Rotary Machine Control Apparatus Voltage Utilization Factor Transition
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Solution Overview
Problem
Existing control systems for three-phase motors face challenges in maintaining high performance when shifting from high to low voltage utilization factors, leading to sudden changes in torque generation and difficulty in maintaining controllability during mode shifts from single-pulse to PWM control.
Innovation Solution
A control apparatus that includes a first drive unit for controlling the power converter in a high voltage utilization range and a second drive unit for a low range, with an estimating unit to adjust parameters for smooth transitions, ensuring the power converter generates the required output voltage and controlled variables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If single-pulse control mode is used in higher velocity range to increase voltage utilization factor, then voltage utilization factor is improved, but torque generation becomes discontinuous and control performance deteriorates during mode transition
Solution Approach 1:
The patent implements dynamic switching between PWM control mode and single-pulse control mode based on the voltage utilization factor. The control apparatus continuously monitors the voltage utilization factor and automatically transitions between control modes to maintain optimal performance across different operating conditions, making the control system adaptive rather than static.
Solution Approach 2:
The patent introduces an estimating unit as an intermediary component that estimates parameters required for smooth transition between control modes. This estimating unit calculates necessary parameters to bridge the gap between PWM and single-pulse control, ensuring continuous and stable torque generation during mode transitions.
2Stability of the object's composition
If PWM control mode is used in higher velocity range, then control smoothness is maintained, but voltage utilization factor is limited to half of input DC voltage
Solution Approach 1:
The patent changes the control parameter strategy by switching between PWM control and single-pulse control based on the voltage utilization factor threshold. When the voltage utilization factor exceeds the threshold (half of input DC voltage), the system transitions from PWM mode to single-pulse mode, allowing the voltage utilization factor to increase beyond the PWM limitation while maintaining control effectiveness through parameter adaptation.
3Reliability
If abrupt transition from PWM control mode to single-pulse control mode is made, then voltage utilization factor increases, but torque generation shows sudden changes and control performance decreases
Solution Approach 1:
The patent applies preliminary action by having the estimating unit pre-calculate the parameters needed for smooth transition before the actual mode switching occurs. This advance preparation ensures that when the transition from PWM to single-pulse control happens, the necessary parameters are already ready, preventing sudden torque changes and maintaining control precision throughout the transition.
Data Source
AI summary
In an apparatus, a first drive unit drives, in a first range of a voltage utilization factor, a switching member to thereby control an output voltage of the power converter to be matched with a command voltage. A second drive unit drives, in a second range of the voltage utilization factor, the switching member to thereby generate a value of a controlled variable of a rotary machine. The second range of the voltage utilization factor is higher than the first range thereof. An estimating unit estimates, during the switching member being driven by the second drive unit, a value of a parameter associated with the output voltage of the power converter. The estimated value is required for the first drive unit to generate the value of the controlled variable generated by the second drive unit.