WO2022222711A1 - Electric motor controller safety state switching circuit and apparatus, and control method - Google Patents

Abstract

An electric motor controller safety state switching circuit, comprising: a waveform conversion circuit (100), which receives an initial waveform frequency signal outputted by an electric motor, and converts the initial waveform frequency signal into a square wave frequency signal; a frequency voltage conversion circuit (200), which converts the square wave frequency signal into a current state voltage signal which is capable of driving a bridge arm of an electric motor controller; a determination circuit (300), which determines a safety state according to the current state voltage signal, and generates a corresponding enabling electrical signal according to the determination result; and a drive circuit (400), which according to the enabling electric signal, controls the turning on and off of the bridge arm of the electric motor controller so as to perform safety state switching. Also disclosed are an electric motor controller safety state switching apparatus and a control method for the electric motor controller safety state switching circuit.

Description

Motor controller safe state switching circuit, device and control method

This application claims the priority of the Chinese patent application with application number 202110427170.8 filed on April 21, 2021, the entire contents of which are incorporated herein by reference.

technical field

The present application relates to the technical field of electric vehicles, and in particular, to a safety state switching circuit, device and control method of a motor controller.

Background technique

At present, the drive motor controller basically adopts an independent low-voltage MCU (Microcontroller Unit, microcontroller unit) or a combination of low-voltage MCU and high-voltage MCU to perform the safe state switching function. Among them, when the independent low-voltage MCU fails, the function of obtaining the vehicle speed in real time fails, and the motor controller cannot perform safe shutdown mode switching according to the vehicle speed; when the combination of the low-voltage MCU and the high-voltage MCU fails due to a common cause (for example: a vehicle collision occurs , resulting in abnormal power supply of low-voltage MCU and high-voltage MCU), similarly, the function of obtaining vehicle speed in real time is invalid, and the motor controller cannot perform safe shutdown mode switching according to vehicle speed. And the cost of dual MCU solution is high, which is not suitable for low-cost products.

When a fault such as MCU failure occurs in the motor controller during vehicle driving, the existing technology relies on the vehicle speed obtained before the MCU fails to execute the corresponding safe state. Due to the failure of the MUC, the function of obtaining the vehicle speed in real time is invalid, and the real-time vehicle speed cannot be obtained according to the real-time vehicle speed. Therefore, the vehicle cannot enter the correct safe state, and the vehicle torque safety target will be violated.

The above content is only used to assist the understanding of the technical solutions of the present application, and does not mean that the above content is the prior art.

technical problem

The main purpose of the present application is to provide a motor controller safe state switching circuit, device and control method, aiming to solve the technical problem that the vehicle cannot effectively switch the safe state when the MCU fails in the prior art.

technical solutions

In order to achieve the above purpose, the present application provides a motor controller safe state switching circuit, the circuit includes: a waveform conversion circuit, a frequency-voltage conversion circuit, a judgment circuit and a drive circuit;

The input terminal of the waveform conversion circuit is connected to the motor frequency detection unit, the output terminal of the waveform conversion circuit is connected to the input terminal of the frequency-voltage conversion circuit, and the output terminal of the frequency-voltage conversion circuit is connected to the input terminal of the judgment circuit. the input end is connected, the output end of the judgment circuit is connected with the input end of the drive circuit, and the output end of the drive circuit is connected with the bridge arm of the motor controller;

The waveform conversion circuit is configured to receive the initial waveform frequency signal output by the motor, convert the initial waveform frequency signal into a square wave frequency signal, and output the square wave frequency signal to the frequency-voltage conversion circuit;

The frequency-voltage conversion circuit is configured to convert the square-wave frequency signal into a current state voltage signal capable of driving the bridge arm of the motor controller, and output the current state voltage signal to the judgment circuit;

The judging circuit is configured to judge the safety state according to the current state voltage signal, generate a corresponding enabling electrical signal according to the judging result, and output the enabling electrical signal to the driving circuit;

The driving circuit is configured to control the on-off of the bridge arm of the motor controller according to the enabling electrical signal to perform safe state switching.

In one embodiment, the waveform conversion circuit includes a filter unit, a first voltage limiting unit, a first comparator and a first power supply unit;

The input end of the filtering unit is connected to the motor frequency detection unit, the output end of the filtering unit is connected to the inverting input end of the first comparator, and the first end of the first voltage limiting unit is connected to the first reference the voltage terminal is connected, the first voltage limiting unit is also connected to the non-inverting input terminal and the output terminal of the first comparator, and the output terminal of the first comparator is connected to the output terminal of the first power supply unit;

the first power supply unit, configured to input a power supply voltage for the waveform conversion circuit;

The filtering unit is configured to receive the initial waveform frequency signal output by the motor, filter the initial waveform frequency signal, and output the filtered initial waveform frequency signal to the first comparator;

The first comparator is configured to receive a first reference voltage input from the first voltage limiting unit, and generate a square wave frequency signal according to the first reference voltage and the filtered initial waveform frequency signal.

