Method and circuit structure for reducing electromagnetic emission of power line of automobile electric control system

Abstract

The invention discloses a method and circuit structure for reducing electromagnetic emission of a power line of an automobile electric control system, and relates to the technical field of electromagnetic compatibility, and the method comprises the steps: finding out a plurality of actuators causing voltage fluctuation on the power line from the automobile electric control system, and taking the actuators as electromagnetic loads of the system; the selected electromagnetic loads are divided into two groups which are respectively controlled by a high-side driving circuit and a low-side driving circuit; and a power line voltage acquisition and control compensation circuit is designed and is used for acquiring a power line voltage signal in real time and outputting a corresponding driving control signal according to the change condition of the signal so as to control the on-off of the high-side driving circuit and the low-side driving circuit. The circuit can realize closed-loop control of a high-side driving circuit and a low-side driving circuit under the condition that the load function is not influenced, two groups of electromagnetic loads are switched to work, the influence of the two groups of electromagnetic loads on the voltage of a power line is neutralized, the voltage fluctuation of the power line can be reduced, and the electromagnetic emission interference of the power line is reduced by maintaining the stable voltage.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electromagnetic compatibility, and in particular to a method and circuit structure for reducing electromagnetic emission of a power line of an automobile electronic control system. BACKGROUND

[0002] With the rapid development of automobile intelligence and electrification, the number of electronic control type electronic products carried by automobiles is increasing day by day, and the integration of various vehicle-mounted electronic control systems (such as power electronic control, vehicle body electronic control, safety electronic control system, etc.) continues to improve, making the vehicle-mounted electromagnetic environment more and more complex. When different electronic control devices are running, electromagnetic emission will be generated through power lines, signal lines, etc., and the sensitivity of various devices to external electromagnetic interference also differs. Electromagnetic interference not only causes signal distortion, control logic disorder, etc. of the electronic control system, but also may affect the safety and reliability of the vehicle operation, so the industry has put forward more and more stringent design requirements for the electromagnetic compatibility performance of the automobile electronic control system. Among them, the suppression of power line conducted emission is a key link in electromagnetic compatibility design: as the energy transmission carrier of the vehicle-mounted electronic control system, the power line is prone to generate interference signals such as surge voltage and peak pulse voltage, which will radiate electromagnetic energy through conduction, thereby causing electromagnetic compatibility problems.

[0003] For the electromagnetic compatibility problem of the automobile electronic control system, various conventional solutions have been formed in the prior art, the core of which includes filter circuit design, system grounding optimization, etc. For example, related patents of diesel engine electronic control system power line conducted emission suppression circuit, the core technical idea of such patents is focused on filter design, which builds a special filter circuit to filter out the surge voltage and peak pulse voltage transmitted on the power line, so as to reduce the electromagnetic emission intensity of the power line and achieve the power line conducted emission index.

[0004] However, the existing technical solutions have obvious technical limitations: the existing power line emission suppression means only governs the propagation path of electromagnetic interference, and does not optimize and improve from the source level of electromagnetic emission. The reason is that the source of electromagnetic emission is strongly related to the core execution function of the electronic control system, and the existing technology generally believes that optimizing such emission source will change the core control logic and power output characteristics of the electronic control system, thereby affecting the original execution function and working stability of the electronic control system. Therefore, the existing filtering scheme cannot meet the long-term development needs of high-integration automobile electronic control systems. SUMMARY

[0005] The present application relates to the technical field of electromagnetic compatibility, and in particular to a method and circuit structure for reducing electromagnetic emission of a power line of an automobile electronic control system. A method for reducing electromagnetic emission of a power line of an automobile electronic control system, the method comprising the following steps: Find several actuators from the automobile electric control system which cause voltage fluctuation on the power line as electromagnetic load of the system; Divide the selected electromagnetic load into two groups, and control them by high-side drive circuit and low-side drive circuit respectively; Design power line voltage acquisition and control compensation circuit, which is used to acquire power line voltage signal in real time, and output corresponding drive control signal according to the change of the signal, to control the on-off of high-side drive circuit and low-side drive circuit, so as to switch the work of two groups of electromagnetic load and realize the compensation of power line voltage fluctuation.

