processing on the high-frequency part of the first output voltage to obtain the second output voltage, and input the second output voltage to the driving circuit through the motor pre-drive chip circuit.

[0025] In a second aspect, the application provides an overcurrent protection system, comprising the PWM signal conditioning circuit, the motor pre-drive chip circuit, the signal amplification circuit, the driving circuit and the microcontroller circuit of the first aspect.

[0026] The first end of the PWM signal conditioning circuit is connected with the first end of the microcontroller circuit, the second end of the PWM signal conditioning circuit is connected with the first end of the motor pre-drive chip circuit, and the third end of the PWM signal conditioning circuit is connected with the first end of the driving circuit and the first end of the signal amplification circuit.

[0027] The drive circuit is used to control the drive motor in the drive circuit to not work based on the second output voltage, and to provide overcurrent protection for the drive motor. The electromagnetic torque generated by the output current corresponding to the second output voltage is less than the load torque of the drive motor, so that the drive motor in the drive circuit does not work.

[0028] Optionally, the second terminal of the microcontroller circuit is connected to the second terminal of the motor pre-drive chip circuit, the third terminal of the microcontroller circuit is connected to the second terminal of the signal amplification circuit, the fourth terminal of the microcontroller circuit is connected to the third terminal of the signal amplification circuit, the fourth terminal of the signal amplification circuit is connected to the second terminal of the drive circuit, the second terminal of the drive circuit is grounded, the third terminal of the motor pre-drive chip circuit is connected to the third terminal of the drive circuit, and the fourth terminal of the drive circuit is connected to an external power supply.

[0029] Thirdly, this application provides an overcurrent protection method, including:

[0030] Obtain the first output voltage of the microcontroller circuit and the DC voltage component of the drive circuit, and determine the total voltage of the first output voltage and the DC voltage component;

[0031] If it is determined that the total voltage is greater than a preset voltage threshold, the duty cycle of the first output voltage in the total voltage is adjusted to be less than the preset duty cycle threshold to obtain the second output voltage of the PWM signal conditioning circuit;

[0032] The second output voltage is input to the drive circuit through the motor pre-drive chip circuit to control the drive motor in the drive circuit to not work and to provide overcurrent protection for the drive motor. The electromagnetic torque generated by the output current corresponding to the second output voltage is less than the load torque of the drive motor, so that the drive motor in the drive circuit does not work.

[0033] Fourthly, this application provides a vehicle including: a PWM signal conditioning circuit as described in the first aspect, or an overcurrent protection system as described in the second aspect.

[0034] By means of the above technical solution, this application provides a PWM signal conditioning circuit and overcurrent protection system, method, and vehicle. The pulse width modulation (PWM) signal conditioning circuit includes: a filtering module, a comparison module, and a shaping module; the first terminal of the filtering module is connected to the first terminal of the microcontroller circuit, the second terminal of the filtering module is connected to the first terminal of the comparison module, the third terminal of the filtering module is connected to the first terminal of the drive circuit and the first terminal of the signal amplification circuit, and the fourth terminal of the filtering module is grounded; the second terminal of the comparison module is connected to the first terminal of the shaping module, the third and fourth terminals of the comparison module are respectively connected to an external power supply, the fifth and sixth terminals of the comparison module are respectively grounded, the second terminal of the shaping module is connected to the first terminal of the motor pre-drive chip circuit, the third terminal of the shaping module is connected to an external power supply, and the fourth terminal of the shaping module is grounded; the filtering module is used to condition the signal of the microcontroller circuit... The first output voltage and the DC voltage component of the drive circuit are input to the comparison module for processing. The comparison module is used to determine the total voltage of the first output voltage and the DC voltage component. If the total voltage is greater than or exceeds a preset voltage threshold, the duty cycle of the first output voltage is adjusted to be less than the preset duty cycle threshold. The shaping module is used to shape the adjusted first output voltage to obtain the second output voltage of the PWM signal conditioning circuit, and input the second output voltage to the drive circuit through the motor pre-drive chip circuit. The drive circuit is used to control the drive motor in the drive circuit to not work based on the second output voltage and to provide overcurrent protection for the drive motor. The electromagnetic torque generated by the output current corresponding to the second output voltage is less than the load torque of the drive motor, so that the drive motor in the drive circuit does not work. Compared with existing technologies, this application uses a PWM signal conditioning circuit to determine the relationship between the total voltage of the first output voltage and the DC voltage component and a preset voltage threshold to determine whether overcurrent protection is triggered. If overcurrent protection is triggered, the duty cycle of the first output voltage is adjusted to be less than the preset duty cycle threshold to obtain a second output voltage. The electromagnetic torque generated by the output current corresponding to the second output voltage is less than the load torque of the drive motor, causing the drive motor in the drive circuit to stop working. This purely hardware-based overcurrent self-protection achieves its purpose, ensuring protection even in the event of software failure or incorrect software preset values. It boasts extremely high response speed, making it suitable for extreme situations involving software failure or errors. It also possesses self-recovery capability, is simple and flexible, easy to implement, and can stably and efficiently implement overcurrent protection. When the fault is cleared, it can automatically recover without software processing.

