TWI646802B - Battery system control network and reset method thereof - Google Patents

Abstract

The invention provides a battery system control network and a reset method thereof. The system includes: a system master terminal, which is electrically connected to a data bus; and more than one slave terminal, which is electrically connected to the data bus. The slaves and slaves control the operation of the battery management system of a battery respectively, and the slaves and slaves have a Watch Dog Timer (WDT); wherein the master of the system scans all slaves at every monitoring time Whether the terminal is transmitting data normally, the number of errors is accumulated for the slaves that cannot transmit normally. When the number of errors of a slave exceeds the reset threshold, the master of the system sends a The reset command. When each slave can't transmit data normally for more than a reset time, the watchdog timer resets the slave.

Description

Battery system control network and reset method thereof

The present invention relates to battery system control technology, and particularly relates to a control network for an electric vehicle high-voltage battery system and a debugging and resetting mechanism thereof.

The CAN BUS communication interface is a standard communication protocol for automotive systems. Before the CAN BUS communication interface had been developed, most of the various electronic components in the vehicle system used point-to-point data transmission and control commands. Integrated communication interface. In early 1980, the German company Bosch first introduced the Controller Area Network (CAN) communication protocol, which is used in evolving automotive systems. It integrates various sensors in the vehicle system with a simple serial interface. Control system. With the development of CAN BUS communication protocol, two international organizations, ISO (International Standards Organization) and SAE (Society of Automotive Engineers), have customized ISO 11898, ISO 11519, and SAE J19392 based on CAN communication rates and application fields. Relevant standards and specifications. In addition to automotive systems, CAN application fields are also widely used in industrial control, medical instrument and automation control fields.

The CAN BUS communication interface is developed to integrate various electronic components, replace point-to-point communication methods with intelligent data nodes, and adopt standard The standardized communication protocol puts all system nodes on the same data bus for data transmission and control. The CAN BUS communication interface is a full-duplex communication protocol, but the data transmission is not transmitted using traditional addresses. It is through the way of message, after the data is packaged into a data packet, and converted into a differential signal, passed to the data bus to complete the data transfer. Because the data packet is transmitted in the form of a message, CAN 2.0B can provide a 29-bit data identifier (Identifier), which is equivalent to a 29th power communication node that can support 2. Therefore, when many data nodes want to send signals at the same time, the How to effectively maintain transmission efficiency, the CAN BUS communication protocol uses Carrier Sense Multiple Access and Collision Detection with Collision Resolution (CSMA / CD-CR) to increase the performance of communication transmission. Through this communication protocol, all packets transmitted to the communication bus can be The data packets are transmitted through a standardized process.

The data types used by CAN BUS are mainly divided into four types: Data Frame, Remote Frame, Error Frame, and Overload Frame. Among them, Error Frame is sent by the CAN controller when an abnormal packet occurs at each node. The CAN BUS controller itself There are two error counters, namely the Transmit Error Counter (TEC) and the Receive Error Counter (REC). The two are used to accumulate the error messages of each data node, and then calculate the error message for each node based on the error count value. The communication functions have different levels of restrictions. The restrictions are divided into three levels: Error Active, Error Passive, and Bus Off, which are described below:

(1) Error Active: When the communication node is initialized, and the TEC or The count value of REC is less than 127, and they are in the Error Active state. The literal meaning of Error Active is a more positive error response. When an error occurs in any data packet, the Error Frame will be sent, and the error data packet will be interrupted. The data node makes an error response and accumulates the error counter. After completing the above actions, the communication bus returns to the normal state, resends the previous data packet, and ends the error message processing.

(2) Error Passive: When the TEC or REC count is greater than 127, the communication node will enter Error Passive, which means a more negative error response. At this time, the communication node has an error message that exceeds a certain level. At this time, the communication node When a node has an error message again, the Error Frame will still be sent, and the error counter will continue to be accumulated, but the data packets in transmission will not be interrupted. However, after the Error Frame is sent, the node must wait for a period of time before sending the information packet again. .

