The present disclosure relates generally to narrowband wireless technology, and more specifically, to packet based wireless communication systems that configure the gain of a wireless receiver according to a power level of an electronic signal including an incoming packet.
Battery management systems (BMS) include an electronic system deployed in industrial or automotive applications to manage an array of lithium chemistry cells, battery packs, or the like to determine a safe operating area within which the battery pack provides the best performance. The BMS provides an electronic system for the complete control of all diagnostic and safety functions for the management and security of high voltage components of an electric vehicle (EV). For example, a BMS can disconnect a battery pack from an array if a predetermined voltage or temperature limit is exceeded. Wireless battery management systems (WBMS) can replace the wired control links of a BMS with a wireless connection, thereby eliminating the need for wiring and volume in the battery pack.
It is desirable for the wireless links of a WBMS to provide comparable performance levels, such as latency, throughput, and so on, as a wired BMS.
The present invention is illustrated by way of example and is not limited by the accompanying figures, in which like references indicate similar elements. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale.
Various wireless technologies, such as Bluetooth Low Energy (BLE), NXP-proprietary Generic Frequency-Shift Keying (also known as “GenFSK”), or other radio technologies such as 2.4 GHz narrowband technologies are often implemented to enable wireless connectivity of a WBMS system. Other wireless technologies such as Ultra-Wideband (UWB) may also apply. However, battery packs typically include a fair amount of reflective material, which yields a high number of signal reflections. These signal reflections, in turn, yield a highly frequency-selective response, which can be a challenge for narrow-band transmissions. The amount of reflection, and the yielded frequency response depends on the geometry of the battery housing, material, or other design parameters. Furthermore, in closed battery pack environments, wireless channel characteristics are expected to vary slowly over time due to aging, temperature change, interference from external wireless devices, and so on, since gain control settings do not change quickly over time. Another factor is that each communication link between a battery management unit (BMU) and a battery cell controller (BCC) of a WBMS may yield unique wireless channel characteristics due to antenna placement. Therefore, two different links will exhibit different frequency response curves.
In brief overview, embodiments of the present inventive concepts include a WBMS system, apparatus, and/or method that includes a narrowband multi-channel sensor system that processes unicast messages exchanged between a master such as a BMU and a high number of slave nodes such as BCCs connected by unicast messages, which experience various wireless channel effects and characteristics. The term “BMU” generally refers to a master node of a wireless network star or star with hops topology, and the term “BCC” generally refers to a slave connecting node. The communications illustrated and described herein can comply with a communication protocol having a physical layer formed between physical interfaces of a BMU and a high number of BCC nodes. In some embodiments, the communication protocol has a physical layer formed between physical interfaces of the BMU and BCCs, respectively. For example, the unicast messages can be transmitted on a dedicated channel optimized for a particular BCC-BMU wireless communication link. The communication protocol can also define the structure of the packet, for example, shown in
In typical configurations, the AGC loop processor is a first block at that input of a receiver, and is constructed and arranged to adjust the gain of the incoming signal so that it reaches the analog to digital converter (ADC) with proper dynamic: not insufficiently low power to ensure a good SNR or avoid quantization effects, and not too strong power to avoid saturation. This action is done automatically when the first part of the packet reaches the receiver.
The receiver may acquire a new packet based on the preamble sequence, and further use it for synchronization and timing estimation at the receiver. The preamble sequence is typically a predefined pattern, sometimes referred to as a ‘golden sequence’ or reference sequence known in advance by the receiver. To realize the acquisition of a new incoming packet, the receiver usually performs comparison, e.g. correlations, of the incoming signal with this reference sequence to detect the start of a packet. Furthermore, the known preamble sequence can be used to realize frequency and time synchronization.
Also, part of the preamble sequence is used by the receiver to set the amplifier gain. The inventive concepts, however, provides a packet structure without a preamble regardless of the wireless connection type, e.g., BLE, UWB, and so on. Unlike conventional receivers that process a preamble to train the AGC component to perform gain determination (see
Although the WBMS 110 is shown as an example, the concept can be applied to general wireless systems implemented in other industrial, commercial, or automotive applications including battery management. As shown in
The BMU 102 provides a data path between the BCCs 104 and a vehicle communication bus. The BMU 102 controls and processes the telemetry data from the BCCs 104 and provides a summary to other electronic vehicle components on the vehicle communication bus.
