Rotary Machine Control Decoupling Phase Amplitude Interference
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Solution Overview
Problem
Existing rotary machine control apparatuses face reduced controllability due to interference between phase and amplitude controls of the output voltage vector, leading to disturbances that affect the amplitude of the output voltage vector, especially when the rotary machine transitions from a steady state to a transient condition.
Innovation Solution
The proposed solution involves an apparatus that calculates an interference-reduction current component in a rotating coordinate system to minimize the impact of phase changes on the amplitude control, using a phase setter and an amplitude setter to adjust the output voltage vector accordingly, ensuring the controlled variable follows the command value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback control based on both phase and amplitude of output voltage vector is implemented, then controllability of the controlled variable is improved, but interference between phase control and amplitude control reduces controllability during transient conditions
Solution Approach 1:
The patent segments the control system into two independent coordinate systems: the d-q coordinate system for phase control (torque control) and the λ-ρ coordinate system for amplitude control (flux control). This segmentation eliminates interference between phase and amplitude controls by decoupling them into separate control loops, each operating independently on its respective coordinate system.
Solution Approach 2:
The patent introduces an intermediary transformation mechanism that converts control commands between the d-q coordinate system and the λ-ρ coordinate system. This intermediary allows the phase control and amplitude control to operate independently in their respective coordinate systems while maintaining coordinated control of the output voltage vector, thus eliminating mutual interference.
2Device complexity
If map-based amplitude control is used, then device complexity is reduced, but accuracy of correlation reduces controllability
Solution Approach 1:
The patent changes the control parameter from using a static map based on rotational speed to using active feedback control in the λ-ρ coordinate system. This parameter change allows the amplitude control to adapt dynamically to transient conditions and disturbances, significantly improving correlation accuracy while maintaining reasonable device complexity through the use of standard feedback control algorithms.
Solution Approach 2:
The patent implements feedback control for amplitude regulation by measuring the actual amplitude of the output voltage vector and comparing it with the command value in the λ-ρ coordinate system. The feedback loop dynamically adjusts the amplitude control to compensate for map inaccuracies and transient conditions, thereby improving correlation accuracy without substantially increasing device complexity.
3Reliability
If d-axis current feedback control is implemented, then amplitude correction capability is improved, but interference from phase changes reduces control accuracy
Solution Approach 1:
The patent segments the control functions by assigning amplitude correction to the λ-axis in the λ-ρ coordinate system, which is independent of the d-axis current feedback control in the d-q coordinate system. This segmentation ensures that phase changes in the d-q system do not interfere with amplitude correction in the λ-ρ system, thereby maintaining high control accuracy.
Solution Approach 2:
The patent employs asymmetric coordinate systems (d-q for phase, λ-ρ for amplitude) where the amplitude control axis (λ-axis) is specifically oriented to be orthogonal to the phase control effects. This asymmetric arrangement ensures that amplitude correction operations do not generate interfering phase components, thereby maintaining high control accuracy in the amplitude feedback loop.
Data Source
AI summary
In a control apparatus, an interference-reduction current calculator calculates, as an interference reduction current, a component of a current vector in a coordinate axis in a rotating coordinate system defined with respect to a rotor of the rotary machine. The current vector flows in the rotary machine, and the coordinate axis serves as an interference reduction coordinate axis in which the component of the current vector has reduced interference from change of the phase of the output voltage vector. An amplitude setter sets, as a manipulated variable for feedback controlling the interference reduction current to a command current value based on a command value for a controlled variable, one of: an amplitude of the output voltage vector, and an amplitude parameter indicative of a component of the output voltage vector. The component of the output voltage vector depends on the amplitude of the output voltage vector.