Control circuit for electric control switch, electric vehicle and control method

Abstract

The invention discloses a control circuit for an electric control switch, and the circuit comprises a trigger chip which receives a real-time control signal and a PWM signal, and outputs a first control signal which is configured to be a signal for initially controlling the switching on or switching off of the electric control switch; the logic AND gate chip is used for receiving the first control signal and a safety state signal and outputting a second control signal, the safety state signal is configured to indicate whether the power management chip is in a normal state or not, the second control signal is configured to be a signal for finally controlling the relay to be switched on or switched off, and the safety state signal is configured to indicate whether the power management chip is in a normal state or not. The PWM signal can be continuously refreshed to generate a trigger signal only when the safety state signal is a normal state level value, and when the control unit is reset accidentally, the PWM signal is no longer refreshed and no longer generates the trigger signal, and the safety state signal keeps the normal state level value within a preset time. Power failure can be delayed when the control unit is reset accidentally, and safety is improved. The invention further discloses an electric vehicle and a control method.

Description

Technical Field

[0001] The present invention relates to the technical field of electric control switch control, and in particular to a control circuit for an electric control switch, an electric vehicle and a control method for an electric control switch. Background Art

[0002] The electronically controlled switch is an important component in the circuit, especially in new energy vehicles. Taking new energy vehicles as an example, the electronically controlled switch can be used to control the on and off of the circuit. For example, the electronically controlled switch can be used in high-voltage circuits to connect or disconnect high-voltage components such as power batteries and drive motors. The electronically controlled switch can achieve isolation between circuits and ensure the safety and stability of the circuit, which is of great significance for ensuring the safety and reliability of the entire vehicle (i.e., new energy vehicles). The electronically controlled switch can be, for example, a relay.

[0003] In the prior art, the I / O port (i.e., the input / output port of the control unit, used for connecting the control unit to an external circuit or the external circuit to the control unit) of a control unit (e.g., a single-chip microcomputer) is usually directly connected to the driving circuit of the electric control switch, and the signal output by the control unit can directly control the closing or opening of the electric control switch. In the above control method, the closing or opening of the electric control switch is only controlled by the I / O port of the control unit, and there is no safety status signal of the power management chip involved in the control. When the program runs away (e.g., after the control unit is disturbed, the program runs away from the normal running path) or the I / O is stuck (e.g., due to improper configuration of the control unit, the data transmission speed cannot keep up with the reading and writing recognition speed), the electric control switch may not close as expected, or may not open as expected.

[0004] More specifically, during the period when the electric control switch is closed, for example, during the high-speed driving of electric vehicles (i.e., new energy vehicles), there may be data overflow, watchdog exceptions, etc., which may cause the program to run away, or the electric vehicle is driving in a harsh external environment, such as a strong electromagnetic field, high temperature vibration and other extreme environments, which may cause the control unit to be reset unexpectedly, and the I / O port output becomes a low-level signal. In the above control method, since the I / O port of the control unit directly controls the electric control switch (such as a relay), once the control unit is reset, the electric control switch will immediately lower the high voltage. The power battery pack and the motor of the electric vehicle are connected by the electric control switch. The high voltage of the electric control switch means that the electric control switch is disconnected, the high-voltage connection between the power battery pack and the motor is interrupted, the power source of the electric vehicle is disconnected, and the electric vehicle loses power instantly. When the electric vehicle is driving at high speed on the highway, this sudden loss of power will cause the electric vehicle to decelerate suddenly, and the rear vehicle will not be able to brake in time, causing a rear-end collision. Therefore, the electric control switch is immediately disconnected due to the accidental reset of the control unit, which poses a serious safety hazard, especially in the field of electric vehicles. Summary of the invention

[0005] The present invention provides a control circuit for an electric control switch, which is used to solve the problem in the prior art that the electric control switch is immediately disconnected when the control unit is accidentally reset.

[0006] In a first aspect, an embodiment of the present invention discloses a control circuit for an electric-controlled switch, comprising:

[0007] A trigger chip, comprising a first input port, a second input port and a first output port, wherein the first input port is configured to receive a real-time control signal from a control unit, the control signal being configured as a signal for initially controlling the electric-controlled switch to be closed or opened, the second input port being configured to receive a PWM signal from the control unit, the PWM signal comprising a trigger signal and a non-trigger signal, the first output port being configured to output a first control signal, and the trigger chip being configured to determine whether the first control signal is a control signal at a current moment or a control signal at a previous moment according to whether the current PWM signal is a trigger signal or a non-trigger signal;

[0008] The logic AND gate chip comprises a third input port, a fourth input port and a second output port, wherein the third input port is configured to receive a first control signal outputted from a first output port of a trigger chip, the fourth input port is configured to receive a safety state signal from a power management chip, the safety state signal is configured to indicate whether the power management chip is in a normal state, the second output port is configured to output a second control signal, and the second control signal is configured to be a signal that ultimately controls the electric control switch to be closed or opened,

[0009] Among them, only when the safety state signal is at the normal state level value, the PWM signal can be continuously refreshed to generate a trigger signal. When the control unit is accidentally reset, the PWM signal is no longer refreshed and no trigger signal is generated. The safety state signal maintains the normal state level value within a preset time.

