PWM Synthesis Circuit for Multi-Motor Control With Fewer PWM Modules
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Solution Overview
Problem
Existing systems for controlling three-phase motors require multiple PWM signals, which can be complex and costly to implement, especially when controlling multiple motors simultaneously.
Innovation Solution
An integrated circuit (IC) with a PWM synthesis circuit that generates additional PWM signals from existing ones, allowing for efficient control of multiple three-phase motors using fewer PWM modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple PWM modules are used to control multiple three-phase motors, then the control capability is improved, but the device complexity and cost increase
Solution Approach 1:
The patent implements a PWM synthesis circuit that can be integrated into existing PWM modules, enabling them to generate additional PWM signals beyond their native capability. This allows a single PWM module to control multiple three-phase motors by synthesizing the required PWM signals from a subset of its generated signals, thereby reducing the total number of PWM modules needed while maintaining full control capability across multiple motors.
Solution Approach 2:
The PWM synthesis circuit generates additional PWM signals by copying and transforming a subset of the original PWM signals through counter-based synthesis. The circuit creates synthesized PWM signals that replicate the functional characteristics needed for motor control, allowing fewer physical PWM modules to effectively control multiple motors by synthesizing the required signal patterns.
2Adaptability or versatility
If multiple PWM modules are used to control multiple three-phase motors, then the control capability is improved, but the cost increases
Solution Approach 1:
The PWM synthesis circuit enables existing PWM modules to perform multiple functions by synthesizing additional PWM signals. This integration approach allows a single PWM module to effectively control multiple three-phase motors, reducing the total component count and associated costs while maintaining full control capability.
Solution Approach 2:
The patent combines the PWM synthesis functionality directly within the PWM module structure, merging signal generation and synthesis functions into a unified circuit. This integration reduces the need for separate PWM modules for each motor, thereby reducing overall system cost while maintaining the ability to control multiple motors simultaneously.
3Measurement precision
If PWM signals are generated for each phase of each motor, then the control precision is improved, but the device complexity increases
Solution Approach 1:
The PWM synthesis circuit creates accurate copies of the required PWM signal patterns through counter-based synthesis. By generating synthesized PWM signals that precisely replicate the timing and duty cycle characteristics of the original signals, the circuit maintains control precision while reducing the number of physical PWM modules needed.
Solution Approach 2:
The synthesis circuit acts as an intermediary between the native PWM signals and the required motor control signals. It transforms a subset of generated PWM signals into the additional signals needed for multi-motor control, ensuring precise timing and phase relationships are maintained while reducing overall system complexity.
Data Source
AI summary
In response to a rising edge on an input pulse width modulation (PWM) signal, a method includes starting a first counter, resetting a second counter, and forcing a second PWM signal to a logic low level. In response to the first counter reaching a first match value, the method includes asserting a rising edge on a first PWM signal. In response to a falling edge on the input PWM signal, the method further includes causing a falling edge of the first PWM signal, resetting the first counter, and starting the second counter. In response to the second counter reaching a second match value, the method includes asserting a rising edge of the second PWM signal.