[0006] The further technical scheme is to divide the selected electromagnetic load into two groups, including: Obtain the electrical parameters and working parameters of each electromagnetic load, and calculate the characteristic parameters of each electromagnetic load according to these parameters ; According to the characteristic parameters of each electromagnetic load, divide the selected electromagnetic load into two groups, and the grouping basis is that the sum of the two groups The value is equal or basically equal. Among them, The value is used to measure the influence degree of electromagnetic load on power line voltage.

[0007] The further technical scheme is to define the characteristic parameter as:

[0008] Among them, In turn, the working frequency, equivalent inductance and working current of the i-th electromagnetic load.

[0009] The further technical scheme is to output corresponding drive control signal according to the change of the signal, to control the on-off of high-side drive circuit and low-side drive circuit, including: Generate corresponding PWM signal according to the change of power line voltage signal in a certain sampling period, and convert it into smooth upper limit threshold and lower limit threshold of power line voltage; Compare the upper limit threshold and lower limit threshold of power line voltage with the real-time acquired power line voltage signal, and output corresponding level change signal; Generate corresponding drive control signal according to the level change signal, which is used to realize the conduction of high-side drive circuit and the shutdown of low-side drive circuit when it is effective drive control signal; and is used to realize the shutdown of high-side drive circuit and the conduction of low-side drive circuit when it is invalid drive control signal.

[0010] The further technical scheme is to generate corresponding PWM signal according to the change of power line voltage signal in a certain sampling period, including: According to the real-time collected power line voltage signal, the power line voltage average value in a certain sampling period is calculated , combined with the allowed power line target fluctuation voltage , the upper and lower limit values of the power line voltage fluctuation range are calculated, respectively represented as: , ; According to the upper and lower limit values of the power line voltage fluctuation range, the duty cycles of the high-side drive circuit and the low-side drive circuit under a certain frequency are calculated to output corresponding high-side PWM signals and low-side PWM signals.

[0011] Further, the inductive components inside the actuators that cause voltage fluctuations on the power line.

[0012] In a second aspect, the application also provides a power line voltage acquisition and control compensation circuit structure for an automobile electric control system, comprising: A power line voltage acquisition circuit for real-time acquisition of voltage signals on the power line of the automobile electric control system; A power line voltage threshold reference circuit for converting the PWM signals output by the MCU into smooth upper and lower threshold values of the power line voltage; A voltage comparison circuit for comparing the real-time voltage signals output by the power line voltage acquisition circuit with the upper and lower threshold values of the power line voltage generated by the power line voltage threshold reference circuit and outputting corresponding level change signals; An MCU for generating corresponding PWM signals according to the change of the real-time voltage signals output by the power line voltage acquisition circuit; and for generating corresponding drive control signals according to the level change signals output by the voltage comparison circuit to control the on-off of the high-side drive circuit and the low-side drive circuit. The high-side drive circuit and the low-side drive circuit are used to control the electromagnetic loads in the automobile electric control system, which are divided into two groups in advance, so that the two groups of electromagnetic loads switch work to realize compensation for the power line voltage fluctuation.

[0013] Further, the power line voltage threshold reference circuit includes two circuits with the same structure for outputting the upper and lower threshold values of the power line voltage, respectively, and each circuit includes two-stage RC filter circuits and a voltage follower circuit, wherein: The input end of the RC filter circuit is connected to the corresponding PWM signal, and the output end is connected to the non-inverting input end of the voltage follower circuit, for processing the PWM signal into a smooth waveform; After filtering, the output end of the voltage follower circuit obtains the upper or lower threshold value of the power line voltage proportional to the PWM duty cycle and transmits it to the input of the voltage comparison circuit.