In some embodiments, the WBMS 110 provides communication between its BMU 102 and BCCs 104 according to a star (or extended-star) topology, where the BMU master controller 102 establishes dialog with each BCC 104 by way of a series of unicast messages, transmitted on a dedicated channel, e.g., a BLE channel or the like optimized for the particular link 107 of a wireless transmission between the BMU 102 and BCC 104. Here, each packet is destined for a predetermined device, which permits the power levels of packets to be received, and predetermined by a transceiver 200 or related analog/RF front-end of the system comprising the antenna(s), power amplifier, AGC, and so on. As used herein, the transceiver 200 may be part of an apparatus and may include transmit and/or receive features that also require digital signal processing circuits and/or software, and so on. Therefore, the gain of the MGC can be adjusted to match the upcoming message power beforehand by the gain control mode module 210. Accordingly, the BMU master controller 102 communicates with each BCC slave 104 in an interleaved, or round-robin arrangement, for example, described above. However, other embodiments may include different scheduling schemes so long as in order to minimize transitions between receiver and transmitter states at the master BMU 102, it is expected that the BMU 102 will transmit and receive bursts of messages. For example, a master BMU 102 may receive the replies from multiple slave nodes back-to-back in a predefined and fixed order with predefined timings.
In order to allow the BMU 102 to communicate with a maximum number of slave nodes 104, it is preferable that the duration of the timeslot grids, i.e., where the system includes a memory that that stores an array of transmit and receive timeslots corresponding to data exchanges between the BMU 102 and BCC slaves 104, is as close as possible with respect to the duration of the messages. In other words, it is desirable for all messages to be output sequentially, or back-to-back, from the BCC slaves 104 to be sent with a minimum time gap between the messages according to the predefined communication protocol so long as compliance with the communication protocol establishing the wireless connection. For example, a time-grid of approximately 0.5 ms may comply with the BLE protocol, which mandates a minimum time gap between messages of 150 μs. The time-grid values may depend on the number of messages to be sent, for example, when there are sufficient cells in the time-grid for the messages. Another factor may include the maximum throughput, for example, 2 Mbps in compliance with the BLE protocol. In another example, a GenFSK-compliant wireless communication can be optimized to allow for a time gap of 50 μs or less. The foregoing factors, e.g., number of messages, maximum throughput, etc. may equally apply.
The WBMS 110 is not limited to those elements described in
The WBMS 110 is constructed and arranged to perform synchronous battery voltage/current measurement, coulomb counting, cell temperature measurement and integrated cell balancing, validation of the measurement integrity, and/or other functions related to automotive battery monitoring and maximizing the life of a vehicle battery, for example, sensing the physical properties of a lithium chemistry battery, monitoring battery functions to validate the integrity of cell measurements, and so on. Each BCC 104 can monitor a battery pack comprising a plurality of battery cells, for example, ranging from 6-18 cells but not limited thereto. In doing so, data communications are established between the BMU 102 and at least one BCC 104. Each wireless BMU to BCC link 107 has a distinct wireless propagation channel characteristic, for example, yielding distinct a Packet Error Rate (PER) and Received Signal Strength Indication (RSSI). The wireless link 107 includes a wireless transmission line to convert data to be exchanged with a BCC 104 via the wireless link 107. The BMU 102 may include a driver circuit 209 constructed and arranged to form a link 107 with a BCC 104. In some embodiments, the driver circuit 209 is part of the transceiver interface 212 of the BMU 102. In other embodiments, the BCC may have a driver circuit that forms the link 107 with the BMU 107. The BMU 102 may include other components such as an RF output device, antenna, microprocessor, memory, and one or more interfaces that in some embodiments can be integrated on a single silicon chip or die, or in other embodiments, be positioned on different chips or related circuit devices. Wireless communication can be bidirectional between the BCCs 104 and BMU 102, which include upstream and downstream transceivers or the like.