(3) Bus Off: After a more negative error state, when the TEC is greater than 255, it will enter the Bus Off state. This data node is equivalent to the bypass state. It can no longer send and receive any information packets. To return to the Error Active state.

The CAN BUS communication interface has a robust communication protocol, which enables the transmission of a lot of information in this system. When encountering a data collision, it can be processed through the communication protocol to allow the data to be transmitted regularly according to its own weight. However, even with a robust communication protocol, The function of resolving data collisions and arbitrations, and monitoring the status of the busbars. When the flow is unstable or even causes the communication node to collapse, the CAN BUS communication protocol can only count the error status through the Error Frame. When a communication node has too many transmission errors (TEC), it will give the communication protocol the wrong arbitration, and will eventually The communication node is cut off from the communication bus, and the abnormal communication node is cut off from the communication bus. The main purpose is to prevent defective information packets from occupying the communication bus for a long time, rather than solving the abnormal state of the communication node. Belongs to passive error handling.

Due to the rise of green energy awareness, the related technologies and products of modern electric vehicles, electric vehicles, electric buses and other electric vehicles are booming. For electric vehicles, the use of electrical energy, power battery management and driving safety regulations are always the most important. Topic. The internal system of electric vehicles uses a communication interface such as CAN Bus as a system control network. It is a very common choice in industry and academia today. However, as mentioned above, due to its inherent design constraints, CAN bus is abnormal for communication nodes in the system. Only passive error processing can be performed, that is, the error node is directly disconnected from the communication network, and its transmission and reception function is turned off, but this processing method means that a battery will be shut down directly in the battery management system of the electric vehicle, and the battery system The energy output of the vehicle is instantly reduced, disrupting the energy management plan preset for the entire vehicle. For safety reasons, the vehicle can only reduce the driving speed or even stop forcibly. The electric vehicle itself has a large number of electronic components and sub-systems, and the data flow of the control network is much larger than that of a traditional internal combustion engine vehicle. Therefore, it is more likely to cause communication data collisions and electronic noise interference to stop the transmission and reception function of a node, resulting in a certain Communication node (controls a group of battery management systems) enters CAN Bus The Bus off state in the error mechanism. In fact, the device (battery) monitored by this node is still functioning normally, but it is forced to close the data transmission function and must stop operating. It is very tricky for the design logic and driving safety of the electric vehicle control system. The problem. In particular, electric buses use a high-voltage battery system. If one of the batteries is in good condition but shut down due to an error in the above communication system, it may not only directly affect driving safety, but also increase unnecessary maintenance times and the operating costs of passenger operators.

In order to solve the disadvantages of the prior art, the present invention provides a battery system control network and a reset method thereof, which can prevent the battery energy management system control network of an electric vehicle from causing battery failure due to non-mechanical failures such as communication interference and message collision. The communication node of the management system is shut down, which affects the situation of electric vehicle energy management and driving safety.

The invention provides a battery system control network, which includes: a system master terminal, which is electrically connected to a data bus; more than one slave terminal, which is electrically connected to the data bus, the slaves Each terminal controls the operation of a battery battery management system, and the slave terminal has a Watch Dog Timer (WDT); wherein the system's master terminal scans all the slave terminals for data normally at every monitoring time Transmission. For the slaves that cannot transmit normally, they accumulate the number of errors. When the number of errors of a slave exceeds a reset threshold, the system master sends a reset command to the slave. When the slave can't transmit data normally for more than a reset time, The watchdog timer resets the slave.

In one embodiment of the present invention, the monitoring time is 0.5 seconds; the reset threshold value is 5; and the reset time is 2 seconds.

In one embodiment of the present invention, the data bus is a CAN Bus.

