Patent Application
20130132635
The present application claims priority to Patent Application No. 201110364854.4, filed on Nov. 17, 2011, with the State Intellectual Property Office of the People's Republic of China.
With the rapid development of electric vehicle (EV) technology, there is an increasing need to improve cooperation between a charger and an EV.
If there is a digital signal communication channel for transferring digital signals between the charger 11 and the BMS 15, the digital signals related to statuses, e.g., a voltage or temperature, of the battery pack 12 can be transferred between the charger 11 and the BMS 15. A battery pack management device, e.g., the BMS 15 or a controller, can manage the battery pack 12 based on the transferred digital signals in an intelligent manner, so as to extend the usage life of the battery pack 12.
In order to establish a digital signal communication channel between the BMS 15 and the charger 11, extra communication interfaces can be added to the conventional EV system 100. However, this method is expensive to implement. Thus, there is a need for a method for establishing a digital signal communication channel between a battery management system and a charger that reduces cost.
A universal asynchronous receiver/transmitter (UART) can achieve full-duplex transmission and reception using an UART standard. Thus, the UART can be used in two-way asynchronous communication. In the embedded design field, the UART can communicate with a computer, e.g., a monitor debugger or other devices.
In one embodiment, a system includes a first digital signal transceiver having a first interface, a second digital signal transceiver having a second interface, and a communication bus coupled between the first interface and the second interface. The communication bus is operable for establishing communication between the first digital signal transceiver and the second digital signal transceiver, and the communication is serial and asynchronous.
Features and advantages of embodiments of the claimed subject matter will become apparent as the following detailed description proceeds, and upon reference to the drawings, wherein like numerals depict like parts, and in which:
Reference will now be made in detail to the embodiments of the present invention. While the invention will be described in conjunction with these embodiments, it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims.
Furthermore, in the following detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be recognized by one of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure aspects of the present invention.
In one embodiment, the present invention provides a digital signal transceiver system that transfers digital signals in a single-wire asynchronous serial manner between a charger and a BMS based on a UART standard. Thus, the digital signals can be transferred between the charger and the BMS via a single communication bus. Existing hardware in an EV system can include a 3-prong alternating current (AC) receptacle having three sockets. In embodiments according to the present invention, two sockets of the 3-prong AC receptacle are used to charge the EV system, and the third socket of the 3-prong AC receptacle, which is idle in the conventional EV system, can be used to establish a communication channel between the BMS and the charger. As a result, the signal transfer between the BMS and the charger can be implemented less expensively.
In one embodiment, a high voltage bus is used as the communication bus 243 between the charger 21 and the BMS 23. The voltage of the high voltage bus is supplied by the battery pack 22, or supplied by a voltage divider that divides the voltage of the battery pack 22. In other words, the communication bus 243 is a data transmission bus that supports a high voltage. In one embodiment, the high voltage can be the voltage of the battery pack 22, or it can be a voltage obtained by dividing the voltage of the battery pack 22 using a voltage divider. In another embodiment, the high voltage is supplied by an external device, e.g., a pull-up resistor for a charging process.
In one embodiment, the charger 21, the battery pack 22, and the BMS 23 share the high voltage bus, e.g., the communication bus 243, and therefore the charger 21, the battery pack 22, and the BMS 23 can share the same ground GND to ensure consistency of communication voltage levels of the charger 21 and the BMS 23, and ensure the possibility of the communication. Therefore, transceiver integrated circuits of the battery pack 22 and the BMS 23 can transmit and receive data via the communication bus 243.
A receiver synchronizes with a transmitter by the synchronous header. In one embodiment, the synchronous header is set to be a data string including, e.g., five consecutive hex numbers such as “5A 5A 5A 5A 5A”. When the receiver receives the data string, the transmitter resets its state machine and assumes the following data is the payload. If the payload includes five consecutive hex numbers “5A” to be transmitted, an escape character, e.g., “0D”, is inserted into the fourth position of the data string. As such, the data string becomes “5A 5A 5A 5A 0D 5A”. When the receiver receives the above data string, the receiver ignores the escape character “0D” and restores the data string to “5A 5A 5A 5A 5A”. If load data used as an escape character appears in the payload, the escape character 0D is inserted before each load data. By way of example, if the load data transmitted by a user is “0D 0D 0D”, then the actual transmitted data is “0D 0D 0D 0D 0D D”.
The payload includes user data to be transmitted.
The LENGTH in the payload represents the byte number of the following data. If there is no data, the LENGTH is zero. In one embodiment, the maximum value of LENGTH is 60 (a decimal number).
In the example at (2) of
In one embodiment, commands in the data frames are classified according to Table 2 shown below.
