Electric Motor Neutral-Point Switching for Higher Torque Output
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Solution Overview
Problem
Existing electric motor systems face challenges in generating sufficient torque due to limitations in inputting multi-phase AC power, particularly with regards to DC voltage utilization and the inefficiency of utilizing zero-phase current for torque enhancement.
Innovation Solution
The electric motor system incorporates a stator core with concentrated winding stator coils and zero-phase switching arms, where plural-phase windings are arranged on teeth, with inverters applying currents to generate rotating and zero-phase fluxes, and zero-phase switching arms adjust the zero-phase current to enhance torque generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multi-phase AC power is applied to generate torque at the rotor, then torque generation is achieved, but the torque output is limited by DC voltage utilization efficiency
Solution Approach 1:
The patent changes the electrical parameter configuration by introducing zero-phase current in addition to multi-phase AC current. This allows the system to utilize the DC voltage more effectively by creating an additional torque generation pathway through the zero-phase winding, thereby increasing overall torque output without being constrained by the traditional multi-phase power limitations.
2Power
If conventional multi-phase windings are used without zero-phase current, then the structure is simple, but torque enhancement is limited
Solution Approach 1:
The patent segments the stator windings into two distinct components: conventional multi-phase windings for basic torque generation and zero-phase windings for torque enhancement. This segmentation allows each winding type to perform its specific function independently, with the zero-phase winding specifically designed to carry zero-phase current for additional torque generation without interfering with the multi-phase winding operation.
Solution Approach 2:
The stator is designed with multi-functional windings that serve different purposes. The multi-phase windings handle the primary AC power conversion while the zero-phase windings handle the zero-phase current for torque enhancement. Both winding systems operate simultaneously within the same stator structure, making the device universally capable of both conventional and enhanced torque generation modes.
3Productivity
If zero-phase current is not utilized, then the control system is simple, but power utilization efficiency is low
Solution Approach 1:
The control system incorporates feedback mechanisms to monitor the DC voltage input and dynamically adjust the zero-phase current generation. By detecting the input voltage conditions and rotor position, the controller optimizes the zero-phase current magnitude and phase angle to maximize torque output, thereby improving power utilization efficiency through active feedback control.
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 configuration effectively increases torque generation at the rotor by utilizing zero-phase current in conjunction with three-phase AC current, improving power utilization efficiency and iron core utilization.
Implementation Method 1
The inverter to which respective first ends of the plural-phase windings are connected, applies a current for generating rotating fluxes around the rotor to the plural-phase windings
Implementation Method 2
The zero-phase switching arm, to which respective second ends of the plural-phase windings are commonly connected, adjusts a zero-phase current flowing through a common connection point of the plural-phase windings and generates torque at the rotor using the zero-phase current
Data Source
AI summary
An electric motor system includes a battery, an inverter, an electric motor, a zero-phase switching arm and a control unit. The inverter converts DC power output from the battery into three-phase AC power and outputs the three-phase AC power to the electric motor. A rotor of the electric motor rotates by the three-phase AC power output from the inverter. A neural point of the electric motor is connected to the zero-phase switching arm. A zero-phase current flowing through respective windings of the electric motor is adjusted by switching of the zero-phase switching arm. By this means, in the electric motor system, torque is generated at the rotor also using the zero-phase current as well as a three-phase AC current flowing through the respective windings.