Segmented DC Bus Voltage for Independent Cart Tracks

Solution Overview

Problem

In motion control systems with independent carts and linear motors, supplying a constant DC voltage along the track leads to undesirable effects like switching losses and radiated emissions, as the same voltage is applied across all segments regardless of varying speed requirements.

Innovation Solution

The system allows for varying DC bus voltage amplitudes along different track segments, with separate power supplies providing distinct DC voltages for segments requiring different speeds, reducing switching losses and emissions while maintaining sufficient torque and speed performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a constant DC voltage is supplied along the entire track, then the system structure is simple and easy to control, but switching losses and radiated emissions increase due to uniformly high voltage across all segments

Engineering Contradiction:

Improvevoltage supply structureVSAvoidswitching losses

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The track is divided into multiple segments, each with its own power supply unit that can independently control DC bus voltage. This segmentation allows each segment to optimize its voltage level according to local speed requirements, reducing switching losses in segments where lower speeds are sufficient

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different DC voltage levels are applied to different track segments based on their specific speed requirements. Segments requiring high speed receive higher voltage, while segments with lower speed needs receive reduced voltage, thereby minimizing switching losses and radiated emissions in those segments

Inventive Principle:

Principle #3Local quality

2Device complexity

If a constant DC voltage is supplied along the entire track, then the control system is simple, but radiated emissions increase due to high voltage switching across all segments

Engineering Contradiction:

Improvecontrol systemVSAvoidradiated emissions

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The track is divided into multiple segments, each with its own power supply unit that can independently control DC bus voltage. This segmentation allows each segment to optimize its voltage level according to local speed requirements, reducing switching losses in segments where lower speeds are sufficient

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different DC voltage levels are applied to different track segments based on their specific speed requirements. Segments requiring high speed receive higher voltage, while segments with lower speed needs receive reduced voltage, thereby minimizing switching losses and radiated emissions in those segments

Inventive Principle:

Principle #3Local quality

3Power

If high DC voltage is applied to all track segments, then sufficient torque and speed are achieved for high-performance segments, but energy efficiency decreases due to excessive voltage in low-performance segments

Engineering Contradiction:

Improvemover speed and torqueVSAvoidswitching losses

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The DC bus voltage in each segment is made dynamically adjustable based on the speed requirements of that segment. Power supply units can modify voltage levels in real-time according to operational conditions, optimizing the balance between power delivery and energy efficiency

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The voltage parameter is changed across different track segments to match their specific performance requirements. By adjusting the DC bus voltage parameter locally, the system achieves sufficient power where needed while minimizing energy losses in segments that require lower speeds

Inventive Principle:

Principle #35Parameter changes

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 reduces switching losses and radiated emissions by optimizing DC bus voltage according to segment-specific requirements, enhancing the operational efficiency and performance of movers along the track.

Implementation Method 1

each drive coil is configured to generate an electromagnetic field responsive to an AC voltage applied to the drive coil

Methodology Applied

Scientific EffectElectromagnetic field generation: Electromagnetic Induction

Implementation Method 2

each mover is configured to travel along the track and includes a drive member configured to interact with the electromagnetic fields generated by each of the drive coils to propel the mover along the track

Methodology Applied

Scientific EffectElectromagnetic interaction: Lorentz Force

Data Source

PatentUS12071313B2Variable DC bus voltage in an independent cart system

Publication Date: 2024.08.27 ROCKWELL AUTOMATION TECH INC

AI summary

A system and method for varying an amplitude of voltage on a DC bus by track segment in a linear drive system for an independent cart system according to application requirements is disclosed. The track includes at least a first portion and a second portion, where a DC voltage at a first amplitude is provided to the first portion of the track, and a DC voltage at a second amplitude is provided to the second portion of the track. The first amplitude of the DC voltage is selected to permit movers traveling along the track to travel at full rated speed with a full rated three applied to the mover. The second amplitude of the DC voltage is selected to permit the movers to travel at a reduced speed with full or increased three applied or to travel at full rated speed with a reduced force applied to the mover.