In some embodiments, wireless communication operations performed by the WBMS 110 include the exchange of packets during a unicast message connection between the BMU 102 and a BCC 104. The packets are structured with less overhead than conventional wireless message exchanges. This is achieved by eliminating the need for a received packet preamble, used by the receiver to control the gain of the receiver. As shown in conventional configurations illustrated in
In addition, new packets acquired based on a preamble sequence may be prone to undesirable reflections within a BMS metal enclosure, which can decay at a slow rate. This behavior can affect a receiver, for example, receiver functions of the BMU transceiver 200, that receives and processes back-to-back messages from different BCCs, where a change in an observed received power level may be gradual so as to drive the AGC to settle in a longer amount of time resulting in a total settling time that is unacceptably long as compared to the duration of the preamble, resulting in packet acquisition performance degradation.
In lieu of processing the contents of a packet preamble, the BMU transceiver 200 relies on manual gain control (MGC) to set the gain of the incoming signal so that it reaches the ADC receiver according to a value of the incoming packet power. This is possible because the receiver stores and manages the interleaved scheduling scheme arrangement of timeslots receiving incoming unicast messages, and therefore the receiver can determine a power level of a next message. The arrangement of timeslots may either be stored as software, hardware, or a combination thereof, for example, in a computer memory such as the table storage 205 and can be accessed by a master controller of the BMU during an initialization phase, for example, a network configurator 202 of the transceiver 200 of
As shown, in some embodiments, a transceiver 200 of the BMU 102 includes an MGC 204, a table storage 205, ADC 206, power detector 208, a gain control mode module 210, and a wireless receiver interface 212 or related input/output device. Some or all these components of the transceiver 200 may be co-located in a common enclosure, or may be part of different devices and in communication with each other via wired or wireless electronic interfaces. As mentioned above, the transceiver 200 can include both transmitter and receiver functions, although
The MGC 204 carries out the features of the inventive concept negating the need for a packet preamble required for an AGC. In some embodiments, an AGC is included and identified when packets are received including a preamble. The optional AGC may be activated by the gain control mode module 210 to adjust the gain of an incoming signal for output to the ADC 206 when the MGC is not required. For example, the gain control mode module 210 can process received signals corresponding to incoming packets 20 in response to a determination by the system that the packets 20 include a preamble including synchronization and timing estimation data or other data, and can communicate with the MGC 204 to process received signals corresponding to incoming packets 20 when a determination is made that the packets 20B do not include a preamble, for example, shown in
In the absence of a preamble in a received packet 20, the MGC 204 sets the gain of the receiver exactly according to the incoming packet power, which is tracked by the power detector 208 and/or known upfront and/or calibrated upfront by the power detector 208. For example, the wireless receiver apparatus can be tracked by means of a power or RSSI (receiver signal strength indicator) measurement, which can be performed in parallel with the decoding of the data section. Here, the power detector 208 may include an RSSI measurement circuit, module, or related processor, or this processor may be separate from the power detector 208. From this RSSI measurement, the MGC can be set to having a predefined headroom, for example, 3 dB but not limited thereto. For example, the BMU transceiver 200 can be calibrated during manufacturing, upgrade, or related event where a gain range or threshold, and therefore corresponding power levels, are established. As mentioned above, the battery cell module 102 is assembled to include a set of particular battery cells 105. During testing, test messages are exchanged between the BMU 102 and BCC 104 managing the battery cells 105, and power and gain values are determined. However, due to environmental conditions, such as temperature change, a battery cell replacement, etc., a desired gain and power level may slowly change over time. Therefore, the MGC 204 can set the receiver's gain to accommodate such changes.
The receiver knows the overall timeslot organization, so it knows the power of the next message formed of the packets 20. Therefore, the gain of the MGC can be adjusted to match the upcoming message power by the gain control mode module 210. As described herein, the gain control mode module manages the gain control modes, for example, MGC, AGC, or a combination thereof. In doing so, the gain control mode module 210 performs a packet acquisition technique that allows recognition of a new packet received via the antenna 211 to a wireless receiver interface 212 of the transceiver 200. The interface 212 may include a driver circuit between the power detector 208 and the transmission line that converts processed bit data for output to the transmission line.