In one embodiment, the filter unit includes a first resistor and a first capacitor, the first voltage limiting unit includes a second resistor and a third resistor, and the first power supply unit includes a fourth resistor; wherein,

The first end of the first resistor is connected to the motor frequency detection unit, the second end of the first resistor and the first end of the first capacitor are connected to the inverting input end of the first comparator, so the second end of the first capacitor is grounded;

The first end of the second resistor is connected to the first reference voltage end, the second end of the second resistor and the first end of the third resistor are connected to the non-inverting input end of the first comparator , the second end of the third resistor is connected to the output end of the first comparator;

The first end of the fourth resistor is connected to the power supply end, and the second end of the fourth resistor and the output end of the first comparator are connected to the input end of the frequency-voltage conversion circuit.

In one embodiment, the frequency-to-voltage conversion circuit includes a first charge and discharge unit and a second charge and discharge unit;

The input terminal of the first charging and discharging unit is connected to the output terminal of the waveform conversion circuit, the input terminal of the second charging and discharging unit is connected to the output terminal of the first charging and discharging unit, and the second charging and discharging unit is connected to the output terminal of the first charging and discharging unit. The output end of the charging and discharging unit is connected with the input end of the judgment circuit;

The first charging and discharging unit and the second charging and discharging unit are configured to perform charging and discharging according to a square wave frequency signal, and generate a current state voltage signal.

In one embodiment, the first charge and discharge unit includes a second capacitor, a first diode and a second diode; the second charge and discharge unit includes a third capacitor and a fifth resistor; wherein,

The first end of the second capacitor is connected to the output end of the waveform conversion circuit, and the second end of the second capacitor, the anode of the first diode and the cathode of the second diode are connected;

The first end of the third capacitor and the cathode of the first diode are connected to the first end of the fifth resistor, and the first end of the third capacitor is also connected to the input end of the judgment circuit , the second end of the fifth resistor and the second end of the third capacitor are connected to the anode of the second diode and grounded.

In one embodiment, the judgment circuit includes: a second voltage limiting unit, a second comparator, and a second power supply unit;

The output terminal of the frequency-voltage conversion circuit is connected to the inverting input terminal of the second comparator, the first terminal of the second voltage limiting unit is connected to the second reference voltage terminal, and the second voltage limiting unit is connected to the second reference voltage terminal. The unit is also connected to the non-inverting input terminal and the output terminal of the second comparator, and the output terminal of the second comparator is connected to the output terminal of the second power supply unit;

the second power supply unit, configured to input a power supply voltage for the judgment circuit;

The second comparator is configured to receive the second reference voltage input by the second voltage limiting unit, and perform a safety state judgment according to the second reference voltage and the current state voltage signal, and generate a corresponding enable according to the judgment result an electrical signal, and outputting the enabling electrical signal to the driving circuit.

In one embodiment, the second voltage limiting unit includes a sixth resistor and a seventh resistor, and the second power supply unit includes an eighth resistor; wherein,

The first end of the sixth resistor is connected to the second reference voltage end, the second end of the sixth resistor and the first end of the seventh resistor are connected to the non-inverting input end of the second comparator , the second end of the seventh resistor is connected to the output end of the second comparator;

The first end of the eighth resistor is connected to the power supply end, and the second end of the eighth resistor and the output end of the second comparator are connected to the input end of the driving circuit.

In addition, in order to achieve the above object, the present application also proposes a device for switching the safety state of a motor controller, the device comprising: the above-mentioned safety state switching circuit of the motor controller.

In addition, in order to achieve the above purpose, the present application also proposes a control method of a motor controller safe state switching circuit, the control method is based on the above-mentioned motor controller safe state switching circuit; the method includes:

The waveform conversion circuit receives the initial waveform frequency signal output by the motor, converts the initial waveform frequency signal into a square wave frequency signal, and outputs the square wave frequency signal to the frequency-voltage conversion circuit;

The frequency-voltage conversion circuit converts the square-wave frequency signal into a current state voltage signal capable of driving the bridge arm of the motor controller, and outputs the current state voltage signal to the judgment circuit;

The judging circuit judges the safety state according to the current state voltage signal, generates a corresponding enabling electrical signal according to the judging result, and outputs the enabling electrical signal to the driving circuit;

The driving circuit controls the on-off of the bridge arm of the motor controller according to the enabling electrical signal to perform safe state switching.

