Detection circuit and vehicle

Abstract

The invention provides a detection circuit and a vehicle, the detection circuit comprises a controlled element and a control element, one end of the controlled element is connected with the control circuit, and the other end of the controlled element is grounded; one end of the control element is connected with the first end of the low-voltage detection connector, the other end of the control element is connected with the second end of the low-voltage detection connector, and the control element controls the on-off of the controlled element according to the connection state of the low-voltage detection connector, so that the controlled element outputs a corresponding detection signal to the control circuit; the control circuit determines the on-off state of the high-voltage interlocking loop and the connection state of the low-voltage detection connector based on the detection signal. According to the circuit, the connection state of the low-voltage detection connector can be converted into a high-low level detection signal which can be identified by the control circuit, so that the fault position and the on-off state corresponding to the high-voltage interlocking loop can be accurately known, the detection and troubleshooting efficiency is improved, and the detection reliability is relatively high.

Description

Technical Field

[0001] The present application relates to the technical field of high-voltage interlock detection, and more specifically, to a detection circuit and a vehicle. Background Art

[0002] With the development of new energy vehicles, electrification has gradually become a trend. Electric vehicles are usually equipped with high-voltage electrical systems, which are used to power high-power electrical equipment (such as motors) in the vehicle. In order to detect the working status of the high-voltage electrical system in real time, a high-voltage interlock (High Voltage Interlock Loop, HVIL) system is usually installed in the vehicle. The high-voltage interlock system is equipped with multiple high-voltage connectors and corresponding low-voltage detection connectors. Each high-voltage connector usually has an interlocking contact, which is connected to a complete high-voltage interlocking circuit through wires. The high-voltage interlocking system can cut off the high-voltage power supply in time when the high-voltage electrical system is abnormal, thereby preventing electric shock accidents and fire risks.

[0003] The high-voltage interlocking system of the related art is usually also provided with a high-voltage interlocking detection circuit and a control system. Once the high-voltage interlocking detection circuit detects that the high-voltage interlocking circuit is disconnected, it will immediately send a signal to the control system, so that the control system cuts off the high-voltage output of all loads to ensure safety. However, the high-voltage interlocking detection circuit in the related art cannot detect the specific location where the high-voltage interlocking circuit is disconnected, resulting in low efficiency in troubleshooting the high-voltage interlocking system. Summary of the invention

[0004] The present application provides a detection circuit and a vehicle, aiming to solve the problem that a high-voltage interlock detection circuit cannot detect the specific location where a high-voltage interlock circuit is disconnected, resulting in low efficiency in troubleshooting high-voltage interlock system faults.

[0005] In a first aspect, a detection circuit is provided, which is applied to a vehicle. The vehicle includes a high-voltage interlocking circuit with a low-voltage detection connector and a control circuit. The detection circuit includes a controlled element and a control element. One end of the controlled element is connected to the control circuit, and the other end of the controlled element is grounded; one end of the control element is connected to the first end of the low-voltage detection connector, and the other end of the control element is connected to the second end of the low-voltage detection connector. The control element is used to control the on and off of the controlled element according to the connection state of the low-voltage detection connector, so that the controlled element outputs a corresponding detection signal to the control circuit. The control circuit can determine the on and off state of the high-voltage interlocking circuit and the connection state of the low-voltage detection connector based on the detection signal.

[0006] In the above technical scheme, the control element provided by the present application can detect the connection status of the low-voltage detection connector in real time, and control the on-off of the controlled element based on the detected real-time connection status of the low-voltage detection connector, so that the controlled element outputs the corresponding detection signal to the control circuit, realizing the accurate detection of the connection status of the low-voltage detection connector and the on-off status of the high-voltage interlocking circuit, and the detection circuit provided by the present application can convert the connection status of the low-voltage detection connector into a high-low level detection signal that can be recognized by the control circuit, and the control circuit can accurately know the fault location (i.e., the abnormally connected low-voltage detection connector) based on the detection signal, so that the staff can determine the fault of the low-voltage detection connector, quickly repair or replace the low-voltage detection connector, improve the detection and troubleshooting efficiency, effectively solve the problem of low efficiency in troubleshooting the high-voltage interlocking system, and improve a certain degree of safety. Secondly, the detection circuit can realize autonomous detection through the control element and the controlled element, without relying on the control of the control circuit or other control circuits, and the detection flexibility is high.

[0007] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the control element is a coil, one end of the coil is connected to the first end of the low voltage detection connector, and the other end of the coil is connected to the second end of the low voltage detection connector; the controlled element is an armature switch, the armature switch is arranged corresponding to the coil, the first end of the armature switch is connected to the control circuit, and the other end of the armature switch is grounded.

[0008] In the above technical solution, the on-off of the contacts of the armature switch can be controlled by changing the current of the coil, that is, the on-off of the contacts is controlled by outputting different high and low levels of the current of the coil to output corresponding high and low level detection signals, which has high flexibility, and the coil only needs a small current to drive, and has low power consumption. Secondly, the coil circuit and the contact circuit of the armature switch in the relay formed by the coil and the armature switch are electrically isolated, that is, there is no direct electrical connection between the control circuit corresponding to the armature switch and the load circuit corresponding to the coil, which can effectively prevent high voltage or large current from damaging the circuit, and improve the service life and reliability of the detection circuit.

[0009] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the control element is a light emitting diode, the positive electrode of the light emitting diode is connected to the first end of the low voltage detection connector, and the negative electrode of the light emitting diode is connected to the second end of the low voltage detection connector; the controlled element is a transistor, the transistor and the light emitting diode are arranged correspondingly, the collector of the transistor is connected to the control circuit, and the emitter of the transistor is grounded.

[0010] In the above technical solution, the on-off of the triode can be controlled by changing the current of the light-emitting diode, that is, the on-off of the triode is controlled by outputting different high and low levels of the current of the light-emitting diode, so as to output corresponding high and low level detection signals, which has high flexibility and fast response speed, and the light-emitting diode only needs a small current to drive the light emission, and has low power consumption. Secondly, the light-emitting diode circuit and the triode circuit in the photoelectric coupler composed of the light-emitting diode and the triode are electrically isolated, that is, there is no direct electrical connection between the control circuit corresponding to the light-emitting diode and the load circuit corresponding to the triode, which can effectively prevent the damage of the circuit by high voltage or large current, realize electrical isolation, and improve the service life and reliability of the detection circuit.

