Safety response circuit and safety response system of multi-drive system

Abstract

The utility model relates to the technical field of electric drive, and provides a safety response circuit and a safety response system of a multi-drive system. The safety response circuit comprises a first filter circuit for receiving a frequency signal representing the motor speed of the fault driving system; the level conversion circuit is used for converting the frequency signal into a level signal; the hysteresis comparison circuit outputs a first rotating speed detection signal used for triggering the fault driving system to enter a first safety state when the level signal rises to be larger than an upper threshold value, and outputs a second rotating speed detection signal used for triggering the fault driving system to enter a second safety state when the level signal drops to be smaller than a lower threshold value. According to the utility model, under the condition that part of the driving systems break down and the high-voltage relay is not disconnected, the rotating speed detection signal is output according to the frequency signal, so that the fault driving system is triggered to accurately enter a corresponding safety state, and the torque output of other driving systems is not influenced by the fault of part of the driving systems.

Description

Technical Field

[0001] The utility model relates to the technical field of electric drive, and specifically to a safety response circuit and a safety response system for a multi-drive system. Background Art

[0002] For electric vehicles configured with a multi-drive system, it has become an increasingly important requirement that the damage of some drive systems does not affect the operation of other drive systems.

[0003] In traditional electric drive technology, when some drive systems fail, the response of the whole vehicle is to decelerate and stop. Taking a dual-drive system as an example, when a drive system has a fault that the L3 software is untrusted, the inverter of the drive system disconnects the high-voltage relay connected to the high-voltage battery. The high-voltage relay connects the high-voltage battery to the inverters of the two drive systems. When the high-voltage relay disconnects, the operation of the other drive system is affected, and the whole vehicle decelerates and stops. During this process, since the high-voltage relay disconnects, the voltage on the high-voltage bus connected to the inverter and the high-voltage battery changes, and then the faulty drive system switches to different safety states according to the voltage on the high-voltage bus. Specifically, when the voltage on the high-voltage bus is high, the faulty drive system enters the first safety state that can avoid back electromotive force; when the voltage on the high-voltage bus is low, the faulty drive system enters the second safety state that can avoid negative torque.

[0004] Based on the requirement that the damage of some drive systems does not affect the operation of other drive systems, when a drive system fails, the high-voltage relay does not disconnect, so that the drive systems without faults can continue to work; at this time, the voltage on the high-voltage bus does not change, and then the faulty drive system cannot accurately switch to different safety states, which is likely to cause a large back electromotive force / negative torque.

[0005] It should be noted that the information disclosed in the above background art is only used to strengthen the understanding of the background of the utility model, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Utility Model

[0006] In view of this, the utility model provides a safety response circuit and a safety response system for a multi-drive system, which can, when some drive systems fail and the high-voltage relay does not disconnect, output a speed detection signal for triggering the faulty drive system to enter the corresponding safety state according to the frequency signal representing the motor speed of the faulty drive system, so that the faulty drive system can accurately and autonomously switch the safety state according to the speed detection signal, avoid negative torque and back electromotive force, and realize that the failure of some drive systems does not affect the torque output of other drive systems.

[0007] According to one aspect of the present utility model, there is provided a safety response circuit for a multi-drive system, including: a first filtering circuit for receiving a frequency signal representing the motor speed of a faulty drive system and filtering the frequency signal; a level conversion circuit connected to the first filtering circuit for converting the frequency signal into a level signal; a hysteresis comparison circuit connected to the level conversion circuit for outputting a speed detection signal according to the relationship between the level signal and a threshold value; wherein when the level signal rises to be greater than an upper threshold value, the hysteresis comparison circuit outputs a first speed detection signal for triggering the faulty drive system to enter a first safety state, and when the level signal drops to be less than a lower threshold value, the hysteresis comparison circuit outputs a second speed detection signal for triggering the faulty drive system to enter a second safety state.

[0008] In some embodiments, the first filtering circuit includes: a first filtering unit connected to a frequency signal input terminal; a follower, a positive input terminal of the follower being connected to an output terminal of the first filtering unit, and a negative input terminal of the follower being connected to an output terminal of the follower; a DC blocking capacitor unit connected to the output terminal of the follower.

[0009] In some embodiments, the first filtering unit includes: a first current-limiting resistor connected in series between the frequency signal input terminal and the positive input terminal of the follower; a first filtering capacitor, a positive electrode of which is connected to the positive input terminal of the follower and a negative electrode of which is grounded.

[0010] In some embodiments, the DC blocking capacitor unit includes a first DC blocking capacitor and a second DC blocking capacitor connected in series between the follower and the level conversion circuit.

[0011] In some embodiments, the safety response circuit further includes any of the following electronic components: a first pull-down resistor, one end of which is connected to an output terminal of the first filtering circuit and the other end of which is grounded; a second pull-down resistor, one end of which is connected to an input terminal of the level conversion circuit and the other end of which is grounded; a second current-limiting resistor connected in series between the output terminal of the first filtering circuit and the input terminal of the level conversion circuit.

[0012] In some embodiments, the level conversion circuit includes: a reverse filtering unit connected to an output terminal of the first filtering circuit for filtering reverse signals in the frequency signal; a level conversion unit connected to an output terminal of the reverse filtering unit for converting the frequency signal into a level signal; a signal amplification unit connected between the level conversion unit and the hysteresis comparison circuit.