beneficial effect

In the present application, a safety state switching circuit of a motor controller is provided, and the circuit includes: a waveform conversion circuit, a frequency-voltage conversion circuit, a judgment circuit and a driving circuit; the waveform conversion circuit is set to receive the initial waveform frequency signal output by the motor , convert the initial waveform frequency signal into a square wave frequency signal, and output the square wave frequency signal to the frequency-voltage conversion circuit; the frequency-voltage conversion circuit is configured to convert the square-wave frequency signal into Can carry out the current state voltage signal driven by the bridge arm of the motor controller, and output the current state voltage signal to the judgment circuit; the judgment circuit is set to judge the safety state according to the current state voltage signal, and according to the judgment As a result, a corresponding enabling electrical signal is generated, and the enabling electrical signal is output to the driving circuit; the driving circuit is configured to control the on-off of the bridge arm of the motor controller according to the enabling electrical signal to Perform a safe state switch. The application performs safe state switching according to the operating frequency of the motor, so that the motor controller enters the correct safe state, satisfies the torque safety target of the whole vehicle, and prevents the vehicle torque safety caused by the inability to switch the safe state when the MCU fails. Fault.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings that are used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained according to the structures shown in these drawings without creative efforts.

FIG. 1 is a structural block diagram of an embodiment of a safety state switching circuit of a motor controller of the present application;

FIG. 2 is a schematic diagram of a waveform conversion circuit of an embodiment of a safety state switching circuit of a motor controller of the present application;

3 is a schematic diagram of a frequency-to-voltage conversion circuit according to an embodiment of a safe state switching circuit of a motor controller of the present application;

4 is a schematic diagram of a judgment circuit of an embodiment of a safety state switching circuit of a motor controller of the present application;

FIG. 5 is a control logic diagram of a safety state mode switching of an embodiment of a safety state switching circuit of a motor controller of the present application;

FIG. 6 is a schematic flowchart of a first embodiment of a control method for a safe state switching circuit of a motor controller according to the present application.

Description of reference numbers:

label	name	label	name
100	Waveform conversion circuit	D1~D2	first to second diodes
200	Frequency voltage conversion circuit	R1~R8	The first to eighth resistors
300	Judgment circuit	C1~C3	first to third capacitors
400	Drive circuit	CP1~CP2	first comparator to second comparator
101	filter unit	GND	ground
102	first pressure limiting unit	202	The second charge and discharge unit
103	first power supply unit	301	The second pressure limiting unit
201	The first charge and discharge unit	302	second power supply unit

The realization, functional characteristics and advantages of the purpose of the present application will be further described with reference to the accompanying drawings in conjunction with the embodiments.

Embodiments of the present invention

It should be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application.

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relationship between various components under a certain posture (as shown in the accompanying drawings). The relative positional relationship, the movement situation, etc., if the specific posture changes, the directional indication also changes accordingly.

In addition, descriptions involving "first", "second", etc. in this application are only for descriptive purposes, and should not be construed as indicating or implying their relative importance or implicitly indicating the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In addition, the technical solutions between the various embodiments can be combined with each other, but must be based on the realization by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that the combination of such technical solutions does not exist. , is not within the scope of protection claimed in this application.

The present application proposes a safety state switching circuit of a motor controller. Referring to FIG. 1, FIG. 1 is a structural block diagram of an embodiment of the safety state switching circuit of the motor controller of the present application; the circuit includes: a waveform conversion circuit 100, a frequency-voltage conversion circuit 200. The judgment circuit 300 and the drive circuit 400;

Wherein, the input terminal of the waveform conversion circuit 100 is connected to the motor frequency detection unit (not shown in the figure, but does not affect the explanation of this embodiment), and the output terminal of the waveform conversion circuit 100 is connected to the frequency voltage The input end of the conversion circuit 200 is connected, the output end of the frequency-voltage conversion circuit 200 is connected with the input end of the judgment circuit 300, the output end of the judgment circuit 300 is connected with the input end of the driving circuit 400, and the The output end of the driving circuit 400 is connected to the controlled end of the motor controller (not shown in the figure, but does not affect the explanation of this embodiment);

It should be noted that the input end of the waveform conversion circuit 100 is connected to the motor frequency detection unit on the PCB (Printed Circuit Board, printed circuit board) in the specific implementation. A sampled sensor, the sampling output end of the sensor is connected to the input end of the waveform conversion circuit 100 .

The waveform conversion circuit 100 is configured to receive the initial waveform frequency signal output by the motor, convert the initial waveform frequency signal into a square wave frequency signal, and output the square wave frequency signal to the frequency-voltage conversion circuit 200;

It should be noted that, in specific implementation, the initial waveform frequency signal may be a single waveform or a mixture of multiple waveforms. For example, the initial waveform frequency signal may be a sine wave frequency signal, but the converted waveform is preferably a square wave. This is because the square wave can appear as a rectangle, and only the high and low level states can control the current state voltage of the subsequent conversion.

The frequency-voltage conversion circuit 200 is configured to convert the square wave frequency signal into a current state voltage signal capable of driving the bridge arm of the motor controller, and output the current state voltage signal to the judgment circuit 300;

It should be noted that the square wave frequency signal is converted into a current state voltage signal, and further, the current state voltage signal can drive the bridge arm to be turned on and off after being output by the frequency-voltage conversion circuit.

