Paralleled Drive DC Bus Configuration for High Power Conveyance
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Solution Overview
Problem
Conveyance systems, such as elevator systems, face challenges in providing varying power levels efficiently due to the high costs and lengthy development times associated with manufacturing suitable high-power drives, especially when a single large drive is not available.
Innovation Solution
A conveyance system is designed with multiple drives arranged in an electrically parallel configuration, utilizing converters and inverters to provide multi-phase drive signals to a motor, allowing for the combination of drive signals through inductive interfaces and synchronized control signals to efficiently power the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single high-power drive is used to meet large elevator duty or load requirements, then the power capability is sufficient, but the design costs and development time become excessively high
Solution Approach 1:
The patent divides a single high-power drive into multiple lower-power drives (first drive and second drive) that operate in parallel. Each drive handles a portion of the total power requirement, allowing the system to achieve high power capability without the excessive costs and development time associated with a single large drive. The drives are connected to common DC buses and coordinate through control signals to share the load.
2Power
If paralleled drives are implemented, then high load demands can be met with lower-cost components, but synchronization and control coordination become more challenging
Solution Approach 1:
The control system implements feedback by having drive controllers exchange reference point information. Each controller adjusts its operation based on the reference point timing from other drives, ensuring synchronized operation. This automated feedback mechanism simplifies the coordination challenge compared to open-loop control approaches.
Solution Approach 2:
The patent creates electrical equipotentiality by connecting all drives to common DC buses with shared positive and negative rails. This unified electrical reference framework simplifies synchronization by providing a common timing and voltage reference for all parallel drives, making control coordination easier despite the multiple components involved.
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 enables the conveyance system to meet high load demands without the need for a single high-power drive, reducing costs and development time by utilizing multiple lower-power drives in parallel, thereby improving efficiency and cost-effectiveness.
Implementation Method 1
an inductive interface coupled to the first inverter and the second inverter, the inductive interface including a plurality of inductive elements, the inductive interface combining drive signals from the first inverter and the second inverter for each phase of the drive signals
Data Source
AI summary
A conveyance system includes a machine having a motor; a source of AC power; a drive system coupled to the source of AC power, the drive system to provide multi-phase drive signals to the motor, the drive system including: a first drive having a first converter and a first inverter, the first convertor including a first positive DC bus and a first negative DC bus; a second drive having a second converter and a second inverter, the second convertor including a second positive DC bus and a second negative DC bus; wherein the first positive DC bus and the second DC positive bus are electrically connected and the first negative DC bus and the second negative DC bus are electrically connected.