[0013] In some embodiments, the reverse filtering unit includes: a first operational amplifier, the positive input terminal of the first operational amplifier is connected to the output terminal of the first filtering circuit, and the output terminal of the first operational amplifier is connected to a first diode and is connected to the negative input terminal of the first operational amplifier via a second diode.

[0014] In some embodiments, the second diode is also grounded via a third current-limiting resistor.

[0015] In some embodiments, the level conversion unit includes: a fourth current-limiting resistor, connected in series between the reverse filtering unit and the signal amplification unit; a second filtering capacitor, with the positive electrode connected to the series node of the fourth current-limiting resistor and the signal amplification unit, and the negative electrode grounded; a third pull-down resistor, with one end connected to the positive electrode of the second filtering capacitor and the other end grounded.

[0016] In some embodiments, the signal amplification unit includes: a second operational amplifier, the positive input terminal of the second operational amplifier is connected to the output terminal of the level conversion unit, and the output terminal of the second operational amplifier is connected to the input terminal of the hysteresis comparison circuit and is connected to the negative input terminal of the second operational amplifier via a fifth current-limiting resistor.

[0017] In some embodiments, the fifth current-limiting resistor is also grounded via a sixth current-limiting resistor.

[0018] In some embodiments, the hysteresis comparison circuit includes: a comparator, the negative input terminal of the comparator is connected to the output terminal of the level conversion circuit, the positive input terminal of the comparator receives a reference signal, and the output terminal of the comparator is connected to the positive input terminal of the comparator via a seventh current-limiting resistor.

[0019] In some embodiments, the seventh current-limiting resistor is also connected to the power supply via an eighth current-limiting resistor.

[0020] In some embodiments, the reference signal is generated by the series node of two voltage-dividing resistors connected in series with the power supply.

[0021] In some embodiments, the hysteresis comparison circuit further includes: a ninth current-limiting resistor, connected in series between the output terminal of the level conversion circuit and the negative input terminal of the comparator; a third filtering capacitor, with the positive electrode connected to the negative input terminal of the comparator and the negative electrode grounded.

[0022] In some embodiments, the safety response circuit further includes a signal latching circuit, connected to a rotational speed detection circuit including the first filtering circuit, the level conversion circuit, and the hysteresis comparison circuit, and the signal latching circuit is configured to latch or release the rotational speed detection signal output by the rotational speed detection circuit according to the power-on self-check signal of the rotational speed detection circuit.

[0023] In some embodiments, the signal latch circuit includes: a D flip-flop, the clock input terminal of the D flip-flop receives a latch reset signal, and the data input terminal of the D flip-flop receives the power-on self-check signal; an AND gate circuit, two input terminals of the AND gate circuit are respectively connected to the output terminal of the D flip-flop and the output terminal of the rotational speed detection circuit; wherein, the D flip-flop outputs a high-level signal according to the power-on self-check signal indicating that the rotational speed detection circuit is fault-free, so that the AND gate circuit releases the rotational speed detection signal, and the D flip-flop outputs a low-level signal according to the power-on self-check signal indicating that the rotational speed detection circuit has a fault, so that the AND gate circuit latches the rotational speed detection signal.

[0024] In some embodiments, the signal latch circuit further includes any of the following electronic components: a tenth current-limiting resistor, connected in series between the latch reset signal input terminal and the clock input terminal; a fourth pull-down resistor, one end connected to the latch reset signal input terminal and the other end grounded; an eleventh current-limiting resistor, connected in series between the power-on self-check signal input terminal and the data input terminal; a fifth pull-down resistor, one end connected to the power-on self-check signal input terminal and the other end grounded; a fourth filter capacitor, the positive electrode connected to the data input terminal and the negative electrode grounded; a sixth pull-down resistor, one end connected to the output terminal of the D flip-flop and the other end grounded.

[0025] In some embodiments, the safety response circuit further includes a signal simulation circuit, the output terminal of the signal simulation circuit is connected to the input terminal of the first filter circuit, and the signal simulation circuit is used to generate an analog frequency signal for the power-on self-check of the rotational speed detection circuit.

[0026] According to another aspect of the present invention, there is provided a safety response system for a multi-drive system, including: a rotational speed output module, configured to obtain a frequency signal representing the rotational speed of the motor of the faulty drive system according to the fault signal of the multi-drive system; the safety response circuit as described in any of the above embodiments, the first filter circuit of the safety response circuit is connected to the rotational speed output module; a drive chip, connected to the hysteresis comparison circuit of the safety response circuit, the drive chip is configured to drive the faulty drive system into a first safety state according to the first rotational speed detection signal output by the hysteresis comparison circuit, and drive the faulty drive system into a second safety state according to the second rotational speed detection signal output by the hysteresis comparison circuit.

[0027] The beneficial effects of the present invention compared with the prior art at least include:

[0028] Through a first filtering circuit, filter the frequency signal representing the motor speed of the fault driving system to avoid the influence of noise on subsequent speed detection, maintain the accuracy of the frequency signal, and make the frequency signal accurately reflect the motor speed of the fault driving system. Among them, to a certain extent, the motor speed is determined by the voltage on the high-voltage bus connecting the inverter of the fault driving system and the high-voltage battery.

[0029] Through a level conversion circuit, convert the frequency signal into a level signal for subsequent comparison of the level high and low; and the level of the level signal is basically positively correlated with the frequency of the frequency signal, while the frequency of the frequency signal is basically positively correlated with the motor speed of the fault driving system.