[0035] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0036] The accompanying drawings, which are included to provide a further understanding of this disclosure and form part of this disclosure, illustrate exemplary embodiments of the present disclosure and are used to explain the disclosure, but do not constitute an undue limitation of the disclosure. In the drawings:

[0037] Figure 1 A schematic diagram of a PWM signal conditioning circuit provided in an embodiment of this disclosure is shown.

[0038] Figure 2 A schematic diagram of an overcurrent protection system provided in an embodiment of this disclosure is shown.

[0039] Figure 3 A schematic diagram illustrating an example provided by an embodiment of this disclosure is shown;

[0040] Figure 4 A schematic diagram illustrating an example provided by an embodiment of this disclosure is shown;

[0041] Figure 5 A schematic flowchart of an overcurrent protection method provided in an embodiment of this disclosure is shown;

[0042] Figure 6 A schematic diagram of an example structure provided by an embodiment of this disclosure is shown;

[0043] exist Figure 1 middle:

[0044] 11-Filtering module;

[0045] 12-Comparison Module;

[0046] 13-Shaping Module.

[0047] exist Figure 2 middle:

[0048] 1-PWM signal conditioning circuit;

[0049] 2-Motor pre-drive chip circuit;

[0050] 3-Signal amplification circuit;

[0051] 4-Drive circuit;

[0052] 5-Microcontroller circuit; Detailed Implementation

[0053] In the description of this disclosure, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.

[0054] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise expressly specified.

[0055] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0056] The present disclosure will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present disclosure can be combined with each other.

[0057] The following is combined with Figure 1 This disclosure describes an overcurrent protection system according to some embodiments of the present disclosure.

[0058] This disclosure provides a PWM signal conditioning circuit, such as... Figure 1 As shown, the feature is that it includes: a filtering module 11, a comparison module 12, and a shaping module 13;

[0059] The first terminal of the filter module 11 is connected to the first terminal of the microcontroller circuit 5, the second terminal of the filter module 11 is connected to the first terminal of the comparison module 12, the third terminal of the filter module 11 is connected to the first terminal of the drive circuit 4 and the first terminal of the signal amplification circuit 3, and the fourth terminal of the filter module 11 is grounded. The filter module 11 is used to filter the first output voltage to obtain the high-frequency part of the first output voltage, and input the DC voltage component of the drive circuit and the high-frequency part of the first output voltage into the comparison module.

[0060] In some examples, the filtering module 11 includes: a first capacitor C1, a first resistor R1, and a second resistor R2; the first end of the first capacitor C1 is connected to the first end of the microcontroller circuit 5 and the first end of the first resistor R1, and the second end of the first capacitor C1 is connected to the first end of the comparison module 12 and the first end of the second resistor R2; the second end of the first resistor R1 is grounded, and the second end of the second resistor R2 is connected to the first end of the drive circuit 4 and the first end of the signal amplification circuit 3; the first capacitor C1 and the second resistor R2 are used to form a high-pass filter to filter the first output voltage to obtain the high-frequency part of the first output voltage, and input the DC voltage component of the drive circuit and the high-frequency part of the first output voltage into the comparison module 12.

[0061] Optionally, a high-pass filter is an electronic filter that allows higher-frequency signals to pass through while attenuating or blocking lower-frequency signals. Its main function is to separate or filter out high-frequency components in a signal while suppressing unwanted low-frequency components.

[0062] As a preferred approach, C1 and R2 form a high-pass filter, the specific value of which is determined by the frequency of the PWM signal. This part of the circuit retains the high-frequency part of the PWM signal. Unlike ordinary high-pass filter circuits, the other end of R2 is not connected to ground, but to the positive terminal Rsense+ of the sampling resistor in the drive circuit 4. This adds a DC voltage component to the output level, which is the voltage value Vsense on the current sampling resistor.

