Field Winding Synchronous Generator-Motor Control
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Solution Overview
Problem
Field winding synchronous generators in hybrid vehicles face challenges in controlling induced voltage and current due to varying rotational speeds, leading to impaired controllability and inefficiency, especially when using DC brushless motors with permanent magnets and existing voltage control methods.
Innovation Solution
A field winding synchronous generator-motor system that includes an electric rotating machine with an armature winding and field winding, a power conversion section, positional detecting means, compensation storage, and a rectangular wave application voltage command section, which allows for improved control of the main magnetic flux and induced voltage without increasing costs, eliminating the need for armature current detecting means and reducing switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PWM switching is used to control current with accuracy, then current control accuracy is improved, but device complexity increases due to the need for rectifier capacitors and additional switching components
Solution Approach 1:
The patent extracts and eliminates the rectifier capacitor from the conventional PWM control circuit. By using a simplified switching circuit without the rectifier capacitor, the invention achieves current control accuracy while reducing device complexity and component count.
Solution Approach 2:
The patent replaces complex, expensive PWM switching components with a simpler, more economical switching circuit. The simplified circuit uses basic switching elements that are cheaper and more reliable, achieving the same current control function without requiring expensive rectifier capacitors or complex PWM controllers.
2Loss of energy
If the number of switching operations of the dc/ac converter is decreased to reduce switching loss, then energy efficiency is improved, but current control accuracy deteriorates
Solution Approach 1:
The patent implements continuous current control through optimized switching sequences that maintain uninterrupted power delivery to the motor. By carefully timing the switching operations and maintaining continuous current flow, the system reduces switching losses while preserving current control accuracy throughout the operating cycle.
Solution Approach 2:
The patent uses periodic switching patterns with optimized duty cycles to control current. By employing regular, predictable switching sequences rather than frequent random switching, the system minimizes switching losses while maintaining precise current control through controlled periodic operation.
3Use of energy by moving object
If a permanent magnet is contained in the rotor to generate induced voltage, then generator efficiency is improved, but adaptability deteriorates because induced voltage cannot be controlled with varying engine speeds
Solution Approach 1:
The patent transitions from a static permanent magnet system to a dynamic field winding system. By using electromagnets with controllable field currents instead of permanent magnets, the system can dynamically adjust the main magnetic flux to match varying engine speeds, maintaining both efficiency and adaptability across the entire operating range.
Solution Approach 2:
The patent changes the fundamental parameter of magnetic flux generation from fixed (permanent magnet) to variable (field winding with controllable current). This allows the main magnetic flux to be adjusted as a control parameter, enabling the system to adapt to different engine speeds while maintaining generator efficiency through optimized flux levels.
4Loss of energy
If rectangular wave voltage with arbitrary conducting width is applied to reduce switching loss, then energy efficiency is improved, but current control accuracy deteriorates because only voltage width is controlled
Solution Approach 1:
The patent introduces feedback control mechanisms that monitor actual current and adjust switching sequences accordingly. By using current feedback information to modify the rectangular wave switching patterns, the system maintains current control accuracy while preserving the energy efficiency benefits of reduced switching operations.
Solution Approach 2:
The patent replaces direct voltage width control with an equivalent control mechanism based on switching sequences and duty cycles. Instead of merely adjusting voltage conducting width, the system uses substituted control methods involving coordinated switching of multiple elements to achieve both current accuracy and energy efficiency.
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
The system enhances controllability and efficiency by compensating for nonlinear variations in the rotor position, enabling accurate control of induced voltage and current, extending the operational range, and reducing the need for additional detection means and smoothing capacitors, thus improving torque generation and power generation capabilities.
Implementation Method 1
an electric rotating machine body (105) provided with a three-phase armature winding (201) and a field winding (202), and having a function of operating as a generator-motor
Implementation Method 2
it is not employed the one in which a permanent magnet is contained in a rotor, but employed a field winding type capable of controlling field currents
Data Source
AI summary
A field winding synchronous generator-motor includes: a power conversion section that is connected to an electric rotating machine and operating as a generator-motor, and that controls the electric rotating machine; a compensation amount storage section that stores a compensation capable of improving characteristics of the electric rotating machine from a reference position of a rotor; a positional compensation operation section that makes a compensation operation of positional information from a rotor position and a value of the compensation amount storage section; a conducting phase storage section that stores a conducting phase to each armature winding from the reference position; and a rectangular wave application voltage command section that commands a rectangular wave application voltage to each armature winding with respect to the power conversion section from a value of the positional compensation operation section and a value of the conducting phase storage section.