[0030] Through a hysteresis comparison circuit, on the one hand, realize the comparison between the level signal and the threshold value, and on the other hand, effectively suppress the noise and interference in the level signal, and accurately output a speed detection signal for triggering the fault driving system to enter the corresponding safety state. When the level signal rises to be greater than the upper threshold value (indicating that the motor speed of the fault driving system is relatively large at this time, that is, the voltage on the high-voltage bus is relatively high), the hysteresis comparison circuit outputs a first speed detection signal for triggering the fault driving system to enter the first safety state to avoid back electromotive force; when the level signal drops to be less than the lower threshold value (indicating that the motor speed of the fault driving system is relatively small at this time, that is, the voltage on the high-voltage bus is relatively low), the hysteresis comparison circuit outputs a second speed detection signal for triggering the fault driving system to enter the second safety state to avoid negative torque.

[0031] Therefore, the safety response circuit of the present utility model, through the cooperation of the first filtering circuit, the level conversion circuit, and the hysteresis comparison circuit, can, when a part of the driving system fails and the high-voltage relay does not open, according to the frequency signal representing the motor speed of the fault driving system, output a speed detection signal for triggering the fault driving system to enter the corresponding safety state, so that the fault driving system can accurately and autonomously switch the safety state according to the speed detection signal, avoid negative torque and back electromotive force, and realize that the failure of a part of the driving system does not affect the torque output of other driving systems.

[0032] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present utility model. Brief Description of the Drawings

[0033] The drawings here are incorporated into the specification and form a part of the specification, showing embodiments in line with the present utility model, and are used together with the specification to explain the principles of the present utility model. Obviously, the drawings described below are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative work, other drawings can also be obtained based on these drawings.

[0034] Figure 1 Schematic diagram of the circuit modules of the safety response circuit in an embodiment of the present utility model;

[0035] Figure 2 Schematic diagram of the circuit structure of the safety response circuit in an embodiment of the present utility model;

[0036] Figure 3 Schematic diagram of the circuit structure of the first filter circuit of the safety response circuit in an embodiment of the present utility model;

[0037] Figure 4 Schematic diagram of the circuit structure of the level conversion circuit of the safety response circuit in an embodiment of the present utility model;

[0038] Figure 5 Schematic diagram of the circuit structure of the hysteresis comparison circuit of the safety response circuit in an embodiment of the present utility model;

[0039] Figure 6 Schematic diagram of the circuit structure of the signal latching circuit of the safety response circuit in an embodiment of the present utility model. Detailed implementation manners

[0040] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the embodiments described herein. On the contrary, these embodiments are provided to make the present utility model more comprehensive and complete, and to fully convey the concept of the example embodiments to those skilled in the art.

[0041] The accompanying drawings are only schematic diagrams of the present utility model and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus repeated descriptions thereof will be omitted.

[0042] The terms "first", "second" and similar terms used in the detailed description do not denote any order, quantity or importance, but are only used to distinguish different components. In the description of the present utility model, it should be noted that when it is said that a device is "connected" to another device, this includes not only the case of direct connection, but also the case of indirect connection through other elements.

[0043] It should be noted that, without conflict, the features in the embodiments of the present utility model and those in different embodiments can be combined with each other.

[0044] The safety response circuit provided in the embodiment of the present utility model is used for a multi-drive system, where the multi-drive system can be an automotive drive system including two or more electric drive systems such as a dual-drive system or a four-drive system.

[0045] Figure 1 Schematically shows the main circuit modules of the safety response circuitFigure 2 Schematically shows the main circuit structure of the safety response circuit, Figure 1 and Figure 2 specifically shows the rotational speed detection circuit part of the safety response circuit. Combining Figure 1 and Figure 2 as shown, the safety response circuit provided by the embodiment of the present utility model includes a first filter circuit 100, a level conversion circuit 200, and a hysteresis comparison circuit 300.

[0046] The first filter circuit 100 is configured to receive a frequency signal representing the rotational speed of the motor of the fault drive system, and perform filtering processing on the frequency signal.

[0047] The frequency signal is specifically a sine wave signal. Through the first filter circuit 100, the frequency signal representing the rotational speed of the motor of the fault drive system is filtered to avoid noise affecting subsequent rotational speed detection, maintain the accuracy of the frequency signal, and enable the frequency signal to accurately reflect the rotational speed of the motor of the fault drive system. Among them, the rotational speed of the motor is determined to a certain extent by the voltage on the high-voltage bus connecting the inverter of the fault drive system to the high-voltage battery.

[0048] Depending on the requirements of actual applications, the first filter circuit 100 may specifically be a high-pass filter circuit, but is not limited thereto.

[0049] The level conversion circuit 200 is connected to the first filter circuit 100 and is configured to convert the frequency signal into a level signal.

[0050] Through the level conversion circuit 200, the frequency signal is converted into a level signal for subsequent comparison of the level high and low; and the level of the level signal is basically positively correlated with the frequency of the frequency signal, and the frequency of the frequency signal is basically positively correlated with the rotational speed of the motor of the fault drive system.

[0051] The hysteresis comparison circuit 300 is connected to the level conversion circuit 200 and is configured to output a rotational speed detection signal according to the relationship between the level signal and the threshold; wherein, when the level signal rises to be greater than the upper threshold, the hysteresis comparison circuit 300 outputs a first rotational speed detection signal for triggering the fault drive system to enter the first safety state, and when the level signal drops to be less than the lower threshold, the hysteresis comparison circuit 300 outputs a second rotational speed detection signal for triggering the fault drive system to enter the second safety state.

