Segmented Permanent-Magnet Motor for Reliable Heavy-Duty Drives
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Solution Overview
Problem
Conventional drive systems in heavy industry, particularly in the raw materials and mining sectors, face challenges with high failure probability due to multiple components, maintenance requirements for air gap maintenance, and weight issues, which affect reliability and efficiency.
Innovation Solution
A segmented permanent magnet excited motor with individually supplied stator segments and a common bearing element for the rotor and stator, eliminating the need for slip rings and brushes, allowing for modular construction, easy assembly, and flexible power control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional drive systems with multiple components (frequency converter, electric motor, coupling, gearbox, brake) are used, then the machine can perform tasks with high drive power and torque, but the probability of drive failure increases due to the large number of components
Solution Approach 1:
The motor is divided into multiple independent motor segments (first motor segment, second motor segment, etc.), each capable of independent operation. This segmentation allows the drive system to maintain high power output while improving reliability, as failure of one segment does not necessarily lead to complete system failure.
Solution Approach 2:
Each motor segment is designed as a universal module that can function independently or in combination with other segments. The common bearing element supports multiple rotor segments simultaneously, creating a multi-functional structure that achieves both power multiplication and reliability improvement.
2Force
If separately excited synchronous motors with slip rings and brushes are used, then high torque and low speed can be provided, but maintenance requirements increase due to wear parts that need inspection and replacement
Solution Approach 1:
The problematic slip rings and brushes are completely removed from the design. Instead of separately exciting the rotor windings through contact-based slip rings, the invention uses a contactless excitation method where the rotor segments are permanently magnetized or excited through the stator segments, eliminating wear parts and associated maintenance.
Solution Approach 2:
The mechanical contact-based excitation system (slip rings and brushes) is replaced with an electromagnetic field-based excitation system. The stator segments generate magnetic fields that excite the rotor segments without physical contact, substituting a mechanical system with an electromagnetic one that has no wear parts.
3Reliability
If robust foundations and support structures are used to maintain the air gap between rotor and stator, then the air gap can be maintained to prevent motor damage, but the overall weight of the drive unit increases
Solution Approach 1:
Multiple rotor segments are mounted on a common bearing element, merging their support functions into a single structural component. This consolidation reduces the overall weight compared to having separate support structures for each rotor segment, while still maintaining the necessary air gaps through the bearing's precise positioning capabilities.
Solution Approach 2:
The air gap maintenance approach changes from relying on robust mechanical foundations to using precision bearing elements with controlled clearance. By changing the parameter of support structure rigidity to precision rotational support, the system maintains air gaps without requiring excessively heavy foundations.
4Reliability
If complete drive components are kept in stock as spare parts to achieve high system availability, then damaged components can be replaced quickly, but the cost and complexity of the overall system increases
Solution Approach 1:
The drive system is segmented into modular motor segments that can be independently replaced. This segmentation reduces spare parts inventory complexity because only individual segments need to be stocked rather than complete motor assemblies, making the spare parts system more manageable and cost-effective.
Solution Approach 2:
The modular segment design enables easy discarding of failed segments and recovery/reuse of functional segments. Healthy segments can be quickly transferred to replace failed ones, reducing the need for extensive spare parts inventory and simplifying the availability management system.
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
Enhances operational reliability, reduces maintenance, and achieves significant weight savings while maintaining high torque and flexibility in power operation, contributing to increased system availability and energy efficiency.
Implementation Method 1
a permanent magnet excited motor (4), in particular a segmented permanent magnet excited motor
Implementation Method 2
the rotor segments (12) arranged on the radially inner rotor wall are assigned to the stator segments (18) opposite it
Implementation Method 3
wherein a seal (22) is provided between the radially outer rotor wall and the stator, which protects the air gap formed in the area between the rotor segments (12) and the stator segments (18) from the ingress of contaminants
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a drive device (2) for a working machine (28) for heavy industry, in particular for the raw-materials and mining industry, comprising a permanent-magnet-excited motor (4) and a frequency converter (6), wherein the motor (4) has a rotor (10) and a stator (16), and wherein the motor (4) is a segment motor, in the case of which the rotor (10) and/or the stator (16) is composed of a plurality of segments (12, 18). Because the motor (4) is of a segment design, considerable improvement in the availability of the motor (4) is achieved, whereby the reliability during operation of the drive device (2) is also increased.