Motor Resonance Frequency Detection Using Voltage Pulse Excitation
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Solution Overview
Problem
Existing methods for determining resonance frequencies in mechanical systems connected to electric motors require the system to operate across a wide range of frequencies, potentially causing resonance conditions and damaging mechanical parts, as they are not always feasible to calculate theoretically.
Innovation Solution
A method involving starting the motor at a predefined target rotational speed, applying a voltage pulse to the supply voltage, measuring mechanical responses, and analyzing stator currents or rotation speed to determine resonance frequencies without causing resonance conditions, using a motor controller and measurement system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the system is made to run across a wide range of frequencies to determine resonance frequencies, then the resonance frequencies can be identified, but the system may enter resonance conditions causing mechanical damage
Solution Approach 1:
The patent applies preliminary action by starting the motor at a predefined target rotational speed that is specifically chosen to avoid resonance conditions. Before determining resonance frequencies, the system establishes a safe operating point, then uses small voltage perturbations around this safe point to excite the system and measure resonance characteristics without causing harmful resonance effects during the measurement process.
Solution Approach 2:
The patent uses periodic action by applying small, periodic voltage perturbations to the motor supply voltage while operating at a safe rotational speed. These periodic excitations allow the system to probe for resonance frequencies through the motor's current response without sustaining continuous operation at harmful resonance conditions, thus identifying resonance frequencies safely.
2Ease of manufacture
If theoretical calculation methods are used to determine resonance frequencies, then the process is simple, but the method is not always feasible in practice
Solution Approach 1:
The patent applies self-service by enabling the mechanical system to determine its own resonance frequencies through automated measurement of its response to voltage perturbations. The system uses the motor's own electrical characteristics (current measurements) to identify resonance frequencies, eliminating the need for external theoretical calculations or complex external testing equipment, thus achieving both simplicity and broad applicability.
Solution Approach 2:
The patent replaces traditional mechanical vibration testing methods with an electrical measurement approach. Instead of using mechanical exciters and sensors to determine resonance frequencies, the system uses electrical voltage perturbations and measures the resulting electrical current response, substituting a mechanical testing system with a simpler electrical measurement system that is equally effective.
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
This approach allows for the determination of resonance frequencies without risking mechanical damage, enabling safe operation by identifying and avoiding resonance frequencies during system operation.
Implementation Method 1
the mechanical system as a whole may exhibit one or more resonance frequencies. If the system enters resonance during operation, there is a risk that some mechanical parts may be damaged
Data Source
AI summary
A method for determining a resonance frequency of a mechanical system including an electric motor coupled to a mechanical load. The method includes starting the motor by providing a supply voltage using a motor controller, and once the electric motor is running at a predefined target rotational speed, applying a first excitation signal comprising a voltage pulse superimposed to the supply voltage. The method further includes measuring a mechanical response of the mechanical system, using a measurement system coupled to the motor, and analyzing the measured response, to determine at least one resonance frequency of the mechanical system.