[0052] Through the hysteresis comparison circuit 300, on the one hand, the comparison between the level signal and the threshold value is realized, and on the other hand, the noise and interference in the level signal are effectively suppressed, and the rotation speed detection signal for triggering the fault drive system to enter the corresponding safe state is accurately output. When the level signal rises to be greater than the upper threshold value (indicating that the motor speed of the fault drive system is relatively large at this time, that is, the voltage on the high-voltage bus is relatively high), the hysteresis comparison circuit 300 outputs the first rotation speed detection signal for triggering the fault drive system to enter the first safe state. The first rotation speed detection signal is, for example, a high-level signal to avoid back electromotive force; when the level signal drops to be less than the lower threshold value (indicating that the motor speed of the fault drive system is relatively small at this time, that is, the voltage on the high-voltage bus is relatively low), the hysteresis comparison circuit 300 outputs the second rotation speed detection signal for triggering the fault drive system to enter the second safe state. The second rotation speed detection signal is, for example, a low-level signal to avoid negative torque.

[0053] Therefore, the safety response circuit of the present utility model, through the cooperation of the first filter circuit 100, the level conversion circuit 200, and the hysteresis comparison circuit 300, can, in the case where a part of the drive system fails and the high-voltage relay does not open, according to the frequency signal representing the motor speed of the fault drive system, output the rotation speed detection signal for triggering the fault drive system to enter the corresponding safe state, so that the fault drive system can accurately and autonomously switch the safe state according to the rotation speed detection signal, avoid negative torque and back electromotive force, and realize that the failure of a part of the drive system does not affect the torque output of other drive systems.

[0054] Figure 3 Schematically shows the circuit structure of the first filter circuit; in combination with Figure 2 and Figure 3 As shown, in some embodiments, the first filter circuit 100 includes:

[0055] The first filter unit 110 is connected to the frequency signal input terminal Vin and is used to filter out the noise signal in the frequency signal.

[0056] The follower U1, its positive input terminal IN+ is connected to the output terminal of the first filter unit 110, its negative input terminal IN- is connected to its output terminal OUT, and the power supply terminal VDD of the follower U1 is connected to the power supply (the power supply is, for example, 5V, but not limited thereto), and the ground terminal GND is grounded. Through the follower U1, the signal quality of the frequency signal is improved.

[0057] The DC-blocking capacitor unit 130 is connected to the output terminal OUT of the follower U1 and is used to isolate the DC signal and at the same time allow the AC signal to pass through, thereby preventing the DC signal from interfering with the AC signal to obtain a clear waveform and facilitating subsequent level conversion.

[0058] In some embodiments, the first filtering unit 110 includes: a first current-limiting resistor R11, connected in series between the frequency signal input terminal Vin and the positive input terminal IN+ of the follower U1; a first filtering capacitor C11, with its positive terminal connected to the positive input terminal IN+ of the follower U1 and its negative terminal grounded.

[0059] The first current-limiting resistor R11 and the first filtering capacitor C11 form an RC filtering circuit. Among them, the resistance value of the first current-limiting resistor R11 is, for example, 10 kΩ, and the capacitance of the first filtering capacitor C11 is, for example, 1 nF, but not limited thereto.

[0060] In other embodiments, the first filtering unit 110 can also be implemented by other suitable filtering circuit structures.

[0061] In some embodiments, an operational amplifier can be used as the follower U1. For example, an operational amplifier of the TLV2372 model is used as the follower U1, but not limited thereto.

[0062] In some embodiments, the DC-blocking capacitor unit 130 includes a first DC-blocking capacitor C21 and a second DC-blocking capacitor C22 connected in series between the follower U1 and the level conversion circuit 200. The capacitance of the first DC-blocking capacitor C21 can be 100 nF, and the capacitance of the second DC-blocking capacitor C22 can be 150 nF, but not limited thereto.

[0063] In other embodiments, the DC-blocking capacitor unit 130 can also be formed by one, more than three, or other numbers of DC-blocking capacitors.

[0064] Furthermore, in some embodiments, the first filtering circuit 100 further includes: a first pull-down resistor R21, with one end connected to the output terminal of the first filtering circuit 100 and the other end grounded. The resistance value of the first pull-down resistor R21 is, for example, 10 kΩ, but not limited thereto.

[0065] Figure 4 Schematically shows the circuit structure of the level conversion circuit; in conjunction with Figure 2 and Figure 4 as shown, in some embodiments, the level conversion circuit 200 includes:

[0066] A reverse filtering unit 210, connected to the output terminal of the first filtering circuit 100, for filtering the reverse signal in the frequency signal to facilitate subsequent level conversion.

[0067] A level conversion unit 220, connected to the output terminal of the reverse filtering unit 210, for converting the frequency signal into a level signal.

[0068] The signal amplification unit 230 is connected between the level conversion unit 220 and the hysteresis comparison circuit 300. The signal amplification unit 230 is used to amplify the level signal of the previous stage, for example, amplify it by two times, so as to perform subsequent level comparison.

[0069] In some embodiments, the reverse filtering unit 210 includes: a first operational amplifier U2. The positive input terminal of the first operational amplifier U2 is connected to the output terminal of the first filter circuit 100. The output terminal of the first operational amplifier U2 is connected to the first diode D1 and is connected to the negative input terminal of the first operational amplifier U2 through the second diode D2.

