Solid State Power Controller Overcurrent Management
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Solution Overview
Problem
High voltage direct current (DC) systems in hybrid vehicles face challenges with excessive heat dissipation in switching devices within solid state power controllers (SSPCs) due to internal resistances, leading to increased complexity, cost, and weight from required thermal management techniques.
Innovation Solution
The implementation of a solid state power controller system with a main switch, an auxiliary switch in parallel, a current limiting resistor, and sensors to detect overcurrent conditions, allowing for current limiting and preventing damage to DC loads by switching off the main switch and engaging the auxiliary switch via a current limiting resistor when overcurrent is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If switching devices are used in solid state power controllers, then fast response time and elimination of arcing are achieved, but excessive heat dissipation occurs due to internal resistances
Solution Approach 1:
A current limiting circuit is introduced as an intermediary component between the power source and the switching device. This circuit actively monitors current levels and limits excessive current flow, thereby reducing the heat dissipation burden on the switching device while preserving its fast response characteristics
2Temperature
If thermal management techniques are implemented to manage heat dissipation, then temperature control is improved, but system complexity, cost and weight increase
Solution Approach 1:
The current limiting circuit performs preliminary action by proactively limiting current before it can cause excessive heat generation. This preventive approach eliminates the need for complex thermal management systems, as heat dissipation is controlled at its source rather than requiring additional cooling infrastructure
3Reliability
If current limiting is implemented to manage overcurrent conditions, then power quality improves, but additional components and control circuitry are required
Solution Approach 1:
The current limiting circuit is designed with multi-functionality, serving both as a protective device for overcurrent conditions and as a power quality management system. By consolidating these functions into a single integrated circuit, the overall system complexity is minimized while achieving multiple objectives
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution improves power quality, reduces system weight, size, and cost by effectively managing overcurrent conditions, avoiding nuisance trips, and eliminating the need for pre-charge functions in switched mode power converters/motor drives.
Implementation Method 1
a current limiting resistor coupled in series to the auxiliary switch
Data Source
AI summary
A solid state power controller system can include a direct current load 115, a solid state power controller apparatus 110 including an alternating current sensor 125 coupled to the direct current load, a direct current sensor 130 coupled to the direct current load, a voltage sensor 135 coupled to the direct current load, a main switch 120 coupled to the direct current load via the alternating and direct current sensors, an auxiliary switch 140 coupled in parallel to the main switch, a current limiting resistor 145 coupled in series to the auxiliary switch and a solid state power controller 160 coupled to the main switch, the auxiliary switch, the alternating current sensor, the direct current sensor, and the voltage sensor, and a direct current power source coupled to the solid state power controller apparatus.