DC Motor PWM Control Circuit for Supply Voltage Stabilization
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Solution Overview
Problem
DC motors are prone to damage due to fluctuations in supply voltage during starting and operation, and existing voltage detection circuits are complex and costly, failing to provide voltage regulation and stabilization.
Innovation Solution
A control circuit for DC motors that includes a voltage monitoring unit, switching circuit, and PWM signal output unit to regulate duty cycle based on voltage and current monitoring, stabilizing output voltage and preventing overload or underload conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the supply voltage drops during motor operation, then the motor torque is greatly reduced, but the motor current must be greatly increased to produce the required torque, leading to overloading and potential damage
Solution Approach 1:
The patent implements a feedback control mechanism where the microcontroller continuously monitors the power supply voltage through a voltage division circuit. When voltage drops are detected, the system automatically adjusts the PWM duty cycle to regulate the motor current, preventing overloading and ensuring motor safety while maintaining required torque output.
2Force
If the supply voltage is lower than the rated voltage during motor starting, then the induced magnetic field and rotating magnetic field are weakened, leading to great reduction of torque or inability to start
Solution Approach 1:
The patent applies preliminary action by detecting voltage conditions before motor starting and pre-adjusting the PWM duty cycle to ensure sufficient starting torque. The system monitors voltage during the starting process and makes proactive adjustments to maintain magnetic field strength and prevent overheating before it occurs.
3Power
If the supply voltage is higher than the rated voltage of the motor, then the excitation current increases with the increase of the applied voltage, which will increase the loss of iron core and reduce the power factor
Solution Approach 1:
The patent uses feedback control to monitor the power supply voltage and automatically adjust the PWM duty cycle when voltage exceeds the rated value. This prevents excessive excitation current, reduces iron core losses, and maintains optimal power factor while preserving motor power output.
4Measurement precision
If a detection circuit for supply voltage is implemented in the prior art, then the supply voltage can be collected for calculation, but the structure becomes complex and cost increases, and voltage regulation and stabilization are not achieved
Solution Approach 1:
The patent integrates multiple functions into the microcontroller unit, which simultaneously performs voltage detection through an integrated voltage division circuit, PWM signal generation, and motor control. This multi-functional approach achieves accurate voltage monitoring and active voltage regulation without requiring separate complex detection circuits, thereby reducing overall system complexity and cost.
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
The control circuit maintains stable output voltage, protects motors from damage by regulating duty cycle, and ensures continuous operation across varying load conditions.
Implementation Method 1
a PWM signal output unit to output PWM signal for controlling the switching circuit. The PWM signal output unit is configured to regulate the duty cycle of the output PWM signal
Implementation Method 2
a voltage monitoring unit to monitor the output voltage of the DC power supply
Implementation Method 3
a switching circuit for controlling operation of the DC motor
Data Source
AI summary
A control circuit and method for DC motors is disclosed in the present application. The control circuit may comprise a voltage monitoring unit for monitoring the output voltage of the DC power supply, a switching circuit for controlling the operation of the DC motor, and a PWM signal output unit to output PWM signal for controlling the switching circuit. The PWM signal output unit may be configured to regulate the duty cycle of the output PWM signal based on the results of the voltage monitoring unit. In this way, motors with different resistances may work continuously in a stabilized state. Also, it may detect when a load like motor is heavy loaded or overloaded, stop motor from starting, and avoid overtime working due to the drop of supply voltage damaging the load like motor. When the voltage of power supply is higher than the rated voltage of the motor, it may regulate the input voltage value of power supply to avoid the increase of excitation current of motor with the increase of the applied voltage, thereby avoid the loss of iron core.