[0070] Through the cooperation of the first operational amplifier U2 with the first diode D1 and the second diode D2, the reverse signal in the frequency signal is filtered out. Among them, the first operational amplifier U2 can adopt an operational amplifier of the LTC6244 model, and the first diode D1 and the second diode D2 can adopt zener diodes of the BAT54 model, but it is not limited thereto.

[0071] Furthermore, in some embodiments, the second diode D2 is also grounded through a third current-limiting resistor R13. The resistance value of the third current-limiting resistor R13 is, for example, 10 kΩ, but it is not limited thereto.

[0072] In some embodiments, the level conversion unit 220 includes: a fourth current-limiting resistor R14, which is connected in series between the reverse filtering unit 210 and the signal amplification unit 230; a second filter capacitor C12, whose positive electrode is connected to the series node of the fourth current-limiting resistor R14 and the signal amplification unit 230, and the negative electrode is grounded; a third pull-down resistor R23, one end of which is connected to the positive electrode of the second filter capacitor C12, and the other end is grounded.

[0073] Through the cooperation of the fourth current-limiting resistor R14, the second filter capacitor C12, and the third pull-down resistor R23, while anti-jitter is achieved, the purpose of converting the frequency signal into a level signal is achieved through the charging and discharging of the capacitor. Among them, the third pull-down resistor R23 has a very large resistance value, for example, 10 MegΩ, so that the charging and discharging process of the second filter capacitor C12 is slow, so that the level of the level signal increases as the frequency of the frequency signal increases. When the frequency of the frequency signal increases to a certain value, the level signal remains stable. In this way, the level signal and the frequency signal are positively correlated as a whole, so that the level signal accurately reflects the motor speed of the fault drive system, and the subsequent speed detection signal generated based on the level signal triggers the fault drive system to accurately enter the corresponding safe state.

[0074] Among them, the resistance value of the fourth current-limiting resistor R14 can be 100 Ω, and the capacitance of the second filter capacitor C12 can be 10 nF, but it is not limited thereto.

[0075] In actual working conditions, when the motor speed of the fault drive system is greater than the critical speed, the fault drive system needs to enter a first safe state that can avoid back electromotive force; when the motor speed of the fault drive system is less than the critical speed, the fault drive system needs to enter a second safe state that can avoid negative torque. The critical speed can be obtained according to the motor configuration of the fault drive system or through measurement; for example, the critical speed is 6000 revolutions per second, but this is not limiting.

[0076] In some embodiments, the signal amplification unit 230 includes: a second operational amplifier U3, the positive input terminal of the second operational amplifier U3 is connected to the output terminal of the level conversion unit 220, and the output terminal of the second operational amplifier U3 is connected to the input terminal of the hysteresis comparison circuit 300 and is connected to the negative input terminal of the second operational amplifier U3 through a fifth current-limiting resistor R15.

[0077] Among them, the second operational amplifier U3 can adopt an operational amplifier of the LTC6244 model, and the resistance value of the fifth current-limiting resistor R15 can be 15 kΩ, but this is not limiting.

[0078] In some embodiments, the fifth current-limiting resistor R15 is also grounded through a sixth current-limiting resistor R16. The resistance value of the sixth current-limiting resistor R16 can be 10 kΩ, but this is not limiting.

[0079] Further, in some embodiments, the level conversion circuit 200 may further include any of the following electronic components: a second pull-down resistor R22, one end of which is connected to the input terminal of the level conversion circuit 200 and the other end is grounded; a second current-limiting resistor R12, which is connected in series between the input terminal of the level conversion circuit 200 and the input terminal of the reverse filtering unit 210. Among them, the resistance value of the second pull-down resistor R22 can be 10 kΩ, and the resistance value of the second current-limiting resistor R12 can be 10 kΩ, but this is not limiting.

[0080] Figure 5 Schematically shows the circuit structure of the hysteresis comparison circuit; in combination with Figure 2 and Figure 5 as shown, in some embodiments, the hysteresis comparison circuit 300 includes:

[0081] A comparator U4, the negative input terminal of the comparator U4 is connected to the output terminal of the level conversion circuit 200, the positive input terminal of the comparator U4 receives a reference signal Vref, and the output terminal of the comparator U4 is connected to the positive input terminal of the comparator U4 through a seventh current-limiting resistor R17.

[0082] Comparator U4 improves the anti-interference ability of the output by introducing positive feedback; the output voltage of comparator U4 is fed back through the seventh current-limiting resistor R17 to adjust the reference signal Vref, thereby achieving hysteresis comparison. Comparator U4 has two threshold voltages, namely the upper threshold (e.g., 5V) and the lower threshold (e.g., 0V). When the level signal input by the level conversion circuit 200 rises and exceeds the upper threshold, the output state of comparator U4 changes, and a high-level signal is output, that is, the first rotational speed detection signal Vdet1 used to trigger the fault drive system to enter the first safe state; and during the process of the level signal increasing from 0V to 5V, the output state of comparator U4 remains unchanged, and a low-level signal is output. When the level signal input by the level conversion circuit 200 drops and is lower than the lower threshold, the output state of comparator U4 changes, and a low-level signal is output, that is, the second rotational speed detection signal Vdet2 used to trigger the fault drive system to enter the second safe state; and during the process of the level signal decreasing from 5V to 0V, the output state of comparator U4 remains unchanged, and a high-level signal is output. In this way, when the level signal changes between the upper threshold and the lower threshold, the rotational speed detection signal remains unchanged, thereby enhancing the stability and anti-interference performance, enabling the generated rotational speed detection signal to more stably trigger the fault drive system to enter the corresponding safe state, and avoiding frequent fluctuations of the rotational speed detection signal.

