USB-PD Controller Duty Cycle Control for Dynamic Load Current Limits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Sensorless BLDC motors face overcurrent fault conditions when powered by USB PD systems due to high current draw during startup and dynamic loading, exceeding the maximum current limit of 5 A, leading to system shutdown.
Innovation Solution
A USB-PD integrated circuit controller with dual control loops to calculate and adjust the duty cycle, ensuring the maximum current delivered over a USB Type-C cable does not exceed 5 A, using a PWM duty cycle to power the load with a corresponding DC voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If sensorless BLDC motors are powered by USB PD systems with high current draw during startup and dynamic loading, then the motor can achieve high starting torque and dynamic performance, but the current exceeds the maximum limit of 5 A causing overcurrent fault conditions and system shutdown
Solution Approach 1:
The patent implements a dynamic duty cycle adjustment mechanism that continuously adapts the PWM duty cycle based on real-time current measurements. The controller monitors the current drawn by the BLDC motor and dynamically modifies the duty cycle to keep the current within the 5 A USB PD limit while maintaining adequate power delivery during startup and dynamic loading conditions
Solution Approach 2:
The patent employs a feedback control system where the controller continuously measures the current drawn by the motor and uses this feedback to adjust the PWM duty cycle. The duty cycle adjustment value is calculated based on the difference between the measured current and the USB PD current limit, creating a closed-loop control that prevents overcurrent conditions while maintaining motor performance
Data Source
AI summary
A Universal Serial Bus (USB)-Power Delivery (PD) integrated circuit (IC) controller includes: a first control loop configured to calculate a duty cycle based on a difference between a measured operating parameter of a dynamic load and a reference operating parameter; and a second control loop configured to calculate a duty cycle adjustment value that ensures a maximum supported current to be delivered over a USB Type-C cable to the dynamic load is not exceeded during operation of the dynamic load. The USB-PD IC controller is configured to adjust the duty cycle based on the duty cycle adjustment value, and to power the dynamic load over the USB Type-C cable with a DC voltage having a magnitude that corresponds to the adjusted duty cycle. An electronic system that includes the dynamic load and the USB-PD IC controller is also described.