[0011] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the detection circuit also includes a first resistor and a filter capacitor; one end of the first resistor is connected to one end of the controlled element, and the other end of the first resistor is connected to the control circuit; the first plate of the filter capacitor is connected to one end of the first resistor and one end of the controlled element, and the second plate of the filter capacitor is grounded.

[0012] In the above technical solution, the RC filter formed by the first resistor and the filter capacitor can filter out high-frequency noise, reduce the interference components in the detection signal output by the controlled element, and remove noise through the first resistor and the filter capacitor, which can improve the signal-to-noise ratio, reduce electromagnetic interference, and make the detection signal easier to be received by the control circuit. Secondly, the first resistor and the filter capacitor can also smooth the detection signal, reduce the fluctuation and jitter of the detection signal, and make the detection signal connected to the control circuit more stable. In this way, the first resistor and the filter capacitor are set between the controlled element and the control circuit, which can filter out high-frequency noise in the detection signal, stabilize the detection signal, improve the signal-to-noise ratio and reduce electromagnetic interference, thereby ensuring the detection reliability of the detection circuit, and then ensuring the reliability of the detection signal received by the control circuit.

[0013] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the detection circuit also includes: a pull-up resistor, one end of the pull-up resistor is connected to the first power supply voltage, and the other end of the pull-up resistor is connected to the first plate of the filter capacitor, one end of the first resistor, and one end of the controlled element.

[0014] In the above technical solution, the pull-up resistor can ensure that the connection point of the control circuit is in a high level state when there is no other driving signal (such as a detection signal), so as to avoid the problem that the connection point of the control circuit may be in an uncertain state (such as a high impedance state or a floating state) when the pull-up resistor is not set, which may cause the control circuit to be accidentally touched. These connection points can be pulled to a high level by the pull-up resistor to avoid the control circuit from accidentally touching. Secondly, the pull-up resistor can also improve the anti-interference ability of the detection circuit and reduce the influence of external noise on the detection circuit and the control circuit.

[0015] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the number of low-voltage detection connectors is multiple, and the number of controlled elements and control elements are respectively multiple; the multiple control elements correspond one-to-one to the controlled elements and the low-voltage detection connectors, respectively, and the multiple control elements are connected in series in sequence.

[0016] In the above technical scheme, multiple control elements can control the on and off of corresponding controlled elements based on the connection status of the low-voltage detection connectors connected thereto, so that the multiple controlled elements can output corresponding detection signals to the control circuit, and the control circuit can determine the connection status of the multiple low-voltage detection connectors and the on and off status of the corresponding high-voltage interlocking circuit based on different detection signals, thereby realizing accurate detection of the connection status of the multiple low-voltage detection connectors and the on and off status of the high-voltage interlocking circuit, and the control circuit can accurately know the fault location (i.e., the low-voltage detection connector with abnormal connection) based on the detection signal, further improving the detection and troubleshooting efficiency, effectively solving the problem of low efficiency in troubleshooting high-voltage interlocking system faults, and improving a certain degree of safety.

[0017] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the detection circuit also includes a second resistor, a first switch module and a current source; one end of the second resistor is connected to the control circuit; the first end of the first switch module is connected to the other end of the second resistor, the second end of the first switch module is grounded, and the third end of the first switch module is connected to the first control element among the multiple control elements; one end of the current source is connected to the fourth end of the first switch module, and the other end of the current source is connected to the last control element among the multiple control elements.

[0018] In the above technical solution, the control circuit can reduce the energy consumption of the detection circuit and save a certain amount of energy by controlling the first switch module to turn off.

[0019] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the first switch module is a photocoupler; the anode of the light-emitting diode in the photocoupler is connected to the other end of the second resistor, the cathode of the light-emitting diode in the photocoupler is grounded, the collector of the transistor in the photocoupler is connected to one end of the current source, and the emitter of the transistor in the photocoupler is connected to the first control element among the multiple control elements.

[0020] In the above technical solution, the control circuit can control the on and off of the transistor by changing the current of the light-emitting diode in the photoelectric coupler to realize the on and off control of the first switch module, which has high flexibility and fast response speed, and the light-emitting diode only needs a small current to drive the light emission, and the power consumption is low. Secondly, the light-emitting diode circuit and the transistor circuit in the photoelectric coupler are electrically isolated, that is, there is no direct electrical connection between the control circuit corresponding to the light-emitting diode and the load circuit corresponding to the transistor, which can effectively prevent the damage of high voltage or large current to the circuit, realize electrical isolation, and improve the service life and reliability of the detection circuit.

[0021] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the detection circuit also includes a third resistor and a second switch module; one end of the third resistor is connected to the second power supply voltage; the first end of the second switch module is connected to the other end of the third resistor, the second end of the second switch module is connected to the first control element among the multiple control elements, and the controlled end of the second switch module is connected to the control circuit.

[0022] In the above technical solution, the control circuit can reduce the energy consumption of the detection circuit and save a certain amount of energy by controlling the second switch module to turn off.

[0023] In a second aspect, an embodiment of the present application provides a vehicle, comprising a high-voltage interlocking circuit and a detection circuit as described in any optional manner of the first aspect, wherein the high-voltage interlocking circuit is provided with a low-voltage detection connector, and the detection circuit is connected to the low-voltage detection connector. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of a module structure of a vehicle provided in an embodiment of the present application;

[0025] Figure 2 is a schematic diagram of a module structure of another vehicle provided in an embodiment of the present application;

[0026] Figure 3 is a circuit structure diagram of a detection circuit provided in an embodiment of the present application;

[0027] Figure 4 is a circuit structure diagram of another detection circuit provided in an embodiment of the present application;

[0028] Figure 5 is a circuit structure diagram of another detection circuit provided in an embodiment of the present application;

[0029] Figure 6 is a circuit structure diagram of another detection circuit provided in an embodiment of the present application;

[0030] Figure 7 is a circuit structure diagram of another detection circuit provided in an embodiment of the present application;

[0031] Figure 8 This is a circuit structure diagram of another detection circuit provided in an embodiment of the present application.

