Range Extender Power Control Using Current-Voltage Feedback
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Solution Overview
Problem
Range-extended electric vehicles face challenges in accurately controlling the generation power of range extenders, leading to overcharging or over-discharging of power batteries due to inaccuracies in torque feedback, especially in low-temperature environments or when the engine is not fully warmed up.
Innovation Solution
A method that calculates the actual generation power of the range extender based on detected currents and voltages of power-generating and power-consuming devices, adjusting the operating point to maintain an offset within a preset range, thereby avoiding overcharging or over-discharging by not relying on engine torque calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the actual generation power is calculated based on engine torque feedback, then the control system can operate with simpler measurement requirements, but the measurement precision deteriorates leading to overcharging or over-discharging of the power battery
Solution Approach 1:
The patent replaces the mechanical torque feedback measurement system with an electrical measurement system based on current and voltage detection. Instead of relying on mechanical torque sensors and feedback loops, the system directly calculates generation power using electrical parameters (current and voltage) from the power-generating and power-consuming devices, thereby improving measurement precision while avoiding the complexity of mechanical torque measurement systems
Solution Approach 2:
The patent introduces current and voltage detection as intermediary measurement elements to indirectly obtain generation power. Rather than directly measuring engine torque, the system uses electrical intermediaries (current sensors and voltage sensors) to calculate power through P=UI relationships, providing a more precise and reliable measurement path that avoids the inaccuracies of direct torque feedback
2Productivity
If the range extender operates in low-temperature environments or when the engine is not fully warmed up, then the vehicle can start and operate immediately, but the torque feedback accuracy deteriorates causing overcharging or over-discharging of the power battery
Solution Approach 1:
The patent replaces the temperature-sensitive mechanical torque feedback system with an electrical measurement system based on current and voltage. This substitution eliminates the dependency on engine warm-up conditions, allowing the vehicle to operate immediately upon startup without the measurement accuracy degradation that plagues traditional torque-based systems in cold conditions
Solution Approach 2:
The patent changes the measurement parameters from mechanical torque (which is temperature-dependent and requires warm-up) to electrical parameters (current and voltage) that are temperature-independent and immediately available. This parameter transformation allows the system to maintain high measurement precision regardless of operating temperature or engine warm-up status, enabling immediate vehicle operation
Data Source
AI summary
A method for controlling a generation power of a range extender includes: calculating obtaining an actual generation power of the range extender according to detected currents and voltages of a power-generating device and a power-consuming device; determining an offset between the actual generation power and a demand generation power of the range extender; and adjusting a target operating point of the range extender according to the offset, to make the offset within a preset range.