[0014] Further technical solutions are that the MCU generates corresponding PWM signals according to the change of the real-time voltage signal output by the power line voltage acquisition circuit, including: The power line voltage average value in a certain sampling period is calculated according to the real-time voltage signal output by the power line voltage acquisition circuit , combined with the allowed power line target fluctuation voltage The upper and lower limit values of the power line voltage fluctuation range are calculated, respectively represented as: , ; According to the upper and lower limit values of the power line voltage fluctuation range, the duty cycles of the high-side drive circuit and the low-side drive circuit at a certain frequency are calculated to output corresponding high-side PWM signals and low-side PWM signals.

[0015] Further technical solutions are that the MCU generates corresponding driving control signals according to the level change signal output by the voltage comparison circuit to control the on-off of the high-side drive circuit and the low-side drive circuit, including: When the real-time voltage signal is higher than the upper limit threshold of the power line voltage, the voltage comparison circuit outputs a valid level signal to the MCU, and the MCU outputs a valid driving control signal to realize the conduction of the high-side drive circuit and the turn-off of the low-side drive circuit; When the real-time voltage signal is lower than the lower limit threshold of the power line voltage, the voltage comparison circuit outputs an invalid level signal to the MCU, and the MCU outputs an invalid driving control signal to realize the turn-off of the high-side drive circuit and the conduction of the low-side drive circuit.

[0016] The beneficial technical effects of the application are: The method proposed in the application can reduce the power line electromagnetic emission interference from the electromagnetic emission source, i.e., the actuators in the automobile electronic control system that can cause voltage fluctuation on the power line. By designing a power line voltage acquisition and control compensation circuit, the circuit can acquire the voltage fluctuation of the power line in real time and output corresponding driving control signals to control electromagnetic loads of different driving forms. Without affecting the function of the load, closed-loop control of the high-low side drive circuit can be realized. When an electromagnetic load of a certain driving form has a great impact on the power line voltage, it can be switched to another driving form in time, so that the impact of the two groups of electromagnetic loads is "neutralized", the power line voltage fluctuation is reduced, and the power line electromagnetic emission interference is reduced by maintaining stable voltage. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a basic structure schematic diagram of the automobile electronic control system proposed in the application; Figure 2are schematic diagrams of electromagnetic valve driving circuit proposed in the present application, wherein (a) is a schematic diagram of high-side driving circuit structure, and (b) is a schematic diagram of low-side driving circuit structure; Figure 3 are schematic diagrams of power line voltage variation when electromagnetic valves of different driving forms work, wherein (a) corresponds to high-side driving form, and (b) corresponds to low-side driving form; Figure 4 is a flowchart of a method for reducing electromagnetic emission of a power line of an automobile electric control system proposed in the present application; Figure 5 is a schematic diagram of a power line voltage acquisition and control compensation circuit structure proposed in the present application; Figure 6 is a power line voltage threshold reference circuit diagram proposed in the present application. DETAILED DESCRIPTION

[0018] The specific embodiments of the present application will be further described in combination with the accompanying drawings.

[0019] The electromagnetic compatibility propagation process generally includes three parts, which are an interference source, a propagation path and a disturbed object. For the automobile electric control system proposed in the present application, the power line of the system is considered as the interference source, the other controllers connected with the system are considered as the disturbed objects, and the method proposed in the present application mainly solves the problems in the background technology from the interference source. Since the principle of electromagnetic emission is rapid voltage / current variation, the energy is propagated to the space in the form of electromagnetic waves. If the voltage / current variation rate or the variation amplitude is reduced, the generated electromagnetic energy is also reduced accordingly, so as to achieve the purpose of electromagnetic emission suppression. Therefore, the present application considers reducing the voltage / current variation to achieve the suppression of the electromagnetic emission of the power line.