[0083] Among them, comparator U4 can adopt a comparator of model LTC6752, and the resistance value of the seventh current-limiting resistor R17 can be 47 kΩ, but not limited thereto.

[0084] In some embodiments, the seventh current-limiting resistor R17 is also connected to the power supply through the eighth current-limiting resistor R18. The resistance value of the eighth current-limiting resistor R18 can be 10 kΩ, but not limited thereto.

[0085] In some embodiments, the reference signal Vref is generated at the series node of two voltage-dividing resistors (including the first voltage-dividing resistor R31 and the second voltage-dividing resistor R32) connected in series with the power supply. Among them, the resistance value of the first voltage-dividing resistor R31 is, for example, 10 kΩ, and the resistance value of the second voltage-dividing resistor R32 is, for example, 18 kΩ, but not limited thereto.

[0086] In some embodiments, the hysteresis comparison circuit 300 further includes: a ninth current-limiting resistor R19, connected in series between the output end of the level conversion circuit 200 and the negative input terminal of comparator U4; a third filter capacitor C13, with the positive electrode connected to the negative input terminal of comparator U4 and the negative electrode grounded.

[0087] The ninth current-limiting resistor R19 and the third filter capacitor C13 form an RC filter circuit. Among them, the resistance value of the ninth current-limiting resistor R19 is, for example, 10 kΩ, and the capacitance of the third filter capacitor C13 is, for example, 100 nF, but not limited thereto.

[0088] Figure 6 Schematically shows the circuit structure of the signal latching circuit; in combination with Figures 1 to 6 As shown, in some embodiments, the safety response circuit further includes a signal latching circuit 400. The signal latching circuit 400 is connected to a rotational speed detection circuit including a first filter circuit 100, a level conversion circuit 200, and a hysteresis comparison circuit 300, and is configured to latch or release a rotational speed detection signal output by the rotational speed detection circuit according to a power-on self-check signal of the rotational speed detection circuit.

[0089] Through the signal latching circuit 400, it is realized that when the power-on self-check signal indicates that the rotational speed detection circuit is working normally, the rotational speed detection signal output by the rotational speed detection circuit is released, so that the rotational speed detection signal can trigger the fault drive system to enter the corresponding safety state; if the power-on self-check signal indicates that the rotational speed detection circuit is abnormal, the signal latching circuit 400 shields the rotational speed detection signal and outputs a fixed result to the drive chip of the fault drive system, for example, outputs a low voltage signal to the drive chip of the fault drive system.

[0090] In some embodiments, the signal latching circuit 400 includes:

[0091] D flip-flop U5. The clock input terminal CP of the D flip-flop U5 receives a latch reset signal LATCH_RESET. The latch reset signal LATCH_RESET can be a periodic rising edge signal, and the data input terminal D of the D flip-flop U5 receives the power-on self-check signal;

[0092] AND gate circuit A. Two input terminals of the AND gate circuit A are respectively connected to the output terminal Q of the D flip-flop U5 and the output terminal of the rotational speed detection circuit;

[0093] Wherein, the D flip-flop U5 outputs a high-level signal FAIL_LATCHED according to the power-on self-check signal Vpost1 (Vpost1 is a high voltage signal) indicating that the rotational speed detection circuit is fault-free, so that the AND gate circuit A releases the rotational speed detection signal (first rotational speed detection signal Vdet1 / second rotational speed detection signal Vdet2). The D flip-flop U5 outputs a low-level signal LATCHED according to the power-on self-check signal Vpost2 (Vpost2 is a low voltage signal) indicating that the rotational speed detection circuit has a fault, so that the AND gate circuit A latches the rotational speed detection signal (first rotational speed detection signal Vdet1 / second rotational speed detection signal Vdet2).

[0094] The D flip-flop U5 can adopt a D flip-flop of the NL17SZ74US model, and its VCC terminal, PR_bar terminal, and CLR terminal are all connected to a power supply (for example, 5V), and the GND terminal is grounded.

[0095] In some embodiments, the signal latching circuit 400 further includes any of the following electronic components:

[0096] The tenth current-limiting resistor R110 is connected in series between the latch reset signal input terminal and the clock input terminal CP; the resistance value of the tenth current-limiting resistor R110 can be 10 kΩ, but is not limited thereto.

[0097] The fourth pull-down resistor R24 has one end connected to the latch reset signal input terminal and the other end grounded; the resistance value of the fourth pull-down resistor R24 can be 4.7 kΩ, but is not limited thereto.

[0098] The eleventh current-limiting resistor R111 is connected in series between the power-on self-check signal input terminal and the data input terminal D; the resistance value of the eleventh current-limiting resistor R111 can be 10 kΩ, but is not limited thereto.

[0099] The fifth pull-down resistor R25 has one end connected to the power-on self-check signal input terminal and the other end grounded; the resistance value of the fifth pull-down resistor R25 can be 4.7 kΩ, but is not limited thereto.