[0010] By adopting the above technical scheme, the present invention can control whether the real-time control signal output by the control unit is valid through the PWM signal. When the control unit is accidentally reset, the PWM signal is no longer refreshed. The first control signal determines whether it is the control signal at the current moment or the control signal at the previous moment according to whether the current PWM signal is a trigger signal or a non-trigger signal. The safety state signal maintains a normal state level value within a preset time, thereby delaying the change of the second control signal. Therefore, within the preset time, the electronically controlled switch can still maintain the state of the previous moment, so that when the electronically controlled switch is originally in a closed state, it will not be immediately disconnected due to the accidental reset of the control unit, thereby improving the safety and stability of the entire circuit.

[0011] According to another specific embodiment of the present invention, when the control unit is accidentally reset and cannot return to normal within a preset time, the safety state signal changes from a normal state level value to an abnormal state level value.

[0012] According to another specific embodiment of the present invention, when the PWM signal is a trigger signal, the control signal at the current moment is triggered, and the first control signal is the control signal at the current moment, and / or, when the PWM signal is a non-trigger signal, the control signal at the current moment is not triggered, and the first control signal is the control signal at the previous moment.

[0013] According to another specific embodiment of the present invention, when the safety state signal is at a normal state level value, the second control signal is determined according to the first control signal.

[0014] According to another specific embodiment of the present invention, the normal state level value is a high level, and the abnormal state level value is a low level. When the safety state signal is a low level, the second control signal is a low level, and the electronically controlled switch is disconnected.

[0015] According to another specific embodiment of the present invention, the trigger signal is a rising edge signal or a falling edge signal. When the safety status signal is at a high level and the PWM signal is a trigger signal, the first control signal and the second control signal are both the same as the control signal at the current moment, and / or, when the safety status signal is at a high level and the PWM signal is a non-trigger signal, the first control signal and the second control signal are both the same as the control signal at the previous moment.

[0016] According to another specific embodiment of the present invention, when the second control signal is at a high level, the electronically controlled switch is closed.

[0017] According to another specific embodiment of the present invention, the preset time is 1ms-2s, and / or the duty cycle of the PWM signal is 1-99% and the frequency is 1Hz-100KHz, and / or the control unit is a single-chip microcomputer, and / or the trigger chip is a D trigger chip.

[0018] In a second aspect, an embodiment of the present invention further discloses an electric vehicle, comprising a control circuit for an electronically controlled switch as described in any one of the embodiments of the first aspect, wherein the electronically controlled switch is a relay, and when the relay is closed, the battery pack of the electric vehicle supplies power to the motor of the electric vehicle, and when the relay is disconnected, the battery pack of the electric vehicle does not supply power to the motor of the electric vehicle.

[0019] By adopting the above technical scheme, the present invention can control whether the real-time control signal output by the control unit is valid through the PWM signal. When the control unit is accidentally reset, the PWM signal is no longer refreshed. The first control signal determines whether it is the control signal at the current moment or the control signal at the previous moment according to whether the current PWM signal is a trigger signal or a non-trigger signal. The safety state signal maintains a normal state level value within a preset time, thereby delaying the change of the second control signal. Therefore, within the preset time, the electronically controlled switch can still maintain the state of the previous moment, so that when the electronically controlled switch is originally in a closed state, it will not be immediately disconnected due to the accidental reset of the control unit, thereby improving the safety and stability of the entire circuit.

[0020] In a third aspect, an embodiment of the present invention further discloses a control method for an electric-controlled switch, wherein the electric-controlled switch is controlled by using the control circuit for an electric-controlled switch described in any one of the embodiments of the first aspect, and the control method comprises:

[0021] Determine a real-time control signal, a PWM signal and a safety status signal, wherein the control signal is configured as a signal for initially controlling the closing or opening of the electric control switch, the PWM signal includes a trigger signal and a non-trigger signal, and the safety status signal is configured to indicate whether the power management chip is in a normal state;

[0022] Determining whether the first control signal is a control signal at a current moment or a control signal at a previous moment according to whether the current PWM signal is a trigger signal or a non-trigger signal;

[0023] Determine a second control signal according to the first control signal and the safety state signal, wherein the second control signal is configured as a signal that ultimately controls the electric-controlled switch to be closed or opened;

[0024] Controlling the electronically controlled switch to close or open according to the second control signal;

[0025] Among them, only when the safety state signal is at the normal state level value, the PWM signal can be continuously refreshed to generate a trigger signal. When the control unit is accidentally reset, the PWM signal is no longer refreshed and no trigger signal is generated. The safety state signal maintains the normal state level value within a preset time.

[0026] By adopting the above technical scheme, the present invention can control whether the real-time control signal output by the control unit is valid through the PWM signal. When the control unit is accidentally reset, the PWM signal is no longer refreshed. The first control signal determines whether it is the control signal at the current moment or the control signal at the previous moment according to whether the current PWM signal is a trigger signal or a non-trigger signal. The safety state signal maintains a normal state level value within a preset time, thereby delaying the change of the second control signal. Therefore, within the preset time, the electronically controlled switch can still maintain the state of the previous moment, so that when the electronically controlled switch is originally in a closed state, it will not be immediately disconnected due to the accidental reset of the control unit, thereby improving the safety and stability of the entire circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram showing the structure of a control circuit for an electric-controlled switch in an embodiment of the present invention is shown;

[0028] Figure 2 A schematic flow chart of a control method for an electric-controlled switch in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0029] The following specific embodiments illustrate the implementation of the present invention, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this implementation. On the contrary, the purpose of introducing the invention in conjunction with the implementation is to cover other options or modifications that may extend based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will include many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0030] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0031] The terms “first”, “second”, etc. are only used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0032] In the description of this embodiment, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this embodiment can be understood according to specific circumstances.