[0063] Optionally, the second terminal of the comparison module 12 is connected to the first terminal of the shaping module 13, the third and fourth terminals of the comparison module 12 are respectively connected to an external power supply, and the fifth and sixth terminals of the comparison module 12 are respectively grounded; the comparison module 12 is used to compare the total voltage of the first output voltage and the DC voltage component with a preset voltage threshold. If the total voltage is greater than the preset voltage threshold, the duty cycle of the high-frequency part of the first output voltage is adjusted to be less than the preset duty cycle threshold, and the high-frequency part of the first output voltage is input to the shaping module 13; the comparison module 12 is also used to input the high-frequency part of the first output voltage to the shaping module 13 if the total voltage is less than or equal to the preset voltage threshold.

[0064] Optionally, the comparison module 12 includes: a comparator U1, a second capacitor C2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6; the positive input terminal of the comparator U1 is connected to the second terminal of the filter module 11 and the first terminal of the third resistor R3, the negative input terminal of the comparator U1 is connected to the first terminal of the second capacitor C2, the first terminal of the fourth resistor R4, and the first terminal of the fifth resistor R5, and the output terminal of the comparator U1 is connected to the second terminal of the third resistor R3, the first terminal of the sixth resistor R6, and the first terminal of the shaping module 13; the second terminal of the second capacitor C2 is grounded, the second terminal of the fourth resistor R4 is connected to an external power supply, the second terminal of the fifth resistor R5 is grounded, and the second terminal of the sixth resistor R6 is connected to an external power supply.

[0065] In some examples, the fourth resistor R4 and the fifth resistor R5 are used to determine a preset voltage threshold; the comparator U1 is used to compare the total voltage of the first output voltage and the DC voltage component with the preset voltage threshold. If the total voltage is greater than the preset voltage threshold, the duty cycle of the high-frequency part of the first output voltage is adjusted to be less than the preset duty cycle threshold, and the high-frequency part of the first output voltage is input to the shaping module 13; the comparator U1 is also used to input the high-frequency part of the first output voltage to the shaping module 13 if the total voltage is less than or equal to the preset voltage threshold.

[0066] In this embodiment, a comparator is an electronic circuit used to compare the voltage or current magnitudes of two or more input signals and output a digital signal (typically a binary logic level) based on the comparison result. A comparator has at least two input terminals, referred to as the positive input (typically labeled **+ or Vin+) and the negative input (typically labeled **- or Vin-**). These input terminals receive the voltage signals to be compared. The comparator has a digital output terminal, typically providing a logic "high" (e.g., "1" or power supply voltage Vcc) or logic "low" (e.g., "0" or ground voltage GND) signal. The state of the output signal depends on the relative magnitudes of the input voltages.

[0067] Specifically, a comparator determines its output state based on preset comparison rules (such as "greater than", "less than", or "equal to"). For the most common two-input comparator, its operating principle is as follows: when the voltage at the positive input terminal is greater than the voltage at the negative input terminal, the comparator outputs a logic "high" (e.g., "1"). When the voltage at the positive input terminal is less than the voltage at the negative input terminal, the comparator outputs a logic "low" (e.g., "0"). When the voltages at the positive and negative input terminals are equal, an ideal comparator will immediately output a definite logic state. However, in practice, comparators may produce uncertain outputs or brief oscillations due to factors such as input offset voltage and hysteresis.

[0068] To avoid frequent output jumps caused by noise or interference when the input voltage approaches a threshold, many comparator designs incorporate hysteresis. A hysteresis comparator requires its input voltage to cross two different thresholds (upper and lower thresholds) before changing its output state, thereby enhancing circuit stability and noise immunity. In this embodiment, the third resistor R3 forms the hysteresis loop of comparator U1, used to maintain the stability of comparator U1.

[0069] For example, the comparison module 12 consists of a comparator and a resistor network forming a hysteresis loop. A voltage divider network composed of R4 and R5 serves as a preset voltage threshold. The signal output from the first part is compared with this threshold. When the signal is higher than this threshold, the comparator outputs a high signal; when the signal is lower than this threshold, the comparator outputs a PWM waveform. Specifically, the preset voltage threshold is determined by R4 and R5 based on Formula 1, as shown below:

[0070]

[0071] In Formula 1, V represents the preset voltage threshold, and VCC represents the voltage corresponding to the external power supply.

[0072] It should be noted that the second capacitor C2 is used for filtering to ensure that the preset voltage threshold remains stable.

