Rotating Electric Machine System with Full-Wave and Half-Wave Drive Modes
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Solution Overview
Problem
Existing rotating electric machine systems face challenges in efficiently managing power transfer across wide rotational speed ranges without increasing system cost or complexity, particularly in motor vehicles, where current configurations require redundant switches and semiconductor elements, leading to size and reliability issues.
Innovation Solution
A rotating electric machine system with a configuration that includes N coils connected to form a neutral point, utilizing N high-side and low-side switches, a selector switch, and drivers for full-wave and half-wave operations, allowing for efficient power transfer without semiconductor elements, minimizing system size, and optimizing switch usage to prevent load concentration and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a DC-DC converter is employed to vary voltage for wide-speed operation, then the rotating electric machine can achieve required performance across low-speed and high-speed regions, but system cost is considerably increased
Solution Approach 1:
The patent makes the existing inverter circuit perform multiple functions by enabling both full-wave and half-wave drive processes. The same inverter switches and circuitry are used across different speed regions, eliminating the need for a separate DC-DC converter and reducing system cost while maintaining wide-speed operation capability
2Adaptability or versatility
If the electrical connection of stator coil is switched between Δ-connection and star-connection during operation, then the rotating electric machine can achieve required performance, but system configuration becomes complicated and operation must be stopped during switching
Solution Approach 1:
The patent dynamically changes the drive mode (full-wave or half-wave) based on rotational speed requirements without physically reconfiguring the coil connections. The inverter control switches between drive processes while the electrical connection remains stable, avoiding operational stops and complex switching mechanisms
3Adaptability or versatility
If a semiconductor element is employed to perform half-wave drive process, then the half-wave drive can be implemented, but the size of motor drive circuit is increased
Solution Approach 1:
The patent enables the existing inverter switches to perform both full-wave and half-wave drive functions without adding dedicated semiconductor elements. The same switches are used in different configurations depending on the drive mode, eliminating the need for additional components and reducing circuit size
4Adaptability or versatility
If high-side switches are kept off during half-wave drive process, then the half-wave drive can be performed, but the high-side switches become redundant and system size increases
Solution Approach 1:
The patent designs the inverter circuit so that all switches including high-side switches remain active and useful during both full-wave and half-wave drive processes. The high-side switches participate in both drive modes, eliminating redundancy and optimizing component utilization across all operating conditions
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
The system enables efficient power transfer across wide rotational speed ranges without redundant switches, minimizing system size, improving reliability by preventing load concentration and heat issues, and reducing torque ripple, while maintaining high average torque.
Implementation Method 1
a rotating electric machine and an electric power conversion circuit between which electric power is transferred
Data Source
AI summary
A rotating electric machine system includes a rotating electric machine and an electric power conversion circuit. The rotating electric machine includes N coils connected with each other to define a neutral point therebetween. The electric power conversion circuit includes N high-side switches, N low-side switches, a selector switch, a full-wave driver, a half-wave driver and a drive controller. The full-wave driver performs a full-wave drive process with high potential-side terminals of the low-side switches respectively connected with low potential-side terminals of the high-side switches by the selector switch. The half-wave driver performs a half-wave drive process with the high potential-side terminals of the low-side switches connected with the neutral point by the selector switch. The drive controller controls both the full-wave driver and the half-wave driver to selectively cause either the full-wave driver to perform the full-wave drive process or the half-wave driver to perform the half-wave drive process.