Hybrid PMSM-Reluctance Motor Control for Sensorless Chiller Startup
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Permanent magnet synchronous motors (PMSM) and their variable speed drives (VSDs) are limited in their application in commercial and industrial scale HVAC&R systems due to low performance requirements, high system costs, and complex control system designs.
Innovation Solution
A hybrid motor system is introduced, combining a permanent magnet motor and a reluctance motor on a common drive shaft, where the reluctance motor generates start-up torque to initiate rotation, and the permanent magnet motor takes over to achieve and maintain higher rotational speeds, eliminating the need for internal sensors and simplifying control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a permanent magnet synchronous motor (PMSM) is used in HVAC&R systems, then efficiency and power density are improved, but system cost and control complexity increase
Solution Approach 1:
The motor control is segmented into two distinct phases: a starting phase using a simple reluctance motor control mode, and a running phase using PMSM control mode. This segmentation allows the system to use complex PMSM control only when necessary (during steady-state operation), while using simpler control during startup, thereby reducing overall control complexity while maintaining efficiency benefits.
Solution Approach 2:
The control system dynamically switches between two operational modes based on motor speed and operational requirements. The controller automatically transitions from reluctance motor mode during startup to PMSM mode during steady-state operation, optimizing the balance between control simplicity and motor efficiency across different operating conditions.
2Productivity
If a PMSM with internal sensors is used for precise control, then motor performance is improved, but system cost and complexity increase
Solution Approach 1:
The invention extracts and removes the internal sensors (encoders or resolvers) from the PMSM system by implementing sensorless control. The controller uses back-EMF detection and mathematical algorithms to estimate rotor position and speed without physical sensors, thereby maintaining motor performance while eliminating sensor-related complexity and cost.
Solution Approach 2:
The physical mechanical sensors are replaced with an electronic sensorless control system that uses electrical signal processing (back-EMF detection) and computational algorithms to achieve the same control objectives. This substitution eliminates mechanical wear, reduces component count, and simplifies the overall system while maintaining control precision.
3Force
If a reluctance motor is used for start-up, then start-up torque is improved, but overall efficiency decreases
Solution Approach 1:
The system employs periodic action by using the reluctance motor mode only during the transient startup phase when high torque is needed, then transitioning to the more efficient PMSM mode for steady-state operation. This time-based switching ensures that each motor mode is used during the period when it provides the most benefit, optimizing both start-up performance and overall efficiency.
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 hybrid motor system enhances performance, reduces costs, and simplifies control by leveraging the high power density of reluctance motors for start-up and the efficiency of permanent magnet motors for sustained operation, thereby overcoming the limitations of traditional PMSM systems in HVAC&R applications.
Implementation Method 1
a permanent magnet rotor... The use of a permanent magnet to generate a substantial air gap magnetic flux
Implementation Method 2
the second stator portion includes electromagnetic windings capable of inducing a rotary magnetic field
Data Source
AI summary
A hybrid motor for powering a compressor of a chiller system includes a first rotor portion and a first stator portion configured as a permanent magnet motor and a second rotor portion and a second stator portion configured as a reluctance motor. The second rotor portion includes a reluctance-type rotor, and the second stator portion includes electromagnetic windings capable of inducing a rotary magnetic field. The first rotor portion and the second rotor portion are attached to a common drive shaft. The reluctance motor is arranged to generate start-up torque and initiate rotation of the drive shaft until the drive shaft achieves a predetermined rotational speed. The permanent magnet motor is arranged to power the drive shaft between the predetermined rotational speed and a maximum rotational speed.