Electric Supercharger Motor Torque Control
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Solution Overview
Problem
Existing control systems for electric superchargers using switched-reluctance motors often operate at maximum torque, leading to inefficient power consumption and potential damage due to constant high current draw, lacking flexibility in power usage and responsiveness.
Innovation Solution
A method and system that dynamically vary the torque cap based on motor speed, allowing multiple torque cap behaviors to maintain current within predetermined thresholds, enabling more efficient and predictable power use, and quicker response times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant torque cap is applied across all motor speeds, then the current is limited to prevent damage and excessive losses, but the motor cannot accelerate quickly and responds slowly to speed changes
Solution Approach 1:
The patent applies dynamics by making the torque cap variable rather than constant. The torque cap is dynamically adjusted based on the actual motor speed, allowing higher torque at lower speeds for faster acceleration and lower torque at higher speeds to maintain safety and efficiency. This resolves the contradiction by adapting the torque limitation to the operating conditions.
Solution Approach 2:
The patent changes the parameter of torque cap from a fixed value to a variable that depends on motor speed. By implementing a full-load curve that defines torque cap as a function of speed, the system allows parameter changes that enable quick acceleration at low speeds while maintaining safety constraints at high speeds, thus resolving the contradiction between acceleration performance and motor safety.
2Use of energy by moving object
If the torque demand is limited by a constant torque cap, then the current drawn by the motor is controlled, but the power consumption becomes inefficient and inflexible
Solution Approach 1:
The system dynamically adjusts the torque cap based on actual motor speed using a full-load curve, allowing optimal power efficiency at different operating points. This dynamic adaptation enables the motor to operate efficiently across varying conditions while maintaining the ability to respond to different power management requirements.
Solution Approach 2:
The full-load curve implementation provides a universal solution that works across the entire operating range of the motor. It simultaneously achieves current control, power efficiency optimization, and adaptability to different operating conditions, making the system versatile for various power management scenarios.
3Object-affected harmful factors
If the torque cap is set to prevent excessive current, then the motor windings and electronics are protected from damage, but the motor speed cannot increase rapidly
Solution Approach 1:
The patent implements parameter changes by making the torque cap a function of motor speed through the full-load curve. At low speeds, the torque cap allows higher values enabling rapid acceleration, while at high speeds, it reduces to prevent excessive current. This speed-dependent parameter adjustment protects against damage while minimizing acceleration time.
Solution Approach 2:
The dynamic torque cap adjustment based on actual speed allows the system to optimize acceleration performance without compromising safety. The continuous adaptation of torque limitation to operating conditions enables fast acceleration when safe and provides protection when necessary, resolving the time-safety contradiction.
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 approach ensures consistent and controlled current draw, reducing the risk of damage and improving power efficiency by tailoring torque cap behaviors to specific conditions, such as battery charge levels, while allowing for flexible power management.
Implementation Method 1
Using a switched-reluctance motor in an electric supercharger (to drive the compressor element) has been found to be particularly beneficial
Data Source
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AI summary
A control system (1) for controlling a motor in an electric supercharger, the system (1) comprises a memory module comprising an input variable cap behaviour (7) (for example a full-load curve), a processor arranged to apply the input variable cap behaviour (7) to impose an input variable cap (for example a torque cap) on the input variable (for example the torque) required to change the speed of the motor from the actual speed towards the target speed. The input variable cap in the input variable cap behaviour (7) preferably varies as a function of the speed of the motor. The input variable cap behaviour (7) is preferably selected from a plurality of different input variablecap behaviours (7), each being designed to achieve a different power consumption by the motor.