Here, the gain control mode module 210 includes a special purpose processor formed of electronics (hardware), software, firmware, or a combination thereof that permits the BMU to set its gain according to predefined and tracked power levels as provided by the power detector 208, for example, described above. In doing so, the gain control mode module 210 may activate or otherwise communicate with the MGC 204 to adjust the gain of the incoming signal so that it is output to the ADC 206 according to a predetermined threshold requirement sufficient for processing by the ADC 206. The wireless receiver apparatus relies on the MGC 204 to set the gain of the incoming signal so that it reaches the ADC receiver 206 of the system according to a value of the incoming packet power. This is possible because the receiver stores and manages an interleaved scheduling scheme arrangement of timeslots receiving incoming unicast messages, and therefore the transceiver can determine a power level of a next message. In embodiments where the packet includes no preamble, the acquisition technique processes relevant contents of the sync address field, for example, shown in
The foregoing depends on whether the incoming packet has a preamble that includes a pattern having a known sequence used for synchronization and timing estimation for processing by the gain control mode module 210. The gain control mode module 210 may therefore permit that MGC 204 to process packets that do not have preambles so that the transceiver 200 operates with less overhead since the training sequence data in the preamble for training the AGC otherwise required for gain setting is not necessary.
At block 302, a link 107 (see
At block 304, MGC settings to be used are stored, for example, at the table storage 205, network configurator 202, or the like, but not limited thereto. Such settings can be unique and applicable to all messages, or dependent on the time instant or dependent of the expected communication source. Considering a fixed timeslotted grid, in some embodiments, the order and the power levels of received packets are thus deterministic, and the BMU 102 may use different MGC settings for receiving messages originating from different BCC. The power level determination permits the BMU 102 to configure the gain accordingly between received packets, since the BMU 102 knows the expected power level(s) for each slave BCC node message, for example, a reply to a BMU message. The receiver, in particular, the power detector 208 can communicate with the table 205 to track the overall timeslot organization, and in doing so stores information regarding expected power level of messages to be received. The AGC settings can be tracked and adapted over time by the power detector 208.
At block 306, the MGC 204 can adjust its gain using MGC settings 304, to match the power level of the next incoming message to be received by the BMU 102.
At block 308, the packet is processed without a preamble, and the system relies on the MGC 204 to set the gain of the receiver according to the incoming packet power.
At block 310, the power, RSSI, or other feature of the incoming packet is determined. The power level of a signal, e.g., RF signal, carrying a packet received by the BMU 102 is determined, for example, by the power detector 208 of the BMU 102, for example during an initialization phase, or during run-time as a continuous measurement. The received signal can be an RF signal or other electromagnetic signal.
At block 312, the power measurement 310 is used to adjust or fine-tune the MGC settings for the next occurrence of a packet sent by this transmitter. Considering a fixed timeslotted grid, in some embodiments, the power levels of received packets are thus deterministic and predefined, and the power detector 208 confirms the predefined power level, or determines an error or the like if the tracked power level is different than the predefined level by a predetermined threshold value.
As shown in
As will be appreciated, embodiments as disclosed include at least the following. In one embodiment, a battery management system comprises a wireless receiver apparatus that receives and processes an electromagnetic signal that includes at least one predefined power level of a packet transmitted to the wireless receiver apparatus relative to the pre-defined power level; a power detector that determines an actual power level or a change in the actual power level of the transmitted packet received at the wireless receiver apparatus; and a manual gain control processor that configures a gain of the wireless receiver apparatus according to the actual power level or the change in the actual power level.
Alternative embodiments of the battery management system include one of the following features, or any combination thereof.
The gain is adjusted to match the actual power level of at least one subsequent packet transmitted to the wireless receiver apparatus.
The battery management system further comprises a table storage that stores timeslot organization data between the wireless receiver apparatus and a plurality of more battery cell controllers monitoring a plurality of battery cells, wherein the timeslot organization data includes predetermined power levels between each of the plurality of more battery cell controllers and the wireless receiver apparatus, which permits a gain control mode module of the battery management system to process a predetermined power level stored in the table storage of a next message for receipt by the wireless receiver apparatus.