[0100] The fourth filter capacitor C14 has its positive electrode connected to the data input terminal D and its negative electrode grounded; the capacitance of the fourth filter capacitor C14 can be 1 nF, but is not limited thereto.

[0101] The sixth pull-down resistor R26 has one end connected to the output terminal Q of the D flip-flop U5 and the other end grounded; the resistance value of the sixth pull-down resistor R26 can be 10 kΩ, but is not limited thereto.

[0102] Furthermore, in some embodiments, the safety response circuit further includes a signal simulation circuit (not specifically shown in the figure), the output terminal of the signal simulation circuit is connected to the input terminal of the first filter circuit 100 (i.e., the frequency signal input terminal Vin), and the signal simulation circuit is used to generate an analog frequency signal for the speed detection circuit to perform a power-on self-check.

[0103] The signal simulation circuit can use multiple different power supplies to simulate frequency signals in the form of sine waves corresponding to different motor speeds. During the power-on self-check, a specific frequency signal is generated by the signal simulation circuit and output to the speed detection circuit; then it is judged whether the speed detection signal output by the speed detection circuit matches the specific frequency signal. If so, it indicates that the speed detection circuit is working normally, and a power-on self-check signal Vpost1 (high voltage signal) indicating that the speed detection circuit has no fault is generated and output to the signal latch circuit, so that the signal latch circuit releases the speed detection signal output by the speed detection circuit (including the first speed detection signal Vdet1 / second speed detection signal Vdet2); if the speed detection signal output by the speed detection circuit does not match the specific frequency signal, if so, it indicates that the speed detection circuit is abnormal, and a power-on self-check signal Vpost2 (low voltage signal) indicating that the speed detection circuit has a fault is generated and output to the signal latch circuit, so that the signal latch circuit latches the speed detection signal output by the speed detection circuit.

[0104] The embodiment of the present utility model further provides a safety response system for a multi-drive system, including:

[0105] A rotational speed output module, configured to obtain a frequency signal representing the motor rotational speed of a faulty drive system according to a fault signal of the multi-drive system;

[0106] The safety response circuit as described in any of the above embodiments, wherein a first filter circuit of the safety response circuit is connected to the rotational speed output module;

[0107] A driving chip, connected to the hysteresis comparison circuit of the safety response circuit, the driving chip is configured to drive the faulty drive system into a first safety state according to a first rotational speed detection signal output by the hysteresis comparison circuit, and drive the faulty drive system into a second safety state according to a second rotational speed detection signal output by the hysteresis comparison circuit.

[0108] The safety response system of the present utility model is configured with the above safety response circuit, and can cooperate with the first filter circuit, the level conversion circuit, and the hysteresis comparison circuit. When some drive systems fail and the high-voltage relay does not open, according to the frequency signal representing the motor rotational speed of the faulty drive system, a rotational speed detection signal for triggering the faulty drive system to enter the corresponding safety state is output, so that the faulty drive system can accurately and autonomously switch the safety state according to the rotational speed detection signal, avoid negative torque and back electromotive force, and realize that the failure of some drive systems does not affect the torque output of other drive systems.

[0109] The safety response circuit and the safety response system of the present utility model are particularly applicable to a dual-drive system, and can achieve that the damage of one drive system does not affect the normal operation of the other drive system, greatly improving the performance of the dual-drive system.

[0110] The above content is a further detailed description of the present utility model in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present utility model is only limited to these descriptions. For those of ordinary skill in the technical field to which the present utility model belongs, without departing from the concept of the present utility model, several simple deductions or substitutions can still be made, and all should be regarded as belonging to the protection scope of the present utility model.

Claims

1. A safety response circuit for a multi-drive system, characterized in that, Comprising: A first filter circuit for receiving a frequency signal characterizing the motor speed of a fault drive system and filtering the frequency signal; A level conversion circuit connected to the first filter circuit for converting the frequency signal into a level signal; A hysteresis comparison circuit connected to the level conversion circuit for outputting a speed detection signal according to the relationship between the level signal and a threshold value; Wherein, when the level signal rises to be greater than an upper threshold value, the hysteresis comparison circuit outputs a first speed detection signal for triggering the fault drive system to enter a first safe state, and when the level signal drops to be less than a lower threshold value, the hysteresis comparison circuit outputs a second speed detection signal for triggering the fault drive system to enter a second safe state.

2. The safety response circuit according to claim 1, wherein, The first filter circuit includes: A first filter unit connected to a frequency signal input terminal; A follower, the positive input terminal of the follower is connected to the output terminal of the first filter unit, and the negative input terminal of the follower is connected to the output terminal of the follower; A DC blocking capacitor unit connected to the output terminal of the follower.

3. The safety response circuit according to claim 2, wherein The first filter unit includes: A first current-limiting resistor connected in series between the frequency signal input terminal and the positive input terminal of the follower; A first filter capacitor, the positive electrode is connected to the positive input terminal of the follower, and the negative electrode is grounded.

4. The safety response circuit according to claim 2, wherein The DC blocking capacitor unit includes a first DC blocking capacitor and a second DC blocking capacitor connected in series between the follower and the level conversion circuit.

5. The safety response circuit according to claim 1, wherein, It further includes any of the following electronic components: A first pull-down resistor, one end is connected to the output terminal of the first filter circuit, and the other end is grounded; A second pull-down resistor, one end is connected to the input terminal of the level conversion circuit, and the other end is grounded; A second current-limiting resistor connected in series between the output terminal of the first filter circuit and the input terminal of the level conversion circuit.