[0032] Among them, the reference numerals in the figure are:

[0033] 1. Detection circuit; 11. Controlled element; 12. Control element; 13. Second switch module; 14. First switch module; 2. Low voltage detection connector; 3. Control circuit; R0, pull-up resistor; R1, first resistor; R2, second resistor; R3, third resistor; C, filter capacitor; VCC1, first power supply voltage; VCC2, second power supply voltage; CCS, current source. DETAILED DESCRIPTION

[0034] The technical solution in the present application will be described clearly and in detail below in conjunction with the accompanying drawings. In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B: "and / or" in the text is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0035] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0036] At present, new energy vehicles are widely used in various scenarios instead of internal combustion engine vehicles. Compared with internal combustion engine vehicles, new energy vehicles produce less noise during driving and do not directly emit exhaust gas, which is more environmentally friendly. At the same time, new energy vehicles are intelligent, have higher energy efficiency conversion rate and lower maintenance cost, so more and more people are starting to use new energy vehicles as a means of transportation. New energy vehicles are usually equipped with power batteries to provide power sources for vehicles and drive motors. For example, the power battery will output direct current to the motor, and the motor controller (Motor Control Unit, MCU) will convert the direct current provided by the power battery into three-phase alternating current for the drive motor according to the target torque and speed sent by the vehicle control unit (VCU), so as to control the motor to complete functions such as starting, acceleration and deceleration, braking, energy recovery, etc., so as to ensure the normal operation of the vehicle.

[0037] New energy vehicles are usually equipped with two electrical systems, high voltage and low voltage. Among them, a high voltage battery (such as a power battery) is provided in the high voltage electrical system. The high voltage battery is used to power high-power electrical equipment (such as a motor) in the vehicle to drive the vehicle to maintain normal driving. At the same time, the power battery will also charge the low voltage battery in the vehicle under the control of the vehicle controller, and the charging voltage is usually about several hundred volts. In order to ensure the safety of the driver, passengers and vehicles, a high voltage interlocking system is usually provided in the vehicle. The high voltage interlocking system includes a high voltage connector and a control system. The high voltage connector is used to connect various components in the high voltage electrical system (such as high voltage components such as high voltage batteries, motors, inverters, etc.) to ensure the safe transmission of high voltage current. Each high voltage connector usually has an interlocking contact, which is connected in series through wires to form a complete high voltage interlocking circuit. The high voltage interlocking circuit and the control system can cut off the high voltage power supply in time when the high voltage electrical system is abnormal, thereby preventing electric shock accidents and fire risks.

[0038] The high-voltage connector may be loose or fall off, and the high-voltage interlocking circuit is abnormal. In order to grasp the connection status of the high-voltage interlocking circuit in real time, the high-voltage interlocking system in the related art usually also includes a high-voltage interlocking detection circuit. The high-voltage interlocking detection circuit includes a low-voltage detection connector and a low-voltage detection port. The low-voltage detection connector is used to connect the low-voltage detection port and the high-voltage interlocking circuit to ensure the reliable transmission of the signal. It is usually distributed between various nodes in the high-voltage interlocking circuit. The low-voltage detection port is used to send and receive low-voltage signals (such as 5V or 12V low-voltage signals) to detect the state of the high-voltage interlocking circuit. Its detection principle is usually: before the vehicle starts, the control system will send a low-voltage excitation signal through the low-voltage detection port. This excitation signal will be transmitted through the low-voltage detection connector and along the interlocking contacts of all high-voltage connectors in the high-voltage interlocking circuit. If all high-voltage connectors are correctly connected, the excitation signal will be smoothly transmitted and returned to the low-voltage detection port through the low-voltage detection connector. If the low voltage detection port receives a feedback signal that matches the sent excitation signal, it means that all high voltage connectors are correctly connected and the high voltage interlock circuit is normal. At this time, the control system will activate the high voltage power supply and the high voltage electrical system will start working. Once a high voltage interlock circuit fault is detected, the control system will take the same approach, that is, cut off the high voltage output of all loads.

[0039] However, the high-voltage interlock detection circuit in the related art can usually only detect whether a high-voltage interlock circuit fails, but cannot accurately locate the specific location of the fault.

[0040] To this end, an embodiment of the present application provides a detection circuit and a vehicle, which can convert the connection status of a low-voltage detection connector into high and low level detection signals that can be recognized by a control circuit, so that the control circuit can accurately know the fault location (i.e., the abnormally connected low-voltage detection connector) and the on-off status of the corresponding high-voltage interlocking circuit based on the detection signal, thereby improving the detection and troubleshooting efficiency, having high detection reliability, and effectively solving the problem of low efficiency in troubleshooting high-voltage interlocking system faults.

[0041] The detection circuit and vehicle provided in the embodiments of the present application are exemplarily introduced below with reference to the accompanying drawings.

[0042] The embodiment of the present application provides a vehicle, and the vehicle provided by the present application includes a high-voltage electrical system and a low-voltage electrical system, wherein a high-voltage battery (such as a power battery) is provided in the high-voltage electrical system, and the high-voltage battery is used to power high-power electrical equipment in the vehicle (such as motors, inverters and other high-voltage components) to drive the vehicle to maintain normal driving. At the same time, the power battery will also charge the low-voltage battery in the low-voltage electrical system under the control of the vehicle controller. A low-voltage battery (such as a 12V battery) and a direct current converter (Direct Current to Direct Current Converter, DCDC) are provided in the low-voltage electrical system. The direct current converter can convert the high voltage electricity of the high-voltage battery into low voltage electricity to meet the transmission / control of signals in the vehicle, which will not be described in detail.

