Motor Drive Circuit With In-Phase Coil Heating
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Solution Overview
Problem
Existing electrical circuits for electric motors require separate circuits to generate drive power and heating power, which complicates the design and increases size due to the need for different voltage and frequency requirements for these states.
Innovation Solution
An electrical circuit with four half-bridges, where three are used for generating a three-phase alternating current system for drive power and a fourth half-bridge connected to a star point allows for in-phase alternating current generation for heating, enabling simultaneous drive and heating operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two separate electrical circuits are used to generate drive power and heating power, then the different voltage and frequency requirements are met, but the device complexity and size increase
Solution Approach 1:
The patent combines two separate electrical circuits into a single integrated circuit that can generate both three-phase AC for drive power and single-phase AC for heating power. The merging is achieved by sharing common components (DC voltage source, half-bridges, coils) while adding a fourth half-bridge to enable dual functionality, thereby reducing device complexity and size while meeting different voltage and frequency requirements
2Reliability
If two separate electrical circuits are used to generate drive power and heating power, then the different voltage and frequency requirements are met, but the device size increases
Solution Approach 1:
The patent merges two separate circuits into one by sharing the DC voltage source, three half-bridges, and motor coils. The fourth half-bridge is added to the common circuit structure to enable single-phase AC generation for heating, while the three-phase AC capability is maintained through the original three half-bridges. This sharing of components significantly reduces the overall circuit size while maintaining both drive and heating functionalities
3Device complexity
If a single electrical circuit is used for both drive and heating operations, then the device size and complexity are reduced, but the ability to meet different voltage and frequency requirements becomes challenging
Solution Approach 1:
The patent implements dynamic switching capabilities within the single electrical circuit. The control unit dynamically selects which half-bridges are active and how they are configured based on the operational mode (drive or heating). For three-phase AC, all three half-bridges are activated with appropriate switching sequences. For single-phase AC, the control unit activates specific half-bridges and adjusts switching patterns to generate the required voltage and frequency, thereby dynamically adapting to different operational requirements
Solution Approach 2:
The single electrical circuit is designed with universal functionality to generate both three-phase AC for drive operations and single-phase AC for heating operations. The circuit uses four half-bridges that can be configured in different patterns: three half-bridges working together for three-phase output, or specific combinations for single-phase output. This multi-functionality is controlled by a control unit that adjusts the switching patterns and activation of half-bridges based on the required operational mode, ensuring reliable meeting of different voltage and frequency requirements
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 solution allows for efficient generation of both drive and heating power using a single electrical circuit, reducing size and complexity while enabling high heating power output, potentially up to 45 kW, while maintaining drive power capabilities.
Implementation Method 1
the coils can be supplied with different (electrical) currents of a three-phase alternating current system and the rotor can be set in rotation about an axis of rotation
Implementation Method 2
the coils can be supplied with an in-phase alternating current... enables, for example, targeted heating of components of a motor housing
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
The invention relates to an electric circuit (1) for an electric motor (2), the electric motor (2) having at least one stator (3) with at least three coils (4, 5, 6) and a rotor (7) with at least two magnetic poles (8, 9); the motor (2) being operable by means of the electric circuit (1) at least in the following two states (10, 11): a) in a first state (10), the coils (4, 5, 6) can each be energised with different currents of a three-phase system (12) and the rotor (7) can be set into rotation about an axis of rotation (13); b) in a second state (11), the coils (4, 5, 6) can be energised with an in-phase alternating current (14).