[0073] Optionally, the second end of the shaping module 13 is connected to the first end of the motor pre-drive chip circuit 3, the third end of the shaping module 13 is connected to an external power supply, and the fourth end of the shaping module 13 is grounded; the shaping module 13 is used to reverse the high-frequency part of the first output voltage to obtain the second output voltage, and input the second output voltage to the drive circuit 4 through the motor pre-drive chip circuit 3.

[0074] In some examples, the shaping module 13 includes: an inverter Q1 and a seventh resistor R7; the input terminal of the inverter Q1 is connected to the second terminal of the comparator module, the output terminal of the inverter Q1 is connected to the first terminal of the motor pre-drive chip circuit 3, the positive power supply terminal of the inverter Q1 is connected to the first terminal of the seventh resistor R7, the ground terminal of the inverter Q1 is grounded, and the second terminal of the seventh resistor R7 is connected to an external power supply; the inverter Q1 is used to invert the high-frequency part of the first output voltage to obtain a second output voltage, and input the second output voltage to the drive circuit 4 through the motor pre-drive chip circuit 3.

[0075] In this embodiment, an inverter, also known as a NOT gate, is a basic logic gate that performs a logical NOT operation. That is, the output state of an inverter is the opposite of its input state. Specifically: if the input of the inverter is logic "1" (high level), its output is logic "0" (low level). If the input of the inverter is logic "0" (low level), its output is logic "1" (high level).

[0076] For example, such as Figure 3 The waveform shown is when the overcurrent protection is not triggered. It can be seen that when the overcurrent protection is not triggered, the duty cycle of the waveform output by the PWM signal conditioning circuit is exactly opposite to that of the input waveform.

[0077] like Figure 4 The waveform shown is when overcurrent protection is triggered. It can be seen that although the MCU still outputs a PWM waveform normally when overcurrent protection is triggered, the waveform output by the PWM signal conditioning circuit has a very low duty cycle and glitches (due to the high-pass filter). Under this extremely low duty cycle, the electromagnetic torque generated by the current flowing through the motor is less than the load torque, and the motor may not rotate or will rotate at a very low speed, thus achieving the purpose of overcurrent self-protection. When the current decreases, the "plateau" portion of the second waveform in the figure will also decrease. When it drops below the threshold set by the circuit, it will return to a normal waveform, achieving the purpose of self-recovery.

[0078] In this embodiment, the external power supply for the fourth resistor R4 and the sixth resistor R6 is the power supply in the microcontroller circuit, and the external power supply for the seventh resistor R7 is the normal power supply. The inverter can be used to perform level conversion between different logic level standards to ensure that the signal can be correctly transmitted between circuits with different level standards.

[0079] It should be noted that due to the presence of the inverter, the PWM is reversed. Therefore, the software needs to adjust the duty cycle in advance. For example, if the pre-driver chip is expected to receive a PWM waveform with a 40% duty cycle, the MCU needs to output a PWM with a 60% duty cycle.

[0080] Compared with existing technologies, this embodiment uses a PWM signal conditioning circuit to determine the relationship between the total voltage of the first output voltage and the DC voltage component and a preset voltage threshold to determine whether overcurrent protection is triggered. If overcurrent protection is triggered, the duty cycle of the first output voltage is adjusted to be less than the preset duty cycle threshold, resulting in a second output voltage. The electromagnetic torque generated by the output current corresponding to the second output voltage is less than the load torque of the drive motor, causing the drive motor in the drive circuit to stop working. This pure hardware method achieves overcurrent self-protection, ensuring protection even in the event of software failure or incorrect software preset values. It boasts extremely high response speed, making it suitable for extreme situations involving software failure or errors. It also possesses self-recovery capability, is simple and flexible, easy to implement, and can stably and efficiently implement overcurrent protection. When the fault is cleared, it recovers automatically without software processing.

[0081] This disclosure provides an overcurrent protection system, such as... Figure 2 As shown, the overcurrent protection system includes: a pulse width modulation (PWM) signal conditioning circuit 1, a motor pre-drive chip circuit 2, a signal amplification circuit 3, a drive circuit 4, and a microcontroller circuit 5;

[0082] The first terminal of the PWM signal conditioning circuit is connected to the first terminal of the microcontroller circuit 5, the second terminal of the PWM signal conditioning circuit 1 is connected to the first terminal of the motor pre-drive chip circuit 2, and the third terminal of the PWM signal conditioning circuit 1 is connected to the first terminal of the drive circuit 4 and the first terminal of the signal amplification circuit 3.