[0033] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0034] The inventors carefully studied the prior art and found that when the control unit is accidentally reset, the control signal of the electric control switch issued by the control unit will become low level, causing the electric control switch to be disconnected immediately and the related electrical components to stop working immediately. Especially in the new energy vehicle, the vehicle is prone to lose power instantly, leading to accidents. The inventors hope to solve the above problem. When the control unit is accidentally reset, the electric control switch will not be disconnected immediately, so as to avoid accidents as much as possible.

[0035] The inventor first thought of the following embodiment, in which the electric switch control signal output by the I / O port of the control unit is first logically ANDed with the safety status signal of the power management chip, and the signal output after the operation is connected to the electric switch drive circuit, thereby controlling the electric switch to be turned off or on. Among them, the power management chip that meets functional safety will have an SS (Safety Status) pin, that is, a safety status signal pin, which can output a safety status signal. When the power management chip is in normal working condition, the safety status signal output is a high level; when the power management chip is abnormal, the safety status signal output is a low level. This embodiment uses a combinational logic AND gate circuit to connect the drive signal of the control unit to the electric switch with the safety status signal of the power management chip, and then controls the electric switch after the AND gate output. Compared with the control method of the prior art mentioned in the background technology, the control method of this embodiment has an additional layer of protection from the safety status signal, which improves a certain degree of safety.

[0036] During actual use, the inventor found that the control method of the above embodiment still has problems. In the above embodiment, since the control signal of the electric control switch and the safety state signal are logically ANDed, as long as one of the signals is low level, the final output signal is low level, so the control unit is reset, the I / O port output becomes a low level signal, and the electric control switch will immediately lower the high voltage. The inventor has made further improvements for this purpose.

[0037] First, reference Figure 1An embodiment of the present invention discloses a control circuit for an electric-controlled switch, including a trigger chip 01 and a logic AND gate chip 02.

[0038] The trigger chip 01 includes a first input port D, a second input port CP and a first output port Q. The first input port D is configured to receive a real-time control signal from a control unit, and the control signal is configured as a signal for initially controlling the closing or opening of an electric control switch. The second input port CP is configured to receive a PWM signal from a control unit, and the PWM signal includes a trigger signal and a non-trigger signal. The first output port Q is configured to output a first control signal, and the trigger chip 01 is configured to determine whether the first control signal is a control signal at the current moment or a control signal at the previous moment according to whether the current PWM signal is a trigger signal or a non-trigger signal. In other words, whether the control signal at the current moment is valid depends on whether the current PWM signal is a trigger signal or a non-trigger signal. If valid, the first control signal is the same as the control signal at the current moment. If invalid, the first control signal maintains the control signal at the previous moment.

[0039] The logic AND gate chip 02 includes a third input port B, a fourth input port A, and a second output port Y. The third input port B is configured to receive a first control signal outputted from the first output port Q of the trigger chip 01, the fourth input port A is configured to receive a safety state signal from the power management chip, and the second output port Y is configured to output a second control signal. The safety state signal is configured to indicate whether the power management chip is in a normal state, and the normal state more specifically refers to a state in which the power management chip can work normally and safely, and the second control signal is configured as a signal that ultimately controls the closing or opening of the relay.

[0040] Among them, only when the safety state signal is at the normal state level value, the PWM signal can be continuously refreshed to generate a trigger signal. When the control unit is accidentally reset, the PWM signal is no longer refreshed and no longer generates a trigger signal, and the safety state signal maintains the normal state level value within a preset time. Among them, when the power management chip is in a normal state, the safety state signal is at the normal state level value.

[0041] In the present application, when the control unit is accidentally reset, the PWM signal is no longer refreshed and no trigger signal appears. The trigger chip 01 determines whether the first control signal is the control signal at the current moment or the control signal at the previous moment according to whether the current PWM signal is a trigger signal or a non-trigger signal. The safety state signal maintains a normal state level value within a preset time, thereby delaying the change of the second control signal. Therefore, within the preset time, the electronic control switch can still maintain the state of the previous moment, so that when the electronic control switch is originally in a closed state, it will not be immediately disconnected due to the accidental reset of the control unit, thereby improving the safety and stability of the entire circuit.

[0042] In other words, the present invention adopts the above-mentioned sequential logic circuit and combines it with a trigger for design, so that the effective output of the control signal of the control unit depends on whether the trigger signal appears in the PWM signal. During the accidental reset of the control unit, since the PWM signal is no longer refreshed and no longer generates a trigger signal, the safety state signal delays indicating that there is an abnormality, and the second control signal can be delayed and changed, so that the electric control switch will not be disconnected immediately, thereby improving the reliability and safety of the entire circuit. By combining the PWM signal, the real-time control signal and the safety state signal, the present invention can avoid the unexpected closure or unexpected disconnection of the electric control switch.

