PWM Multiplexing Circuit for Multi-Axis Drive Control
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Solution Overview
Problem
Existing multi-axis electric motor driving systems face challenges due to limited microprocessor PWM resources, leading to increased hardware and software complexity and reduced system robustness.
Innovation Solution
A multi-axis drive control circuit incorporating a drive axis selection circuit and PWM signal multiplexing unit, utilizing logic gates for signal gating and low-side gate drive protection, enables efficient multiplexing of PWM signals on limited microprocessor resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple microcontrollers are used to control electric motor drive along various specific axes, then multi-axis drive control capability is improved, but hardware cost increases
Solution Approach 1:
The patent merges multiple PWM output functions into a single microcontroller by using logic gate circuits to multiplex PWM signals. The first PWM signal output end and second PWM signal output end share the same microcontroller PWM resource, with logic gates (AND, OR, NOT gates) combining control signals to enable the single microcontroller to generate PWM signals for multiple drive axes simultaneously, thereby reducing hardware cost while maintaining multi-axis control capability
Solution Approach 2:
The patent makes the single microcontroller universal by enabling it to perform multiple PWM output functions through logic gate multiplexing. The microcontroller can dynamically switch between controlling different drive axes by receiving control signals that activate specific logic gate combinations, allowing one microcontroller to serve multiple drive axes that would traditionally require separate microcontrollers
2Adaptability or versatility
If on-chip multiple PWM output signals are used to control electric motor drive, then multi-axis drive control is achieved, but software design workload increases and system robustness decreases
Solution Approach 1:
The patent introduces logic gate circuits as intermediary components between the microcontroller and the PWM output paths. These logic gates (AND gates, OR gates, NOT gates) act as mediators that automatically handle the signal routing and combination, replacing complex software control logic with simple hardware-level signal processing. This reduces software design workload by offloading the multiplexing control to hardware circuits
Solution Approach 2:
The patent replaces software-based PWM multiplexing control with hardware-based logic gate circuits. Instead of using software programs to manage the complexity of multi-axis PWM signal generation and switching, the invention uses physical logic gate circuits to automatically perform the signal combination and routing functions, thereby reducing software complexity and improving system robustness
3Productivity
If PWM resources inside a microprocessor are used for common electric motor drive, then drive control is achieved, but PWM resources are insufficient for multi-axis driving
Solution Approach 1:
The patent changes the parameter of PWM signal generation by introducing logic gate-based multiplexing. Instead of relying on the microcontroller's native multiple independent PWM outputs, the system uses a single PWM output combined with logic gate circuits that dynamically adjust the signal parameters (activation, deactivation, combination) based on control inputs, thereby creating multiple effective PWM outputs from a single physical resource
Data Source
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AI summary
Embodiments of the present application disclose a multi-axis drive control circuit. For multiple drive axes with no need for linkage of each phase, the multi-axis drive control circuit respectively comprises: a drive axis selection circuit unit, which is used for outputting a selection signal that enables a target drive axis; and a PWM signal multiplexing circuit unit, which is used, according to the selection signal, for causing a PWM signal output path of the target drive axis to be on, and causing PWM signal output paths of drive axes other than the target drive axis to be off. The technical solutions in embodiments of the present application can achieve multi-axis drive control in a situation where microprocessor resources are limited.