[0083] The PWM signal conditioning circuit 1 is used to judge the first output voltage of the microcontroller circuit 5 and the DC voltage component of the drive circuit 4. When it is determined that the total voltage of the first output voltage and the DC voltage component exceeds the preset voltage threshold, the duty cycle of the first output voltage current is adjusted to be less than the preset duty cycle threshold to obtain the second output voltage of the PWM signal conditioning circuit 1. The second output voltage is then input to the drive circuit 4 through the motor pre-drive chip circuit 2.

[0084] The drive circuit 4 is used to control the drive motor in the drive circuit 4 to stop working based on the second output voltage, and to provide overcurrent protection for the drive motor. The electromagnetic torque generated by the output current corresponding to the second output voltage is less than the load torque of the drive motor, so that the drive motor in the drive circuit stops working.

[0085] In this embodiment, Pulse Width Modulation (PWM) is a technique that regulates output voltage, current, or power by changing the duty cycle of a pulse signal (i.e., the ratio of the high-level duration to the entire cycle time). PWM works by rapidly switching (typically transistors or field-effect transistors) to simulate the desired average voltage (or current). For example, in DC motor control, by adjusting the duty cycle of the PWM signal, the average voltage applied across the motor can be changed, thereby achieving precise control of the motor speed or torque.

[0086] In some examples, the ratio of the high-level duration of each pulse to the total cycle time is called the duty cycle. In this embodiment, the first output voltage is the output voltage after PWM speed regulation in the microcontroller circuit; correspondingly, the second output voltage is the output voltage of the first output voltage after the duty cycle has been adjusted in the PWM signal conditioning circuit.

[0087] For example, in the PWM signal conditioning circuit 1, the total voltage of the first output voltage of the microcontroller circuit and the DC voltage component of the drive circuit 4 is judged. If the total voltage is greater than a preset voltage threshold, it is judged to be an overcurrent condition. The duty cycle of the first output voltage current is adjusted to be less than the preset duty cycle threshold to obtain the second output voltage of the PWM signal conditioning circuit 1. The second output voltage is then input to the drive circuit 4 through the motor pre-drive chip circuit 2.

[0088] It should be noted that the preset voltage threshold can be determined by the PWM signal conditioning circuit, and the preset duty cycle threshold is a pre-set duty cycle that cannot drive the motor in the drive circuit to work normally.

[0089] In a preferred embodiment, the second terminal of the microcontroller circuit 5 is connected to the second terminal of the motor pre-drive chip circuit 2, the third terminal of the microcontroller circuit 5 is connected to the second terminal of the signal amplification circuit 3, the fourth terminal of the microcontroller circuit 5 is connected to the third terminal of the signal amplification circuit 3, the fourth terminal of the signal amplification circuit 3 is connected to the second terminal of the drive circuit 4, the second terminal of the drive circuit 4 is grounded, the third terminal of the motor pre-drive chip 2 module is connected to the third terminal of the drive circuit 4, and the fourth terminal of the drive circuit 4 is connected to an external power supply.

[0090] Compared with existing technologies, this embodiment uses a PWM signal conditioning circuit to determine the relationship between the total voltage of the first output voltage and the DC voltage component and a preset voltage threshold to determine whether overcurrent protection is triggered. If overcurrent protection is triggered, the duty cycle of the first output voltage is adjusted to be less than the preset duty cycle threshold, resulting in a second output voltage. The electromagnetic torque generated by the output current corresponding to the second output voltage is less than the load torque of the drive motor, causing the drive motor in the drive circuit to stop working. This pure hardware method achieves overcurrent self-protection, ensuring protection even in the event of software failure or incorrect software preset values. It boasts extremely high response speed, making it suitable for extreme situations involving software failure or errors. It also possesses self-recovery capability, is simple and flexible, easy to implement, and can stably and efficiently implement overcurrent protection. When the fault is cleared, it recovers automatically without software processing.

[0091] To better understand the above-mentioned objectives, features, and advantages of this application, the solution of this application will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0092] To improve upon current technology, it is necessary to connect Hall effect sensors to the DC motor and rely on software to determine whether protection is required. This increases the cost of overcurrent protection circuitry and, in the event of software errors or incorrect preset parameters, can lead to the inability to protect the DC motor. This embodiment provides an overcurrent protection method, such as... Figure 5 As shown, the method includes:

[0093] Step 101: Obtain the first output voltage of the microcontroller circuit and the DC voltage component of the drive circuit, and determine the total voltage of the first output voltage and the DC voltage component.

[0094] For example, if the first output voltage is A and the DC voltage component of the driving circuit is B, then A and B are input to the PWM signal conditioning circuit to determine the total voltage C of the first output voltage A and the DC voltage component B.