[0020] The basic structure of the automobile electric control system is shown in Figure 1 The system includes an electronic control unit ECU, which collects external sensor signals (such as vehicle motor temperature, tire pressure and speed, etc.), exchanges information with other controllers by using CAN communication, etc., finally forms a strategy in the electric control unit through MCU calculation, and finally outputs control commands to control external execution mechanisms such as vehicle lamps, relays, electromagnetic valves, etc. The main source of the power line current variation in the above function implementation is the electromagnetic valve. The driving of the electromagnetic valve is a main source of electromagnetic emission, so the present application further considers reducing the electromagnetic emission from optimizing the driving of the electromagnetic valve.

[0021] The working principle of the electromagnetic valve is that there is a coil inside the electromagnetic valve, the coil generates magnetic force when electrified, the magnetic force drives the electromagnetic valve core to move, and the electromagnetic valve opening control is realized by controlling the movement amplitude of the valve core. The magnetic force is controlled by the current, and the current is realized by the electromagnetic valve driving circuit. For example,Figure 2 As shown, the present application provides two different driving forms of electromagnetic valve driving circuit, which can realize the control of electromagnetic valve: wherein Figure 2 - (a) is a high-side drive schematic diagram, ECU controls MOS tube conduction, power supply accesses electromagnetic valve high side, forming a loop of "power supply→MOS tube→electromagnetic valve→ground", and the electromagnetic valve works; Figure 2 - (b) is a low-side drive schematic diagram, ECU controls MOS tube conduction, electromagnetic valve low side is grounded, forming a loop of "power supply→electromagnetic valve→MOS tube→ground", and the electromagnetic valve works.

[0022] In combination Figure 3 As shown, further analysis of the influence of high-side drive and low-side drive on the voltage change of power supply line. When the electromagnetic valve is controlled by high-side drive, from Figure 3 - (a), it can be seen that the high-side drive MOS conduction moment corresponds to the t1 time period, the current charges the electromagnetic valve coil from the power supply line through the high-side MOS, at this time the power supply line appears a voltage drop. When the high-side MOS is turned off, the electromagnetic valve charging process ends, the power supply line voltage rises, corresponding to the t2 time period. The electromagnetic valve needs to control the on-off of MOS to control the electromagnetic valve coil current, and finally the power supply line appears a triangular waveform voltage drop as shown in the figure. Due to the continuous change of power supply line voltage, electromagnetic energy conversion occurs, resulting in electromagnetic emission to the outside. Similarly, when the electromagnetic valve is controlled by low-side drive, from Figure 3 - (b), it can be seen that the low-side drive MOS is turned off, corresponding to the t2 time period, because the electromagnetic valve internal electrical structure is a coil, which is equivalent to inductance, and the electric energy can store energy. When the MOS is turned off, the energy inside the electromagnetic valve charges the controller power supply through the freewheeling diode, so the power supply voltage rises. When the low-side drive MOS is turned on, the electromagnetic valve current flows to the ground through the MOS, and the charging process through the diode ends, the power supply voltage falls, corresponding to the t1 time period.

[0023] Through the analysis of the working characteristics of high-side drive electromagnetic valve and low-side drive electromagnetic valve, it can be found that different electromagnetic valve control modes have different influences on the power supply voltage. If the influence of high-side and low-side drive electromagnetic valves on the power supply line can be neutralized, the power supply line voltage fluctuation will be greatly reduced, and the electromagnetic emission of the power supply line to the outside will also be reduced.

[0024] The present application is based on the above-mentioned discovery, in one embodiment, a method for reducing the electromagnetic emission of the power line of the automobile electric control system is proposed, the core of the method is to re-design the driving form of the automobile electric control system, and to distribute the electromagnetic load, so that the voltage fluctuation on the power line is offset when the electromagnetic valve is working. At the same time, a power line voltage acquisition and control compensation circuit structure for the automobile electric control system is designed, which is used for monitoring and compensating the power line voltage, and calibrating the control of high and low side driving. Finally, the power line voltage fluctuation is reduced, and the purpose of suppressing the electromagnetic emission of the power line is achieved. As shown in Figure 4 The method comprises the following steps: Step 1: Analysis of automobile electric control system actuators.