[0043] Among them, the voltage in the high-voltage electrical system is usually above hundreds of volts. When repairing or inspecting the vehicle, personnel may accidentally touch the high-voltage components that are not completely disconnected, resulting in electric shock accidents. Secondly, the short circuit or poor connection of the high-voltage electrical system may cause sparks or overheating, which in turn causes fires, and there are great safety hazards. To this end, the vehicle provided by the present application is provided with a high-voltage interlocking system, which includes a high-voltage connector, which is used to connect various components in the high-voltage electrical system to ensure the safe transmission of high-voltage current. Each high-voltage connector usually has an interlocking contact, which is connected in series through wires to form a complete high-voltage interlocking circuit. The high-voltage interlocking circuit can ensure that when the high-voltage connector is not completely connected or disconnected, the high-voltage power supply will not be activated, thereby preventing personnel from contacting the live high-voltage components. At the same time, when the high-voltage electrical system is short-circuited or poorly connected, the high-voltage interlocking circuit can quickly cut off the high-voltage power supply to prevent fires caused by electrical faults.

[0044] In order to realize the fault detection of the high voltage interlocking circuit, in one example, Figure 1 As shown, the vehicle provided in the present application also includes a detection circuit 1, a low-voltage detection connector 2 and a control circuit 3. The low-voltage detection connector 2 is arranged in a high-voltage interlocking circuit (not shown in the figure) and corresponds to a high-voltage connector (not shown in the figure). The detection circuit 1 is connected to the low-voltage detection connector 2, and the control circuit 3 is connected to the detection circuit 1. The control circuit 3 in the present application can detect the connection status of the low-voltage detection connector 2 based on the detection circuit 1, thereby realizing fault detection of the high-voltage interlocking circuit.

[0045] In order to enable the detection circuit 1 to accurately detect the connection status of the low voltage detection connector 2, in one example, Figure 1As shown, the detection circuit 1 includes a controlled element 11 and a control element 12, one end of the controlled element 11 is connected to the control circuit 3, the other end of the controlled element 11 is grounded, one end of the control element 12 is connected to the first end of the low voltage detection connector 2, and the other end of the control element 12 is connected to the second end of the low voltage detection connector 2. The control element 12 is used to control the on and off of the controlled element 11 according to the connection state of the low voltage detection connector 2, so that the controlled element 11 outputs a corresponding detection signal to the control circuit 3, and the control circuit 3 can determine the on and off state of the high voltage interlocking circuit and the connection state of the low voltage detection connector 2 based on the detection signal.

[0046] Among them, the connection status includes normal connection and abnormal connection. When the low-voltage detection connector 2 is normally connected, the high-voltage interlocking circuit is connected, that is, the high-voltage interlocking circuit is normal; abnormal connection refers to the low-voltage detection connector 2 being loose or falling off. At this time, the low-voltage detection connector 2 is abnormally connected, resulting in the disconnection of the high-voltage interlocking circuit, that is, the high-voltage interlocking circuit is abnormal.

[0047] In this example, the control element 12 will detect the connection status of the low-voltage detection connector 2 in real time to control the on and off of the controlled element 11 accordingly, so that the controlled element 11 outputs a corresponding detection signal to the control circuit 3. Exemplarily, when the low-voltage detection connector 2 corresponding to the control element 12 is normally connected, the control element 12 will not receive current, and at this time the control element 12 controls the controlled element 11 to turn off. It can be understood that when the control element 12 does not receive current, the control element 12 is not turned on, and the controlled element 11 is not turned on, that is, it is turned off. At this time, the controlled element 11 will output a corresponding high-level detection signal to the control circuit 3, so that the control circuit 3 knows that the low-voltage detection connector 2 is normally connected based on the high-level detection signal, and the high-voltage interlocking circuit remains connected, that is, the high-voltage interlocking circuit has not failed at this time. When the low voltage detection connector 2 corresponding to the control element 12 is abnormally connected, the control element 12 will receive current, and at this time the control element 12 controls the controlled element 11 to be turned on. It can be understood that when the control element 12 receives current, the control element 12 is turned on, and the corresponding controlled element 11 is turned on. At this time, the controlled element 11 will output a corresponding low-level detection signal to the control circuit 3, so that the control circuit 3 knows that the low voltage detection connector 2 is abnormally connected based on the low-level detection signal, and the high-voltage interlocking circuit is turned off, that is, at this time, the control circuit 3 can determine that the high voltage interlocking circuit has a fault based on the low-level detection signal. When a fault in the high voltage interlocking circuit is detected and the fault location (i.e., the low voltage detection connector 2 with abnormal connection) is determined, the staff can repair or replace the low voltage detection connector 2 based on the fault location to efficiently eliminate the high voltage interlocking system fault.

[0048] It can be understood that the detection circuit 1 provided in the present application can convert the connection status of the low-voltage detection connector 2 into high and low level detection signals that can be recognized by the control circuit 3, so that the control circuit 3 can determine the connection status of multiple low-voltage detection connectors 2 and the on-off status of the corresponding high-voltage interlocking circuit based on the high and low level detection signals.

[0049] In this way, the control element 12 provided by the present application can detect the connection state of the low-voltage detection connector 2 in real time, and control the on-off of the controlled element 11 based on the detected real-time connection state of the low-voltage detection connector 2, so that the controlled element 11 outputs the corresponding detection signal to the control circuit 3, realizing the accurate detection of the connection state of the low-voltage detection connector 2 and the on-off state of the high-voltage interlocking circuit, and the detection circuit 1 provided by the present application can convert the connection state of the low-voltage detection connector 2 into a high-low level detection signal that can be recognized by the control circuit 3, and the control circuit 3 can accurately know the fault location (i.e., the abnormally connected low-voltage detection connector 2) based on the detection signal, so that the staff can determine the fault of the low-voltage detection connector 2, quickly repair or replace the low-voltage detection connector 2, improve the detection and troubleshooting efficiency, effectively solve the problem of low efficiency in troubleshooting the high-voltage interlocking system, and improve a certain degree of safety. Secondly, the control element 12 and the controlled element 11 can enable the detection circuit 1 to realize autonomous detection without relying on the control of the control circuit 3 or other control circuits, and the detection flexibility is high.

[0050] Optionally, the detection circuit 1 provided in the present application may be connected to the low voltage detection connector 2 via a low voltage detection port.

[0051] Optionally, the control circuit 3 provided in the present application may be a microcontroller unit (MCU).