[0043] For example, when the control unit is accidentally reset and not restored, the PWM signal is no longer refreshed and no trigger signal is generated. When the control unit recovers to normal state from the accidental reset, for example, after detecting that the current state (such as the vehicle self-test state, the vehicle high voltage request and vehicle speed, etc.) is normal, the PWM signal continues to be refreshed.

[0044] Furthermore, the PWM signal is sent by the control unit, and the reset mechanism of the corresponding PWM module in the control unit can ensure that when the control unit is accidentally reset, the PWM signal will no longer be refreshed to generate a trigger signal.

[0045] Among them, the trigger signal can be selected according to the setting method of the control unit. Specifically, the trigger signal can be determined according to the reset mechanism of the control unit. The trigger signal can be an edge signal. It can be understood that the edge signal refers to the process in which the signal quickly switches from one state to another during the signal transmission process. Exemplarily, when the control unit itself is set to no longer generate a rising edge when it is reset, the trigger signal can be set to a rising edge signal accordingly; when the control unit itself is set to no longer generate a falling edge when it is reset, the trigger signal can be set to a falling edge signal accordingly.

[0046] Specifically, when reset, the pin of the control unit will return to the default state, for example, the default state is a low level, then the trigger signal can be set to be valid on the rising edge, that is, when the trigger signal is a rising edge signal, the control signal issued by the control unit at the current moment is valid, and the first control signal output by the trigger chip 01 is the control signal issued by the control unit at the current moment; and when it is a non-trigger signal, that is, a non-rising edge signal (such as a falling edge signal or a high-low level signal), the control signal issued by the control unit at the current moment is invalid, and the first control signal output by the trigger chip 01 is still the control signal issued by the control unit at the previous moment. In this case, when reset, the PWM signal becomes a low level and can maintain a low level, or the pin of the control unit is stuck, the PWM signal is a high level, the PWM signal may continue to maintain a high level, or become a low level after a period of time, and no rising edge signal will be generated.

[0047] For another example, the default state is a high level. At this time, the corresponding trigger signal is set to be effective on the falling edge, that is, when the trigger signal is a falling edge signal, the control signal issued by the control unit at the current moment is effective, and the first control signal output by the trigger chip 01 is the control signal issued by the control unit at the current moment; while in the case of a non-trigger signal, that is, a non-falling edge signal (such as a rising edge signal or a high-low level signal), the control signal issued by the control unit at the current moment is invalid, and the first control signal output by the trigger chip 01 is still the control signal issued by the control unit at the previous moment. In this case, the pins of the control unit may also become stuck. When reset, the PWM signal becomes a high level. The PWM signal may maintain a high level, or it may change from a low level to a high level, or it may still be stuck at a low level and will no longer change from a high level to a low level, that is, no falling edge signal will be generated.

[0048] More specifically, in one embodiment, when the control unit is set to accidentally reset when the control signal becomes a low level and the PWM signal becomes a low level, the trigger signal can be set to a rising edge signal. That is, the control signal at the current moment is valid only when the PWM signal is a rising edge signal. When the control unit is accidentally reset and does not return to normal, the PWM signal may be stuck at a high level, or may have a falling edge (i.e., quickly change from a high level to a low level), or may remain at a low level, but no rising edge (i.e., quickly change from a low level to a high level) may occur.

[0049] More specifically, in another embodiment, when the control unit is set to accidentally reset when the control signal becomes a high level and the PWM signal becomes a high level, the trigger signal can be set to a falling edge signal. That is, the control signal at the current moment is valid only when the PWM signal is a falling edge signal. When the control unit is accidentally reset and does not return to normal, the PWM signal may be stuck at a low level, or a rising edge may appear (i.e., it quickly changes from a low level to a high level), or it may remain at a low level, but no falling edge (i.e., it quickly changes from a high level to a low level) may appear.

[0050] In the above embodiment, the trigger chip 01 further includes a power input port VCC for connecting a power source, and the power source supplies power to the trigger chip 01 through the power input port VCC on the trigger chip 01. The trigger chip 01 further includes a ground port GND for grounding to ensure stable working performance of the trigger chip 01.

[0051] The logic AND gate chip 02 also has a power input port VCC for connecting a power source, and the power source supplies power to the logic AND gate chip 02 through the power input port VCC on the logic AND gate chip 02. The logic AND gate chip 02 also has a ground port GND for grounding to ensure stable working performance of the logic AND gate chip 02.

[0052] Exemplarily, when the control signal output by the control unit is at a high level, it indicates a request to close the electric control switch; when the control signal output by the control unit is at a low level, it indicates a request to open the electric control switch. The electric control switch may be, for example, a relay, and may further be a high-voltage relay for controlling a high-voltage circuit.

[0053] Further, in the above embodiment, when the control unit is unexpectedly reset and cannot return to normal within a preset time, the safety state signal changes from a normal state level value to an abnormal state level value.

[0054] Specifically, when the control unit is normal, the safety status signal output by the power management chip is at a normal state level value, that is, the safety status signal can be initially at a normal state level value by default. When the control unit is accidentally reset and cannot return to normal within a preset time, the safety status signal output by the power management chip will be converted to an abnormal state level value. In the above manner, a buffering effect can be played by setting a preset time, providing the control unit with response time to return to normal and then take over control of the electric switch again.

