Inverter Generator Back-EMF Sensorless Control
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Solution Overview
Problem
Inverter generators require additional sensors to estimate electrical angles in synchronous electric motors, which increases complexity and cost.
Innovation Solution
An inverter generator system that estimates electrical angles using a circuit connected to an ECU, which generates pulses at predetermined rotation angles, allowing for the conversion of AC power to DC power and then back to AC power without the need for additional sensors on the synchronous electric motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional sensors are installed on the synchronous electric motor to measure electrical angles, then the converter can accurately control the conversion mode, but the device complexity and cost increase
Solution Approach 1:
The synchronous electric motor itself generates the electrical angle information through its back electromotive force (back-EMF) during normal operation. The converter controller detects the zero-crossing points of the back-EMF signals from the motor windings to determine the electrical angle, eliminating the need for external sensors. The motor serves its dual function of both power generation and position sensing.
Solution Approach 2:
The back electromotive force (back-EMF) acts as an intermediary that carries electrical angle information. By detecting the characteristics of the back-EMF signal generated during motor operation, the controller can infer the electrical angle without direct mechanical sensing. This intermediary approach converts the motor's electrical output into position information.
2Measurement precision
If additional sensors are installed on the synchronous electric motor to measure electrical angles, then the converter can accurately control the conversion mode, but the manufacturing cost increases
Solution Approach 1:
The synchronous electric motor itself generates the electrical angle information through its back electromotive force (back-EMF) during normal operation. The converter controller detects the zero-crossing points of the back-EMF signals from the motor windings to determine the electrical angle, eliminating the need for external sensors. The motor serves its dual function of both power generation and position sensing.
Solution Approach 2:
The back electromotive force (back-EMF) acts as an intermediary that carries electrical angle information. By detecting the characteristics of the back-EMF signal generated during motor operation, the controller can infer the electrical angle without direct mechanical sensing. This intermediary approach converts the motor's electrical output into position information.
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 efficient and cost-effective control of voltage and frequency in the output electricity by eliminating the need for position sensors, simplifying the system while maintaining accurate electrical angle measurement.
Implementation Method 1
an electric generator driven by the motor configured to generate alternating current electric power
Implementation Method 2
a converter configured to convert the alternating current electric power into direct current electric power
Implementation Method 3
an inverter configured to convert the direct current electric power into alternating current output electric power
Data Source
AI summary
An inverter generator includes a motor, an electric generator and an ECU generating a pulse at each predetermined rotation angle of the motor. Estimating means estimates an initial electrical angle of alternating voltage produced by the generator from the pulse and calculates a phase shift angle to estimate continuous electrical angle of the alternating voltage. A converter converts the alternating current electric power into direct current electric power under d-q control based on the phase shift angle. An inverter converts the direct current electric power into alternating current output electric power.