In automotive electric drive systems, multiple power devices are often connected in parallel to increase power output. Traditional current sharing control employs a "one-size-fits-all" approach to load distribution, focusing solely on instantaneous current balancing while ignoring individual device variations, aging, and mismatches in thermal characteristics. During long-term operation, aged or weaker devices are forced to share the current equally with healthy devices, which can easily lead to localized overheating and stress concentration, causing the weaker devices to fail prematurely while preventing the healthy devices from fully utilizing their load-carrying capacity.
This patent innovatively proposes a tiered control scheme centered on current health profiling, which is divided into three main stages:
1.Create a current health profile for each device: A set of sensors collects real-time operational data from each parallel-connected power device, quantifies information such as device health, degradation level, and load margin, and generates an independent current health profile.
2.Health Assessment and Differentiated Load Distribution: Based on device profiling, construct a correlated health profile for adjacent devices to quantify health differences between them. Following the strategy of "the strong bear more, while the weak rest," devices with higher health levels assume a greater load, while aging devices have their load appropriately reduced. The system calculates the optimal load-sharing ratios for each device, dynamically adjusts parameters, and outputs current distribution control data.
3.Closed-loop dynamic current balancing: Using the results of differentiated load distribution as the target command, the system compares the current command with the actual sampled values in real time to perform closed-loop current balancing. This unifies macro-level differentiated load distribution with micro-level dynamic current balancing, ensuring stable system current without oscillations.
The entire technology relies on the coordinated operation of three major modules-device health analysis, adjacent-state analysis, and current-sharing control-to resolve the conflict inherent in traditional current-sharing solutions, where "balancing current distribution sacrifices device lifespan, while protecting devices compromises system stability."
This technology effectively mitigates unreasonable operating conditions-such as device overload and waste caused by light loads-balances the system's aging rate, reduces the risk of device failure due to overheating, and enhances the stability, reliability, and service life of automotive power systems. It also improves the safety and durability of automotive power conversion systems and is suitable for power parallel scenarios such as automotive power conversion and motor drives.
Going forward, the company will continue to focus on power semiconductor system control technology, develop new generations of highly reliable solutions, and support the high-quality development of the automotive power electronics industry.
