Voltage detection circuit and automobile

Abstract

The utility model relates to a voltage detection circuit and an automobile, and relates to the technical field of automobile electronics. The method and the device are used for improving the reliability and the safety of bus voltage acquisition. A first sampling circuit in the voltage detection circuit is connected with the battery and is also connected with the controller, a second sampling circuit is connected with the battery and is also connected with the controller, and the first sampling circuit is connected with the second sampling circuit in parallel. The first sampling circuit and the second sampling circuit obtain first sampling voltage and second sampling voltage and transmit the first sampling voltage and the second sampling voltage to the controller. The controller is connected with the battery and can obtain the voltage of the battery, receive the first sampling voltage and the second sampling voltage and judge whether the working states of the first sampling circuit and the second sampling circuit are normal or not. When the working states of the first sampling circuit and the second sampling circuit are normal, the first sampling circuit is controlled to detect the battery voltage, and the second sampling circuit is dormant. When the first sampling circuit is abnormal, the second sampling circuit is controlled to detect the battery voltage. Redundant design avoids the risk of system failure caused by single-point failure, and a dormancy mechanism realizes energy-saving optimization.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of automobile electronics, and in particular relates to a voltage detection circuit and an automobile. BACKGROUND

[0002] The main purpose of the DC bus voltage collection of the motor controller is to monitor the voltage value on the DC bus in real time, to provide accurate voltage information for the motor controller, so as to perform accurate control and protection.

[0003] Referring to CN113156194A, a bus voltage sampling method and device of a motor controller, the method obtains a sampling value corresponding to each preset voltage from the bus voltage of the motor controller according to each preset bus voltage, and determines the bus voltage by comparing the sampling voltage with the preset bus voltage.

[0004] However, the above-mentioned device is single in sampling the DC bus voltage of the motor controller, and has low functional safety. Utility model content

[0005] The application provides a voltage detection circuit and an automobile, which are used for improving the reliability and safety of the collection of the DC bus voltage of the motor controller.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the application is as follows:

[0007] In a first aspect, the voltage detection circuit provided by the application is applied to a battery system of an automobile and is used for detecting a bus voltage. The voltage detection circuit comprises a first sampling circuit, a second sampling circuit and a controller. The first sampling circuit is connected with a battery, and the first sampling circuit is also connected with the controller. The second sampling circuit is connected with the battery, and the second sampling circuit is also connected with the controller. The first sampling circuit and the second sampling circuit are connected in parallel. The first sampling circuit is configured to obtain a first sampling voltage and transmit the first sampling voltage to the controller. The second sampling circuit is configured to obtain a second sampling voltage and transmit the second sampling voltage to the controller. The controller is connected with the battery, and the controller is configured to obtain the voltage of the battery, receive the first sampling voltage and the second sampling voltage, judge whether the working state of the first sampling circuit is normal according to the voltage of the battery and the first sampling voltage, judge whether the working state of the second sampling circuit is normal according to the voltage of the battery and the second sampling voltage, control the first sampling circuit to detect the battery voltage in the case that the working states of the first sampling circuit and the second sampling circuit are both normal, and control the second sampling circuit to sleep. In the case that the first sampling circuit is abnormal, the second sampling circuit is controlled to detect the battery voltage.

[0008] The embodiments of the present application can effectively improve the reliability of voltage detection by using two parallel sampling circuits, i.e., a first sampling circuit and a second sampling circuit. The voltage detection circuit defaults to using the first sampling circuit to detect the voltage when the working states of the first sampling circuit and the second sampling circuit are both normal, and switches to the second sampling circuit to detect the voltage when the working state of the first sampling circuit is abnormal. Such a redundant design ensures that voltage detection can still be stably performed even in the case of abnormality of the first sampling circuit, avoiding the risk of system failure due to single-point failure. The controller can obtain the voltage of the battery, the first sampling voltage and the second sampling voltage, thereby reliably determining whether the working states of the first sampling circuit and the second sampling circuit are normal. Moreover, in the case where the working states of the first sampling circuit and the second sampling circuit are both normal, the controller will put the second sampling circuit into hibernation, thereby reducing unnecessary energy consumption and achieving energy saving optimization while ensuring voltage detection.

[0009] As a possible implementation manner, the first sampling circuit includes a first voltage dividing circuit, an optocoupler circuit and a first operational amplifier circuit. The first input end of the first voltage dividing circuit is connected with the anode of the battery, the second input end of the first voltage dividing circuit is connected with the cathode of the battery, the first output end of the first voltage dividing circuit is connected with the first input end of the optocoupler circuit, the second output end of the first voltage dividing circuit is connected with the second input end of the optocoupler circuit, the first output end of the optocoupler circuit is connected with the first input end of the first operational amplifier circuit, the second output end of the optocoupler circuit is connected with the second input end of the first operational amplifier circuit, and the output end of the first operational amplifier circuit is connected with the first end of the controller. The second sampling circuit includes a second voltage dividing circuit, a flyback power supply circuit and a second operational amplifier circuit. The first input end of the second voltage dividing circuit is connected with the anode of the battery, the second input end of the second voltage dividing circuit is connected with the cathode of the battery, the first output end of the second voltage dividing circuit is connected with the first input end of the flyback power supply circuit, the second output end of the second voltage dividing circuit is connected with the second input end of the flyback power supply circuit, the first output end of the flyback power supply circuit is connected with the first input end of the second operational amplifier circuit, the second output end of the flyback power supply circuit is connected with the second input end of the second operational amplifier circuit, the output end of the second operational amplifier circuit is connected with the second end of the controller, and the control end of the flyback power supply circuit is connected with the third end of the controller.