[0055] Among them, the accidental reset of the control unit may be caused by the control unit program running away, or it may be caused by the I / O port being stuck, or it may be caused by stopping feeding the watchdog, or it may be caused by other reasons. It is difficult to completely avoid the occurrence of accidental reset of the control unit. Therefore, it is necessary to design a circuit so that when the control unit is accidentally reset, the electric control switch will not be disconnected immediately.

[0056] Among them, the explanation for "stop feeding the watchdog" is as follows: In the control system, there is a hardware timer called the watchdog timer, which is used to monitor the normal operation of the system. When the system starts, the watchdog timer will also be started. During the normal operation of the system, the software must periodically "feed the dog", that is, reset the watchdog timer. If the software fails to "feed the dog" in time for some reason (such as software failure, hardware failure or system overload, etc.), the watchdog timer will count to zero and time out. Once the timeout occurs, the watchdog timer will trigger a reset signal, causing the control unit in the control system to restart, which will cause the control unit to reset unexpectedly.

[0057] In the above embodiment, a delay circuit can be set in the power management chip, which is implemented by the internal timer of the power management chip, so that the power management chip can delay the preset time before converting the safety state signal to the abnormal state level value. Designing the delay circuit by means of an internal timer instead of using a simple RC circuit (i.e., a circuit that only uses a combination of resistors and capacitors) as a delay circuit helps to improve the accuracy of timing and helps to control the preset time more accurately.

[0058] Further, in each of the above embodiments, when the safety state signal is a normal state level value, the PWM signal can be continuously refreshed to generate a trigger signal. When the PWM signal is a trigger signal, the control signal at the current moment is triggered, and the first control signal is the control signal at the current moment. That is, only when the safety state signal is a normal state level value can the PWM signal be continuously refreshed to generate a trigger signal, and only when the PWM signal is a trigger signal can the first control signal be re-determined according to the control signal output by the control unit at the current moment, and the first control signal is consistent with the control signal output by the control unit at the current moment. Exemplarily, if the control signal output by the control unit at the current moment indicates that the electric control switch is disconnected, the first control signal also indicates that the electric control switch is disconnected; if the control signal output by the control unit at the current moment indicates that the electric control switch is closed, the first control signal also indicates that the electric control switch is closed.

[0059] When the PWM signal is not a trigger signal, the control signal at the current moment is not triggered, and the first control signal is the control signal at the previous moment. That is, even if the safety state signal is at the normal state level, the PWM signal can be continuously refreshed to generate a trigger signal. As long as the PWM signal is not a trigger signal at the current moment, the first control signal maintains its state at the previous moment, and will not be re-determined according to the control signal output by the control unit at the current moment.

[0060] By adopting the above method, the control circuit can play the role of a latch circuit, and can realize the latching of the control signal, that is, at a specific moment (for example, the moment when the control unit is accidentally reset), the first control signal of the previous moment is locked at the first output port Q to realize the temporary storage and state retention of the signal. Specifically, when the control unit is accidentally reset, it indicates that there is an abnormality. Taking the reset mechanism of the control unit as an example, the control signal output by the control unit becomes a low level, the PWM signal is no longer refreshed and no trigger signal is generated, so the first control signal will maintain the state of the previous moment within a preset time, and will not be re-determined according to the control signal output by the control unit at the current moment. At the same time, the safety state signal is also delayed to become an abnormal state level value accordingly, so that the electric control switch will not be disconnected immediately. In the field of electric vehicles, when the electric control switch is a relay, especially a high-voltage relay, the above control method can avoid the situation where the control unit is reset accidentally and the high voltage is immediately lowered, the relay is immediately disconnected, and the power is instantly interrupted, thereby improving safety and stability.

[0061] By combining the design of a latch circuit in the control circuit, a pure logic circuit can be transformed into a sequential logic circuit, that is, the control signal output by the circuit at any time depends not only on the control signal input by the control unit at the current moment, but also on the control signal input at the previous moment, thereby preventing the electric control switch from being disconnected immediately when the control unit is accidentally reset.

[0062] Among them, the above-mentioned trigger signal is a rising edge signal or a falling edge signal, and it only needs to be a short-term rapid mutation signal. Once the trigger signal is selected as a rising edge signal, the trigger signal is always a rising edge signal and will not change to a falling edge signal during use. Similarly, once the trigger signal is selected as a falling edge signal, the trigger signal is always a falling edge signal and will not change to a rising edge signal during use. Using this type of trigger signal to design a latch circuit helps ensure that the signal can be processed at the right time and ensure the stability of the signal.

[0063] The trigger chip 01 used to realize the function of latching the control signal is a D trigger chip. The D trigger chip is the smallest basic unit of a sequential logic circuit, and the latch circuit with the latching signal function can be designed based on the D trigger chip.

[0064] Further, in each of the above embodiments, when the safety status signal is a normal state level value, the second control signal is determined according to the first control signal. Among them, when the safety status signal is a normal state level value, in the first case, the power management chip is normal and in a normal state, and the control unit is also in a normal state. At this time, the electric control switch can be controlled normally, and the second control signal can be directly determined according to the first control signal; in the second case, the control unit is accidentally reset, but it is still within the preset time, and the control unit is waiting for the control unit to return to a normal state. At this time, the first control signal can maintain the state of the previous moment, and thus the second control signal determined according to the first control signal can also maintain the state of the previous moment, thereby preventing the electric control switch from being disconnected immediately.