[0052] In one example, if Figure 2 As shown, a plurality of low-voltage detection connectors 2 are provided in the high-voltage interlocking circuit, that is, the number of low-voltage detection connectors 2 is multiple, and correspondingly, the number of controlled elements 11 and the number of control elements 12 are multiple, respectively, and the plurality of control elements 12 correspond one-to-one to the controlled elements 11 and the low-voltage detection connectors 2. It can be understood that the number of the plurality of control elements 12 is the same as the number of low-voltage detection connectors 2 and the number of low-voltage detection connectors 2, each low-voltage detection connector 2 is connected to a control element 12, and each control element 12 has a corresponding controlled element 11. For example, when the number of low-voltage detection connectors 2 is 4, the corresponding number of controlled elements 11 and the number of control elements 12 are also 4. Among them, as Figure 2 As shown, a plurality of control elements 12 are connected in series in sequence, and a plurality of controlled elements 11 are connected to each other and grounded.

[0053] In this example, each control element 12 can control the on / off state of the corresponding controlled element 11 based on the connection state of the low-voltage detection connector 2 connected thereto, so that the controlled element 11 can output a corresponding detection signal to the control circuit 3, and the control circuit 3 can determine the on / off state of the high-voltage interlocking circuit and the connection state of multiple low-voltage detection connectors 2 based on multiple detection signals, so as to realize accurate detection of the connection state of multiple low-voltage detection connectors 2 and the on / off state of the high-voltage interlocking circuit.

[0054] Exemplarily, when the connection status of all low-voltage detection connectors 2 is normally connected, multiple control elements 12 will not receive current. At this time, the control element 12 controls the corresponding controlled element 11 to be turned off. At this time, multiple controlled elements 11 will output corresponding high-level detection signals to the control circuit 3, so that the control circuit 3 can determine that the low-voltage detection connectors 2 are all normally connected based on the high-level detection signals from the multiple controlled elements 11, and the high-voltage interlocking circuit remains connected, that is, the high-voltage interlocking circuit has not failed at this time. When the connection status of one of the low voltage detection connectors 2 is abnormal connection, and the connection status of the other low voltage detection connectors 2 is normal connection, the control element 12 corresponding to one of the low voltage detection connectors 2 will receive current, and then the control element 12 controls the corresponding controlled element 11 to be turned on, so that the controlled element 11 outputs the corresponding low level detection signal to the control circuit 3, and the control elements 12 corresponding to the other low voltage detection connectors 2 will not receive current, so that the corresponding controlled elements 11 output high level detection signals to the control circuit 3, and the control circuit 3 can determine that the corresponding low voltage detection connectors 2 are all abnormally connected based on the low level detection signal, and determine that the corresponding low voltage detection connectors 2 are all normally connected based on the high level detection signal. It can be understood that if any one of the multiple low voltage detection connectors 2 is abnormally connected, the high voltage interlocking circuit is turned off, that is, at this time, the control circuit 3 can determine that the high voltage interlocking circuit has a fault based on the low level detection signal. When a fault is detected in the high-voltage interlock circuit and the fault location is determined (i.e., the abnormally connected low-voltage detection connector 2), the staff can repair or replace the low-voltage detection connector 2 based on the fault location to efficiently eliminate the high-voltage interlock system fault.

[0055] It is worth noting that the number of low-voltage detection connectors can be equal to or less than the number of high-voltage connectors. When the number of low-voltage detection connectors is equal to the number of high-voltage connectors, the high-voltage connectors and the low-voltage detection connectors are one-to-one corresponding to ensure that the state of each high-voltage connector can be independently detected, thereby improving the safety of the system; when the number of low-voltage detection connectors is less than the number of high-voltage connectors, multiple high-voltage connectors can be connected to the same low-voltage detection connector to save manufacturing costs. The specific settings can be made according to actual needs, and this application does not make specific restrictions on this.

[0056] In this way, multiple control elements 12 can control the on and off of corresponding controlled elements 11 based on the connection status of the low-voltage detection connector 2 connected thereto, so that multiple controlled elements 11 can output corresponding detection signals to the control circuit 3. The control circuit 3 can determine the connection status of multiple low-voltage detection connectors 2 and the on and off status of the corresponding high-voltage interlocking circuit based on different detection signals, thereby realizing accurate detection of the connection status of multiple low-voltage detection connectors 2 and the on and off status of the high-voltage interlocking circuit. The control circuit 3 can accurately know the fault location (i.e., the low-voltage detection connector 2 with abnormal connection) based on the detection signal, further improving the detection and troubleshooting efficiency, effectively solving the problem of low efficiency in troubleshooting high-voltage interlocking system faults, and improving a certain degree of safety.

[0057] In one example, if Figure 3 As shown, the control element 12 is a coil, one end of the coil is connected to the first end of the low voltage detection connector 2, and the other end of the coil is connected to the second end of the low voltage detection connector 2. The controlled element 11 is an armature switch, and the armature switch is arranged corresponding to the coil. The first end of the armature switch is connected to the control circuit 3, and the other end of the armature switch is grounded. At this time, the controlled element 11 and the control element 12 together constitute a relay.

[0058] The armature switch has a normally open contact. When the low-voltage detection connector 2 corresponding to the coil is connected normally, the coil will not receive current and the coil is not turned on. At this time, the normally open contact of the armature switch is in an open state, that is, the armature switch is turned off, and the armature switch will output a corresponding high-level detection signal to the control circuit 3, so that the control circuit 3 knows that the low-voltage detection connector 2 is normally connected based on the signal. When the low-voltage detection connector 2 corresponding to the coil is abnormally connected, the coil will receive current and the coil is turned on. At this time, the normally open contact of the armature switch is in a closed state, that is, the armature switch is turned on, and the armature switch will output a corresponding low-level detection signal to the control circuit 3, so that the control circuit 3 knows that the low-voltage detection connector 2 is abnormally connected based on the signal.

[0059] It is worth noting that when there are multiple low-voltage detection connectors 2, each low-voltage detection connector 2 is connected to a corresponding coil, each coil is provided with a corresponding armature switch, wherein the other ends of the multiple armature switches are mutually connected to ground.