[0010] As a possible implementation manner, the controller internally stores the first preset value and the second preset value, and the working state of the first sampling circuit is determined according to the voltage of the battery and the first sampling voltage, and specifically configured as follows: a first difference value is obtained according to the voltage of the battery and the first sampling voltage, and in the case that the first difference value is less than or equal to the first preset value, the working state of the first sampling circuit is normal, and in the case that the first difference value is greater than the first preset value, the working state of the first sampling circuit is abnormal. The working state of the second sampling circuit is determined according to the voltage of the battery and the second sampling voltage, and specifically configured as follows: a second difference value is obtained according to the voltage of the battery and the second sampling voltage, and in the case that the second difference value is less than or equal to the second preset value, the working state of the second sampling circuit is normal, and in the case that the first difference value is greater than the second preset value, the working state of the second sampling circuit is abnormal.

[0011] As a possible implementation manner, the controller is further configured to: in the case that the working states of the first sampling circuit and the second sampling circuit are both normal, send a sleep signal to the flyback power supply circuit. In the case that the first sampling circuit is abnormal, and the second sampling circuit is in the sleep state, send a wake-up signal to the flyback power supply circuit. The flyback power supply circuit is configured to: in the case of receiving the sleep signal, enter the sleep state, and in the case of receiving the wake-up signal, enter the working state.

[0012] As a possible implementation manner, the first voltage dividing circuit includes a plurality of series resistors, a first resistor in the plurality of series resistors is connected to the first input terminal of the first voltage dividing circuit, a last resistor in the plurality of series resistors is connected to the second input terminal of the first voltage dividing circuit, and the two ends of the last resistor in the plurality of series resistors are also connected to the first output terminal and the second output terminal of the first voltage dividing circuit, respectively. The second voltage dividing circuit includes a plurality of series resistors, a first resistor in the plurality of series resistors is connected to the first input terminal of the second voltage dividing circuit, a last resistor in the plurality of series resistors is connected to the second input terminal of the second voltage dividing circuit, and the two ends of the last resistor in the plurality of series resistors are also connected to the first output terminal and the second output terminal of the second voltage dividing circuit, respectively.

[0013] As a possible implementation manner, the plurality of series resistors in the second voltage dividing circuit are the same as the plurality of series resistors in the first voltage dividing circuit in terms of number, resistance value and series order, and the first preset value and the second preset value stored in the controller are the same.

[0014] As a possible implementation manner, the voltage resistance values of the plurality of resistors in the first voltage dividing circuit are greater than the first threshold value, and the voltage resistance values of the plurality of resistors in the second voltage dividing circuit are greater than the second threshold value.

[0015] As a possible implementation, the controller is further configured to detect the working state of the first sampling circuit or the second sampling circuit that detects the battery voltage at preset time intervals in the case that the first sampling circuit or the second sampling circuit alone detects the battery voltage.

[0016] As a possible implementation, the controller is configured to alarm in the case that both the first sampling circuit and the second sampling circuit are abnormal.

[0017] In a second aspect, the application provides an automobile, which comprises a battery and a voltage detection circuit as mentioned in the first aspect and possible implementations thereof, and the voltage detection circuit is connected with the battery. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A schematic diagram of a voltage detection circuit provided by an embodiment of the application;

[0019] Figure 2 A composition schematic diagram of a voltage detection circuit provided by an embodiment of the application;

[0020] Figure 3 A composition schematic diagram of another voltage detection circuit provided by an embodiment of the application;

[0021] Figure 4 A schematic diagram of an automobile provided by an embodiment of the application.

[0022] In the figure, 1-first sampling circuit, 2-second sampling circuit, 3-controller, 4-battery, 11-first voltage dividing circuit, 12-opto-coupler circuit, 13-first operational amplifier circuit, 21-second voltage dividing circuit, 22-flyback power supply circuit, 23-second operational amplifier circuit, 100-automobile, 50-voltage detection circuit. DETAILED DESCRIPTION

[0023] The embodiments of the application will be described in detail with reference to the drawings and preferred embodiments, and those skilled in the art can easily understand other advantages and effects of the application from the contents disclosed in the specification. The application can also be implemented or applied by different specific embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the application. It should be understood that the preferred embodiments are only for illustrating the application, but not for limiting the protection scope of the application.

