Synchronous Machine Angle Correction via Three-Phase Short Circuit
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Solution Overview
Problem
Existing synchronous machine drive control devices struggle to accurately calculate the rotation angle correction amount at high speeds due to induced voltage issues, limiting the calculation to low-speed states and restricting the timing of correction.
Innovation Solution
A synchronous machine drive control device that includes a current detection device, a power converter, and a control unit capable of calculating the rotation angle correction amount through a three-phase short circuit during high-speed rotation, allowing for continuous and accurate correction across a wide range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the synchronous machine rotates at high speed, then the rotation speed increases, but the induced voltage increases causing the d-axis current and q-axis current to deviate from zero state, making rotation angle correction calculation impossible
Solution Approach 1:
The patent extracts the rotation angle correction calculation from the normal operating state and performs it separately during a three-phase short circuit period. By isolating the correction calculation to a specific short circuit window, the system can obtain accurate correction amounts even at high speeds where normal operation would be affected by induced voltage and current deviations.
Solution Approach 2:
The patent performs rotation angle correction calculation in advance during the three-phase short circuit period before normal operation resumes. This preliminary action ensures that the correction amount is obtained and stored for use during subsequent normal high-speed operation, preventing the calculation from being limited by high-speed induced voltage effects.
2Measurement precision
If the d-axis current and q-axis current are set to zero for rotation angle correction calculation, then the calculation can be implemented at low speed, but the calculation cannot be implemented at high speed due to induced voltage
Solution Approach 1:
The system performs the rotation angle correction calculation in advance during the three-phase short circuit period when the machine is still rotating at the target speed. This allows the correction to be prepared beforehand for use during normal high-speed operation, expanding the adaptable speed range.
Solution Approach 2:
The patent enables continuous rotation angle correction across the entire operating range by performing calculations during three-phase short circuit periods that occur throughout operation. This continuous action ensures correction amounts are always available and up-to-date, regardless of speed changes.
3Measurement precision
If rotation angle correction is limited to low-speed states, then calculation can be performed with d-axis and q-axis currents at zero, but the timing of correction calculation is restricted
Solution Approach 1:
The patent utilizes periodic three-phase short circuit periods to perform rotation angle correction calculations. These periodic short circuits occur throughout operation, providing multiple opportunities to calculate and update correction amounts, thereby eliminating timing restrictions and improving responsiveness.
Solution Approach 2:
By performing correction calculations during periodic short circuit events throughout the entire operating range, the system maintains continuous correction capability. This eliminates gaps in correction timing and ensures the correction amount is always current, reducing time loss and improving overall system responsiveness.
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 the detection of rotation angle correction amounts at high speeds and over a wide range, improving accuracy and reducing rotational fluctuations, and facilitating rotation sensor failure diagnosis.
Implementation Method 1
a rotation angle correction amount calculator that calculates a correction amount of a rotation angle of the synchronous machine and controls the power converter. The correction amount of the rotation angle is calculated based on a current detected by the current detection device by a three-phase short circuit being implemented in a state wherein the synchronous machine is rotating
Data Source
AI summary
A synchronous machine drive control device such that a rotation angle correction amount can be detected even when a synchronous machine is rotating at high speed, and the rotation angle correction amount can be detected over a wide range, is obtained. A rotation angle correction amount calculation unit that calculates a correction amount of a rotation angle of a synchronous machine is included in an inverter control device, and the correction amount of the rotation angle is calculated based on a current detected by a current sensor by a three-phase short circuit being implemented in a state wherein the synchronous machine is rotating.