Inductive Exciter Switching Control for Lower Electric Machine Losses
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Solution Overview
Problem
Existing methods for operating electric machines, particularly in motor vehicles, face efficiency challenges, especially in partial load regions, due to switching and diode losses.
Innovation Solution
The method involves operating the inductive exciter device between switching states in a non-switching state where the switch devices remain unswitched, allowing the electric machine to continue operating without signal transmission, thereby reducing losses and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If switch devices are continuously operated in switching states to transmit electrical signals, then the electric machine can maintain operation, but switching losses and diode losses increase reducing efficiency
Solution Approach 1:
The patent applies periodic action by alternating between switching states and non-switching states. The exciter device operates in switching states for a predetermined number of clock cycles, then transitions to non-switching states for another predetermined number of clock cycles. This periodic operation reduces switching losses while maintaining average power transmission levels, directly resolving the contradiction between energy loss reduction and operational continuity.
Solution Approach 2:
The patent implements dynamics by making the exciter device's operational state variable rather than fixed. The control device dynamically adjusts between switching and non-switching states based on predetermined patterns, allowing the system to adapt its power transmission characteristics. This dynamic state changes enable the system to optimize efficiency by reducing switching frequency while maintaining operational flexibility.
2Power
If the electric machine operates in partial load regions, then power requirements are reduced, but efficiency of the transmission device decreases
Solution Approach 1:
The patent applies partial action by operating the exciter device in non-switching states during partial load conditions. Instead of continuously transmitting power at reduced levels (which would be inefficient), the system uses partial switching states where excitation is applied only for predetermined clock cycles. This allows the electric machine to operate in partial load regions while maintaining transmission device efficiency by avoiding continuous operation at inefficient power levels.
Solution Approach 2:
The patent changes the operational parameters of the exciter device by alternating between switching and non-switching states. This parameter change allows the system to maintain efficient operating points by adjusting the duty cycle and average power transmission levels. The control device modifies switching frequency and duration parameters to optimize efficiency across different power output levels, preventing operation in inefficient partial load regions.
3Loss of energy
If switching frequency is increased to maintain efficient operating points, then transmission efficiency improves, but switching losses increase
Solution Approach 1:
The patent resolves this contradiction through periodic action by implementing alternating switching and non-switching states with predetermined clock cycle durations. This periodic operation allows the system to achieve efficient average power transmission without requiring continuous high-frequency switching. The exciter device switches at high frequency only during switching states, then rests during non-switching states, reducing overall switching energy consumption while maintaining transmission efficiency.
Solution Approach 2:
The patent applies preliminary action by pre-determining the sequence and duration of switching and non-switching states. The control device is configured to switch the exciter device according to predetermined patterns before actual load changes occur. This preliminary structuring of switching patterns allows the system to optimize the balance between transmission efficiency and switching losses in advance, rather than reacting to instantaneous conditions.
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 enhances the overall efficiency of the electric machine, particularly in partial load regions, by minimizing switching losses and allowing operation at more efficient operating points.
Implementation Method 1
Switch devices of the inductive exciter device are operated in a defined switching state with a defined switching frequency in order to transmit an electrical signal inductively from the primary side to the secondary side by means of the inductive exciter device
Data Source
AI summary
A method for the operation of an electric machine, particularly of a motor vehicle, having a transmission device with a primary side, particularly a stationary primary side, an inductive exciter device and includes a secondary side particularly connected to a rotor of the electric machine, switch devices of the inductive exciter device being operated in a defined switching state with a defined switching frequency in order to transmit an electrical signal inductively from the primary side to the secondary side by the inductive exciter device. The inductive exciter device is operated between at least two switching states in a non-switching state in which switch devices of the inductive exciter device are not switched, in particular until a subsequent switching state.