[0024] It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the application in a schematic manner, and only the components related to the application are shown in the diagrams, but not drawn according to the number, shape and size of the components in actual implementation. The type, number and proportion of each component in actual implementation can be arbitrarily changed, and the layout type of the components can be more complex.

[0025] In the description of the embodiments, unless otherwise specified, " / " means "or", for example, A / B can mean A or B. "And / or" herein is only a description of the relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can mean that A exists alone, A and B exist together, and B exists alone. In addition, "at least one" and "multiple" mean two or more. "First", "second", and the like do not limit the quantity and execution order, and "first", "second", and the like do not necessarily mean different.

[0026] As the main energy supply source of new energy vehicles, the battery provides energy to the motor and other vehicle-mounted electronic devices through a DC-DC converter or an inverter (which converts direct current into alternating current). The bus voltage is an important parameter of the vehicle control system, and in the design of the power system of an electric vehicle, the battery voltage is usually matched or close to the bus voltage to maximize efficiency.

[0027] The stability of the bus voltage is crucial in an electric vehicle, and when the bus voltage is unstable, it may affect the operation of the motor and the normal work of other electronic devices, and to maintain the stability of the bus voltage, it is necessary to be able to detect the bus voltage in time and accurately.

[0028] Therefore, the embodiments of the present application provide a voltage detection circuit applied to a battery system of a vehicle to detect a bus voltage. As shown in Figure 1 The voltage detection circuit includes a first sampling circuit 1, a second sampling circuit 2, and a controller 3. The first sampling circuit 1 is connected to the battery 4, and the first sampling circuit 1 is also connected to the controller 3. The second sampling circuit 2 is connected to the battery 4, and the second sampling circuit 2 is also connected to the controller 3. The first sampling circuit 1 and the second sampling circuit 2 are connected in parallel.

[0029] The first sampling circuit 1 is configured to obtain a first sampling voltage and transmit it to the controller 3. The second sampling circuit 2 is configured to obtain a second sampling voltage and transmit it to the controller 3. The controller 3 is connected to the battery 4, and the controller 3 is configured to obtain the voltage of the battery 4, receive the first sampling voltage and the second sampling voltage, determine whether the working state of the first sampling circuit 1 is normal according to the voltage of the battery 4 and the first sampling voltage, determine whether the working state of the second sampling circuit 2 is normal according to the voltage of the battery 4 and the second sampling voltage, control the first sampling circuit 1 to detect the voltage of the battery 4 when the working states of the first sampling circuit 1 and the second sampling circuit 2 are normal, and control the second sampling circuit 2 to sleep. In the case of abnormality of the first sampling circuit 1, control the second sampling circuit 2 to detect the battery voltage.

[0030] The embodiments of the present application can effectively improve the reliability of voltage detection by using two parallel sampling circuits, i.e., the first sampling circuit 1 and the second sampling circuit 2. The first sampling circuit 1 and the second sampling circuit 2 can both sample the bus voltage. Since the battery 4 voltage is usually matched or close to the bus voltage, the controller 3 can determine whether the working state of the first sampling circuit 1 and the second sampling circuit 2 is normal according to the difference between the bus voltage and the battery voltage. When the difference between the battery voltage and the bus voltage measured by the first sampling circuit 1, i.e., the first sampling voltage, is too large, it indicates that the working state of the first sampling circuit 1 is abnormal. When the difference between the battery voltage and the bus voltage measured by the second sampling circuit 2, i.e., the second sampling voltage, is too large, it indicates that the working state of the second sampling circuit 2 is abnormal.

[0031] It should be understood that the connection of the first sampling circuit 1 and the two poles of the battery 4 refers to the connection of the battery 4 after being converted by a direct current-direct current converter (DC-DC converter). In the case that the first sampling circuit 1 works normally, the first sampling voltage measured by the first sampling circuit 1 is the bus voltage, and the second sampling circuit 2 is the same. The present application does not limit the connection mode of the controller 3 and the battery 4. The controller 3 can obtain the voltage of the battery 4 through wired connection or wireless connection.

[0032] The voltage detection circuit uses the first sampling circuit 1 to detect the voltage by default in the case that the working state of the first sampling circuit 1 and the second sampling circuit 2 is normal. When the working state of the first sampling circuit 1 is abnormal, the voltage detection is switched to the second sampling circuit 2. Such a redundant design ensures that the voltage detection can still be stable even in the case that the first sampling circuit 1 is abnormal, avoiding the risk of system failure due to single point failure. The controller 3 can obtain the battery voltage, the first sampling voltage and the second sampling voltage, and compare the differences between them to determine the working state of the first sampling circuit 1 and the second sampling circuit 2, thereby improving the safety of the entire voltage detection process. Even if a sampling circuit works abnormally, the system can detect it in time and switch to the abnormal sampling circuit, thereby avoiding the influence of the false bus voltage signal on the normal operation of the motor controller. Moreover, in the case that the working state of the first sampling circuit 1 and the second sampling circuit 2 is normal, the controller 3 will make the second sampling circuit 2 dormant, thereby reducing unnecessary energy consumption and achieving energy saving optimization while ensuring voltage detection.

