Variable Torque Linear Motor with Dynamic Magnetic Field Adjustment
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Solution Overview
Problem
Permanent magnet electric motors and generators have limited efficiency when operating outside their rated speed and torque specifications, leading to significant efficiency drops in applications with varying speed and torque requirements, such as in transportation and renewable energy systems.
Innovation Solution
The motor/generator transmission system dynamically adjusts the magnetic field by varying the connection of non-twisted parallel coil wires in the stator between series and parallel configurations and modularly engages/disengages rotor/stator sets, allowing for efficient operation across a wide range of torque and RPM conditions through electronic reconfiguration and mechanical shifting of the rotor magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If permanent magnet linear motors are used to simplify construction and increase efficiency range, then construction is simplified and efficiency range increases, but efficiency still drops significantly when operating outside rated specifications
Solution Approach 1:
The patent applies dynamics by making the magnetic field strength adjustable rather than fixed. The controller dynamically changes the current supplied to the stator windings based on real-time operating conditions (speed and force demands), allowing the motor to adapt its magnetic field strength to match varying operational requirements. This dynamic adjustment prevents the severe efficiency drops that occur in permanent magnet motors when operating outside their rated specifications.
Solution Approach 2:
The patent implements parameter changes by varying the electrical parameters (current magnitude and winding configuration) of the stator to adjust the magnetic field strength. The controller modifies these parameters in response to changing speed and force demands, enabling the motor to maintain high efficiency across a wide operating range rather than being constrained to a narrow rated operating point.
2Loss of energy
If motors are designed for high efficiency at rated RPM and torque, then efficiency reaches 90-98%, but efficiency dramatically decreases to 30-60% when operating outside specified ratings
Solution Approach 1:
The patent transforms the static magnetic field of traditional motors into a dynamic, adjustable field. The controller continuously adjusts the stator current and winding connections based on real-time feedback about speed and force demands, enabling the motor to adapt its characteristics to maintain high efficiency whether operating at low speeds, high speeds, low forces, or high forces.
Solution Approach 2:
The patent makes the motor universally adaptable to multiple operating conditions through its reconfigurable winding system. By providing multiple winding connections and adjustable current levels, the motor can function efficiently across diverse operating scenarios - from starting conditions to high-speed operation, from low-force to high-force demands - rather than being optimized for a single rated operating point.
3Ease of operation
If permanent magnets continuously pass by the iron core in coast mode, then the motor can coast freely, but extreme drag is generated reducing efficiency
Solution Approach 1:
The patent extracts or removes the permanent magnets from the rotor, eliminating the source of the problem. Instead of using permanent magnets that continuously interact with the stator iron core during coasting, the invention uses an electromagnet-based system where the magnetic field can be completely deactivated by stopping current flow to the stator windings, allowing frictionless coasting without drag.
Solution Approach 2:
The patent replaces the permanent magnet mechanical field with an electrically controllable electromagnetic field. This substitution allows the magnetic field to be precisely controlled - present when needed for motor or generation operation, and completely absent during coasting - thereby eliminating the extreme drag that occurs when permanent magnets continuously pass by the iron core.
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 enables high efficiency over a broader range of operating conditions, optimizing energy conversion in hybrid vehicles and renewable energy systems by dynamically adjusting the magnetic field and stator winding configurations to match varying power demands.
Implementation Method 1
electric current supplied to the stator windings generates a magnetic field that interacts with the rotor magnetic field
Implementation Method 2
the interaction between magnetic fields produces an electromagnetic force
Implementation Method 3
the rotor magnetic field interacts with the stator windings to induce an electrical current
Data Source
AI summary
A linear motor/generator/transmission system includes a guideway with rails and a plurality of stator cores and coils evenly disposed along the length and in the center of the guideway. The system also includes a carriage configured to travel along the guideway having at least two magnet bars with alternating pole magnets, each successive magnet of each magnet bar mounted in front of the other in a direction of travel of the carriage. In embodiments, the magnet bars are mounted parallel to and on either side of a longitudinal centerline of the carriage such that, when adjacent to the center line and each other, the at least two magnet bars are positioned over the stator coils and are configured to be slidably translated away from the center line of the carriage to a position where the at least two magnet bars are not over the stator coils.