It is easy to understand that the frequency signal cannot directly generate the enable signal for switching the safe state, so the square wave frequency signal needs to be converted into a voltage signal, and the switching of the safe state is controlled by the voltage signal. Therefore, the square wave frequency signal is converted into the current state voltage signal by the frequency-to-voltage conversion circuit 200, and the conversion may be performed by means of charging and discharging in the specific implementation.

The judging circuit 300 is configured to judge the safety state according to the current state voltage signal, generate a corresponding enabling electrical signal according to the judging result, and output the enabling electrical signal to the driving circuit 400;

It should be noted that the security status includes ASC (Active short circuit, active short-circuit) state and Freewheeling (freewheeling) safe state, when the conditions for switching to another safe state are not reached, the current safe state is maintained. The current state voltage signal can represent the current frequency. By comparing the current state voltage signal with the reference voltage, if the switching condition is satisfied, the judging circuit 300 outputs a corresponding enabling electrical signal to enable the driving circuit 400 to control the motor controller's The bridge arm is switched on and off for safe state switching.

The driving circuit 400 is configured to control the on-off of the bridge arm of the motor controller according to the enabling electrical signal to perform safe state switching.

Referring to FIG. 5 , FIG. 5 is a control logic diagram of the safe state mode switching of an embodiment of the safety state switching circuit of the motor controller of the present application;

It is easy to understand that the vertical axis in Figure 5 represents the safe state, and the horizontal axis represents the current operating frequency of the motor. In response to the current operating frequency of the motor being greater than or equal to the second preset frequency f2, the motor controller will execute the ASC safe state. When the motor is currently running During the process of reducing the frequency from the second preset frequency f2 to the first preset frequency f1, the motor controller will remain in the ASC safe state; in response to the current operating frequency of the motor being less than or equal to the first preset frequency f1, the motor controller will be controlled by The ASC safe state switches to the Freewheeling safe state. When the motor operating frequency increases from the first preset frequency f1 to the second preset frequency f2, the motor controller will remain in the Freewheeling safe state. Therefore, the safe state mode will follow the It can switch arbitrarily with the change of the current operating frequency of the motor and has strong anti-interference ability.

It should be noted that, the first preset frequency f1 and the second preset frequency f2 are two different operating frequencies of the permanent magnet synchronous motor, and the amplitude of the second preset frequency f2 is greater than the first preset frequency f1.

It is easy to understand that the solution adopted in this embodiment does not require MCU control, which prevents the safe state from being unable to be effectively switched when the MCU fails during the driving process of the vehicle. Before the permanent magnet synchronous motor stops, the safe state can be performed according to the current operating frequency of the motor. Switch to make the motor controller enter a safe state that meets the vehicle torque safety target.

Further, referring to FIG. 2 , FIG. 2 is a schematic diagram of a waveform conversion circuit of an embodiment of a safety state switching circuit of a motor controller of the present application;

The waveform conversion circuit 100 includes a filter unit 101, a first voltage limiting unit 102, a first comparator CP1 and a first power supply unit 103;

The input end of the filtering unit 101 is connected to the motor frequency detection unit, the output end of the filtering unit 101 is connected to the inverting input end of the first comparator CP1, and the first end of the first voltage limiting unit 102 connected to the first reference voltage terminal, the first voltage limiting unit 102 is also connected to the non-inverting input terminal and the output terminal of the first comparator CP1, and the output terminal of the first comparator CP1 is connected to the first power supply The output terminal of unit 103 is connected;

The filter unit 101 includes a first resistor R1 and a first capacitor C1, the first voltage limiting unit 102 includes a second resistor R2 and a third resistor R3, and the first power supply unit 103 includes a fourth resistor R4; wherein,

The first end of the first resistor R1 is connected to the motor frequency detection unit, the second end of the first resistor R1, the first end of the first capacitor C1 and the inverting input of the first comparator CP1 terminal is connected, and the second terminal of the first capacitor C1 is grounded to GND;

The filtering unit 101 is configured to receive the sine wave frequency signal output by the motor, filter the sine wave frequency signal, and output the filtered sine wave frequency signal to the first comparator CP1;

It should be noted that the first resistor R1 and the first capacitor C1 in the filtering unit 101 filter the input sine wave frequency signal.

The first end of the second resistor R2 is connected to the first reference voltage end, the second end of the second resistor R2 and the first end of the third resistor R3 are connected to the first comparator CP1. the non-inverting input terminal is connected, and the second terminal of the third resistor R3 is connected to the output terminal of the first comparator CP1;

The first comparator CP1 is configured to receive the first reference voltage Vref1 input from the first voltage limiting unit 102 and generate a square wave frequency signal according to the first reference voltage Vref1 and the filtered sine wave frequency signal.

It is easy to understand that the inverting input terminal of the first comparator CP1 receives the filtered sine wave frequency signal, and the non-inverting input terminal receives the first reference voltage Vref1 input through the second resistor R2. The filtered sine wave frequency signal outputs the corresponding square wave frequency signal. The second resistor R2 and the third resistor R3 receive the first reference voltage Vref1 and determine the threshold voltage amplitude of the first comparator CP1 according to the first reference voltage Vref1.