[0033] In some embodiments, as Figure 2As shown, the first sampling circuit 1 comprises a first voltage dividing circuit 11, an optocoupler circuit 12 and a first operational amplifier circuit 13. The first input end 11-1 of the first voltage dividing circuit 11 is connected with the anode of the battery 4, the second input end 11-2 of the first voltage dividing circuit 11 is connected with the cathode of the battery 4, the first output end 11-3 of the first voltage dividing circuit 11 is connected with the first input end 12-1 of the optocoupler circuit 12, the second output end 11-4 of the first voltage dividing circuit 11 is connected with the second input end 12-2 of the optocoupler circuit 12, the first output end 12-3 of the optocoupler circuit 12 is connected with the first input end 13-1 of the first operational amplifier circuit 13, the second output end 12-4 of the optocoupler circuit 12 is connected with the second input end 13-2 of the first operational amplifier circuit 13, and the output end 13-3 of the first operational amplifier circuit 13 is connected with the first end 3-1 of the controller 3.

[0034] The second sampling circuit 2 comprises a second voltage dividing circuit 21, a flyback power supply circuit 22 and a second operational amplifier circuit 23. The first input end 21-1 of the second voltage dividing circuit 21 is connected with the anode of the battery 4, the second input end 21-2 of the second voltage dividing circuit 21 is connected with the cathode of the battery 4, the first output end 21-3 of the second voltage dividing circuit 21 is connected with the first input end 22-1 of the flyback power supply circuit 22, the second output end 21-4 of the second voltage dividing circuit 21 is connected with the second input end 22-2 of the flyback power supply circuit 22, the first output end 22-3 of the flyback power supply circuit 22 is connected with the first input end 23-1 of the second operational amplifier circuit 23, the second output end 22-4 of the flyback power supply circuit 22 is connected with the second input end 23-2 of the second operational amplifier circuit 23, the output end 23-3 of the second operational amplifier circuit 23 is connected with the second end 3-2 of the controller 3, and the control end 22-5 of the flyback power supply circuit 22 is connected with the third end 3-3 of the controller 3.

[0035] Since the bus voltage is usually high, direct measurement of the bus voltage may exceed the voltage withstand range of the components in the circuit, therefore, a voltage dividing circuit (the first sampling circuit adopts a first voltage dividing circuit, and the second sampling circuit adopts a second voltage dividing circuit) is adopted to reduce the bus voltage to a suitable voltage range for measurement. Since the bus voltage measurement belongs to a high-voltage system, the safety needs to be considered, therefore, the embodiments provided in the present application are designed with an optocoupler circuit and a flyback power supply circuit for electrical isolation.

[0036] The optocoupler circuit 12 can utilize optical signals to transmit signals between the high-voltage side (close to the battery side) and the low-voltage side (far away from the battery side), thereby realizing electrical isolation. Since direct connection of the circuit is avoided, it can prevent the high voltage from entering the low-voltage side when measuring the bus, thereby damaging the components in the first sampling circuit, thereby reducing the safety hazard and effectively protecting the circuit on the low-voltage side.

[0037] The core element in the flyback power supply circuit 22 is a transformer, which has a primary winding and a secondary winding. The primary winding is connected to the high-voltage side (close to the battery side), and the secondary winding is connected to the low-voltage side (far from the battery side). The primary winding and the stimulus winding are coupled by a magnetic field to transmit signals, thereby achieving electrical isolation.

[0038] The directly obtained sampling voltage (the first sampling voltage in the first sampling circuit and the second sampling voltage in the second sampling circuit) may be weak or mixed with noise after being divided by the voltage dividing circuit, optocoupler circuit or flyback power supply circuit. The operational amplifier circuit (the first operational amplifier circuit in the first sampling circuit and the second operational amplifier circuit in the second sampling circuit) can amplify the signal and filter out the noise, thereby improving the accuracy of the bus voltage detection.

[0039] As a possible implementation manner, the controller internally stores a first preset value and a second preset value. Whether the working state of the first sampling circuit is normal is determined according to the voltage of the battery and the first sampling voltage. Specifically, a first difference value is obtained according to the voltage of the battery and the first sampling voltage. In a case where the first difference value is less than or equal to the first preset value, the working state of the first sampling circuit is normal. In a case where the first difference value is greater than the first preset value, the working state of the first sampling circuit is abnormal. Whether the working state of the second sampling circuit is normal is determined according to the voltage of the battery and the second sampling voltage. Specifically, a second difference value is obtained according to the voltage of the battery and the second sampling voltage. In a case where the second difference value is less than or equal to the second preset value, the working state of the second sampling circuit is normal. In a case where the first difference value is greater than the second preset value, the working state of the second sampling circuit is abnormal.