[0095] It should be noted that the total voltage C can be the sum of the first output voltage A and the DC voltage component B, or it can be determined in other ways. The method for determining the total voltage C is not specifically limited in the embodiments of this application.

[0096] Step 102: If the total voltage is determined to be greater than the preset voltage threshold, the duty cycle of the first output voltage in the total voltage is adjusted to be less than the preset duty cycle threshold to obtain the second output voltage of the PWM signal conditioning circuit.

[0097] Optionally, step 102 may specifically include: comparing the total voltage with a preset voltage threshold using a comparator in the PWM signal conditioning circuit; if it is determined that the total voltage is greater than the preset voltage threshold, adjusting the duty cycle of the first output voltage in the total voltage to be less than the preset duty cycle threshold; and reversing the adjusted first output voltage to obtain the second output voltage.

[0098] For example, based on step 102, if it is determined that the total voltage C is greater than the preset voltage threshold, the duty cycle of the first output voltage current is adjusted to be less than the preset duty cycle threshold to obtain the second output voltage of the PWM signal conditioning circuit.

[0099] Step 103: Input the second output voltage into the drive circuit through the motor pre-drive chip circuit to control the drive motor in the drive circuit to stop working and provide overcurrent protection for the drive motor.

[0100] The electromagnetic torque generated by the output current corresponding to the second output voltage is less than the load torque of the drive motor, causing the drive motor in the drive circuit to not work.

[0101] In this embodiment, the motor load torque refers to the rotational resistance generated on the motor shaft by external loads (such as mechanical equipment, transmission devices, etc.) during motor operation. This torque is the force that the motor must overcome to maintain the rotation of the load or to drive the load to do work.

[0102] It should be noted that the electromagnetic torque generated by the output current corresponding to the second output voltage is less than the load torque of the drive motor, which will cause the motor to not rotate or to rotate at a very low speed, thus making the drive motor in the drive circuit not work.

[0103] In this embodiment, DC motors are extensively used in the body area of ​​the electric vehicle, such as in seats, windows, and tailgates, and are controlled by the BCM. When the motor stalls, its current is many times greater than the normal operating current, thereby generating a large amount of heat in the coil. Since the heat dissipation of motors in automobiles is poor, excessive heat accumulation may damage the motor and cause it to malfunction, thus affecting the normal operation of the vehicle.

[0104] Currently, there are two most commonly used protection methods, such as Figure 6The first method uses a Hall sensor in a DC motor. Software determines the number of Hall sensor waveform transitions per second. When the waveform transition frequency is too low, the motor is considered stalled, and the PWM drive signal of the switching device is cut off, stopping the motor and protecting it. The second method uses a current-sensing resistor connected in series with the motor drive circuit to detect the drive current. The MCU monitors the current, and when it exceeds a preset value, the PWM drive signal of the switching device is cut off, ensuring normal vehicle function. Both methods have limitations. First, not all motors include Hall sensors, as this increases cost. Second, both methods are software-controlled; errors in software operation or incorrect preset parameters may prevent the protection from being achieved.

[0105] Compared with existing technologies, this embodiment uses a PWM signal conditioning circuit to determine the relationship between the total voltage of the first output voltage and the DC voltage component and a preset voltage threshold to determine whether overcurrent protection is triggered. If overcurrent protection is triggered, the duty cycle of the first output voltage is adjusted to be less than the preset duty cycle threshold, resulting in a second output voltage. The electromagnetic torque generated by the output current corresponding to the second output voltage is less than the load torque of the drive motor, causing the drive motor in the drive circuit to stop working. This pure hardware method achieves overcurrent self-protection, ensuring protection even in the event of software failure or incorrect software preset values. It boasts extremely high response speed, making it suitable for extreme situations involving software failure or errors. It also possesses self-recovery capability, is simple and flexible, easy to implement, and can stably and efficiently implement overcurrent protection. When the fault is cleared, it recovers automatically without software processing.

[0106] Based on this understanding, this disclosure also provides a vehicle, which may specifically include: such as Figure 1 The circuit shown or as Figure 2 The system shown. The vehicle can be a new energy vehicle or a traditional vehicle, etc.