The first end of the fourth resistor R4 is connected to the power supply end, and the second end of the fourth resistor R4 and the output end of the first comparator CP1 are connected to the input end of the frequency-voltage conversion circuit 200 .

The first power supply unit 103 is configured to input a power supply voltage for the waveform conversion circuit 100;

It is easy to understand that the fourth resistor R4 is a pull-up resistor of the output end of the first comparator CP1, and the power supply end is connected to the power supply VDD.

Further, referring to FIG. 3 , FIG. 3 is a schematic diagram of a frequency-voltage conversion circuit according to an embodiment of the safety state switching circuit of the motor controller of the present application;

The frequency-to-voltage conversion circuit 200 includes a first charge and discharge unit 201 and a second charge and discharge unit 202;

The first charging and discharging unit 201 includes a second capacitor C2, a first diode D1 and a second diode D2; the second charging and discharging unit 202 includes a third capacitor C3 and a fifth resistor R5; wherein,

The first end of the second capacitor C2 is connected to the output end of the waveform conversion circuit 100, the second end of the second capacitor C2, the anode of the first diode D1 and the second diode D2 the cathode connection;

The first end of the third capacitor C3, the cathode of the first diode D1 and the first end of the fifth resistor R5 are connected, and the first end of the third capacitor C3 is also connected to the judgment circuit The input terminal of 300 is connected, the second terminal of the fifth resistor R5 and the second terminal of the third capacitor C3 are connected to the anode of the second diode D2 and grounded to GND.

The input terminal of the first charging and discharging unit 201 is connected to the output terminal of the waveform conversion circuit 100 , the input terminal of the second charging and discharging unit 202 is connected to the output terminal of the first charging and discharging unit 201 , The output end of the second charging and discharging unit 202 is connected to the input end of the judging circuit 300;

The first charging and discharging unit 201 and the second charging and discharging unit 202 are configured to perform charging and discharging according to a square wave frequency signal, and generate a current state voltage signal.

It should be noted that the square wave frequency signal received by the second capacitor C2 presents a high-low level change with the change of the current operating frequency of the motor (in the specific implementation, the high level can be 5V, and the low level can be 0V) signal, when the square wave frequency signal is high level, the second capacitor C2 is charged so that the voltage at both ends thereof is high level, the first diode D1 is turned on, so that the third capacitor C3 can also enter On the other hand, when the square wave frequency signal is at a low level, the voltage across the second capacitor C2 drops at the same time. Since the capacitor voltage will not undergo abrupt changes, the second end of the second capacitor C2 is connected to the cathode of the second diode D2. The potential at the GND terminal is lower than the grounding GND terminal voltage, the second capacitor C2 conducts freewheeling through the second diode D2 to realize capacitor discharge, and at the same time the third capacitor C3 discharges through the fifth resistor R5. To sum up, in the process of changing the current operating frequency of the motor to make the square wave frequency signal show a high-low level transformation, the second capacitor C2 and the third capacitor C3 repeat the charging and discharging process, and the output represents the current operating frequency of the motor. Status voltage signal.

Further, referring to FIG. 4 , FIG. 4 is a schematic diagram of a judgment circuit of an embodiment of the safety state switching circuit of the motor controller of the present application;

The judgment circuit 300 includes: a second voltage limiting unit 301, a second comparator CP2 and a second power supply unit 302;

The output terminal of the frequency-to-voltage conversion circuit 200 is connected to the inverting input terminal of the second comparator CP2, the first terminal of the second voltage limiting unit 301 is connected to the second reference voltage terminal, and the first terminal of the second voltage limiting unit 301 is connected to the second reference voltage terminal. The two voltage limiting units 301 are also connected to the non-inverting input terminal and the output terminal of the second comparator CP2, and the output terminal of the second comparator CP2 is connected to the output terminal of the second power supply unit 302;

The second comparator CP2 is configured to receive the second reference voltage Vref2 input from the second voltage limiting unit 301, and to determine the safety state according to the second reference voltage Vref2 and the current state voltage signal, and to generate a The corresponding enable electrical signal is output to the drive circuit 400 .

The second voltage limiting unit 301 includes a sixth resistor R6 and a seventh resistor R7, and the second power supply unit 302 includes an eighth resistor R8; wherein,

The first end of the sixth resistor R6 is connected to the second reference voltage end, the second end of the sixth resistor R6, the first end of the seventh resistor R7 and the second comparator CP2 The non-inverting input terminal is connected, and the second terminal of the seventh resistor R7 is connected to the output terminal of the second comparator CP2;

It should be noted that the inverting input terminal of the second comparator CP2 receives the current state voltage signal, the non-inverting input terminal receives the second reference voltage Vref2 input through the sixth resistor R6, and outputs the corresponding voltage signal according to the reference voltage value and the current state electrical signal. Enable electrical signal. The sixth resistor R6 and the seventh resistor R7 receive the second reference voltage Vref2 and determine the threshold voltage amplitude of the second comparator CP2 according to the second reference voltage Vref2.

