Electric Starter Current Injection for Motor Parameter Identification
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for determining characteristic parameters of electric machines connected to electric starters are imprecise, leading to approximate adjustment of losses, which depend on the electric machine and are influenced by cable resistance, without full identification of machine parameters.
Innovation Solution
An electronic determination device that uses the switching arms of the electric starter to generate current injections in the electric machine at standstill, allowing for precise calculation of parameters like stator resistance, rotor resistance, leakage inductance, and main inductance through current and voltage measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If approximate adjustment of losses is used with electric starter, then ease of operation is improved, but measurement precision deteriorates
Solution Approach 1:
The system performs preliminary identification of machine parameters by controlling the electric starter to generate specific voltage waveforms before normal operation. This preliminary measurement phase allows accurate determination of characteristic parameters without affecting subsequent operational ease.
Solution Approach 2:
The control module periodically generates different voltage waveforms through the electric starter's switching arms to excite the electric machine at standstill. These periodic excitation signals enable accurate parameter identification while maintaining simple operational control through automated waveform switching.
2Measurement precision
If full identification of machine parameters is implemented, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The electric starter's switching arms are made multi-functional by controlling them to generate different voltage waveforms for parameter identification, in addition to their normal starting function. This eliminates the need for separate identification hardware, maintaining device simplicity while achieving full parameter measurement.
Solution Approach 2:
The electric machine itself serves as the measurement instrument by using its own windings and magnetic circuit to respond to excitation signals. The machine's electrical characteristics directly provide the parameter information needed, eliminating complex external measurement equipment.
3Measurement precision
If current injection method is used at standstill, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The system applies partial action by injecting current only into specific phases through selected switching arms while leaving other phases inactive. This selective excitation reduces the total measurement time compared to comprehensive multi-phase testing, while still obtaining all necessary parameter information.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
This electronic determination device (20) is configured for determining at least one characteristic parameter of an electric machine (12) with P phases (22), P ≥ 3, connected to an electric starter (14) and including at least P-1 switching arms (24), each switching arm (24) being connected to a respective phase (22) of the electric machine (12). This determination device (20) comprises a control module (30) configured to control respective switching arm(s) (24) to close and the other switching arm(s) (24) to open, so as to generate a current injection on two phases (22) of the electric machine (12); an acquisition module (34) configured to acquire measurements of respective current(s) and voltage(s) for said two phases (22), further to the generation of the current injection; and a calculation module (36) configured to calculate at least one characteristic parameter of the electric machine (12) according to the respective current(s) and voltage(s) measurements.