The present invention provides a method for resetting the control network of a battery management system, the steps of which include: (a) the system main control terminal sends a detection message to all slaves through the data bus at every monitoring time, and monitors each Whether the slave has responded; (b) When the slave responds normally to the detection message, the system master end accumulates the number of errors of the normally responded slave to zero, and repeats the action of step (a); (c) When the slave does not respond to the detection message normally, the system master adds one to the number of errors of the slave which did not respond normally, and repeats the action of step (a); (d) When the slave When the number of errors of the slave exceeds a reset threshold, the system master sends a reset command to the slave to force the slave to restart.

In one embodiment of the present invention, the method for resetting the battery management system control network further includes:

(e) Each time the slave receives the message from the data bus normally, it resets the watchdog timer; (f) When the slave does not receive the message normally after a reset time, the watchdog timer resets the slave.

The above summary and the following detailed description and drawings are all for further explaining the methods, means and effects adopted by the present invention to achieve the intended purpose. Other objects and advantages of the present invention will be described in the following description and drawings.

11‧‧‧System master

121‧‧‧ servant

122‧‧‧ servant

13‧‧‧Data Bus

S1 ~ S7‧‧‧‧System master reset method logic flow

S01 ~ S05‧‧‧‧Reset method logic flow

FIG. 1 is a schematic diagram of an embodiment of a battery system control network according to the present invention.

FIG. 2 is a logic flow chart of the reset method of the main control end of the system of the present invention.

FIG. 3 is a logic flowchart of the slave-side reset method of the present invention.

The following is a description of specific embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

The invention is a high-voltage power battery system for electric buses, because the operating voltage (hundreds of volts) of the battery system of electric buses is much higher than the battery (12V, 24V) of traditional internal combustion engine vehicles, and the battery system is the main The (only) source of power, once a battery in the battery pack fails or stops operating, it will directly affect the driving performance and driving safety of the electric bus. Therefore, the control logic and safety specifications of the on-board system control network of electric vehicles, especially electric buses, must also be different from traditional vehicles. CAN mentioned in the prior art The bus error handling mechanism is to exclude the faulty nodes from the in-vehicle network, but as mentioned above, this type of error handling mechanism is directly transferred to electric vehicles, which is less suitable and may cause dangerous factors for vehicle driving. Therefore, in order to solve the shortcomings of the prior art, the present invention proposes a battery system control network and a reset method thereof to meet the battery system control mechanism and driving safety requirements on electric vehicles.

FIG. 1 is a schematic diagram of an embodiment of a battery system control network according to the present invention. As shown in the figure, this embodiment includes a system master terminal 11, a plurality of slave terminals 121, 122, and a data bus 13. The system master controller The terminal is a microcomputer or a microcontroller, which has an error counter to accumulate the number of errors of each slave; the slave can be a microcontroller or a microcomputer, and the slave has a data register inside the slave. It is connected to each Battery Management System (BMS) of the battery pack to upload the operating status information of each battery management system to the system master and receive control commands from the system master. The data bus is the CAN Bus used in vehicle control networks, but it can also be CANopen, MiCAN, FlexRay or other types of motor vehicle system control networks. In practical applications of the present invention, the number of slaves is not limited to the number disclosed in the embodiment, nor is it limited to the control function connected to the battery management system, as long as it is an electronic component that is connected to a vehicle control network, such as a car Electronic components on electric vehicles, such as lamp control, brake control, brake energy feedback control, etc., can be applied to the control network architecture disclosed in the embodiments of the present invention to monitor the operating status of each electronic component.