[0025] This step mainly analyzes the external actuators of the automobile electric control system, and finds out several actuators that have an impact on the power line current, such as the voltage fluctuation on the power line. In this embodiment, the actuators with inductance components inside are taken as the electromagnetic load of the system, and the typical representative is the electromagnetic valve.

[0026] Step 2: Automobile electric control system electromagnetic load distribution.

[0027] This step mainly divides the electromagnetic load selected in the previous step into two groups, and controls them by using high side driving circuit and low side driving circuit respectively. The division method includes: (1) Electromagnetic load parameter test: test the electrical parameters and working parameters of each electromagnetic load, including load resistance , equivalent inductance , working current , working frequency .

[0028] (2) Electromagnetic load characteristic parameter calculation: according to the test results of each load parameter, the characteristic parameter of each electromagnetic load is calculated according to the following formula In this embodiment, The value is used to measure the influence of the electromagnetic load on the power line voltage, which can be expressed as:

[0029] (3) Electromagnetic load distribution: according to the characteristic parameters of each electromagnetic load, the selected electromagnetic load is divided into two groups, and the grouping basis is that the sum of the two groups The value is equal or basically equal. One of the two groups of electromagnetic loads uses high side driving control, and the other group uses low side driving control.

[0030] Among them, the realization principle of high side driving circuit and low side driving circuit can refer to Figure 2The structure diagram is shown. In high-side driving, the MOS tube is responsible for controlling the "power end" of the electromagnetic load, and a P-channel MOS tube is selected in this embodiment. When the ECU outputs a low-level signal (such as ground) to the gate (G) of the P-channel MOS tube, the P-channel MOS tube is turned on. In low-side driving, the MOS tube is responsible for controlling the "ground end" of the electromagnetic load, and an N-channel MOS tube is selected in this embodiment. When the ECU outputs a high-level signal to the gate (G) of the N-channel MOS tube, the N-channel MOS tube is turned on. The high-level signal is defined as an invalid signal, and the low-level signal is defined as a valid signal, and the definitions are used in subsequent descriptions.

[0031] Step 3: Design a power line voltage acquisition and control compensation circuit.

[0032] After grouping the loads according to the Q value, there may be certain deviations in the actual execution process. To compensate for this deviation, a compensation circuit as shown in Figure 5 is designed. The circuit is used to acquire the power line voltage signal in real time, and outputs corresponding driving control signals according to the change of the signal, respectively controls the on-off of the high-side driving circuit and the low-side driving circuit, makes the two groups of electromagnetic loads switch work, realizes the compensation of the power line voltage fluctuation, and maintains the stability of the power line voltage.

[0033] Among them, the corresponding driving control signals are output according to the change of the signal to control the on-off of the high-side driving circuit and the low-side driving circuit, specifically including: (1) According to the change of the power line voltage signal in a certain sampling period, a corresponding PWM signal is generated, and is converted into a smooth upper limit threshold and a lower limit threshold of the power line voltage. Specifically, according to the real-time acquired power line voltage signal, the average value of the power line voltage in a certain sampling period is calculated , and the upper and lower limit values of the power line voltage fluctuation range are calculated in combination with the allowed target fluctuation voltage of the power line , which are respectively represented as: , . Then, according to the upper and lower limit values of the power line voltage fluctuation range, the duty cycles of the high-side driving circuit and the low-side driving circuit at a certain frequency (such as 30 kHz, which can be adjusted according to the actual circuit filtering parameters) are calculated, and then the corresponding high-side PWM signal and low-side PWM signal are output by the single-chip microcomputer.