[0060] In this example, the on-off of the contacts of the armature switch can be controlled by changing the current of the coil, that is, the on-off of the contacts is controlled by outputting different high and low levels of the current of the coil to output corresponding high and low level detection signals, which has high flexibility, and the coil only needs a small current to drive, and has low power consumption. Secondly, the coil circuit and the contact circuit of the armature switch in the relay formed by the coil and the armature switch are electrically isolated, that is, there is no direct electrical connection between the control circuit corresponding to the armature switch and the load circuit corresponding to the coil, which can effectively prevent high voltage or large current from damaging the circuit, realize electrical isolation, and improve the service life and reliability of the detection circuit 1.

[0061] In one example, if Figure 4 As shown, the control element 12 is a light emitting diode (LED), the positive electrode of the light emitting diode is connected to the first end of the low voltage detection connector 2, and the negative electrode of the light emitting diode is connected to the second end of the low voltage detection connector 2. The controlled element 11 is a transistor, and the transistor is arranged corresponding to the light emitting diode. The collector of the transistor is connected to the control circuit 3, and the emitter of the transistor is grounded. At this time, the controlled element 11 and the control element 12 together constitute a photoelectric coupler.

[0062] It is worth noting that when there are multiple low voltage detection connectors 2, each low voltage detection connector 2 is connected to a corresponding light emitting diode, each light emitting diode is provided with a corresponding transistor, wherein the emitters of the multiple transistors are interconnected and grounded.

[0063] In this example, when the low-voltage detection connector 2 corresponding to the light-emitting diode is connected normally, the light-emitting diode will not receive current, the light-emitting diode is not turned on, and the light-emitting diode does not emit light at this time, then the transistor is turned off, and the transistor will output a corresponding high-level detection signal to the control circuit 3, so that the control circuit 3 knows that the low-voltage detection connector 2 is connected normally based on the signal. When the low-voltage detection connector 2 corresponding to the light-emitting diode is abnormally connected, the light-emitting diode will receive current, the light-emitting diode is turned on, and the light-emitting diode emits light at this time, then the transistor is turned on, and the transistor will output a corresponding low-level detection signal to the control circuit 3, so that the control circuit 3 knows that the low-voltage detection connector 2 is abnormally connected based on the signal.

[0064] In this example, the on and off of the transistor can be controlled by changing the current of the light-emitting diode, that is, the on and off of the transistor can be controlled by outputting different high and low levels of the current of the light-emitting diode to output corresponding high and low level detection signals, which has high flexibility and fast response speed. Moreover, the light-emitting diode only needs a small current to drive the light emission, and the power consumption is low. Secondly, the light-emitting diode circuit and the transistor circuit in the photoelectric coupler composed of the light-emitting diode and the transistor are electrically isolated, that is, there is no direct electrical connection between the control circuit corresponding to the light-emitting diode and the load circuit corresponding to the transistor, which can effectively prevent the damage of high voltage or large current to the circuit, realize electrical isolation, and improve the service life and reliability of the detection circuit.

[0065] In order to improve the reliability of the detection signal output by the controlled element 11, in one example, Figure 5 As shown, the detection circuit 1 also includes a first resistor R1 and a filter capacitor C, one end of the first resistor R1 is connected to one end of the controlled element 11, the other end of the first resistor R1 is connected to the control circuit 3, the first plate of the filter capacitor C is connected to one end of the first resistor R1 and one end of the controlled element 11, and the second plate of the filter capacitor C is grounded.

[0066] In this example, the RC filter formed by the first resistor R1 and the filter capacitor C can filter out high-frequency noise, reduce the interference components in the detection signal output by the controlled element 11, and remove noise through the first resistor R1 and the filter capacitor C, which can improve the signal-to-noise ratio, reduce electromagnetic interference, and make the detection signal easier to be received by the control circuit 3. Secondly, the first resistor R1 and the filter capacitor C can also smooth the detection signal, reduce the fluctuation and jitter of the detection signal, and make the detection signal connected to the control circuit 3 more stable. In this way, the first resistor R1 and the filter capacitor C are set between the controlled element 11 and the control circuit 3, which can filter out high-frequency noise in the detection signal, stabilize the detection signal, improve the signal-to-noise ratio, and reduce electromagnetic interference, thereby ensuring the detection reliability of the detection circuit 1, and then ensuring the reliability of the detection signal received by the control circuit 3.

[0067] It is worth noting that when there are multiple low voltage detection connectors 2, each detection branch corresponding to the low voltage detection connector 2 is provided with a first resistor R1 and a filter capacitor C, wherein the second plates of the multiple filter capacitors C are interconnected to be grounded.

[0068] In one example, if Figure 5 As shown, the detection circuit 1 also includes a pull-up resistor R0, one end of which is connected to the first power supply voltage VCC1, and the other end of which is connected to the first plate of the filter capacitor C, one end of the first resistor R1 and one end of the controlled element 11.

[0069] In this example, the pull-up resistor R0 can ensure that the connection points of the control circuit 3 are in a high-level state when there are no other drive signals (such as detection signals), so as to avoid the problem that the connection points of the control circuit 3 may be in an uncertain state (such as a high-impedance state or a floating state) when the pull-up resistor R0 is not set, which may cause the control circuit 3 to be accidentally touched. These connection points can be pulled to a high level by the pull-up resistor R0 to avoid the control circuit 3 from being accidentally touched. Secondly, the pull-up resistor R0 can also improve the anti-interference ability of the detection circuit 1 and reduce the influence of external noise on the detection circuit 1 and the control circuit 3.

[0070] It is worth noting that when there are multiple low voltage detection connectors 2 , each detection branch corresponding to each low voltage detection connector 2 is provided with a pull-up resistor R0 , wherein one end of the multiple pull-up resistors R0 are interconnected to access the first power supply voltage VCC1 .

