UPS BMS Address Allocation via RS485 for Modular Battery Expansion
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Solution Overview
Problem
Conventional UPS systems face limitations in scalability and conversion due to the fixed allocation of BMS addresses, which require additional port pins for each BMS, making it inconvenient for expansion and incompatible with different battery types.
Innovation Solution
A method for BMS address allocation that utilizes RS485 bus communication to serially connect BMSs, allowing flexible expansion without additional chip select pins, enabling address reallocation through input and output ports, and supporting both lead-acid and lithium-ion batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If chip selection manner is used for BMS address allocation, then each BMS can be identified by the UPS system, but the quantity of required port pins increases directly with the quantity of BMSs, limiting scalability
Solution Approach 1:
The patent introduces an RS485 bus as an intermediary communication medium between the UPS system and multiple BMS units. Instead of using separate port pins for each BMS, the RS485 bus provides a shared communication channel that can accommodate multiple BMS addresses, thereby reducing the number of required port pins while maintaining the ability to identify and communicate with each BMS individually
Solution Approach 2:
The RS485 bus serves as a universal communication interface that can handle multiple BMS connections simultaneously. A single RS485 bus can support multiple addresses, allowing the same hardware interface to communicate with different BMS units by addressing them logically rather than requiring dedicated physical pins for each device
2Adaptability or versatility
If fixed address allocation is implemented, then BMS communication is established, but older UPSs without redundant port pins cannot support extension or conversion to different battery types
Solution Approach 1:
The patent implements dynamic address allocation where BMS addresses are not fixed to specific physical pins but are instead assigned through software configuration on the RS485 bus. This dynamic addressing scheme allows the system to adapt to different configurations and battery types without requiring physical hardware changes or additional port pins
Solution Approach 2:
The patent uses virtual address copying where multiple BMS units can be addressed through the same physical RS485 interface by assigning different logical addresses to each BMS. This allows the system to simulate multiple dedicated connections through a single shared physical interface, enabling extension and conversion capabilities without additional hardware
Data Source
AI summary
Methods for BMS address allocation in a UPS system are provided. The method includes: S1: broadcasting an address allocation start instruction; S2: setting its output port to a second preset level and its address allocation flag as “uncompleted”, and setting, by the built-in BMS, its address allocation flag to “uncompleted”; S3: broadcasting, by the UPS, an address allocation instruction; S4: performing, by a BMS whose input port is at the first preset level and whose address allocation flag is uncompleted, address setting, and after the address setting is completed, setting its address allocation flag as “completed” and replying address information to the UPS; S5: receiving, by the UPS, the replied address information, and sending a port configuration instruction to the BMS, so that the BMS sets its output port to the first preset level; and S6: repeating steps S3 to S5 until all BMSs have completed address allocation.