[0065] Furthermore, in the above embodiments, the normal state level value is a high level, and the abnormal state level value is a low level. When the safety state signal is a low level, the second control signal is a low level, and the electric control switch is disconnected. Among them, when the safety state signal is a low level, it means that the control unit has been accidentally reset and cannot automatically restore to a normal state. In order to prevent a greater accident or more serious damage, the second control signal becomes a low level, and the electric control switch is controlled to be disconnected.

[0066] As mentioned above, the trigger signal is a rising edge signal or a falling edge signal. Further, in the above embodiments, taking the trigger signal as a rising edge signal as an example, when the safety state signal is a high level and the PWM signal is a rising edge signal, the first control signal and the second control signal are the same as the control signal at the current moment. When the safety state signal is a high level and the PWM signal is a non-rising edge signal, the first control signal and the second control signal are the same as the control signal at the previous moment.

[0067] Combine the following Figure 1The value-added table corresponding to the control circuit for the electric control switch in the embodiment further specifically explains the input and output of the control circuit. Taking the trigger signal as a rising edge signal as an example, Table 1 shows the value-added table of the control circuit for the electric control switch.

[0068] Table 1 Value-added table for control circuit of electric control switch

[0069]

[0070] In Table 1, "CP" represents the second input port CP of the trigger chip 01, which receives the PWM signal output by the control unit. "D" represents the first input port D of the trigger chip 01, which receives the real-time control signal output by the control unit. "A" represents the fourth input port A of the logic AND gate chip 02, which receives the safety status signal output by the power management chip. "Q+1" represents the state of the output second control signal at the next moment, "Q" represents the current state of the output, and "Q" and "Q+1" are the relationship between the output values ​​of the sequential logic circuit. "L" represents a low level, "H" represents a high level, and "↑" represents a rising edge. "X" means that regardless of whether the control signal is a high level or a low level, the output second control signal does not depend on the control signal input at this time.

[0071] When the control signal is low level L, the PWM signal is rising edge↑, and the safety state signal is low level L, it means that although the control unit is in a normal state and there is no accidental reset, the power management chip has not entered the normal state (i.e. the state of normal and safe operation), then the second control signal output at the next moment is low level L, and the electric control switch is in the disconnected state. If the electric control switch is in the disconnected state at the current moment, the electric control switch will maintain the disconnected state at the next moment. If the electric control switch is in the closed state at the current moment, the electric control switch will be disconnected at the next moment.

[0072] When the control signal is low level L, the PWM signal is rising edge↑, and the safety state signal is high level H, it means that the control unit is in a normal state, the power management chip is in a normal state (i.e., a normal and safe working state), and the second control signal output at the next moment is low level L. If the electric control switch is in an open state at the current moment, the electric control switch will maintain an open state at the next moment. If the electric control switch is in a closed state at the current moment, the control unit can normally control the electric control switch to be open at the next moment.

[0073] When the control signal is high level H, the PWM signal is rising edge↑, and the safety state signal is low level L, it means that although the control unit is in a normal state and there is no accidental reset, the power management chip is abnormal, and the second control signal output at the next moment is low level L. If the electric control switch is in the open state at the current moment, the electric control switch will remain in the open state at the next moment. If the electric control switch is in the closed state at the current moment, the electric control switch will be open at the next moment.

[0074] When the control signal is high level H, the PWM signal is rising edge↑, and the safety state signal is high level H, it means that the control unit is in a normal state, the power management chip is in a normal state (i.e., a normal and safe working state), and the second control signal output at the next moment is high level H. If the electric control switch is in an open state at the current moment, the control unit can normally control the electric control switch to close at the next moment. If the electric control switch is in a closed state at the current moment, the electric control switch can maintain a closed state at the next moment.

[0075] When the control unit is reset unexpectedly, the PWM signal no longer generates a rising edge ↑, and may be reset to a low level L accordingly. Within a preset time, the control unit is waiting to return to normal, the safety state signal is maintained at a high level H, and the current state of the second control signal is Q. The state of the second control signal at the next moment remains Q. The electric control switch still maintains the current state at the next moment.

[0076] When the control unit is reset unexpectedly, the PWM signal no longer generates a rising edge ↑ and may be reset to a low level L accordingly. If the control unit cannot return to normal within the preset time, the safety state signal becomes a low level L, and the second control signal becomes a low level L at the next moment. If the electric control switch is in the disconnected state at the current moment, the electric control switch will remain in the disconnected state at the next moment. If the electric control switch is in the closed state at the current moment, the electric control switch will be disconnected at the next moment.

[0077] In another embodiment, taking the trigger signal as a falling edge signal as an example, when the safety state signal is at a high level and the PWM signal is a falling edge signal, the first control signal and the second control signal are both the same as the control signal at the current moment. When the safety state signal is at a high level and the PWM signal is a non-falling edge signal, the first control signal and the second control signal are both the same as the control signal at the previous moment.

[0078] Exemplarily, the duty cycle of the PWM signal output by the control unit is 1-99% and the frequency is 1Hz-100KHz. The duty cycle and frequency of the PWM signal can be more specifically selected according to the duration requirements of the preset time in the aforementioned embodiments. In this embodiment, the PWM signal can be set to a duty cycle of 50% and a frequency of 1KHz, for example.

