Synchronous Motor Inverter Control for Stable DC Parameter Tuning
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Solution Overview
Problem
Existing methods for acquiring motor parameters of synchronous machines using inverters are unstable and prone to noise and vibration, especially when applying AC or high-frequency signals, affecting reliability.
Innovation Solution
An inverter control apparatus that applies a DC voltage to synchronous machines during parameter acquisition, using flag generation and high-frequency voltage superimposition to stabilize the process and accurately calculate motor parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a three-phase unbalanced AC voltage is applied to acquire motor parameters, then the acquisition process can be automated, but noise is generated when frequency is raised and the synchronous machine easily rotates when frequency is lowered, reducing stability and reliability
Solution Approach 1:
The patent changes the voltage type from AC to DC during the parameter acquisition process. By applying DC voltage instead of AC voltage, the synchronous machine avoids rotation issues and noise generation associated with AC frequency variations, while still enabling automatic parameter acquisition through controlled DC voltage application and current measurement.
2Measurement precision
If a high frequency signal is superimposed on the applied signal to acquire differential inductance, then motor parameters can be calculated, but vibration occurs in addition to noise, affecting system stability
Solution Approach 1:
The patent eliminates the need for high frequency signal superimposition by using DC voltage application. The motor parameters are acquired by measuring current response to DC voltage steps, which avoids the vibration and noise problems caused by high frequency signal injection while maintaining measurement capability through alternative mathematical modeling.
3Measurement precision
If preliminary testing is performed to acquire motor winding resistance and inductance data, then accurate motor parameters can be obtained, but the time until synchronous machine operation starts is extended
Solution Approach 1:
The patent performs parameter acquisition actions during the normal startup sequence rather than requiring separate preliminary testing. By integrating the DC voltage application and current measurement into the existing startup routine, the system acquires motor parameters without extending the time to operational startup, while maintaining measurement accuracy through controlled DC excitation and mathematical calculation.
Data Source
AI summary
According to an embodiment, an inverter control apparatus includes a voltage command generation unit that generates a voltage command to be applied to a synchronous machine; a current detector that detects a current flowing from an inverter main circuit to the synchronous machine; a flag generation unit that switches between a motor parameter tuning operation and a normal driving operation; and a parameter arithmetic unit that calculates a motor parameter using a value of the voltage command and a detection value of the current detector at a time of a motor parameter tuning operation. The voltage command generation unit generates the voltage command to apply a DC voltage to the synchronous machine at a time of motor parameter tuning operation.