[0040] The first preset value stored in the controller is the maximum value of the allowed error between the voltage of the battery and the first sampling voltage in the normal case of the first sampling circuit, and the first difference value is the actual difference value. For example, the voltage of the battery is 110V, the first sampling voltage is 95V, and the first preset value is 10V. That is, the measured bus voltage should be within the interval of 100V-110V, and the first sampling voltage is 95V at this time, which is 15V different from the voltage of the battery 110V, that is, the first difference value is 15V, which is greater than the preset value 10V, so the measurement of the bus voltage is abnormal at this time. Similarly, the second preset value stored in the controller is the maximum value of the allowed error between the voltage of the battery and the second sampling voltage in the normal case of the second sampling circuit, and the second difference value is the actual difference value. Therefore, the voltage detection circuit provided by the application can accurately determine the working state of the first sampling circuit and the second sampling circuit, and improve the safety of the entire voltage detection process. Even if a sampling circuit is abnormal, the system can detect it in time.

[0041] As a possible implementation, the controller is further configured to send a sleep signal to the flyback power supply circuit when the working states of the first sampling circuit and the second sampling circuit are both normal. When the first sampling circuit is abnormal and the second sampling circuit is in the sleep state, a wake-up signal is sent to the flyback power supply circuit. The flyback power supply circuit is configured to enter the sleep state when the sleep signal is received, and enter the working state when the wake-up signal is received.

[0042] Referring to Figure 2 When the controller 3 first judges the working states of the first sampling circuit 1 and the second sampling circuit 2, there are several cases:

[0043] The first case is that the controller 3 detects that the working states of the first sampling circuit 1 and the second sampling circuit 2 are both abnormal. In some embodiments, the controller 3 is configured to alarm when the first sampling circuit 1 and the second sampling circuit 2 are both abnormal, and to prompt the user through a buzzer or a light, so as to avoid the risk of out-of-control motor controller and improve the safety guarantee for the user.

[0044] The second case is that the controller 3 detects that the working states of the first sampling circuit 1 and the second sampling circuit 2 are both normal. In this case, in order to save energy, the controller 3 will control the second sampling circuit 2 to enter the sleep state, so as to reduce the energy consumption to the greatest extent. The specific implementation is that the controller 3 sends a sleep signal to the control end 22-5 of the flyback power supply circuit 22 through the third end 3-3. After receiving the sleep signal, the control end 22-5 of the flyback power supply circuit 22 enters the sleep state, stops transmitting the signal transmitted by the second voltage dividing circuit 21 to the second operational amplifier circuit 23, and the controller 3 also does not need to judge the working state of the second sampling circuit 2, so the operation amount of the controller is reduced, and the energy is saved. When the controller 3 detects that the working state of the first sampling circuit 1 becomes abnormal, the bus voltage measured by the first sampling circuit 1 cannot be used as a reference, at this time the third end of the controller 3 sends a wake-up signal to the control end of the flyback power supply circuit 22, and the flyback power supply circuit 22 is woken up from the sleep state, and the second sampling circuit 2 intervenes and replaces the first sampling circuit 1 to measure the bus voltage, thereby enhancing the reliability of the voltage detection circuit.

[0045] The third case is that the working state of any one of the sampling circuits is abnormal, for example, the controller 3 detects that the working state of the first sampling circuit 1 is abnormal, and the working state of the second sampling circuit 2 is normal, at this time, the bus voltage is detected by the second sampling circuit 2. For another example, the controller 3 detects that the working state of the second sampling circuit 2 is abnormal, and the working state of the first sampling circuit 1 is normal, at this time, the bus voltage is detected by the first sampling circuit 1. When the sampling circuit with normal working state in the above two examples is also identified as abnormal by the controller 3, that is, the first sampling circuit 1 and the second sampling circuit 2 are both abnormal, the controller 3 alarms.

[0046] In some embodiments, as shown in FIG. 1, the first voltage dividing circuit 11 includes a plurality of series resistors, the first resistor R1 of the plurality of series resistors is connected with the first input end 11-1 of the first voltage dividing circuit 11, the last resistor R2 of the plurality of series resistors is connected with the second input end 11-2 of the first voltage dividing circuit 11, and the two ends of the last resistor R2 of the plurality of series resistors are also connected with the first output end 11-3 and the second output end 11-4 of the first voltage dividing circuit 11 respectively. Figure 3

[0047] The second voltage dividing circuit 21 includes a plurality of series resistors, the first resistor R3 of the plurality of series resistors is connected with the first input end 21-1 of the second voltage dividing circuit 21, the last resistor R4 of the plurality of series resistors is connected with the second input end 21-2 of the second voltage dividing circuit 21, and the two ends of the last resistor R4 of the plurality of series resistors are also connected with the first output end 21-3 and the second output end 21-4 of the second voltage dividing circuit 21 respectively.