[0034] In this embodiment, the duty cycles of the high-side and low-side driving circuits are set to , and the highest voltage output by the single-chip microcomputer port is , so the required duty cycle is calculated according to the following formula: ,

[0035] (2) The upper and lower threshold values of the power line voltage are compared with the real-time collected power line voltage signal, and the corresponding level change signal is output. When the real-time voltage signal is higher than the upper threshold value of the power line voltage, the valid level signal is output; when the real-time voltage signal is lower than the lower threshold value of the power line voltage, the invalid level signal is output.

[0036] (3) The corresponding driving control signal is generated according to the level change signal: when the level change signal is a valid level signal, the single-chip microcomputer generates a valid driving control signal correspondingly, which is used to realize the conduction of the high-side drive circuit and the shutdown of the low-side drive circuit; when the level change signal is an invalid level signal, the single-chip microcomputer generates an invalid driving control signal correspondingly, which is used to realize the shutdown of the high-side drive circuit and the conduction of the low-side drive circuit. Thus, the compensation and correction of the power line voltage are realized.

[0037] Based on the same inventive concept, one embodiment of the present application also provides a power line voltage collection and control compensation circuit structure for an automobile electric control system, which has a circuit structure as shown in Figure 5 The power line voltage collection and control compensation circuit structure for the automobile electric control system includes a power line voltage collection circuit, a power line voltage threshold reference circuit, a voltage comparison circuit, and a single-chip microcomputer (MCU). The power line voltage collection circuit is used to collect the voltage signal on the power line of the automobile electric control system in real time, and one path is transmitted to the MCU, which is used to generate the corresponding PWM signal according to the change of the real-time voltage signal; and the other path is transmitted to the voltage comparison circuit. The power line voltage threshold reference circuit is used to convert the PWM signal output by the MCU into smooth upper and lower threshold values of the power line voltage. The voltage comparison circuit is used to compare the real-time voltage signal output by the power line voltage collection circuit with the upper and lower threshold values of the power line voltage generated by the power line voltage threshold reference circuit, and output the corresponding level change signal. Finally, the MCU generates the corresponding driving control signal according to the level change signal output by the voltage comparison circuit, so as to control the on-off of the high-side drive circuit and the low-side drive circuit. The high-side drive circuit and the low-side drive circuit in the embodiment are used to control the electromagnetic loads in the automobile electric control system, which are divided into two groups in advance, so that the two groups of electromagnetic loads are switched to work, and the compensation of the power line voltage fluctuation is realized.

[0038] In the embodiment, the power line voltage threshold reference circuit includes two circuits with the same structure, which are used to output the upper and lower threshold values of the power line voltage respectively, and each circuit includes two-stage RC filter circuit and voltage follower circuit, as shown in Figure 6The input end of the RC filter circuit is connected to the corresponding PWM signal, and the output end is connected to the non-inverting input end of the voltage follower circuit, which is used to process the PWM signal into a smooth waveform with an amplitude fluctuation of no more than 5 mV. After filtering, the output end of the voltage follower circuit obtains a power line voltage upper threshold or lower threshold proportional to the PWM duty cycle and transmits it to the input of the voltage comparison circuit. The voltage follower circuit can improve the stability of the voltage threshold. In order to ensure the accuracy of the voltage threshold, the output signal of the voltage follower circuit is also collected and transmitted to the MCU, which can be calibrated after internal analog-to-digital conversion to generate a PWM signal.

[0039] Optionally, the power line voltage acquisition circuit includes a voltage dividing circuit and a filter circuit. Their specific circuit structure with the voltage comparison circuit can refer to the existing circuit connection mode that can achieve the same function, which will not be described here.

