Permanent Magnet Synchronous Submersible Motor Stator Design
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Solution Overview
Problem
Submersible motors have low power factor, high energy consumption, and cannot be directly started with conventional V/F-controlled converters, leading to inefficiencies in power grid utilization and increased load on power generation and transmission equipment.
Innovation Solution
A motor stator with an odd number of stator slots and dual-phase coil winding, combined with a permanent magnet synchronous motor design featuring a rotor core with neodymium iron boron or samarium cobalt magnets, allowing for improved magnetic field distribution and eliminating the need for excitation current, thereby enhancing efficiency and enabling starting with V/F-controlled converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional AC asynchronous motor structure is used in submersible motors, then the motor can operate in submerged environment, but the power factor is low and energy consumption is high
Solution Approach 1:
The patent changes the fundamental operating parameters by transitioning from asynchronous motor principle to synchronous motor principle with permanent magnets. This involves changing the rotor structure from squirrel cage to permanent magnet rotor, and adjusting the stator winding configuration to accommodate the new motor type, thereby improving power factor and energy efficiency
Solution Approach 2:
The patent replaces the electromagnetic induction mechanism of asynchronous motors with a direct magnetic field interaction mechanism using permanent magnets. The permanent magnets on the rotor create a synchronous magnetic field that directly interacts with the stator field, eliminating the need for rotor induction and improving overall efficiency
2Use of energy by moving object
If permanent magnet submersible motor is designed, then energy efficiency is improved, but the motor cannot be started directly with conventional V/F-controlled converters
Solution Approach 1:
The patent designs the motor with universal compatibility features that allow it to operate with both conventional V/F converters and advanced vector control systems. The motor controller is designed to accommodate multiple control modes, enabling the same motor design to work across different application requirements and converter types
Solution Approach 2:
The patent introduces a motor controller as an intermediary device that bridges the permanent magnet motor and conventional V/F converters. The controller translates the simple voltage-frequency control signals into appropriate current waveforms that can properly start and control the permanent magnet motor, while maintaining compatibility with existing converter infrastructure
3Ease of operation
If odd number of stator slots is used, then magnetic field distribution is improved and power factor increases, but manufacturing complexity increases
Solution Approach 1:
The patent deliberately uses an odd number of stator slots (such as 15 or 21 slots) instead of the conventional even number. This asymmetric configuration creates a more uniform magnetic field distribution in the air gap, reducing harmonic content and improving power factor. The odd slot configuration prevents certain harmonic patterns that would occur with even slots, leading to better electromagnetic performance
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 improves power factor, reduces energy consumption by 26%, decreases motor volume and weight by 50%, and allows for efficient starting with V/F-controlled converters, resulting in higher efficiency and extended service life.
Implementation Method 1
each of the rotor punching sheets is provided with rotor slots in which a permanent magnet is inserted
Implementation Method 2
The solution improves power factor, reduces energy consumption by 26%, decreases motor volume and weight by 50%, and allows for efficient starting with V/F-controlled converters
Data Source
AI summary
The present invention is a permanent magnet synchronous submersible motor comprised of a motor stator and a rotor core. The motor stator includes a stator core formed by laminating a plurality of stator punching sheets. Each of the stator punching sheets is provided with an odd number of stator slots and any two of a X-phase coil, a Y-phase coil and a Z-phase coil are wound in each of the stator slots. The rotor core is formed by laminating a plurality of rotor punching sheets wherein each of the rotor punching sheets is provided with rotor slots and a permanent magnet inserted into each of the rotor slots. Furthermore, the permanent magnet submersible motor can be started with a conventional V/F controlled (variable frequency) converter.