[0071] The specific implementation scheme of the high-voltage interlocking circuit can be classified into voltage source type and current source type according to the circuit excitation source. For example, please refer to Figures 1 to 5 The high-voltage interlocking circuit adopts a voltage source type, and the control element 12 and the low-voltage detection connector 2 are connected to the second power supply voltage VCC2. In order to reduce the energy consumption of the detection circuit 1, in one example, Figure 6 As shown, the detection circuit 1 also includes a third resistor R3 and a second switch module 13, one end of the third resistor R3 is connected to the second power supply voltage VCC2, the first end of the second switch module 13 is connected to the other end of the third resistor R3, the second end of the second switch module 13 is connected to the first control element 12 among the multiple control elements 12, and the controlled end of the second switch module 13 is connected to the control circuit 3.

[0072] Here, it is worth pointing out that Figure 6 As shown, multiple control elements 12 are connected in series in sequence, wherein the control element 12 at the head end is the first control element 12 among the multiple control elements 12 , and the control element 12 at the end and grounded is the last control element 12 among the multiple control elements 12 .

[0073] In this example, when the detection circuit 1 is required to perform detection, the control circuit 3 controls the second switch module 13 to be turned on, so that the second power supply voltage VCC2 is loaded into the loop where the low-voltage detection connector 2 is located, so that the low-voltage detection connector 2 and the detection circuit 1 can operate normally. When the detection circuit 1 is not required to perform detection, the control circuit 3 controls the second switch module 13 to be turned off, so that the second power supply voltage VCC2 is not loaded into the loop where the low-voltage detection connector 2 is located, and the low-voltage detection connector 2 and the detection circuit 1 do not work at this time. In this way, the control circuit 3 can reduce the energy consumption of the detection circuit 1 and save a certain amount of energy by controlling the second switch module 13 to be turned off.

[0074] Optionally, the second switch module 13 can be a switch, an N-type metal oxide semiconductor (NMOS) field effect transistor, a P-type metal oxide semiconductor (PMOS) field effect transistor, an IGBT, a transistor, a relay circuit or other devices or circuits that can achieve on-off functions, and the present application does not make any specific restrictions on this.

[0075] Optional, such as Figure 7 As shown, the second switch module 13 can be a PNP transistor, the emitter of the PNP transistor is connected to the other end of the third resistor R3, the base of the PNP transistor is connected to the control circuit 3, and the collector of the PNP transistor is connected to the first control element 12 among the multiple control elements 12. In the on state, the saturation voltage drop of the PNP transistor is low, which helps to reduce the power loss and heat generation of the second switch module 13. The second switch module 13 can also use other switches, and this application does not make specific restrictions on this.

[0076] In this example, one end of a plurality of pull-up resistors R0 is connected to each other to access the first power supply voltage VCC1, and the second switch module 13 and the control element 12 are connected to the second power supply voltage VCC2, and the first power supply voltage VCC1 and the second power supply voltage VCC2 are used to provide independent power supplies for different circuit components (i.e., the pull-up resistor R0, the second switch module 13 and the control element 12), respectively, to reduce mutual interference. Moreover, by using an independent power supply, the voltage input to different components can be better controlled and adjusted, and the stability of the entire detection circuit 1 is improved. Secondly, even if one of the power supplies (the first power supply providing the first power supply voltage VCC1 or the second power supply providing the second power supply voltage VCC2) fails, the other power supply can still continue to supply power to other components, thereby improving the operational reliability of the detection circuit 1. The number of power supplies can be set according to actual needs, and this application does not make specific restrictions.

[0077] For example, please refer to Figure 8 The high-voltage interlocking circuit adopts a current source type. The detection circuit 1 also includes a second resistor R2, a first switch module 14 and a current source CCS. One end of the second resistor R2 is connected to the control circuit 3, the first end of the first switch module 14 is connected to the other end of the second resistor R2, the second end of the first switch module 14 is grounded, the third end of the first switch module 14 is connected to the first control element 12 among the multiple control elements 12, one end of the current source CCS is connected to the fourth end of the first switch module 14, and the other end of the current source CCS is connected to the last control element 12 among the multiple control elements 12.

[0078] In this example, when the detection circuit 1 needs to be detected, the control circuit 3 controls the first switch module 14 to be turned on, and the loop formed between the first switch module 14 and the ground terminal is turned on, so that the current source CCS is loaded into the loop where the low-voltage detection connector 2 is located, so that the low-voltage detection connector 2 and the detection circuit 1 can operate normally. When the detection circuit 1 is not needed to be detected, the control circuit 3 controls the first switch module 14 to be turned off, so that the current source CCS is not loaded into the loop where the low-voltage detection connector 2 is located, and the low-voltage detection connector 2 and the detection circuit 1 do not work at this time. In this way, the control circuit 3 can reduce the energy consumption of the detection circuit 1 and save a certain amount of energy by controlling the first switch module 14 to be turned off.

[0079] Optional, such as Figure 8 As shown, the first switch module 14 can be a photoelectric coupler, the anode of the light-emitting diode in the photoelectric coupler is connected to the other end of the second resistor R2, the cathode of the light-emitting diode in the photoelectric coupler is grounded, the collector of the triode in the photoelectric coupler is connected to the current source CCS, and the emitter of the triode in the photoelectric coupler is connected to the first control element 12 among the multiple control elements 12. The control circuit 3 can control the on-off of the triode by changing the current of the light-emitting diode in the photoelectric coupler to achieve the control of the on-off of the first switch module 14, which has high flexibility and fast response speed, and the light-emitting diode only needs a small current to drive the light emission, and the power consumption is low. Secondly, the light-emitting diode circuit and the triode circuit in the photoelectric coupler are electrically isolated, that is, there is no direct electrical connection between the control circuit corresponding to the light-emitting diode and the load circuit corresponding to the triode, which can effectively prevent the damage of high voltage or large current to the circuit, realize electrical isolation, and improve the service life and reliability of the detection circuit 1. The first switch module 14 can also select other circuits or devices that can achieve isolation and switching functions, and this application does not make specific restrictions on this.

