Half-Step Stepper Motor Driver for Lower Peak Current
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Solution Overview
Problem
HVAC systems face challenges in efficiently controlling stepper motors due to the high global warming potential of refrigerants like R-134a, requiring more powerful motors and larger electric currents, which complicates driver circuit upgrades and replacements.
Innovation Solution
A control assembly that limits the number of stator windings energized at a time in HVAC systems, using a half-step excitation method to reduce peak currents supplied to stepper motors, allowing for more efficient control of motors with fewer windings energized simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If more powerful stepper motors are employed to accommodate increased mechanical forces and torque, then the motors can handle higher loads, but larger electric currents are required which complicates driver circuit upgrades and replacements
Solution Approach 1:
The patent applies half-step excitation which periodically energizes stator windings in a sequence, alternating between different winding combinations. This periodic action allows the motor to generate required torque while limiting peak current demands on the driver circuit, as not all windings are energized simultaneously.
Solution Approach 2:
The patent uses partial action by energizing only a subset of stator windings at any given time during half-step operation. Instead of energizing all windings simultaneously, the system alternates between different partial combinations, achieving the necessary mechanical force while reducing peak current requirements.
2Power
If all stator windings are energized simultaneously, then maximum torque is achieved, but peak currents become excessively high
Solution Approach 1:
The half-step excitation method employs periodic action by alternating between different winding energization patterns. During each half-step cycle, different combinations of stator windings are energized sequentially rather than simultaneously, maintaining average torque output while reducing peak current demands.
Solution Approach 2:
The patent segments the total torque requirement by dividing the stator windings into different groups that are energized at different times during the half-step sequence. This segmentation allows the system to achieve cumulative torque effect while limiting the number of windings energized simultaneously, thus reducing peak current.
3Stability of the object's composition
If driver circuits are permanently built into the system, then integration is improved, but upgrades or replacements become difficult
Solution Approach 1:
The patent changes the operational parameters of the driver circuit by implementing half-step excitation mode. This parameter change allows the existing driver circuit to operate more efficiently with reduced peak current demands, effectively extending its capability without requiring hardware upgrades or replacements.
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 peak currents and simplifies upgrades or replacements of driver circuits, improving energy efficiency and environmental impact by minimizing the use of high-global-warming-potential refrigerants.
Implementation Method 1
A driver circuit connected to a controller can be used to supply such stepper motors with electric currents
Data Source
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AI summary
Half-step motor driver. A system (1) for heating, ventilation, air-conditioning comprising an appliance (2a - 2d), a control assembly (3a - 3d, 4a - 4d), a first motor (5a - 5d) having a first winding and a first terminal, a second motor (6a - 6d) having a first winding and a first terminal; the control assembly (3a - 3d, 4a - 4d) applying a first electric signal selected from an electric high signal and an electric low signal to the first terminal of the first winding of the first motor (5a - 5d) for a first number of regular intervals of time, applying the first electric signal to the first terminal of the first winding of the second motor (6a - 6d) for a second number of regular intervals of time, the first number of regular intervals of time and the second number of regular intervals of time differing by one regular interval of time.