Rotating Machine Power Conversion Device Torque Control
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Solution Overview
Problem
Existing rotating machine power conversion devices face challenges in maintaining operation and preventing discomfort to vehicle occupants when a single phase of the electrical power conversion means experiences a turn-off failure, leading to torque vibration and excessive regenerative torque due to increased rotational speed.
Innovation Solution
A rotating machine power conversion device with an electrical power conversion means connected in series and parallel with a DC power source, incorporating a rotational speed calculation means, abnormality determination means, and electric current control means that includes normality-case and abnormality-case current control units, as well as a power conversion halt unit to manage operational continuation and torque control during failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If abnormality-case current control is applied when a single phase turn-off failure occurs, then operational continuation is enabled, but torque vibration increases and excessive regenerative torque is generated at high rotational speeds
Solution Approach 1:
The patent applies parameter changes by switching between different current control strategies based on rotational speed. At low speeds, abnormality-case current control is used to maintain operation, while at high speeds, the control strategy changes to prevent excessive regenerative torque and torque vibration. This dynamic parameter adjustment resolves the contradiction by adapting the control approach to the operating conditions.
2Reliability
If abnormality-case current control is applied when rotational speed increases, then operational continuation is maintained, but excessive regenerative torque is generated into the DC power source
Solution Approach 1:
The patent implements dynamics by making the current control strategy adaptive to rotational speed changes. The system dynamically switches between normality-case and abnormality-case current control units based on the detected rotational speed, ensuring that the control approach matches the operational conditions. This prevents excessive regenerative torque at high speeds while maintaining operational continuation at low speeds.
3Reliability
If a single phase turn-off failure occurs in the electrical power conversion means, then the rotating machine can still operate, but vehicle occupants experience discomfort due to torque vibration
Solution Approach 1:
The patent resolves this contradiction by changing control parameters based on rotational speed. At low speeds, the abnormality-case current control unit maintains continuous operation despite the turn-off failure. At high speeds, the system switches to a different control strategy that minimizes torque vibration, thereby reducing occupant discomfort while maintaining operation. This parameter adaptation allows the system to balance reliability and comfort across different operating conditions.
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
Enables operational continuation and reduces torque vibration by using abnormality-case current control only within feasible rotational speed ranges, preventing excessive regenerative torque and maintaining vehicle stability.
Implementation Method 1
The electrical power conversion means converts DC power of a DC power source into predetermined AC power by turning on or off a plurality of semiconductor switches at a predetermined switching frequency
Implementation Method 2
the three-phase AC rotating machine operates as an electric power generator depending on an operational condition(s), so that regenerative power generated according to the electric power generation is charged into the DC power source
Data Source
AI summary
A rotating machine power conversion device is obtained which achieves operational continuation in a rotational speed range in which the operational continuation is enabled, even when a single phase of an electrical power conversion device made of switching devices causes a disconnection or turn-off failure. The rotating machine power conversion device comprises: a normality-case/abnormality-case current control device selection device for transferring between a normality-case current control device and an abnormality-case current control device in accordance with a determination result of an abnormality determination device; and an abnormality-case current control device/power conversion halt device selection device, using a rotational speed calculation device, for transferring between the abnormality-case current control device used when a rotational speed is lower than that being prespecified, and the power conversion halt device used when a rotational speed is higher than that being prespecified.