Pole-Phase Modulated Induction Motor Drive for Gearless EV Torque Control
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Solution Overview
Problem
Existing electric vehicle powertrains with induction motors face limitations in achieving variable speed and torque without the need for rare earth magnetic materials, often requiring complex constructions and mechanical reconnection of windings, which can lead to inefficiencies and increased weight and volume.
Innovation Solution
A pole-phase modulation multiphase induction motor drive system with a single stator winding, utilizing a multilevel inverter and indirect field-oriented control, allows for variable speed and torque without mechanical reconnection, reducing weight and volume by eliminating the need for a gearbox and minimizing torque ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional induction motor is used in EV powertrains, then the motor structure is simple and does not require rare earth magnetic materials, but the motor cannot achieve variable speed and torque without a gearbox, increasing overall system weight and volume
Solution Approach 1:
The patent applies pole-phase modulation to enable the induction motor to dynamically change its number of poles and phases during operation. This allows the motor to adapt its speed-torque characteristics without mechanical gearboxes, achieving variable speed operation while maintaining a simple motor structure without rare earth materials
Solution Approach 2:
The invention changes the electrical parameters of the motor by modulating the number of phases and poles through power electronic converters. This parameter change enables the motor to deliver different torques and speeds similar to a multispeed gear system, resolving the contradiction between simplicity and adaptability
2Adaptability or versatility
If mechanical reconnection of windings is used to achieve variable speed, then speed variation is possible, but the construction becomes complex and reliability decreases
Solution Approach 1:
The patent replaces mechanical reconnection of windings with an electrical solution using power electronic converters. The converters electrically modulate the phases and poles without any mechanical movement or reconnection, thereby achieving speed variation while maintaining high reliability and simple construction
Solution Approach 2:
The invention extracts the speed variation function from the mechanical gearbox system and implements it through electrical pole-phase modulation. This removes the need for complex mechanical reconnection mechanisms, improving reliability while maintaining adaptability
3Adaptability or versatility
If a gearbox is added to achieve multispeed operation, then speed-torque range is extended, but the weight and volume of the powertrain increase
Solution Approach 1:
The patent makes the induction motor itself multi-functional by enabling it to operate in multiple pole and phase configurations. This allows the motor to directly provide a wide speed-torque range without requiring an external gearbox, eliminating unnecessary components and reducing powertrain volume
Solution Approach 2:
The invention substitutes the mechanical gearbox system with an electrical pole-phase modulation system. This replacement achieves the same speed-torque range extension without the weight and volume penalty of mechanical gears, clutches, and associated components
4Power
If rare earth magnetic materials are used to achieve high performance, then power handling capability is improved, but cost and material scarcity issues arise
Solution Approach 1:
The patent achieves high power handling capability through pole-phase modulation that optimizes the utilization of the motor's electromagnetic parameters. By dynamically changing the number of phases and poles, the system maximizes power output from a standard induction motor without requiring expensive rare earth magnetic materials
Solution Approach 2:
The invention uses conventional, inexpensive induction motor materials instead of expensive rare earth magnets. The pole-phase modulation technique compensates for the lower inherent power density of standard materials, achieving high power handling capability through intelligent control rather than expensive materials
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 solution enables a gearless electric vehicle powertrain with reduced size, weight, and increased fault tolerance, achieving a wide range of speed-torque characteristics similar to multispeed gear systems while avoiding the use of rare earth materials and mechanical gearboxes.
Implementation Method 1
pole-phase modulation multiphase induction motor
Implementation Method 2
controller configured to perform vector control of the multiphase induction motor using indirect field-oriented control
Data Source
AI summary
A Pole Phase Modulated (PPM) nine-phase induction motor drive may be used in gearless electric vehicle applications. A single stator winding multiphase induction motor may deliver variable speed-torques by varying the number of phases and poles with respect to a multiphase power converter. A multilevel inverter controlled with carrier phase shifted space vector pulse width modulator (PWM) may further improve the PPM based multiphase induction motor (MIM) drive with respect to efficiency, torque ripple, and direct current (DC) link utilization. To operate the PPM based MIM drive smoothly in different pole phase combinations, indirect field oriented vector control may used.