Electric Drive Power Electronics Segmentation for Torque Control
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Solution Overview
Problem
Existing electric drive systems with multiple electrical machines lack efficient control methods to harness synergy effects, leading to suboptimal torque summation and operational flexibility.
Innovation Solution
The implementation of separate power electronics for each electrical machine, with options for hard-wiring or switchable connections to shared power systems, and the use of controllers to regulate power units based on movement and operating parameters, allowing for flexible control and reduced sensor requirements through synergy-based parameter estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate power electronics units are assigned to each electric machine, then control flexibility is maximized, but device complexity and installation space increase
Solution Approach 1:
The control system is segmented into multiple independent power electronics units, each capable of independently controlling one or more electric machines. This segmentation enables flexible allocation where each unit can be assigned to different machines based on operational requirements, achieving maximum control flexibility while allowing the system to scale according to complexity needs.
Solution Approach 2:
Each power electronics unit is designed as a universal controller that can manage one or more electric machines interchangeably. Through switchable hard-wiring connections, the same power electronics unit can be dynamically assigned to different machines, making each unit multi-functional and reducing the total number of units required compared to dedicated one-to-one assignments.
2Device complexity
If multiple electric machines are connected to the same power electronics through hard-wiring, then device complexity is reduced, but control flexibility decreases
Solution Approach 1:
The hard-wiring connections between power electronics units and electric machines are designed to be switchable rather than fixed. This dynamic reconfigurability allows the system to adapt the connection topology based on operational demands, enabling a single power electronics unit to control different combinations of machines as needed, thus maintaining flexibility while reducing overall device complexity.
3Measurement precision
If sensors are provided for direct acquisition of operating parameters in all electric machines, then measurement precision is maximized, but device complexity and costs increase
Solution Approach 1:
Instead of directly measuring operating parameters in every electric machine with dedicated sensors, the system uses sensors in representative machines to obtain parameter data, then copies or estimates these parameters for other machines through controller processing. This approach maintains sufficient measurement precision for control purposes while dramatically reducing the total number of sensors required.
Solution Approach 2:
The controllers receive feedback on operating parameters from sensors in selected electric machines and use this information to infer the state of other machines. The feedback loop enables the system to maintain accurate knowledge of overall system operation without requiring direct measurement from every component, balancing precision with complexity reduction.
4Adaptability or versatility
If a large number of power electronics units are used for each electric machine, then control flexibility is maximized, but installation space and costs increase
Solution Approach 1:
Multiple electric machines are electrically interconnected and connected to the same power electronics unit through switchable hard-wiring arrangements. This merging of control resources allows a single power electronics unit to manage multiple machines, reducing the total number of units required and consequently decreasing the installation space and associated costs while preserving control flexibility through dynamic reconfiguration.
Data Source
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AI summary
The invention relates to an electric drive, comprising a motor assembly (10) comprising a plurality of electric machines (12) having motor shafts arranged parallel to each other, an output assembly, and a speed-changing stage (26), which is connected to the motor assembly on one side and to the output assembly on the other side and which has a speed-changing sun (34) connected to the output assembly and a plurality of speed-changing planets (28), which are each connected to one of the electric machines (12) and which are each fixed on the motor shafts and arranged annularly around the speed-changing sun (34) and which roll on the speed-changing sun in a torque-transmitting manner. The invention is characterized in that one or more power electronics units connected to one or more voltage sources are provided for controlling the electrical sub-phases of the electric machines (12).