Drive System Eliminates Slip Rings via Dual Stator Windings
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Solution Overview
Problem
Conventional double-fed asynchronous motors rely on slip rings for rotor current dissipation, which are prone to failure and maintenance issues.
Innovation Solution
A drive system utilizing a three-phase motor with two stator windings and a rotor winding system, where the inverter is mechanically and electrically coupled to the rotor, generating control signals to create interacting rotating fields that compensate rotor power without slip rings, allowing for rectified torques and efficient energy management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If slip rings are used to dissipate rotor currents in a double-fed asynchronous motor, then the motor can operate with variable speed and torque control, but the slip rings are prone to failure and require maintenance
Solution Approach 1:
The invention extracts and eliminates the slip rings from the double-fed asynchronous motor system. By using a standard three-phase motor with two stator windings instead of a double-fed motor with rotor windings and slip rings, the problematic slip rings are completely removed from the system while maintaining the variable speed and torque control capabilities through inverter-based control of the stator windings
Solution Approach 2:
The invention replaces the mechanical slip ring system with an electrical/inverter-based control system. Instead of using mechanical contacts (slip rings) to transfer power to the rotor, the system uses two stator windings controlled by inverters to generate the necessary rotating magnetic fields, thereby substituting a mechanical system with a more reliable electrical control system
2Reliability
If a double-fed asynchronous motor with two inverters is used to eliminate slip rings, then reliability improves, but the device complexity increases
Solution Approach 1:
The invention makes the standard three-phase motor universal by enabling it to perform the functions of both a single-fed motor and a double-fed motor. By equipping a conventional motor with two stator windings and controlling them through inverters, the system achieves variable speed and torque control (typically requiring a double-fed motor) while using a simpler, more reliable standard motor structure
Solution Approach 2:
Instead of modifying the rotor side of the motor (as in a double-fed motor with rotor windings and slip rings), the invention inverts the approach by implementing the dual-winding configuration on the stator side. This inversion allows the use of a standard rotor and eliminates the need for rotor-side power transmission components, simplifying the overall system
3Productivity
If two stator windings with different pole pairs are used to generate counter-rotating fields, then torque compensation and rectified torque are achieved, but the manufacturing complexity increases
Solution Approach 1:
The invention segments the stator winding system into two independent three-phase windings (first and second stator windings) with different pole pairs. Each winding can be controlled independently by separate inverter systems, allowing for flexible generation of rotating magnetic fields with different characteristics. This segmentation enables torque compensation and rectified torque production while maintaining manufacturing feasibility through standardized winding techniques
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 solution eliminates the need for slip rings, improves operating properties, and enables efficient power compensation and torque generation, reducing maintenance and increasing reliability.
Implementation Method 1
The inverter 3 generates control signals in the form of control voltages and/or control currents for the rotor winding system 2 in such a way that a first rotating magnetic rotor field and a second rotating magnetic rotor field rotating in opposite directions to the first rotating rotor field are generated
Implementation Method 2
The first rotating rotor field interacts with the first rotating stator field in such a way that a first motor speed and a first torque result, and with the second rotating rotor field interacting with the second rotating stator field
Data Source
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AI summary
The invention relates to a drive system (100) having: a three-phase motor having: a shaft, a first three-phase stator winding (1 a) which can be connected to a three-phase AC voltage network (U, V, W), a second three-phase stator winding (1b) which can be connected to the three-phase AC voltage network (U, V, W) to generate a second stator rotating field rotating in the opposite direction to that of a first stator rotating field produced by means of the first stator winding (1a), a rotor winding system (2) mechanically coupled to the shaft for conjoint rotation, and at least one inverter (3, 4), which is mechanically coupled to the shaft for conjoint rotation and is electrically coupled to the rotor winding system (2). The at least one inverter (3, 4) is designed to generate drive signals for the rotor winding system (2) in such a manner that a first rotor rotating field and a second rotor rotating field are produced. The first rotor rotating field interacts with the first stator rotating field in such a manner that a first motor rotational speed and a first torque result, and the second rotor rotating field interacts with the second stator rotating field in such a manner that the first motor rotational speed and a second torque result, the second torque having an identical direction of action in relation to the first torque.