[0048] As a possible implementation, the first voltage dividing circuit 11 samples the bus voltage, the resistors in the first voltage dividing circuit 11 divide the bus voltage, the voltage divided by the last resistor R2 of the plurality of series resistors in the first voltage dividing circuit 11 is electrically isolated by the optocoupler circuit 12, the optocoupler circuit 12 differentially outputs the voltage divided by the resistor R2 to the first operational amplifier circuit 13, and the first operational amplifier circuit 13 converts the differential output of the optocoupler circuit 12 into a single-ended analog output for sampling by the analog-digital sampling interface of the controller 3. Since the first voltage dividing circuit 11 includes a plurality of resistors, each of which can divide part of the bus voltage, the voltage divided by the last resistor R2 of the plurality of series resistors in the first voltage dividing circuit 11 is clamped within a safe voltage range, avoiding the possibility of large current breakdown and failure of the subsequent circuit caused by high voltage, thereby improving the safety and reliability of the voltage detection circuit as a whole.

[0049] ​Similarly, the second voltage dividing circuit 21 samples the bus voltage, the resistors in the second voltage dividing circuit 21 divide the bus voltage, the voltage divided by the last resistor R4 in the series of resistors in the second voltage dividing circuit 21 is input to the flyback power supply circuit 22, the transformer in the flyback power supply circuit 22 performs isolation output to the second operational amplifier circuit 23, and the second operational amplifier circuit 23 converts the output of the flyback power supply circuit 22 into a single-ended analog output for sampling by the analog-digital sampling interface of the controller 3. Similarly, since the second voltage dividing circuit 21 includes a plurality of resistors, each of which can divide part of the bus voltage, the voltage divided by the last resistor R4 in the series of resistors in the second voltage dividing circuit 21 is clamped within a safe voltage range, avoiding the possibility of large current breakdown and resulting in failure of the downstream circuit caused by high voltage, thereby improving the safety and reliability of the voltage detection circuit as a whole.

[0050] It should be understood that the number, series order, and resistance value of the series of resistors in the first voltage dividing circuit 11 and the number, series order, and resistance value of the series of resistors in the second voltage dividing circuit 21 can be selected as needed according to actual conditions. In some embodiments, the number, series order, and resistance value of the series of resistors in the first voltage dividing circuit 11 and the number, series order, and resistance value of the series of resistors in the second voltage dividing circuit 21 are not consistent. In this case, the bus voltage divided by the last resistor in the first voltage dividing circuit 11 and the bus voltage divided by the last resistor in the second voltage dividing circuit 21 are not necessarily the same, and the first preset value and the second preset value stored in the controller are determined according to the allowable measurement error and the voltage division ratio between the last resistor and the series of resistors in the voltage dividing circuit, so the first preset value and the second preset value will also change with the number, series order, and resistance value of the series of resistors in the voltage dividing circuit.

[0051] As one possible implementation, the number, resistance value, and series order of the series of resistors in the second voltage dividing circuit 21 are the same as those of the series of resistors in the first voltage dividing circuit 11, and the first preset value and the second preset value stored in the controller 3 are the same. Since the number, resistance value, and series order of the series of resistors in the second voltage dividing circuit 21 are the same as those of the series of resistors in the first voltage dividing circuit 11, the bus voltage divided by the last resistor in the first voltage dividing circuit 11 is the same as the bus voltage divided by the last resistor in the second voltage dividing circuit 21, and the first preset value and the second preset value stored in the controller are determined according to the allowable measurement error and the voltage division ratio between the last resistor and the series of resistors in the voltage dividing circuit, so in this case, the first preset value and the second preset value stored in the controller 3 are the same.

[0052] It should also be understood that, regardless of whether the number, resistance value, and series order of the plurality of resistors in series in the second voltage dividing circuit 21 are the same as those in the first voltage dividing circuit 11, the voltage withstand value of each resistor in the voltage dividing circuit should be greater than the voltage that it can withstand. That is, the voltage withstand value of the plurality of resistors in the first voltage dividing circuit 11 is greater than the first threshold value, and the voltage withstand value of the plurality of resistors in the second voltage dividing circuit 21 is greater than the second threshold value. Among them, the first threshold value is the minimum value of the voltage that the plurality of resistors in the first voltage dividing circuit 11 can withstand, and the second threshold value is the minimum value of the voltage that the plurality of resistors in the second voltage dividing circuit 21 can withstand. In the case of ensuring the voltage withstand value, the high-precision resistors are selected as much as possible to further improve the accuracy of the bus voltage detection on the basis of ensuring safety.

[0053] In some embodiments, the controller is further configured to, in the case where the first sampling circuit or the second sampling circuit detects the battery voltage alone, detect the working state of the first sampling circuit or the second sampling circuit that detects the battery voltage at a preset time interval. According to the above-mentioned three cases of “when the controller first judges the working state of the first sampling circuit and the second sampling circuit”, when the first sampling circuit measures the bus voltage and the second sampling circuit is in sleep, in order to ensure that the bus voltage value detected by the first sampling circuit is always accurate, the working state of the first sampling circuit needs to be checked constantly. When the working state of the first sampling circuit is detected to be abnormal, the bus voltage value measured by the first sampling circuit at this time cannot be used as a reference.

