Integration and fusion of new energy system PCS and BMS – high-precision on-board current sensor serves as a bridge

Introduction: Due to the pioneering flagship product of our company, Shanghai Dexie Electronic Technology Co., Ltd., the high-precision fluxgate on-board current sensor (with an accuracy of up to 0.01%), we have established cooperation with many leading enterprises in the domestic battery formation, capacity grading, and testing industry. At recent new energy exhibitions, some PCS companies have communicated with our company about integrating PCS and BMS for current detection solutions. After discussion, the fluxgate on-board current sensor with an accuracy of 0.1% perfectly solves the problem and has been implemented.

Next, let’s briefly discuss the necessity of integrating PCS and BMS, as well as the role of high-precision on-board current sensors in this integration.

The necessity of integrating PCS with BMS

1. System efficiency optimization

●Dynamic collaborative control: After the integration of PCS (responsible for charging and discharging, as well as grid interaction) and BMS (responsible for battery state monitoring), real-time data sharing (such as SOC, SOH, current/voltage) becomes possible, enabling dynamic adjustment of charging and discharging strategies. For instance, in a photovoltaic energy storage system, when the BMS detects insufficient battery capacity, the PCS immediately switches to charging mode to prevent energy waste.

●Reducing communication latency: The traditional split design requires communication through the CAN bus, which introduces millisecond-level latency. After integration, through hardware-level data exchange (such as shared memory), the response speed is improved by more than 10 times.

2. Improvement in safety and reliability

●Fault linkage protection: When the BMS detects overvoltage/overtemperature of the battery, it directly triggers the PCS to cut off the current (without external communication) to prevent thermal runaway (such as the risk of battery explosion in electric vehicles).

●Consistency management: The integrated system can accurately balance the current of multiple battery packs (with an accuracy of ± 0.5%), avoiding the barrel effect.

3. Cost and space savings

●Hardware reuse: After integration, the sampling circuit and control unit are shared, reducing redundant components (such as ADC and isolation modules) and lowering BOM costs by more than 30%.

●Compact design: suitable for space constrained scenarios such as distributed energy storage and vehicle mounted energy packs.

The role of high-precision onboard current sensors in integration

1. Accurate energy metering

●SOC estimation correction: Traditional splitters have large temperature drift (± 100ppm/° C), resulting in SOC cumulative error>5%; The flux gate sensor (± 5ppm/° C) can compress errors to<1% and extend battery life.

●Bidirectional current detection: supports μ A leakage current monitoring (such as PID effect in photovoltaic systems) to avoid power generation loss.

2. Real time protection and diagnosis

●Fast response to overcurrent: The onboard sensor is directly embedded in the PCS power circuit, and when a ns level current peak is detected, it triggers the IGBT to turn off (more than 10 μ s faster than traditional solutions).

●Insulation fault location: Through multi-sensor data fusion (such as PCS input/output terminal current difference), accurately locate the internal short circuit point of the battery pack.

3. System level performance enhancement

●Efficiency optimization: High precision current feedback helps PCS achieve MPPT (maximum power point tracking) efficiency>99% (traditional solutions are about 97%).

●Predictive maintenance: Current ripple analysis can predict battery degradation (such as lithium deposition trend) and provide early warning.

The deep integration of PCS and BMS is a necessary path for new energy systems to move towards efficiency and intelligence, and high-precision onboard current sensors, as the core of the “data sensing layer”, play an irreplaceable role in energy metering, safety protection, and performance optimization. The future integrated systems will further increase the bandwidth and voltage requirements for sensors, which will inevitably drive the development of flux gate technology towards higher integration levels.