Field-Oriented Control of Synchronous Reluctance Machine
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Solution Overview
Problem
Existing methods for field-oriented control of permanent-magnet synchronous machines with reluctance torque require complex multi-dimensional characteristic diagrams for determining current setpoints, leading to high computing power requirements and delayed responses, especially when achieving desired torque at higher speeds.
Innovation Solution
A method that determines flux-forming and torque-forming current components using one-dimensional characteristic maps, processed through PI controllers, to achieve the required torque with minimal machine current, independent of speed, by vectorially summing voltage components and accounting for maximum voltage and saturation behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multi-dimensional characteristic maps are used to determine current setpoints, then torque control precision is improved, but computing power requirements increase and response time decreases
Solution Approach 1:
The patent segments the control approach by separating the determination of flux-generating current component (id) from torque-generating current component (iq). The id component is determined based on saturation behavior and voltage limits, while iq is determined based on torque requirements. This segmentation allows each component to be calculated independently using simpler one-dimensional characteristic maps rather than complex multi-dimensional maps, thereby reducing computational complexity while maintaining control precision.
Solution Approach 2:
The patent applies preliminary action by pre-determining the flux-generating current component (id) based on voltage limits and saturation behavior before determining the torque-generating component (iq). This preliminary determination of id ensures that voltage constraints are satisfied from the outset, allowing the subsequent torque calculation to proceed with reduced computational requirements and faster response time.
2Measurement precision
If multi-dimensional characteristic maps are used to determine current setpoints, then torque control precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the control approach by separating the determination of flux-generating current component (id) from torque-generating current component (iq). The id component is determined based on saturation behavior and voltage limits, while iq is determined based on torque requirements. This segmentation allows each component to be calculated independently using simpler one-dimensional characteristic maps rather than complex multi-dimensional maps, thereby reducing computational complexity while maintaining control precision.
3Power
If torque is required at higher speeds, then power output is improved, but current setpoint selection becomes constrained by voltage and current limits
Solution Approach 1:
The patent applies preliminary action by pre-determining the flux-generating current component (id) based on voltage limits and saturation behavior before determining the torque-generating component (iq). This preliminary determination of id ensures that voltage constraints are satisfied from the outset, allowing the subsequent torque calculation to proceed with reduced computational requirements and faster response time.
Solution Approach 2:
The patent applies dynamics by making the flux-generating current component (id) variable based on operating conditions such as speed and voltage limits. At higher speeds where voltage constraints are more restrictive, the id component is adjusted accordingly, allowing the system to adaptively maintain optimal performance across different operating ranges rather than using fixed current setpoints.
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 allows for precise and rapid control of current components, reducing computing power needs and achieving the desired torque within milliseconds, enabling efficient and cost-effective operation of synchronous machines.
Implementation Method 1
process the difference in a PI voltage regulator, obtaining a first difference value (Δid) as the output
Implementation Method 2
synchronous machine with reluctance torque
Implementation Method 3
reluctance torque occurs when the inductances differ in the field direction and perpendicular to it
Data Source
Figure 1
AI summary
The invention relates to a method for the field-oriented control of a permanently excited synchronous reluctance machine (1), which comprises at least the following steps: a) determining a flux-generating current component to be injected id,MTPC and a torque-generating current component iqMTPC as a function of a required torque Tref; b) determining a voltage component in the flux direction udref and a voltage component perpendicular to the flux direction uqref as a function of the current components id,MTPC and iq,MTPC; c) calculating a differential amount from a vectorial sum us of the voltage components ud,ref and uq,ref and a maximum voltage umax and processing the differential amount in a PI-voltage controller (2), wherein a first differential value Δid is obtained as a starting parameter; and d) adding up the flux-generating current components id,MTPC and the first differential value Δid and determining a voltage component ud for injection into the synchronous machine (1).