Switched Reluctance Motor Current Feedback Control
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Solution Overview
Problem
Switched reluctance motors (SR motors) face challenges in maintaining efficient regeneration and generation at low-speed rotation due to low generated voltage and energy loss from complex circuitry and timer-based excitation coil switching, leading to suspended generation and reduced efficiency.
Innovation Solution
A motor and control method that includes a rotor, a source, rotation means for magnetic force-driven rotation, current measurement, and control means to adjust current supply to maintain generating or regenerating operations by increasing current when measured values fall below predetermined limits, without relying on timer-based switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If timer-based switching control is used for excitation coil, then switching operation is simplified, but energy loss increases and generating efficiency decreases
Solution Approach 1:
The patent employs feedback control by measuring the actual current through the excitation coil and comparing it with the target current value. The switching control is adjusted based on this feedback to maintain optimal current levels, replacing the open-loop timer-based switching. This feedback mechanism enables precise control that minimizes energy loss while maintaining operational simplicity.
2Loss of energy
If complex regeneration circuit with reactor and capacitor is used, then energy recovery efficiency is improved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the complex reactor and capacitor components from the regeneration circuit. Instead of using these additional energy storage elements, the invention utilizes the inherent inductance of the excitation coil and a simplified switching arrangement to achieve effective energy recovery. This extraction of unnecessary components reduces device complexity while maintaining or improving energy recovery efficiency.
Solution Approach 2:
The excitation coil serves multiple functions: it provides the necessary magnetic field for motor operation and simultaneously acts as an energy storage element during regeneration. The simplified circuit leverages the multi-functionality of existing components rather than requiring dedicated separate components for each function, thereby reducing overall system complexity.
3Speed
If generated voltage is low in low-speed rotation range, then motor operation is maintained, but generation operation is suspended
Solution Approach 1:
The patent dynamically adjusts the target current value and switching timing parameters based on the detected rotation speed. In the low-speed range, the control system modifies these parameters to optimize the generated voltage and maintain generation operation. This parameter adaptation allows the system to overcome the inherent limitation of low generated voltage at low speeds without suspending generation.
4Stability of the object's composition
If current is gradually increased by timer-based switching, then closed-loop is reestablished, but generating efficiency is reduced
Solution Approach 1:
The patent replaces timer-based current increase with feedback-controlled current adjustment. The actual current is continuously measured and compared with the target value, and the switching control is adjusted in real-time to achieve the desired current profile. This feedback mechanism establishes a stable closed-loop control that minimizes energy loss during current transitions while maintaining system stability.
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 enhances generating and regeneration efficiency by stabilizing operations at low-speed rotation, minimizing energy loss, and ensuring continuous energy conversion without complex circuitry, thereby improving overall motor performance.
Implementation Method 1
rotation means for rotating the rotor by magnetic force produced with a current supplied by the source
Implementation Method 2
rotation means for rotating the rotor by magnetic force produced with a current supplied by the source and for making a generating operation to convert rotational energy of the rotor into electrical energy
Data Source
AI summary
A motor and control method for making the generating and regeneration efficiency higher than before are provided. A motor including a rotor, a storage battery and a capacitor (a source) is provided to charge a produced electrical energy, a SR motor portion rotates the rotor by magnetic force produced with a current supplied by the source and generates by converting rotational energy of the rotor into electrical energy, current sensors measure the currents supplied to excitation coils, and a semiconductor switching control circuit for driving and generation to maintain the rotation by increasing the current with supply of electrical energy from the source to the excitation coils if the currents measured by the current sensors fall below a predetermined lower limit for making the rotor rotate due to the charging.