In specific implementation, the threshold width between the first preset frequency f1 and the second preset frequency f2 can be adjusted by changing the resistance values of the sixth resistor R6 and the seventh resistor R7. The embodiment does not limit this.

It is easy to understand that, further, the driving circuit 400 can perform corresponding safe state switching and execution functions according to the received enable signal.

The second power supply unit 302 is configured to input a supply voltage for the judgment circuit 300;

The first end of the eighth resistor R8 is connected to the power supply end, and the second end of the eighth resistor R8 and the output end of the second comparator CP2 are connected to the input end of the driving circuit 400 .

It is easy to understand that the eighth resistor R8 is a pull-up resistor of the output end of the second comparator CP2, and the power supply end is connected to the power supply VDD.

This embodiment uses the above circuit to switch the safe state according to the operating frequency of the motor, so that the motor controller enters the correct safe state, which satisfies the torque safety target of the entire vehicle and prevents the failure of the MCU to perform safe state switching. Vehicle torque safety fault.

In addition, an embodiment of the present application also proposes a method for controlling a safety state switching circuit of a motor controller. Referring to FIG. 6 , FIG. 6 is a schematic flowchart of a first embodiment of the method for controlling a safety state switching circuit of a motor controller of the present application.

The control method is based on the above-mentioned motor controller safe state switching circuit; the method includes:

Step S10: the waveform conversion circuit receives the sine wave frequency signal output by the motor, converts the sine wave frequency signal into a square wave frequency signal, and outputs the square wave frequency signal to the frequency-voltage conversion circuit;

It should be noted that the input end of the waveform conversion circuit 100 is connected to the motor frequency detection unit on the PCB (Printed Circuit Board, printed circuit board) in the specific implementation. A sampled sensor, the sampling output end of the sensor is connected to the input end of the waveform conversion circuit 100 .

It should be noted that, in specific implementation, the initial waveform frequency signal may be a single waveform or a mixture of multiple waveforms. For example, the initial waveform frequency signal may be a sine wave frequency signal, but the converted waveform is preferably a square wave. This is because the square wave can appear as a rectangle, and only the high and low level states can control the current state voltage of the subsequent conversion.

Step S20: the frequency-voltage conversion circuit converts the square wave frequency signal into a current state voltage signal capable of driving the bridge arm of the motor controller, and outputs the current state voltage signal to the judgment circuit;

It should be noted that the square wave frequency signal is converted into a current state voltage signal, and further, the current state voltage signal can drive the bridge arm to be turned on and off after being output by the frequency-voltage conversion circuit.

It is easy to understand that the frequency signal cannot directly generate the enable signal for switching the safe state, so the square wave frequency signal needs to be converted into a voltage signal, and the switching of the safe state is controlled by the voltage signal. Therefore, the square wave frequency signal is converted into the current state voltage signal by the frequency-voltage conversion circuit, which can be converted by charging and discharging in the specific implementation.

Step S30: the judging circuit judges the safety state according to the current state voltage signal, generates a corresponding enabling electrical signal according to the judging result, and outputs the enabling electrical signal to the driving circuit;

It should be noted that the security status includes ASC (Active short circuit, active short-circuit) state and Freewheeling (freewheeling) safe state, when the conditions for switching to another safe state are not reached, the current safe state is maintained. The current state voltage signal can represent the current frequency. By comparing the current state voltage signal with the reference voltage, if the switching condition is satisfied, the judgment circuit outputs a corresponding enable electrical signal to enable the drive circuit to control the bridge arm of the motor controller On and off for safe state switching.

Step S40 : the drive circuit controls the on-off of the bridge arm of the motor controller according to the enabling electrical signal to perform safe state switching.

Referring to FIG. 5 , FIG. 5 is a control logic diagram of the safe state mode switching of an embodiment of the safety state switching circuit of the motor controller of the present application;

It is easy to understand that the vertical axis in Figure 5 represents the safe state, and the horizontal axis represents the current operating frequency of the motor. In response to the current operating frequency of the motor being greater than or equal to the second preset frequency f2, the motor controller will execute the ASC safe state. When the motor is currently running During the process of reducing the frequency from the second preset frequency f2 to the first preset frequency f1, the motor controller will remain in the ASC safe state; in response to the current operating frequency of the motor being less than or equal to the first preset frequency f1, the motor controller will be controlled by The ASC safe state switches to the Freewheeling safe state. When the motor operating frequency increases from the first preset frequency f1 to the second preset frequency f2, the motor controller will remain in the Freewheeling safe state. Therefore, the safe state mode will follow the It can switch arbitrarily with the change of the current operating frequency of the motor and has strong anti-interference ability.

