Dynamic Current Allocation for Electric Vehicle Battery Charging
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Solution Overview
Problem
Conventional electrical distribution systems are inadequate for handling highly variable current loads, particularly in electric vehicle battery charging, as they lack the flexibility to maximize charging rates when excess capacity is available, leading to inefficiencies and potential damage to batteries.
Innovation Solution
A method and apparatus that measure the instantaneous current reserve in a distributor and dynamically adjust the current allocation to a variable load circuit, allowing it to draw either the full load current when reserve is positive or a combination of full load and reserve when reserve is negative, thereby optimizing current usage and preventing exceeding the main breaker's capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional load-shedding is used to prevent exceeding main breaker capacity, then system safety is maintained, but charging speed is reduced due to inability to utilize excess capacity
Solution Approach 1:
The patent implements dynamic current allocation that continuously monitors main breaker capacity and adjusts branch circuit current limits in real-time. Unlike static load-shedding, the system dynamically transfers excess capacity from the main breaker to the battery charger branch circuit, allowing charging speed to vary with available capacity while maintaining safety constraints.
Solution Approach 2:
The system employs feedback mechanisms through current sensors that continuously measure main breaker current and branch circuit current. This feedback loop enables the control system to adjust current allocation dynamically, transferring excess capacity when available and preventing overloads when capacity is constrained, thereby resolving the contradiction between safety and charging speed.
2Productivity
If branch circuit current rating is increased to enable faster charging, then charging efficiency improves, but risk of exceeding main breaker capacity increases
Solution Approach 1:
The patent allows branch circuits to be rated for higher current capacity than traditional designs, but implements dynamic current limiting through the control system. The branch circuit can draw up to its full rated capacity when main breaker excess capacity is available, while the control system prevents sustained overloads by adjusting the current limit in real-time based on main breaker conditions.
3Device complexity
If static current allocation is used to simplify system design, then device complexity is reduced, but adaptability to varying load conditions deteriorates
Solution Approach 1:
The patent changes the parameter of current allocation from static to dynamic. The system monitors multiple parameters including main breaker current, branch circuit current, and calculated excess capacity, and adjusts the branch circuit current limit parameter in real-time. This enables adaptability to varying load conditions while maintaining a relatively simple overall system architecture.
Data Source
AI summary
The present invention provides a method and apparatus for allocating current (20) from a distributor (22), having a maximum rated current, among a plurality of load circuits (24), including a variable load circuit (24α) that benefits from a full load current allocation but is operable at a lower current allocation. The invention provides for measuring the instantaneous current reserve of the distributor (22) as the maximum rated current of the distributor (22) less the instantaneous current flowing from the distributor (22) to the plurality of load circuits (24), and limiting the instantaneous current of the variable load circuit (24α) to the full load current of the variable load circuit (24α) if the instantaneous current reserve is greater than zero, and the sum of the full load current of the variable load circuit (24α) plus the instantaneous current reserve, if the instantaneous current reserve is less than or equal to zero.