In the example at (3) of
Referring to
In step S500, a digital signal transceiver, e.g., the first digital signal transceiver 241, or the second digital signal transceiver 242, used as a receiver, checks a receiving end buffer, e.g., the receiving end buffer 2412, or the receiving end buffer 2422, of a UART interface of the digital signal transceiver.
In step S501, the receiver detects whether the receiving end buffer has received a predetermined length of data, e.g., a byte of a data. If the receiving end buffer has received the predetermined length of data, then the flowchart turns to step S502; otherwise, it turns to step S500.
In step S502, the receiver checks a received data buffer of the digital signal transceiver.
In step S503, the receiver detects whether the received data buffer is full. If the received data buffer is full, then the flowchart turns to step S505; otherwise, it turns to step S504.
In step S504, the receiver saves data of the receiving end buffer of the UART interface in the received data buffer. The flowchart returns to step S500 and conducts data receiving for a next byte.
In step S505, the receiver returns information indicating that the received data buffer is full.
According to step S504 shown in
In step S600, the receiver checks the received data buffer.
In step S601, the receiver detects whether the received data buffer is empty. If the received data buffer is empty, then the flowchart turns to step S603; otherwise, it turns to step S602.
In step S602, the receiver reads data of the received data buffer and returns the data. The flowchart returns to step S600.
In step S603, the receiver returns information indicating that the received data buffer is empty.
Since the present invention utilizes a UART interface to conduct single-wire asynchronous serial communication, the first digital signal transceiver 241 and the second digital signal transceiver 242 need to avoid transmission conflict when transmit data.
According to the example of
In step S700, a digital signal transceiver, e.g., the first digital signal transceiver 241, or the second digital signal transceiver 242, used as a transmitter, checks a status of the communication bus 243.
In step S701, the transmitter detects whether the status of the communication bus 243 is idle. If the status is idle, then the flowchart turns to step S702; otherwise, it turns to S706.
In step S702, the transmitter transmits data saved in the transmitting end buffer of the UART interface via the communication bus 243. More specifically, the digital signal transceiver writes the data from a transmitted data buffer into the transmitting end buffer of the UART interface and transmits the data to the receiver via the communication bus 243. The flowchart turns to step S703.
In step S703, the transmitter reads data from the transmitting end buffer of the UART interface. More specifically, when the transmitter transmits data via the communication bus 243, the receiving end buffer of the UART interface of the transmitter receives the data from the transmitting end buffer of the UART interface of the transmitter via the communication bus 243. The transmitter reads the data from the receiving end buffer of the UART interface and returns the data in a way as described in
In step S704, the transmitter detects whether the data transmission is successful. If the data transmission is successful, then the flowchart turns to S705; otherwise, it turns to S706′. More specifically, the transmitter checks whether the data of the receiving end buffer of the UART interface is the same as the data of the transmitting end buffer of the UART interface. If they are the same, the data transmission is successful; otherwise, it fails.
In step S705, the transmitter returns information indicating that the data transmission is successful.
In step S706, the transmitter detects whether the number of times to retry the step S701, e.g., determining the status of the communication bus, has reached a predetermined maximum number. If the number of times to retry the step S701 has reached the maximum number, the flowchart turns to step S707; otherwise, it turns to step S708.
In step S706′, the transmitter checks whether the number of times to retry the step S704, e.g., determining whether the received data is the same as the transmitted data, has reached a predetermined maximum number. If the number of times to retry the step S704 has reached the maximum number, the flowchart turns to step S707; otherwise, it turns to step S708.
In step S707, the transmitter returns information indicating that the communication bus is busy.
In step S708, the transmitter delays for a predefined time, and then performs step S700 to retry the transmission of the data.
Thus, according to one embodiment of the present invention, a battery management system in an EV is coupled to the aforementioned first digital signal transceiver. However, the invention is not so limited. Other controlling devices, e.g., including a controller, in the EV can also be coupled to the first digital signal transceiver. Additionally, a digital signal transceiver system according to the present invention can be applied to an EV charging process, and also can be applied to other applications, e.g., including a battery detecting process. Therefore, other external digital signal processing devices, e.g., including a monitor (display device) for the EV, can also be coupled to the second digital signal transceiver.
While the foregoing description and drawings represent embodiments of the present invention, it will be understood that various additions, modifications and substitutions may be made therein without departing from the spirit and scope of the principles of the present invention as defined in the accompanying claims. One skilled in the art will appreciate that the invention may be used with many modifications of form, structure, arrangement, proportions, materials, elements, and components and otherwise, used in the practice of the invention, which are particularly adapted to specific environments and operative requirements without departing from the principles of the present invention. The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims and their legal equivalents, and not limited to the foregoing description.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201110364854.4 | Nov 2011 | CN | national |