[0107] Through the above description of the disclosed embodiments, those skilled in the art can clearly understand that this disclosure can be implemented using software plus necessary general-purpose hardware platforms, or it can be implemented in hardware. Compared with the prior art, this embodiment uses a PWM signal conditioning circuit to determine the relationship between the total voltage of the first output voltage and the DC voltage component and a preset voltage threshold to determine whether overcurrent protection is triggered. If overcurrent protection is triggered, the duty cycle of the first output voltage is adjusted to be less than the preset duty cycle threshold to obtain a second output voltage. The electromagnetic torque generated by the output current corresponding to the second output voltage is less than the load torque of the drive motor, so that the drive motor in the drive circuit does not work. The purpose of overcurrent self-protection is achieved using a pure hardware method. Even in the case of software failure or incorrect software preset values, the protection purpose can still be achieved. The response speed is extremely high, making it suitable for extreme situation protection under software failure or error conditions. It has self-recovery capability, is simple and flexible, easy to implement, and can stably and efficiently implement the overcurrent protection function. When the fault is eliminated, it can recover automatically without software processing.

[0108] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variations thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0109] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

[0110] It should be noted that the technical solutions in this disclosure are not limited to the control of PWM signal conditioning circuits, but can also be extended to related applications that require control. All of these should fall within the protection scope of this disclosure, and no specific limitations are made here for the related applications that require control.

[0111] All articles and references disclosed above, including patent applications and publications, are incorporated herein by reference for various purposes. The term “substantially constitutes…” used to describe a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novelty of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, components, parts, or steps herein also contemplates embodiments substantially constituted by such elements, components, parts, or steps. The use of the term “may” herein is intended to indicate that any described attribute included by “may” is optional.

[0112] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.

[0113] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and published disclosures, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be considered as a failure of the applicant to consider that subject matter as part of the disclosed subject matter. It will be apparent to those skilled in the art that various modifications and variations can be made to this disclosure without departing from its spirit and scope. Thus, this disclosure is also intended to include such modifications and variations if they fall within the scope of the claims of this disclosure and their equivalents.

Claims

1. A pulse width modulation (PWM) signal conditioning circuit, characterized in that, include: Filtering module, comparison module, and shaping module; The first terminal of the filtering module is connected to the first terminal of the microcontroller circuit, the second terminal of the filtering module is connected to the first terminal of the comparison module, the third terminal of the filtering module is connected to the first terminal of the driving circuit and the first terminal of the signal amplification circuit, and the fourth terminal of the filtering module is grounded. The second end of the comparison module is connected to the first end of the shaping module. The third and fourth ends of the comparison module are respectively connected to an external power supply. The fifth and sixth ends of the comparison module are respectively grounded. The second end of the shaping module is connected to the first end of the motor pre-drive chip circuit. The third end of the shaping module is connected to an external power supply. The fourth end of the shaping module is grounded. The filtering module is used to input the first output voltage of the microcontroller circuit and the DC voltage component of the driving circuit into the comparison module for processing. The comparison module is used to determine the total voltage of the first output voltage and the DC voltage component. If the total voltage is determined to be greater than or exceed a preset voltage threshold, the duty cycle of the first output voltage is adjusted to be less than the preset duty cycle threshold. The shaping module is used to shape the adjusted first output voltage to obtain the second output voltage of the PWM signal conditioning circuit, and input the second output voltage to the drive circuit through the motor pre-drive chip circuit. The drive circuit is used to control the drive motor in the drive circuit to not work based on the second output voltage, and to provide overcurrent protection for the drive motor. The electromagnetic torque generated by the output current corresponding to the second output voltage is less than the load torque of the drive motor, so that the drive motor in the drive circuit does not work.

2. The PWM signal conditioning circuit according to claim 1, characterized in that, The filtering module includes: a first capacitor, a first resistor, and a second resistor; The first terminal of the first capacitor is connected to the first terminal of the microcontroller circuit and the first terminal of the first resistor, and the second terminal of the first capacitor is connected to the first terminal of the comparator module and the first terminal of the second resistor. The second end of the first resistor is grounded, and the second end of the second resistor is connected to the first end of the driving circuit and the first end of the signal amplification circuit. The first capacitor and the second resistor are used to form a high-pass filter to filter the first output voltage, obtain the high-frequency part of the first output voltage, and input the DC voltage component of the driving circuit and the high-frequency part of the first output voltage into the comparison module.

3. The PWM signal conditioning circuit according to claim 1, characterized in that, The comparison module includes: a comparator, a second capacitor, a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor; The positive input terminal of the comparator is connected to the second terminal of the filter module and the first terminal of the third resistor; the negative input terminal of the comparator is connected to the first terminal of the second capacitor, the first terminal of the fourth resistor, and the first terminal of the fifth resistor; and the output terminal of the comparator is connected to the second terminal of the third resistor, the first terminal of the sixth resistor, and the first terminal of the shaping module. The second terminal of the second capacitor is grounded, the second terminal of the fourth resistor is connected to an external power supply, the second terminal of the fifth resistor is grounded, and the second terminal of the sixth resistor is connected to an external power supply.