[0040] In one possible implementation, the MCU generates a corresponding PWM signal according to the change of the real-time voltage signal output by the power line voltage acquisition circuit, specifically including: calculating the average value of the power line voltage in a certain sampling period according to the real-time voltage signal output by the power line voltage acquisition circuit , combining the allowed power line target voltage fluctuation to calculate the upper and lower limit values of the power line voltage fluctuation range, respectively represented as: , . Then, according to the upper and lower limit values of the power line voltage fluctuation range, the duty cycles of the high-side drive circuit and the low-side drive circuit at a certain frequency (such as 30 kHz, which can be adjusted according to the actual circuit filtering parameters) are calculated, and then the corresponding high-side PWM signal and low-side PWM signal are output by the MCU.

[0041] In one possible implementation, the MCU generates a corresponding drive control signal according to the level change signal output by the voltage comparison circuit to control the on-off of the high-side drive circuit and the low-side drive circuit, specifically including: when the real-time voltage signal is higher than the upper limit threshold of the power line voltage, the voltage comparison circuit outputs an effective level signal to the MCU, and the MCU outputs an effective drive control signal to realize the conduction of the high-side drive circuit and the turn-off of the low-side drive circuit. When the real-time voltage signal is lower than the lower limit threshold of the power line voltage, the voltage comparison circuit outputs an ineffective level signal to the MCU, and the MCU outputs an ineffective drive control signal to realize the turn-off of the high-side drive circuit and the conduction of the low-side drive circuit. Thus, the compensation and correction of the power line voltage are realized.

[0042] The above merely describes the preferred embodiments of the present application, and the present application is not limited to the above embodiments. It can be understood that other improvements and changes directly derived or thought by those skilled in the art without departing from the spirit and concept of the present application shall be considered to be within the protection scope of the present application.

Claims

1. A method for reducing electromagnetic emissions from the power lines of an automotive electronic control system, characterized in that, The method includes: Identify several actuators in the automotive electronic control system that cause voltage fluctuations on the power line, and use them as the electromagnetic load of the system. The selected electromagnetic loads are divided into two groups, and controlled by high-side drive circuits and low-side drive circuits respectively. Design a power line voltage acquisition and control compensation circuit to acquire power line voltage signals in real time and output corresponding drive control signals according to the changes in the signals, so as to control the on / off of the high-side drive circuit and the low-side drive circuit, so that the two sets of electromagnetic loads switch to work and realize the compensation for power line voltage fluctuations.

2. The method for reducing electromagnetic emissions from the power lines of an automotive electronic control system according to claim 1, characterized in that, The process of dividing the selected electromagnetic load into two groups includes: Obtain the electrical and operating parameters of each electromagnetic load, and calculate the characteristic parameters of each electromagnetic load based on these parameters. ; Based on the characteristic parameters of each electromagnetic load, the selected electromagnetic loads are divided into two groups, and the grouping is based on the two groups. The sum of their values ​​is equal or nearly equal; in, The value is used to measure the degree of influence of the electromagnetic load on the power line voltage.

3. The method for reducing electromagnetic emissions from the power lines of an automotive electronic control system according to claim 2, characterized in that, The feature parameters are defined as follows: in, The values ​​are, in order, the operating frequency, equivalent inductance, and operating current of the i-th electromagnetic load.

4. The method for reducing electromagnetic emissions from the power lines of an automotive electronic control system according to claim 1, characterized in that, The step of outputting a corresponding drive control signal based on the changes in the signal to control the on / off state of the high-side drive circuit and the low-side drive circuit includes: The corresponding PWM signal is generated based on the changes in the power line voltage signal within a certain sampling period, and then converted into a smooth upper and lower threshold of the power line voltage. The upper and lower threshold values ​​of the power line voltage are compared with the real-time acquired power line voltage signal, and the corresponding level change signal is output. A corresponding drive control signal is generated based on the level change signal. When it is a valid drive control signal, it is used to turn on the high-side drive circuit and turn off the low-side drive circuit. When it is an invalid drive control signal, it is used to turn off the high-side drive circuit and turn on the low-side drive circuit.

