Parallel Power Storage Overcurrent Protection via Dynamic Load Driving Control
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Solution Overview
Problem
In electric vehicles with power storage devices connected in parallel, existing systems fail to adequately protect components from overcurrent while ensuring motive energy performance, as they do not effectively manage the output power limits across multiple devices.
Innovation Solution
A load driving device equipped with multiple current sensors and a control device that calculates and adjusts output power limits based on detected currents, performing excess current feedback control to prevent overcurrent and optimize power usage across parallel-connected power storage devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple power storage devices are connected in parallel to increase capacity, then the storage capacity and motive energy performance are improved, but the risk of overcurrent to components increases
Solution Approach 1:
The control device continuously monitors the output currents from each power storage device and the total current from the power storage portion, comparing these values against threshold values. When thresholds are exceeded, the control device adjusts the output power limits dynamically to prevent overcurrent damage to components such as fuses, relays, and power elements while maintaining optimal power distribution across the parallel-connected devices.
Solution Approach 2:
The output power limit values for each power storage device are not fixed but are dynamically adjusted based on real-time current measurements. The control device modifies these limits in response to changing operating conditions, ensuring that the system can fully exploit the capacities of all power storage devices while preventing overcurrent conditions that would damage components.
2Reliability
If the output power of power storage devices is limited to protect components, then overcurrent protection is improved, but the motive energy performance deteriorates
Solution Approach 1:
The system uses dynamic adjustment of output power limit values based on real-time current monitoring. When current levels are within safe thresholds, the full power capacity of each power storage device is permitted, maximizing motive energy performance. When thresholds are approached or exceeded, the control device selectively reduces power limits only for affected devices, maintaining optimal performance while preventing overcurrent damage.
Solution Approach 2:
The control device changes the operational parameters (output power limits) of individual power storage devices based on their current output levels and the overall system state. This allows the system to adapt power distribution dynamically, ensuring component protection while maintaining maximum possible motive energy performance through optimized power utilization across all devices.
Data Source
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Figure 3~4
AI summary
A Wout calculating portion (104) summates limit values (Woutl, Wout2) of respective power storage devices to calculate an output power limit value (Wout) of a power storage portion. An excess current FB control portion (108) executes an excess current FB control if at least one of currents IBl, IB2, and IBT exceeds a predetermined threshold. A Woutf correction processing portion (112) corrects the output power limit value (Wout) given to a motor power calculating portion (110) to a motor power command value (Pm) at a timing when at least one of the currents IBl, IB2, and IBT reaches the threshold. In a load driving device that includes a plurality of power storage devices connected in parallel to one another, respective parts may be appropriately protected from overcurrent while sufficiently exploiting the capacities of the plurality of the power storage devices to ensure motive energy performance.