6. The safety response circuit according to claim 1, wherein, The level conversion circuit includes: A reverse filtering unit connected to the output terminal of the first filter circuit for filtering reverse signals in the frequency signal; A level conversion unit connected to the output terminal of the reverse filtering unit for converting the frequency signal into a level signal; A signal amplification unit connected between the level conversion unit and the hysteresis comparison circuit.

7. The safety response circuit according to claim 6, wherein The reverse filtering unit includes: A first operational amplifier, the positive input terminal of the first operational amplifier is connected to the output terminal of the first filter circuit, the output terminal of the first operational amplifier is connected to a first diode and is connected to the negative input terminal of the first operational amplifier through a second diode.

8. The safety response circuit according to claim 7, wherein The second diode is also grounded through a third current-limiting resistor.

9. The safety response circuit according to claim 6, wherein The level conversion unit includes: A fourth current-limiting resistor connected in series between the reverse filtering unit and the signal amplification unit; A second filter capacitor, the positive electrode is connected to the series node of the fourth current-limiting resistor and the signal amplification unit, and the negative electrode is grounded; A third pull-down resistor, one end is connected to the positive electrode of the second filter capacitor, and the other end is grounded.

10. The security response circuit according to claim 6, wherein, The signal amplification unit includes: A second operational amplifier, wherein the positive input terminal of the second operational amplifier is connected to the output terminal of the level conversion unit, and the output terminal of the second operational amplifier is connected to the input terminal of the hysteresis comparison circuit and is connected to the negative input terminal of the second operational amplifier via a fifth current-limiting resistor.

11. The safety response circuit according to claim 10, wherein The fifth current-limiting resistor is also grounded via a sixth current-limiting resistor.

12. The safety response circuit according to claim 1, characterized in that, The hysteresis comparison circuit includes: A comparator, wherein the negative input terminal of the comparator is connected to the output terminal of the level conversion circuit, the positive input terminal of the comparator receives a reference signal, and the output terminal of the comparator is connected to the positive input terminal of the comparator via a seventh current-limiting resistor.

13. The safety response circuit according to claim 12, characterized in that, The seventh current-limiting resistor is also connected to the power supply via an eighth current-limiting resistor.

14. The safety response circuit according to claim 12, wherein The reference signal is generated at the series node of two voltage-dividing resistors connected in series with the power supply.

15. The safety response circuit according to claim 12, characterized in that The hysteresis comparison circuit further includes: A ninth current-limiting resistor, connected in series between the output terminal of the level conversion circuit and the negative input terminal of the comparator; A third filter capacitor, with the positive electrode connected to the negative input terminal of the comparator and the negative electrode grounded.

16. The safety response circuit according to claim 1, characterized in that, There is also a signal latching circuit, connected to the rotational speed detection circuit including the first filter circuit, the level conversion circuit, and the hysteresis comparison circuit. The signal latching circuit is used to latch or release the rotational speed detection signal output by the rotational speed detection circuit according to the power-on self-check signal of the rotational speed detection circuit.

17. The safety response circuit according to claim 16, wherein The signal latching circuit includes: A D flip-flop, wherein the clock input terminal of the D flip-flop receives a latch reset signal, and the data input terminal of the D flip-flop receives the power-on self-check signal; An AND gate circuit, with the two input terminals of the AND gate circuit respectively connected to the output terminal of the D flip-flop and the output terminal of the rotational speed detection circuit; Wherein, the D flip-flop outputs a high-level signal according to the power-on self-check signal indicating that the rotational speed detection circuit is fault-free, enabling the AND gate circuit to release the rotational speed detection signal. The D flip-flop outputs a low-level signal according to the power-on self-check signal indicating that the rotational speed detection circuit has a fault, enabling the AND gate circuit to latch the rotational speed detection signal.

18. The safety response circuit according to claim 17, wherein, The signal latching circuit further includes any of the following electronic components: A tenth current-limiting resistor, connected in series between the latch reset signal input terminal and the clock input terminal; A fourth pull-down resistor, with one end connected to the latch reset signal input terminal and the other end grounded; An eleventh current-limiting resistor, connected in series between the power-on self-check signal input terminal and the data input terminal; A fifth pull-down resistor, with one end connected to the power-on self-check signal input terminal and the other end grounded; A fourth filter capacitor, with the positive electrode connected to the data input terminal and the negative electrode grounded; A sixth pull-down resistor, with one end connected to the output terminal of the D flip-flop and the other end grounded.

19. The safety response circuit according to claim 16, characterized in that, There is also a signal simulation circuit, with the output terminal of the signal simulation circuit connected to the input terminal of the first filter circuit. The signal simulation circuit is used to generate an analog frequency signal for the power-on self-check of the rotational speed detection circuit.

20. A safety response system for a multi-drive system, characterized in that, It includes: A rotational speed output module, used to obtain a frequency signal representing the rotational speed of the motor of the faulty drive system according to the fault signal of the multi-drive system. The safety response circuit according to any one of claims 1-19, wherein a first filter circuit of the safety response circuit is connected to the rotation speed output module; A drive chip is connected to the hysteresis comparison circuit of the safety response circuit. The drive chip is configured to drive the fault drive system into a first safety state according to a first rotation speed detection signal output by the hysteresis comparison circuit, and drive the fault drive system into a second safety state according to a second rotation speed detection signal output by the hysteresis comparison circuit.

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