Drive System Changeover Switching for Loss Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional drive systems for rotating electrical machines with open-delta windings experience increased power losses due to the use of semiconductor switches in changeover switches, which have high on-resistance, leading to inefficiencies in switching and power management.
Innovation Solution
The drive system incorporates a semiconductor switch for high potential side changeover and a relay switch in parallel for low potential side changeover, allowing for mode switching between H-bridge and Y-connection driving, thereby reducing conduction losses and maintaining high responsiveness during mode changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If semiconductor switches are used in changeover switches, then switching responsiveness is improved, but conduction losses increase due to high on-resistance
Solution Approach 1:
The changeover switch is segmented into two parallel paths: one with a semiconductor switch (IGBT) for high-speed switching, and another with a contactor for low-loss conduction. This allows the system to divide the switching function between two different switch types, each optimized for its specific role.
Solution Approach 2:
The system dynamically switches between two operating modes: a first mode where the semiconductor switch is ON and the contactor is OFF for rapid response, and a second mode where the semiconductor switch is OFF and the contactor is ON for reduced losses. This dynamic mode switching optimizes performance based on operational requirements.
2Loss of energy
If relay switches are used for changeover, then conduction losses are reduced, but switching responsiveness deteriorates
Solution Approach 1:
The changeover function is segmented between a contactor for low-loss conduction and a semiconductor switch for rapid response. The contactor handles the bulk of the current with minimal losses, while the semiconductor switch provides fast switching capability when needed.
Solution Approach 2:
The system dynamically transitions between two modes: using the contactor for efficient conduction during steady-state operation, and switching to the semiconductor switch when rapid response is required. This dynamic allocation optimizes both efficiency and responsiveness.
3Adaptability or versatility
If mode switching is performed, then adaptability to different operating conditions is improved, but system complexity increases
Solution Approach 1:
The control device monitors the operating state of the rotating electrical machine and automatically determines the appropriate mode (first or second) based on real-time conditions. This feedback mechanism simplifies the complexity by providing automated mode selection rather than requiring manual intervention or complex control logic.
Solution Approach 2:
The control device serves multiple functions: it controls both the semiconductor switch and the contactor, monitors the operating state, determines the appropriate mode, and manages the transition between modes. This multi-functionality reduces overall system complexity by consolidating control responsibilities.
Data Source
AI summary
A drive system includes: first and second inverters; a high-potential-side connection line; a low-potential-side connection line; a first changeover switch provided to at least one of the high-potential-side and low-potential side connection lines; a second changeover switch connected in parallel to the first changeover switch; a mode control section changing between a first mode in which to perform switching driving of upper and lower arm switches in one of the inverters and perform neutral point driving of at least one of the upper and lower arm switches in the other inverter to maintain in an on state and a second mode in which to perform switching driving of the upper and lower arm switches in both the inverters; and a changeover control section that, at the time of a changeover between the first and second modes, changes the first and second changeover switches between the on and off states.