[0080] In summary, the control element 12 provided by the present application can detect the connection state of the low-voltage detection connector 2 in real time, and control the on-off of the controlled element 11 based on the detected real-time connection state of the low-voltage detection connector 2, so that the controlled element 11 outputs the corresponding detection signal to the control circuit 3, realizing the accurate detection of the connection state of the low-voltage detection connector 2 and the on-off state of the high-voltage interlocking circuit, and the detection circuit 1 provided by the present application can convert the connection state of the low-voltage detection connector 2 into a high-low level detection signal that can be recognized by the control circuit 3, and the control circuit 3 can accurately know the fault location (i.e., the abnormally connected low-voltage detection connector 2) based on the detection signal, so that the staff can determine the fault of the low-voltage detection connector 2, quickly repair or replace the low-voltage detection connector 2, improve the detection and troubleshooting efficiency, effectively solve the problem of low efficiency in troubleshooting the high-voltage interlocking system, and improve a certain degree of safety. Secondly, the detection circuit 1 can realize autonomous detection through the control element 12 and the controlled element 11, without relying on the control of the control circuit 3 or other control circuits, and the detection flexibility is high.

[0081] The vehicle of the embodiment of the present application can be an electric vehicle, that is, a vehicle that uses electric energy as a power source and drives the wheels through an electric motor. Electric vehicles include, but are not limited to, pure electric vehicles (Battery Electric Vehicle, BEV), plug-in hybrid electric vehicles (Plug-in Hybrid Electric Vehicle, PHEV), hybrid electric vehicles (Hybrid Electric Vehicle, HEV), extended-range vehicles (Extended-Range Electric Vehicle, EREV), etc. Among them, pure electric vehicles rely entirely on the electric energy stored in the battery to drive the motor to achieve the power output of the vehicle. Plug-in hybrid vehicles combine electric motors and internal combustion engines. The electric motor can drive the vehicle alone or work with the internal combustion engine, and the battery can be charged by an external power supply. Hybrid vehicles are equipped with both electric motors and internal combustion engines. The electric motor assists the internal combustion engine in working, but cannot drive the vehicle alone. Extended-range vehicles are mainly driven by electric motors, and the internal combustion engine acts as a generator to charge the battery and does not directly drive the wheels.

[0082] The vehicle provided in the embodiment of the present application has the detection circuit 1 and the control circuit 3 of the above-mentioned embodiment, and therefore has all the beneficial effects of the above-mentioned detection circuit 1 and the control circuit 3, which will not be elaborated herein.

[0083] Through the description of the above implementation methods, technical personnel in the relevant field can understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0084] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0085] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A detection circuit, applied to a vehicle, comprising a high voltage interlocking circuit with a low voltage detection connector and a control circuit, characterized in that: The detection circuit comprises: a controlled element, one end of which is connected to the control circuit and the other end of which is grounded; and A control element, one end of which is connected to the first end of the low voltage detection connector, and the other end of which is connected to the second end of the low voltage detection connector, wherein the control element is used to control the on / off state of the controlled element according to the connection state of the low voltage detection connector, so that the controlled element outputs a corresponding detection signal to the control circuit, and the control circuit can determine the on / off state of the high voltage interlocking circuit and the connection state of the low voltage detection connector based on the detection signal.

2. The detection circuit according to claim 1, characterized in that: The control element is a coil, one end of the coil is connected to the first end of the low voltage detection connector, and the other end of the coil is connected to the second end of the low voltage detection connector; The controlled element is an armature switch, which is arranged corresponding to the coil, a first end of the armature switch is connected to the control circuit, and the other end of the armature switch is grounded.

3. The detection circuit according to claim 1, characterized in that: The control element is a light emitting diode, the positive electrode of the light emitting diode is connected to the first end of the low voltage detection connector, and the negative electrode of the light emitting diode is connected to the second end of the low voltage detection connector; The controlled element is a triode, which is arranged corresponding to the light emitting diode, the collector of the triode is connected to the control circuit, and the emitter of the triode is grounded.

4. The detection circuit according to claim 1, characterized in that: The detection circuit also includes: a first resistor, one end of which is connected to one end of the controlled element, and the other end of which is connected to the control circuit; and A filter capacitor, wherein a first plate of the filter capacitor is connected to one end of the first resistor and one end of the controlled element, and a second plate of the filter capacitor is grounded.

5. The detection circuit according to claim 4, characterized in that: The detection circuit also includes: A pull-up resistor, one end of which is connected to a first power supply voltage, and the other end of which is connected to a first plate of the filter capacitor, one end of the first resistor, and one end of the controlled element.

6. The detection circuit according to any one of claims 1 to 5, characterized in that: The number of the low-voltage detection connectors is multiple, and the number of the controlled elements and the number of the control elements are multiple respectively; The plurality of control elements correspond to the controlled elements and the low-voltage detection connectors one by one, respectively, and the plurality of control elements are connected in series in sequence.

7. The detection circuit according to claim 6, characterized in that: The detection circuit also includes: a second resistor, one end of which is connected to the control circuit; a first switch module, wherein a first end of the first switch module is connected to the other end of the second resistor, a second end of the first switch module is grounded, and a third end of the first switch module is connected to a first control element among the plurality of control elements; and A current source, one end of which is connected to the fourth end of the first switch module, and the other end of which is connected to the last control element among the plurality of control elements.

8. The detection circuit according to claim 7, characterized in that: The first switch module is a photoelectric coupler; The anode of the light-emitting diode in the photoelectric coupler is connected to the other end of the second resistor, the cathode of the light-emitting diode in the photoelectric coupler is grounded, the collector of the transistor in the photoelectric coupler is connected to one end of the current source, and the emitter of the transistor in the photoelectric coupler is connected to the first control element among the multiple control elements.

9. The detection circuit according to claim 6, characterized in that: The detection circuit also includes: A third resistor, one end of which is connected to a second power supply voltage; and A second switch module, wherein a first end of the second switch module is connected to the other end of the third resistor, a second end of the second switch module is connected to the first control element among the plurality of control elements, and a controlled end of the second switch module is connected to the control circuit.

10. A vehicle, characterized in that: The vehicle comprises: A high voltage interlocking circuit, wherein the high voltage interlocking circuit is provided with a low voltage detection connector; The detection circuit according to any one of claims 1 to 9, wherein the detection circuit is connected to the low voltage detection connector; and A control circuit is connected to the detection circuit.

Images