The gain control mode module compares the predetermined power levels to the actual power or change in the actual power level to upfront the gain of the MGC to match the actual power level of the received electromagnetic signal.
The table storage stores an array of transmit and receive timeslots corresponding to data exchanges in an interleaved scheduling scheme arrangement between the wireless receiver apparatus and the battery cell controllers so that the messages output from the battery cell controllers are sent with a minimum time gap therebetween according to a communication protocol.
The wireless receiver apparatus relies on the wireless receiver apparatus relies on the manual gain controller to set the gain of the incoming signal so that it reaches an analog-to-digital converter of the system according to a value of the incoming packet power.
The wireless receiver apparatus tracks the overall timeslot organization, and in doing so stores information at the table storage regarding a known power level of one or more unicast messages to be received from by the wireless receiver apparatus.
The manual gain control processor acquires a new packet based on a sync address field of the transmitted packet.
The gain of the wireless receiver apparatus is calibrated in advance of receipt of the packet according to a preconfigured arrangement of timeslots by adjusting the gain of the MGC to match the actual power level of the transmitted packet.
The battery management system further comprises a battery management unit that configures its gain between two consecutive packets transmitted to the wireless receiver apparatus.
The packet is absent a preamble.
The battery management system further comprises a special-purpose computer processor that executes an acquisition procedure at the wireless receiver apparatus to recognizes new packets to be received, wherein the acquisition procedure includes a comparison of the header of the new packets to a reference sequence known in advance by the wireless receiver apparatus.
In another embodiment, a wireless receiving device comprises a driver circuit that forms an electronic communication link between a battery management unit and at least one battery cell controller; a power detector that determines an actual power level or a change in the actual power level of a packet absent a preamble transmitted with the electronic communication link relative to a pre-defined power level; and a manual gain control processor that processes the packet absent the preamble and configures a gain of the wireless receiver apparatus according to the actual power level.
Alternative embodiments of the wireless receiving device include one of the following features, or any combination thereof.
The power detector tracks or calibrates the incoming power level in advance of the manual gain control processor processing the packet absent the preamble.
The wireless receiving device further comprises a gain control mode module that controls the manual gain control processor to adjust the gain according to the incoming power level.
The wireless transceiver device further comprises a table storage that stores timeslot organization data between the wireless receiver apparatus and the at least one battery cell controller monitoring a plurality of battery cells, wherein the timeslot organization data includes predetermined power levels between each of the at least one battery cell controller and the wireless receiver apparatus, which permits a gain control mode module of the wireless transceiver device to process a predetermined power level stored in the table storage of a next message for receipt by the wireless receiver apparatus.
The gain of the manual gain control processor is adjusted to match the upcoming message power by the gain control mode module.
The wireless transceiver device further comprises a special-purpose computer processor that executes an acquisition procedure at the wireless receiver apparatus to recognizes new packets to be received, wherein the acquisition procedure includes a comparison of the header of the new packets to a reference sequence known in advance by the wireless receiver apparatus.
In another embodiment, a method for manual gain control for optimizing a packet structure exchanged between elements of a battery pack comprises forming an electronic communication link between a battery management unit and at least one battery cell controller; determining an actual power level or a change in the actual power level of a packet absent a preamble transmitted with the electronic communication link relative to a pre-defined power level; and processing the packet absent the preamble and configures a gain of the wireless receiver apparatus according to the actual power level.
Alternative embodiments of the method include one of the following features, or any combination thereof.
Processing the packet according to the actual power level includes the adjusting the gain to match the actual power level of at least one subsequent packet exchanged by the battery management system.
Although the invention is described herein with reference to specific embodiments, various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present invention. Any benefits, advantages, or solutions to problems that are described herein with regard to specific embodiments are not intended to be construed as a critical, required, or essential feature or element of any or all the claims.
Unless stated otherwise, terms such as “first” and “second” are used to arbitrarily distinguish between the elements such terms describe. Thus, these terms are not necessarily intended to indicate temporal or other prioritization of such elements.
Number | Date | Country | Kind |
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21305640.1 | May 2021 | EP | regional |