[0079] Taking the trigger signal being a rising edge signal as an example, when the control unit works normally, the real-time control signal input by the control unit is valid only when the PWM signal is a rising edge signal. When the PWM signal is not a rising edge signal, for example, it is a falling edge signal, or it is in a high level state, or in a low level state, the real-time control signal input by the control unit is invalid. Among them, illustratively, the rising edge refers to the moment when the digital level changes from a low level (digital "0") to a high level (digital "1").

[0080] Taking the case where the trigger signal is a falling edge signal as an example, when the control unit works normally, the real-time control signal input by the control unit is valid only when the PWM signal is a falling edge signal. When the PWM signal is not a falling edge signal, for example, it is a rising edge signal, or it is in a high level state, or in a low level state, the real-time control signal input by the control unit is invalid. Among them, illustratively, the falling edge refers to the moment when the digital level changes from a high level (digital "1") to a low level (digital "0").

[0081] Further, in the above embodiments, when the second control signal is at a high level, the electronically controlled switch is closed. Correspondingly, when the second control signal is at a low level, the electronically controlled switch is disconnected. By setting the second control signal and the control signal output by the control unit to control the electronically controlled switch in the same manner, that is, when both are at a high level, the electronically controlled switch is closed, and when both are at a low level, the electronically controlled switch is disconnected, and the control method is simple, easy to understand, and not prone to error.

[0082] In the above embodiments, the preset time is 1ms-2s. Specifically, the preset time may depend on the selection of the power management chip, and the corresponding time setting register may be configured by the program during initialization. Specifically, it may be in the power management chip. The preset time can be used as a buffer time to give a reminder. When the control unit cannot return to normal within the preset time, other electrical components can be controlled in time to take corresponding measures to prevent accidents, and the user can be reminded to take timely measures to remedy the situation, thereby improving safety.

[0083] In the above embodiments, the control unit may be a single chip microcomputer, and the electric control switch may be a relay. In particular, the electric control switch may be a high voltage relay.

[0084] By adopting the control circuit for the electric control switch in the above-mentioned embodiments of the present invention, the electric control switch can be effectively prevented from being unexpectedly closed or opened, and the delayed opening control of the electric control switch can be effectively realized, and the electric control switch will not be immediately opened due to an unexpected reset of the control unit.

[0085] In a second aspect, an embodiment of the present invention further discloses an electric vehicle, comprising a control circuit for an electronically controlled switch as described in any of the aforementioned embodiments, wherein the electronically controlled switch is a relay, and when the relay is closed, the battery pack of the electric vehicle supplies power to the motor of the electric vehicle, and when the relay is disconnected, the battery pack of the electric vehicle does not supply power to the motor of the electric vehicle.

[0086] By adopting the above technical scheme, the present invention can control whether the real-time control signal output by the control unit is valid through the PWM signal. When the control unit is accidentally reset, the PWM signal is no longer refreshed. The first control signal determines whether it is the control signal at the current moment or the control signal at the previous moment according to whether the current PWM signal is a trigger signal or a non-trigger signal. The safety state signal maintains a normal state level value within a preset time, thereby delaying the change of the second control signal. Therefore, within the preset time, the electronically controlled switch can still maintain the state of the previous moment, so that when the electronically controlled switch is originally in a closed state, it will not be immediately disconnected due to the accidental reset of the control unit, thereby improving the safety and stability of the entire circuit.

[0087] In particular, when an electric vehicle is driving at high speed, the power will not be immediately cut off due to a short-term accidental reset of the control unit, which will cause a dangerous situation of power loss. This helps to improve the safety and stability of the use of electric vehicles and has very high practicality and reliability for improving the safety of electric vehicles.

[0088] Thirdly, reference Figure 2 The embodiment of the present invention further discloses a control method for an electric-controlled switch, wherein the control circuit for an electric-controlled switch described in any of the above embodiments is used to control the electric-controlled switch, and the control method specifically comprises the following steps:

[0089] S1: Determine the real-time control signal, PWM signal and safety status signal.

[0090] The control signal is configured as a signal for initially controlling the closing or opening of the electric control switch, the PWM signal includes a trigger signal and a non-trigger signal, and the safety status signal is configured to indicate whether the power management chip is in a normal state.

[0091] S2: Determine whether the first control signal is a control signal at the current moment or a control signal at the previous moment according to whether the current PWM signal is a trigger signal or a non-trigger signal.

[0092] S3: Determine a second control signal according to the first control signal and the safety state signal; wherein the second control signal is configured as a signal that ultimately controls the electric-controlled switch to be closed or opened.

[0093] S4: Controlling the electronically controlled switch to close or open according to the second control signal.

[0094] Among them, only when the safety state signal is at the normal state level value, the PWM signal can be continuously refreshed to generate a trigger signal. When the control unit is accidentally reset, the PWM signal is no longer refreshed and no trigger signal is generated. The safety state signal maintains the normal state level value within a preset time.