In one embodiment of the present invention, the main control terminal of the system is the control core of the energy management system (managing the operation of the power battery organization) on the electric vehicle. The main control terminal of the system focuses on the state control of the entire system and the charge and discharge protection switch. Brake, and the basis of the state control comes from the information transmitted by the measurement system of each slave node of the system (ie, the battery management system of each battery), so the accuracy and update rate of these information are very important. In one embodiment of the present invention, the system master scans the data register of all the slave nodes at a frequency of 0.5 seconds, on the one hand, it updates all the parameter information, on the other hand, it confirms whether the data is missing, And further monitoring. When the continuity of any slave end node does not update the data, there are two possibilities: one is that the slave end node loses data due to a large amount of data collision, and the other is that the slave end node receives a lot of electromagnetic signals. It can't normally receive the information from the data bus (CAN Bus) due to the interference of the signal. The default mechanism of the CAN Bus will cut off the slave node from the network, so that the node's transmission function is disabled. In order to maintain the operation of the high-voltage power battery system of the electric bus, at this time, the system master of the present invention will issue a reset command of the slave node, and an example of the communication protocol message content of the reset command (using the CAN Bus communication protocol as Example) As shown in Table 1. After the slave end node is reset, the slave end node will return to the data bus, so that the system master can receive the battery system information controlled by the slave end node for the entire vehicle battery system operation. Control,

FIG. 2 is a logic flow chart of the reset method of the master of the system according to the present invention. As shown in the figure, the master of the system executes the operation of detecting the operating status of each slave and slave every 0.5 seconds (S1); Reply information (S2) on the status of the temporarily stored data; use the receiving flag to determine whether the information of the slave has been received (the flag is HIGH, which means that the message from the slave has been received) (S3); The slave responds to the message, then clears the receive flag, and returns to step (S1) to wait for the next execution of the scanning operation (S4); if no response is received from the slave, the error counter of the slave is accumulated and calculated + 1 (S5); determine whether the error count of the slave end reaches 5, if not, return to step (S1) and wait for the next execution of the scanning operation (S6); if the error count of the slave end reaches 5, then The system master sends a reset command to the slave to force the slave to restart (S7).

The battery system control network of the present invention is to keep the high-voltage battery system of the electric bus operating reliably, and it is to check whether the data transmission function of each slave (the battery management system that controls a battery) is normal at any time. The slave node processing method. The present invention is to improve the method of forcibly taking a node offline by using a CAN bus for the control network of a conventional vehicle. The management system has a built-in mechanism (software) for managing the battery charge and discharge status. As long as communication interference factors such as signal interference and message collision are eliminated, and the slave and the slave are restarted, the system master can read the slave again. Battery status information controlled by the client to continue to maintain the operation of the entire vehicle battery system. The battery system control network of the present invention gives priority to maintaining the overall operation of the battery system and avoids the existing Vehicle control network (CAN BUS) forced shutdown of node communication. At the same time, it cooperates with the built-in watchdog timer reset mechanism of the slave to ensure that the battery system will not stop due to non-mechanical failure such as signal interference and message collision.

FIG. 3 is a logic flowchart of the slave-side reset method of the present invention. As shown in the figure, the slave-side system has a Watch Dog Timer (WDT). The watchdog timer will turn on the timer function (S01); determine whether the transmission function of the slave terminal is normal according to whether the slave terminal has received a message on the data bus (CAN Bus); if the slave terminal receives If the function is normal, reset the time of the watchdog timer to zero and return to step (S01). If the slave no longer receives messages, the watchdog timer will continue to count (S03); Whether the time (that is, the time when the slave does not receive the message normally) exceeds a reset time (for example, 2 seconds) (S04); if the watchdog timer time exceeds the reset time, the watchdog timer will restart The slave terminal (S05) eliminates the situation where the slave terminal cannot communicate due to information collision, noise interference and other factors, so that the slave terminal can continue to upload its matching battery management system information and the data bus. Receive control commands from the main control end of the system to ensure the power The system can function properly.