[0054] For example, taking 5s as the preset time interval, in the case where the working state of the first sampling circuit and the second sampling circuit is normal at the initial detection, the working process of the voltage detection circuit is described as follows: the controller confirms that the working state of the first sampling circuit is normal according to the comparison of the first difference value and the first preset value. The controller confirms that the working state of the second sampling circuit is normal according to the comparison of the second difference value and the second preset value. In order to save energy, the controller controls the second sampling circuit to enter the sleep state, and at this time the first sampling circuit realizes the detection of the bus voltage. In order to ensure that the bus voltage value detected by the first sampling circuit is always accurate, the working state of the first sampling circuit needs to be checked constantly, so every 5s, the controller calculates the difference value between the voltage of the battery and the first sampling voltage, that is, obtains the first difference value, and compares the first difference value with the first preset value. In the case where the first difference value is less than or equal to the first preset value, it is indicated that the first sampling circuit is still in the normal working state.

[0055] Until the controller detects that the first difference is greater than the first preset value, at which time the first sampling circuit turns to an abnormal working state, the bus voltage measured by the first sampling circuit loses accuracy. The controller wakes up the second sampling circuit, and the second sampling circuit replaces the first sampling circuit to measure the bus voltage. In order to ensure that the bus voltage value detected by the second sampling circuit is always accurate, the working state of the second sampling circuit needs to be checked constantly, therefore, every 5s, the controller calculates the difference between the voltage of the battery and the second sampling voltage, that is, obtains the second difference, and compares the second difference with the second preset value, in the case that the second difference is less than or equal to the second preset value, it indicates that the second sampling circuit is still in a normal working state. Until the controller detects that the second difference is greater than the second preset value, at which time the second sampling circuit turns to an abnormal working state, the controller alarms.

[0056] The embodiment of the present application also provides a car, for example, as shown in Figure 4 The voltage detection circuit 50 provided by the embodiment of the present application improves the reliability of voltage detection by adopting two parallel sampling circuits, and the redundancy design ensures that even in the case of abnormality of the first sampling circuit, voltage detection can still be stably performed, avoiding the risk of system failure due to single point failure. The controller can obtain the voltage of the battery, the first sampling voltage and the second sampling voltage, so as to reliably determine whether the working states of the first sampling circuit and the second sampling circuit are normal. And in the case that the working states of the first sampling circuit and the second sampling circuit are normal, the controller will make the second sampling circuit sleep, which reduces unnecessary energy consumption while ensuring voltage detection, and realizes energy saving optimization. The improvement of the reliability of the voltage detection circuit helps to better monitor the bus voltage, so that timely adjustment can be made when the bus voltage is unstable, thereby improving the safety of the car. The energy saving of the voltage detection circuit also reduces the energy consumption of the car in the aspect of bus voltage detection, so that the energy configuration can be shifted to a more important direction, for example, the driving direction, thereby improving the performance of the car and optimizing the user experience.

[0057] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any change or replacement within the technical scope disclosed in the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A voltage detection circuit (50), applied to a battery (4) system of an automobile (100), for detecting bus voltage, characterized in that, include: The system comprises a first sampling circuit (1), a second sampling circuit (2), and a controller (3); The first sampling circuit (1) is connected to the battery (4) and is also connected to the controller (3). The second sampling circuit (2) is connected to the battery (4) and is also connected to the controller (3). The first sampling circuit (1) and the second sampling circuit (2) are connected in parallel. The first sampling circuit (1) is configured to: acquire a first sampling voltage and transmit it to the controller (3); The second sampling circuit (2) is configured to: acquire the second sampling voltage and transmit it to the controller (3); The controller (3) is connected to the battery (4). The controller (3) is configured to: acquire the voltage of the battery (4), receive the first sampling voltage and the second sampling voltage, determine whether the working state of the first sampling circuit (1) is normal based on the voltage of the battery (4) and the first sampling voltage, determine whether the working state of the second sampling circuit (2) is normal based on the voltage of the battery (4) and the second sampling voltage, control the first sampling circuit (1) to detect the voltage of the battery (4) and control the second sampling circuit (2) to go into sleep mode when both the first sampling circuit (1) and the second sampling circuit (2) are working normally; and control the second sampling circuit (2) to go into sleep mode when the first sampling circuit (1) is abnormal.

