Field Winding Dynamo Control via Torque Calculation
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Solution Overview
Problem
Existing methods for controlling exciting current in field winding type dynamo-electric machines and induction motors suffer from low calculation accuracy, leading to errors in generated torque and electric current, particularly due to non-linear relationships caused by magnetic saturation and hysteresis characteristics.
Innovation Solution
An apparatus with an exciting current detecting circuit, rotation speed detecting circuit, and generation torque calculation circuit that calculates and supplies appropriate exciting current to the dynamo-electric machine, considering multi-valued dependency of generation torque on exciting current, using correction maps to account for hysteresis and magnetic saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional output control means is used to control generator output by adjusting exciting current duty ratio, then the basic output control function is achieved, but calculation accuracy is low leading to errors in generated torque and electric current
Solution Approach 1:
The patent segments the control system into distinct functional modules: exciting current detection unit, rotation speed detection unit, generation torque calculation unit, and exciting current control unit. Each module performs a specific function, allowing for modular implementation and improved calculation accuracy without overwhelming system complexity.
Solution Approach 2:
The patent implements feedback control by detecting the actual exciting current and rotation speed, calculating the generation torque based on these detected values, and then adjusting the exciting current to achieve the desired generation torque. This closed-loop feedback mechanism significantly improves calculation accuracy and reduces errors in generated torque and electric current.
2Reliability
If simple duty ratio control of exciting current is used, then the control implementation is simple, but estimation errors in generation torque occur due to non-linear relationships from magnetic saturation and hysteresis
Solution Approach 1:
The patent uses feedback control to detect actual exciting current and rotation speed, then calculates generation torque based on these detected values. This feedback mechanism compensates for non-linear relationships caused by magnetic saturation and hysteresis, significantly improving torque control accuracy and reducing estimation errors.
Solution Approach 2:
The patent changes the control parameter from simple duty ratio to generation torque calculation based on detected exciting current and rotation speed. By using the actual detected values and calculating torque based on these parameters, the system accounts for magnetic saturation and hysteresis effects, improving reliability without excessive complexity.
3Measurement precision
If generation torque control based on detected exciting current and rotation speed is implemented, then torque estimation accuracy is improved, but the system requires multiple detection units and calculation units increasing device complexity
Solution Approach 1:
The patent divides the control system into specialized detection and calculation units: exciting current detection unit, rotation speed detection unit, and generation torque calculation unit. This segmentation allows each unit to focus on a specific function, improving torque estimation accuracy while organizing complexity into manageable, modular components.
Solution Approach 2:
The detected exciting current and rotation speed serve multiple purposes: they are used to calculate generation torque, monitor system operation, and provide feedback for control adjustments. This multi-functionality of the detection units reduces the need for separate specialized sensors, balancing accuracy improvement with acceptable device complexity.
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 significantly improves the accuracy of torque and current control, reducing estimation errors and achieving precise generation torque and electric current output.
Implementation Method 1
An electric generator generates three-phase alternate current in a stator coil provided to a stator upon rotation of a rotor having a field coil
Implementation Method 2
non-linear relationships caused by magnetic saturation and hysteresis characteristics
Implementation Method 3
non-linear relationships caused by magnetic saturation and hysteresis characteristics
Data Source
AI summary
A control apparatus for controlling an exciting current of a field winding type dynamo-electric machine having an exciting winding so as to obtain a demanded output thereof comprises an exciting current detecting circuit being configured to detect an exciting current of the field winding type dynamo-electric machine, a rotation speed detecting circuit being configured to detect a rotation speed of a rotor of the field winding type dynamo-electric machine, an output estimating circuit being configured to estimate an output of the field winding type dynamo-electric machine, an exciting current control circuit being configured to correct the exciting current of the field winding type dynamo-electric machine so as to obtain the demanded output and to supply the corrected exciting current to an exciting winding of the field winding type dynamo-electric machine considering a multi-valued functionality of the output of the field winding type dynamo-electric machine with respect to the exciting current.