Motor Generator Coil State Control for Torque and Friction
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Solution Overview
Problem
The ACG starter, when coupled to the crankshaft without a reduction gear, faces challenges in generating sufficient torque to overcome engine compression at startup, leading to increased friction and reduced acceleration performance when used as both a starter and generator.
Innovation Solution
A power generation unit with a motor generator featuring a rotor and stator with independent three-phase coils, controlled by a driving part that manages coil states to optimize torque output and reduce friction, using a bridge circuit with switching elements to adjust coil states based on engine speed, crank angle, and battery charging rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the motor generator is used as a starter motor with independently driven coils to overcome engine compression, then torque output performance is improved, but friction increases when used as a generator
Solution Approach 1:
The patent applies dynamics by making the coil states changeable based on operating conditions. The control part dynamically switches between three states (torque generation, electrical release, short-circuit) depending on whether the motor generator is functioning as a starter or generator, and on the rotor speed. This dynamic adjustment optimizes torque output during starting while minimizing friction during power generation.
Solution Approach 2:
The patent changes the electrical state parameters of the coils based on operating conditions. By transitioning coils between different electrical states (connected for torque, released for low friction, short-circuited for energy recovery) according to rotor speed thresholds and operational mode, the system achieves optimal performance across different functions.
2Force
If all coils are brought into the first state for engine starting, then sufficient torque is generated to overcome compression, but friction becomes excessively large during power generation
Solution Approach 1:
The patent segments the coil control into independent phases that can be managed separately. By dividing the three-phase coils into independently controllable units, the control part can selectively apply different states to different phases based on operational requirements, allowing optimized torque generation when needed and friction reduction when not needed.
Solution Approach 2:
The patent applies partial action by bringing only the necessary coils into the torque generation state based on actual demand. During power generation, only specific coils are activated while others are released or short-circuited, avoiding the excessive friction that would result from all coils being in the torque generation state.
3Force
If the coils are independently driven to provide larger torque, then starting performance is improved, but the amount of power generation becomes excessively large when functioning as a generator
Solution Approach 1:
The patent changes the electrical connection parameters of the coils based on the desired function. By adjusting the electrical state (connected, released, or short-circuited) according to whether the system should prioritize torque output or power generation, the patent achieves versatile performance from the same hardware configuration.
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 enhances torque output performance while minimizing friction, improving acceleration ability and reducing power generation-related friction, especially during engine startup and varying rotation ranges.
Implementation Method 1
a motor generator formed by the rotor, the rotor having magnets, and a stator with coils, the coils constituting three or more phases
Implementation Method 2
when the motor generator is made to generate electric power using the output of the internal combustion engine
Data Source
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AI summary
A power generation unit includes a motor generator having a rotor with magnet, and a stator with coils driven in a plurality of phases, the coils of the respective phases not being connected to each other; and a driving control part that performs control so that a coil of each phase of the stator is brought into any one of a first state in which torque is generated by the rotor, a second state in which both ends of the coil are electrically released, and a third state in which both ends of the coil are short-circuited.