2. The voltage detection circuit (50) according to claim 1, characterized in that, The first sampling circuit (1) includes a first voltage divider circuit (11), an optocoupler circuit (12), and a first operational amplifier circuit (13); The first input terminal of the first voltage divider circuit (11) is connected to the anode of the battery (4), the second input terminal of the first voltage divider circuit (11) is connected to the cathode of the battery (4), the first output terminal of the first voltage divider circuit (11) is connected to the first input terminal of the optocoupler circuit (12), the second output terminal of the first voltage divider circuit (11) is connected to the second input terminal of the optocoupler circuit (12), the first output terminal of the optocoupler circuit (12) is connected to the first input terminal of the first operational amplifier circuit (13), the second output terminal of the optocoupler circuit (12) is connected to the second input terminal of the first operational amplifier circuit (13), and the output terminal of the first operational amplifier circuit (13) is connected to the first terminal of the controller (3). The second sampling circuit (2) includes a second voltage divider circuit (21), a flyback power supply circuit (22), and a second operational amplifier circuit (23); The first input terminal of the second voltage divider circuit (21) is connected to the anode of the battery (4), the second input terminal of the second voltage divider circuit (21) is connected to the cathode of the battery (4), the first output terminal of the second voltage divider circuit (21) is connected to the first input terminal of the flyback power supply circuit (22), the second output terminal of the second voltage divider circuit (21) is connected to the second input terminal of the flyback power supply circuit (22), the first output terminal of the flyback power supply circuit (22) is connected to the first input terminal of the second operational amplifier circuit (23), the second output terminal of the flyback power supply circuit (22) is connected to the second input terminal of the second operational amplifier circuit (23), the output terminal of the second operational amplifier circuit (23) is connected to the second terminal of the controller (3), and the control terminal of the flyback power supply circuit (22) is connected to the third terminal of the controller (3).

3. The voltage detection circuit (50) according to claim 2, characterized in that, The controller (3) stores a first preset value and a second preset value. The step of determining whether the working state of the first sampling circuit (1) is normal based on the voltage of the battery (4) and the first sampling voltage is specifically configured as follows: a first difference is obtained based on the voltage of the battery (4) and the first sampling voltage. If the first difference is less than or equal to the first preset value, the working state of the first sampling circuit (1) is normal. If the first difference is greater than the first preset value, the working state of the first sampling circuit (1) is abnormal. The method of determining whether the working state of the second sampling circuit (2) is normal based on the voltage of the battery (4) and the second sampling voltage is specifically configured as follows: a second difference is obtained based on the voltage of the battery (4) and the second sampling voltage. If the second difference is less than or equal to the second preset value, the working state of the second sampling circuit (2) is normal. If the first difference is greater than the second preset value, the working state of the second sampling circuit (2) is abnormal.

4. The voltage detection circuit (50) according to claim 3, characterized in that, The controller (3) is also configured to: send a sleep signal to the flyback power supply circuit (22) when both the first sampling circuit (1) and the second sampling circuit (2) are operating normally; and send a wake-up signal to the flyback power supply circuit (22) when the first sampling circuit (1) is abnormal and the second sampling circuit (2) is in a sleep state. The flyback power supply circuit (22) is configured to enter a sleep state upon receiving the sleep signal and to enter a working state upon receiving the wake-up signal.

5. The voltage detection circuit (50) according to claim 3, characterized in that, The first voltage divider circuit (11) includes a plurality of resistors connected in series. The first resistor in the plurality of resistors connected in series is connected to the first input terminal of the first voltage divider circuit (11), and the last resistor in the plurality of resistors connected in series is connected to the second input terminal of the first voltage divider circuit (11). The two ends of the last resistor in the plurality of resistors connected in series are also connected to the first output terminal and the second output terminal of the first voltage divider circuit (11), respectively. The second voltage divider circuit (21) includes a plurality of resistors connected in series. The first resistor in the plurality of resistors connected in series is connected to the first input terminal of the second voltage divider circuit (21), the last resistor in the plurality of resistors connected in series is connected to the second input terminal of the second voltage divider circuit (21), and the two ends of the last resistor in the plurality of resistors connected in series are also connected to the first output terminal and the second output terminal of the second voltage divider circuit (21), respectively.

6. The voltage detection circuit (50) according to claim 5, characterized in that, The number, resistance value and series sequence of the multiple series resistors in the second voltage divider circuit (21) are the same as those in the first voltage divider circuit (11), and the first preset value stored in the controller (3) is the same as the second preset value.

7. The voltage detection circuit (50) according to claim 5, characterized in that, The withstand voltage of multiple resistors in the first voltage divider circuit (11) is greater than the first threshold, and the withstand voltage of multiple resistors in the second voltage divider circuit (21) is greater than the second threshold.

8. The voltage detection circuit (50) according to any one of claims 1 to 7, characterized in that, The controller (3) is further configured to detect the operating status of the first sampling circuit (1) or the second sampling circuit (2) that detects the battery (4) voltage at preset time intervals when the first sampling circuit (1) or the second sampling circuit (2) detects the battery (4) voltage alone.

9. The voltage detection circuit (50) according to any one of claims 1 to 7, characterized in that, The controller (3) is configured to issue an alarm when both the first sampling circuit (1) and the second sampling circuit (2) are abnormal.

10. A car (100), characterized in that, The vehicle (100) includes a battery (4) and a voltage detection circuit (50) as claimed in any one of claims 1 to 7, the voltage detection circuit (50) being connected to the battery (4).

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