4. The PWM signal conditioning circuit according to claim 3, characterized in that, The fourth and fifth resistors are used to determine the preset voltage threshold. The comparator is used to compare the total voltage of the first output voltage and the DC voltage component with a preset voltage threshold. If the total voltage is greater than the preset voltage threshold, the duty cycle of the high-frequency part of the first output voltage is adjusted to be less than the preset duty cycle threshold, and the high-frequency part of the first output voltage is input to the shaping module. The comparator is also used to input the high-frequency portion of the first output voltage to the shaping module when the total voltage is less than or equal to the preset voltage threshold.

5. The PWM signal conditioning circuit according to claim 1, characterized in that, The shaping module includes: an inverter and a seventh resistor; The input terminal of the inverter is connected to the second terminal of the comparator module, the output terminal of the inverter is connected to the first terminal of the motor pre-drive chip circuit, the positive power supply terminal of the inverter is connected to the first terminal of the seventh resistor, the ground terminal of the inverter is grounded, and the second terminal of the seventh resistor is connected to an external power supply. The inverter is used to invert the high-frequency portion of the first output voltage to obtain the second output voltage, and the second output voltage is input to the drive circuit through the motor pre-drive chip circuit.

6. An overcurrent protection system, characterized in that, include: The PWM signal conditioning circuit, motor pre-drive chip circuit, signal amplification circuit, drive circuit, and microcontroller circuit according to any one of claims 1 to 5; The first terminal of the PWM signal conditioning circuit is connected to the first terminal of the microcontroller circuit, the second terminal of the PWM signal conditioning circuit is connected to the first terminal of the motor pre-drive chip circuit, and the third terminal of the PWM signal conditioning circuit is connected to the first terminal of the drive circuit and the first terminal of the signal amplification circuit. The drive circuit is used to control the drive motor in the drive circuit to not work based on the second output voltage, and to provide overcurrent protection for the drive motor. The electromagnetic torque generated by the output current corresponding to the second output voltage is less than the load torque of the drive motor, so that the drive motor in the drive circuit does not work.

7. The overcurrent protection system according to claim 6, characterized in that, The second terminal of the microcontroller circuit is connected to the second terminal of the motor pre-drive chip circuit. The third terminal of the microcontroller circuit is connected to the second terminal of the signal amplification circuit. The fourth terminal of the microcontroller circuit is connected to the third terminal of the signal amplification circuit. The fourth terminal of the signal amplification circuit is connected to the second terminal of the drive circuit. The second terminal of the drive circuit is grounded. The third terminal of the motor pre-drive chip circuit is connected to the third terminal of the drive circuit. The fourth terminal of the drive circuit is connected to an external power supply.

8. An overcurrent protection method, characterized in that, include: Obtain the first output voltage of the microcontroller circuit and the DC voltage component of the drive circuit, and determine the total voltage of the first output voltage and the DC voltage component; If the total voltage is determined to be greater than a preset voltage threshold, the duty cycle of the first output voltage in the total voltage is adjusted to be less than the preset duty cycle threshold to obtain the second output voltage of the PWM signal conditioning circuit; The second output voltage is input to the drive circuit through the motor pre-drive chip circuit to control the drive motor in the drive circuit to not work and to provide overcurrent protection for the drive motor. The electromagnetic torque generated by the output current corresponding to the second output voltage is less than the load torque of the drive motor, so that the drive motor in the drive circuit does not work.

9. The method according to claim 8, characterized in that, If the total voltage is determined to be greater than a preset voltage threshold, the duty cycle of the first output voltage in the total voltage is adjusted to be less than the preset duty cycle threshold to obtain the second output voltage of the PWM signal conditioning circuit, including: The total voltage is compared with the preset voltage threshold by a comparator in the PWM signal conditioning circuit; If it is determined that the total voltage is greater than a preset voltage threshold, then the duty cycle of the first output voltage in the total voltage is adjusted to be less than the preset duty cycle threshold. The adjusted first output voltage is reversed to obtain the second output voltage.

10. A vehicle, characterized in that, It includes a PWM signal conditioning circuit as described in any one of claims 1 to 5, or an overcurrent protection system as described in any one of claims 6 to 7.

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