It should be noted that, the first preset frequency f1 and the second preset frequency f2 are two different operating frequencies of the permanent magnet synchronous motor, and the amplitude of the second preset frequency f2 is greater than the first preset frequency f1.

It is easy to understand that the solution adopted in this embodiment does not require MCU control, which prevents the safe state from being unable to be effectively switched when the MCU fails during the driving process of the vehicle. Before the permanent magnet synchronous motor stops, the safe state can be performed according to the current operating frequency of the motor. Switch to make the motor controller enter a safe state that meets the vehicle torque safety target.

In this embodiment, through the above method, the safe state switching is performed according to the operating frequency of the motor, so that the motor controller enters the correct safe state, which satisfies the torque safety target of the entire vehicle, and prevents the failure of the MCU to perform safe state switching. Vehicle torque safety fault.

In addition, an embodiment of the present application also provides a device for switching the safety state of a motor controller, the device comprising: the above-mentioned safety state switching circuit of the motor controller.

Since the device for switching the safety state of the motor controller adopts all the technical solutions of the above-mentioned embodiments, it has at least all the functions brought by the technical solutions of the above-mentioned embodiments, and will not be repeated here.

It should be understood that the above are only examples, and do not constitute any limitation to the technical solutions of the present application. In specific applications, those skilled in the art can make settings as required, which is not limited in the present application.

It should be noted that the above-described workflow is only illustrative, and does not limit the protection scope of the present application. In practical applications, those skilled in the art can select some or all of them to implement according to actual needs. The purpose of the solution in this embodiment is not limited here.

In addition, for technical details that are not described in detail in this embodiment, reference may be made to the safe state switching circuit of the motor controller provided by any embodiment of the present application, which will not be repeated here.

Furthermore, it should be noted that, herein, the terms "comprising", "comprising" or any other variation thereof are intended to encompass non-exclusive inclusion, such that a process, method, article or system comprising a series of elements includes not only those elements, but also other elements not expressly listed or inherent to such a process, method, article or system. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in the process, method, article or system that includes the element.

The above-mentioned serial numbers of the embodiments of the present application are only for description, and do not represent the advantages or disadvantages of the embodiments.

From the description of the above embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus a necessary general hardware platform, and of course hardware can also be used, but in many cases the former is better implementation. Based on this understanding, the technical solutions of the present application can be embodied in the form of software products in essence or the parts that make contributions to the prior art. The computer software products are stored in a storage medium (such as a read-only memory (Read Only Memory). , ROM)/RAM, magnetic disk, optical disk), including several instructions to make a terminal device (which may be a mobile phone, a computer, a server, or a network device, etc.) execute the methods described in the various embodiments of the present application.

The above are only optional embodiments of the present application, which are not intended to limit the scope of the patent of the present application. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present application, or directly or indirectly applied to other related technologies Fields are similarly included within the scope of patent protection of this application.

Claims (9)

1. A safety state switching circuit of a motor controller, wherein the circuit comprises: a waveform conversion circuit, a frequency-voltage conversion circuit, a judgment circuit and a drive circuit;

   The input terminal of the waveform conversion circuit is connected to the motor frequency detection unit, the output terminal of the waveform conversion circuit is connected to the input terminal of the frequency-voltage conversion circuit, and the output terminal of the frequency-voltage conversion circuit is connected to the input terminal of the judgment circuit. the input end is connected, the output end of the judgment circuit is connected with the input end of the drive circuit, and the output end of the drive circuit is connected with the bridge arm of the motor controller;

   The waveform conversion circuit is configured to receive the initial waveform frequency signal output by the motor, convert the initial waveform frequency signal into a square wave frequency signal, and output the square wave frequency signal to the frequency-voltage conversion circuit;

   The frequency-voltage conversion circuit is configured to convert the square-wave frequency signal into a current state voltage signal capable of driving the bridge arm of the motor controller, and output the current state voltage signal to the judgment circuit;

   The judging circuit is configured to judge the safety state according to the current state voltage signal, generate a corresponding enabling electrical signal according to the judging result, and output the enabling electrical signal to the driving circuit;

   The driving circuit is configured to control the on-off of the bridge arm of the motor controller according to the enabling electrical signal to perform safe state switching.
2. The safe state switching circuit of the motor controller according to claim 1, wherein the waveform conversion circuit comprises a filtering unit, a first voltage limiting unit, a first comparator and a first power supply unit;

   The input end of the filtering unit is connected to the motor frequency detection unit, the output end of the filtering unit is connected to the inverting input end of the first comparator, and the first end of the first voltage limiting unit is connected to the first reference the voltage terminal is connected, the first voltage limiting unit is also connected to the non-inverting input terminal and the output terminal of the first comparator, and the output terminal of the first comparator is connected to the output terminal of the first power supply unit;

   the first power supply unit, configured to input a power supply voltage for the waveform conversion circuit;