5. The method for reducing electromagnetic emissions from the power lines of an automotive electronic control system according to claim 4, characterized in that, The step of generating a corresponding PWM signal based on the changes in the power line voltage signal within a certain sampling period includes: The average power line voltage during a certain sampling period is calculated based on the real-time acquired power line voltage signal. Combined with the allowable target fluctuation voltage of the power line The upper and lower limits of the power line voltage fluctuation range are calculated and expressed as follows: , ; Based on the upper and lower limits of the power line voltage fluctuation range, the duty cycle of the high-side drive circuit and the low-side drive circuit at a certain frequency is calculated to output the corresponding high-side PWM signal and low-side PWM signal.

6. The method for reducing electromagnetic emissions from the power lines of an automotive electronic control system according to claim 1, characterized in that, The actuators that cause voltage fluctuations on the power line contain inductive components.

7. A power line voltage acquisition and control compensation circuit structure for an automotive electronic control system, characterized in that, include: Power line voltage acquisition circuit, used to acquire voltage signals on the power line of the automotive electronic control system in real time; The power line voltage threshold reference circuit is used to convert the PWM signal output by the MCU into a smooth upper and lower threshold of the power line voltage. A voltage comparison circuit is used to compare the real-time voltage signal output by the power line voltage acquisition circuit with the upper and lower limit thresholds of the power line voltage generated by the power line voltage threshold reference circuit, and output the corresponding level change signal. The MCU is used to generate a corresponding PWM signal based on the changes in the real-time voltage signal output by the power line voltage acquisition circuit; it is also used to generate a corresponding drive control signal based on the level change signal output by the voltage comparison circuit, so as to control the on / off state of the high-side drive circuit and the low-side drive circuit. The high-side drive circuit and the low-side drive circuit are used to control the electromagnetic loads pre-divided into two groups in the automotive electronic control system, so that the two groups of electromagnetic loads switch to work and realize compensation for power line voltage fluctuations.

8. The circuit structure according to claim 7, characterized in that, The power line voltage threshold reference circuit comprises two identical circuits for outputting the upper and lower threshold values ​​of the power line voltage, respectively. Each circuit includes a two-stage RC filter circuit and a voltage follower circuit, wherein: The input terminal of the RC filter circuit is connected to the corresponding PWM signal, and the output terminal is connected to the non-inverting input terminal of the voltage follower circuit, which is used to process the PWM signal into a smooth waveform. After filtering, the output of the voltage follower circuit obtains the upper or lower threshold of the power line voltage, which is proportional to the PWM duty cycle, and transmits it to the input of the voltage comparison circuit.

9. The circuit structure according to claim 7, characterized in that, The MCU generates a corresponding PWM signal based on the changes in the real-time voltage signal output by the power line voltage acquisition circuit, including: The average power line voltage during a certain sampling period is calculated based on the real-time voltage signal output by the power line voltage acquisition circuit. Combined with the allowable target fluctuation voltage of the power line The upper and lower limits of the power line voltage fluctuation range are calculated and expressed as follows: , ; Based on the upper and lower limits of the power line voltage fluctuation range, the duty cycle of the high-side drive circuit and the low-side drive circuit at a certain frequency is calculated to output the corresponding high-side PWM signal and low-side PWM signal.

10. The circuit structure according to claim 7, characterized in that, The MCU generates corresponding drive control signals based on the level change signals output by the voltage comparison circuit to control the on / off state of the high-side drive circuit and the low-side drive circuit, including: When the real-time voltage signal is higher than the upper limit threshold of the power line voltage, the voltage comparison circuit outputs a valid level signal to the MCU, and the MCU outputs a valid drive control signal to enable the high-side drive circuit to be turned on and the low-side drive circuit to be turned off. When the real-time voltage signal is lower than the lower limit threshold of the power supply line voltage, the voltage comparison circuit outputs an invalid level signal to the MCU, and the MCU outputs an invalid drive control signal to realize the high-side drive circuit being turned off and the low-side drive circuit being turned on.

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