In one embodiment of the present invention, the slave terminal is connected to the battery management system of the power battery, performs the measurement system operation, and transmits the measurement information to the system master terminal, and issues and operates through the system master terminal status command. Global active balance logic. The system master and slave are closely related, so the communication stability is very important. When the slave and slave cannot normally receive the data from the system master, There are two possibilities for the status information or control commands: One is that the system master has entered an offline state of the communication node due to too many Error Frames, and the message cannot be sent normally, but the message from the system master, Has the highest communication priority, is not easy to suffer from data collision, so the probability of occurrence is low, and the other state is that the module battery management system has abnormal receiving functions due to too many invalid messages, and cannot normally receive messages on the communication bus.

In summary, the present invention provides a battery system control network and a reset method thereof, which can prevent the battery energy management system control network of an electric vehicle from causing battery management system failure due to non-mechanical failures such as communication interference and message collision. The suspension of communication nodes affects the energy management and driving safety of electric vehicles. The present invention improves the method of CAN Bus preset forcibly taking a node with poor communication function offline, and proposes a method of resetting the battery system control network instead of turning off the node transmission function to meet the requirements of electric vehicles, especially high-voltage battery power systems. Energy management and driving safety requirements for electric buses. The invention uses the dual monitoring mechanism of the system master controlling the entire monitoring and the slave-self-detection, and uses the highest command authority of the system master and the watchdog timer built in the slave to solve the noise interference and message collision. Node communication is down. The invention can be applied to transportation vehicles such as electric passenger cars, electric buses, and electric vehicles, and can also be used for energy management of green energy generation and energy storage devices, and has wide application value and flexibility.

The above-mentioned embodiments are merely illustrative for describing the features and effects of the present invention, and are not intended to limit the scope of the essential technical content of the present invention. any Those skilled in the art can modify and change the above embodiments without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the rights of the present invention should be listed in the scope of patent application described later.

Claims (9)

A battery system control network includes: a system master terminal, which is electrically connected to a data bus, the data bus is CAN BUS; a plurality of slaves, which are electrically connected to the data bus, The slaves and slaves respectively control the operation of a battery battery management system, and the slaves and slaves have a Watch Dog Timer (WDT); wherein the master of the system scans all slaves at every monitoring time Whether the data transmission is normal. The slaves and slaves that cannot transmit normally accumulate the number of errors. When the number of errors of a slave exceeds the reset threshold, the master of the system sends a duplicate to the slave. The watchdog timer resets the slave when the time that each slave cannot transmit data normally exceeds a reset time. The battery system control network according to claim 1, wherein the monitoring time is 0.5 seconds. The battery system control network according to claim 1, wherein the reset threshold is 5. The battery system control network according to claim 1, wherein the reset time is 2 seconds. The battery system control network according to claim 1, wherein the data bus is a CANopen, MiCAN, FlexRay, or other type of motor vehicle system control network. A reset method for a battery system control network is used for a battery management system control network. The battery management system control network includes: a system master terminal, which is electrically connected to a data bus, and the data The bus is CAN BUS; multiple slaves are electrically connected to the data bus. The slaves control the operation of a battery's battery management system, and the slave has a watchdog timer (Watch Dog Timer (WDT); The method of resetting the battery management system control network includes: (a) the system master sends detection messages to all slaves through the data bus at every monitoring time, and monitors each Whether the slave has responded; (b) When the slave responds normally to the detection message, the system master end accumulates the number of errors of the normally responded slave to zero, and repeats the action of step (a); (c) When the slave does not respond to the detection message normally, the system master adds one to the number of errors of the slave which did not respond normally, and repeats the action of step (a); (d) When the slave When the number of slave errors exceeds a reset threshold, The system master sends a reset command to the slave to force the slave to restart; (e) Each time the slave receives the message from the data bus normally, it should check the gatekeeper. The dog timer is reset to zero; (f) When the slave terminal does not receive the message normally after a reset time, the watchdog timer resets the slave terminal. The method for resetting the battery system control network according to claim 6, wherein the monitoring time is 0.5 seconds. The method for resetting the battery system control network according to claim 6, wherein the reset threshold is 5. The method for resetting the battery system control network according to claim 7, wherein the reset time is 2 seconds.