   The filtering unit is configured to receive the initial waveform frequency signal output by the motor, filter the initial waveform frequency signal, and output the filtered initial waveform frequency signal to the first comparator;

   The first comparator is configured to receive a first reference voltage input from the first voltage limiting unit, and generate a square wave frequency signal according to the first reference voltage and the filtered initial waveform frequency signal.
3. The safe state switching circuit of the motor controller according to claim 2, wherein the filtering unit includes a first resistor and a first capacitor, the first voltage limiting unit includes a second resistor and a third resistor, the first The power supply unit includes a fourth resistor; wherein,

   The first end of the first resistor is connected to the motor frequency detection unit, the second end of the first resistor and the first end of the first capacitor are connected to the inverting input end of the first comparator, so the second end of the first capacitor is grounded;

   The first end of the second resistor is connected to the first reference voltage end, the second end of the second resistor and the first end of the third resistor are connected to the non-inverting input end of the first comparator , the second end of the third resistor is connected to the output end of the first comparator;

   The first end of the fourth resistor is connected to the power supply end, and the second end of the fourth resistor and the output end of the first comparator are connected to the input end of the frequency-voltage conversion circuit.
4. The safe state switching circuit of the motor controller according to claim 1, wherein the frequency-voltage converting circuit comprises a first charging and discharging unit and a second charging and discharging unit;

   The input terminal of the first charging and discharging unit is connected to the output terminal of the waveform conversion circuit, the input terminal of the second charging and discharging unit is connected to the output terminal of the first charging and discharging unit, and the second charging and discharging unit is connected to the output terminal of the first charging and discharging unit. The output end of the charging and discharging unit is connected with the input end of the judgment circuit;

   The first charging and discharging unit and the second charging and discharging unit are configured to perform charging and discharging according to a square wave frequency signal, and generate a current state voltage signal.
5. The safe state switching circuit of the motor controller according to claim 4, wherein the first charging and discharging unit comprises a second capacitor, a first diode and a second diode; the second charging and discharging unit comprises a first Three capacitors and fifth resistors; among them,

   The first end of the second capacitor is connected to the output end of the waveform conversion circuit, and the second end of the second capacitor, the anode of the first diode and the cathode of the second diode are connected;

   The first end of the third capacitor and the cathode of the first diode are connected to the first end of the fifth resistor, and the first end of the third capacitor is also connected to the input end of the judgment circuit , the second end of the fifth resistor and the second end of the third capacitor are connected to the anode of the second diode and grounded.
6. The safe state switching circuit of the motor controller according to claim 1, wherein the judging circuit comprises: a second voltage limiting unit, a second comparator and a second power supply unit;

   The output terminal of the frequency-voltage conversion circuit is connected to the inverting input terminal of the second comparator, the first terminal of the second voltage limiting unit is connected to the second reference voltage terminal, and the second voltage limiting unit is connected to the second reference voltage terminal. The unit is also connected to the non-inverting input terminal and the output terminal of the second comparator, and the output terminal of the second comparator is connected to the output terminal of the second power supply unit;

   the second power supply unit, configured to input a power supply voltage for the judgment circuit;

   The second comparator is configured to receive the second reference voltage input by the second voltage limiting unit, and perform a safety state judgment according to the second reference voltage and the current state voltage signal, and generate a corresponding enable according to the judgment result an electrical signal, and outputting the enabling electrical signal to the driving circuit.
7. The safe state switching circuit of the motor controller according to claim 6, wherein the second voltage limiting unit includes a sixth resistor and a seventh resistor, and the second power supply unit includes an eighth resistor; wherein,

   The first end of the sixth resistor is connected to the second reference voltage end, the second end of the sixth resistor and the first end of the seventh resistor are connected to the non-inverting input end of the second comparator , the second end of the seventh resistor is connected to the output end of the second comparator;

   The first end of the eighth resistor is connected to the power supply end, and the second end of the eighth resistor and the output end of the second comparator are connected to the input end of the driving circuit.
8. A motor controller safe state switching device, wherein the device comprises: the motor controller safe state switching circuit according to any one of claims 1 to 7.
9. A method for controlling a safety state switching circuit of a motor controller, wherein the control method is based on the safety state switching circuit of a motor controller according to any one of claims 1 to 7; the method comprises:

   The waveform conversion circuit receives the initial waveform frequency signal output by the motor, converts the initial waveform frequency signal into a square wave frequency signal, and outputs the square wave frequency signal to the frequency-voltage conversion circuit;

   The frequency-voltage conversion circuit converts the square-wave frequency signal into a current state voltage signal capable of driving the bridge arm of the motor controller, and outputs the current state voltage signal to the judgment circuit;

   The judging circuit judges the safety state according to the current state voltage signal, generates a corresponding enabling electrical signal according to the judging result, and outputs the enabling electrical signal to the driving circuit;

   The driving circuit controls the on-off of the bridge arm of the motor controller according to the enabling electrical signal to perform safe state switching.