[0095] By adopting the above technical scheme, the present invention can control whether the real-time control signal output by the control unit is valid through the PWM signal. When the control unit is accidentally reset, the PWM signal is no longer refreshed. The first control signal determines whether it is the control signal at the current moment or the control signal at the previous moment according to whether the current PWM signal is a trigger signal or a non-trigger signal. The safety state signal maintains a normal state level value within a preset time, thereby delaying the change of the second control signal. Therefore, within the preset time, the electronically controlled switch can still maintain the state of the previous moment, so that when the electronically controlled switch is originally in a closed state, it will not be immediately disconnected due to the accidental reset of the control unit, thereby improving the safety and stability of the entire circuit.

[0096] Although the present invention has been illustrated and described with reference to certain preferred embodiments of the present invention, it should be understood by those skilled in the art that the above is a further detailed description of the present invention in conjunction with specific embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. Those skilled in the art may make various changes in form and details, including making several simple deductions or substitutions, without departing from the spirit and scope of the present invention.

Claims

1. A control circuit for an electronically controlled switch, characterized in that: include: A trigger chip, comprising a first input port, a second input port and a first output port, wherein the first input port is configured to receive a real-time control signal from a control unit, wherein the control signal is configured to be a signal for initially controlling the electric switch to be closed or opened, wherein the second input port is configured to receive a PWM signal from the control unit, wherein the PWM signal comprises a trigger signal and a non-trigger signal, wherein the first output port is configured to output a first control signal, and wherein the trigger chip is configured to determine whether the first control signal is a control signal at a current moment or a control signal at a previous moment according to whether the current PWM signal is a trigger signal or a non-trigger signal; A logic AND gate chip, comprising a third input port, a fourth input port and a second output port, wherein the third input port is configured to receive the first control signal outputted from the first output port of the trigger chip, the fourth input port is configured to receive a safety status signal from a power management chip, the safety status signal is configured to indicate whether the power management chip is in a normal state, the second output port is configured to output a second control signal, and the second control signal is configured to be a signal that ultimately controls the electric control switch to be closed or opened, Among them, only when the safety status signal is a normal state level value, the PWM signal can be continuously refreshed to generate the trigger signal. When the control unit is accidentally reset, the PWM signal is no longer refreshed and no longer generates the trigger signal, and the safety status signal maintains the normal state level value within a preset time.

2. The control circuit for an electric control switch according to claim 1, characterized in that: When the control unit is accidentally reset and cannot return to normal within the preset time, the safety state signal changes from the normal state level value to the abnormal state level value.

3. The control circuit for an electric control switch according to claim 2, characterized in that: When the PWM signal is the trigger signal, the control signal at the current moment is triggered, and the first control signal is the control signal at the current moment, and / or, when the PWM signal is the non-trigger signal, the control signal at the current moment is not triggered, and the first control signal is the control signal at the previous moment.

4. The control circuit for an electric control switch according to claim 3, characterized in that: When the safety state signal is at the normal state level value, the second control signal is determined according to the first control signal.

5. The control circuit for an electric control switch according to claim 4, characterized in that: The normal state level value is a high level, and the abnormal state level value is a low level. When the safety state signal is a low level, the second control signal is a low level, and the electronically controlled switch is disconnected.

6. The control circuit for an electronically controlled switch according to claim 5, wherein the trigger signal is a rising edge signal or a falling edge signal, and when the safety status signal is at a high level and the PWM signal is the trigger signal, the first control signal and the second control signal are both the same as the control signal at the current moment, and / or, when the safety status signal is at a high level and the PWM signal is a non-trigger signal, the first control signal and the second control signal are both the same as the control signal at the previous moment.

7. The control circuit for an electric control switch according to claim 6, characterized in that: When the second control signal is at a high level, the electronically controlled switch is closed.

8. The control circuit for an electric control switch according to claim 1, characterized in that: The preset time is 1ms-2s, and / or the duty cycle of the PWM signal is 1-99% and the frequency is 1Hz-100KHz, and / or the control unit is a single-chip microcomputer, and / or the trigger chip is a D trigger chip.

9. An electric vehicle, characterized in that: It comprises a control circuit for an electric-controlled switch as described in any one of claims 1 to 8, wherein the electric-controlled switch is a relay, and when the relay is closed, the battery pack of the electric vehicle supplies power to the motor of the electric vehicle, and when the relay is disconnected, the battery pack of the electric vehicle does not supply power to the motor of the electric vehicle.

10. A control method for an electric control switch, characterized in that: The electronically controlled switch is controlled by using the control method for the electronically controlled switch according to any one of claims 1 to 8, the control method comprising: Determine a real-time control signal, a PWM signal and a safety status signal, wherein the control signal is configured as a signal for initially controlling the closing or opening of the electric control switch, the PWM signal includes a trigger signal and a non-trigger signal, and the safety status signal is configured to indicate whether the power management chip is in a normal state; Determining whether the first control signal is a control signal at a current moment or a control signal at a previous moment according to whether the current PWM signal is a trigger signal or a non-trigger signal; Determine a second control signal according to the first control signal and the safety state signal, wherein the second control signal is configured as a signal that ultimately controls the electric control switch to be closed or opened; Controlling the electronically controlled switch to be closed or opened according to the second control signal; Among them, only when the safety status signal is a normal state level value, the PWM signal can be continuously refreshed to generate the trigger signal. When the control unit is accidentally reset, the PWM signal is no longer refreshed and no longer generates the trigger signal, and the safety status signal maintains the normal state level value within a preset time.

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