Motor Driving Circuit Speed Control via Transistor Voltage Regulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing motor driving circuits for heat dissipation, such as those using heat-dissipating fans, face limitations in noise reduction and power efficiency due to voltage adjustments being influenced by load current and relying on resistors for voltage regulation, which restricts speed adjustment and increases power consumption.
Innovation Solution
A motor driving circuit comprising a motor-driving unit, a control unit, and a determining unit, where the determining unit adjusts the voltage between the motor-driving unit's collector and base by switching devices, allowing for linear speed control of the motor without using resistors, thereby reducing noise and enhancing power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a resistor is used to lower the voltage VIN2, then the voltage can be adjusted, but the amount by which the voltage is lowered varies with load current, limiting speed adjustment ability
Solution Approach 1:
The patent changes the control parameter from resistor-based voltage division to transistor-based voltage regulation. By controlling the transistor's conduction state through a control signal, the voltage VIN2 can be adjusted independently of load current, achieving linear speed control from 0 to maximum speed.
Solution Approach 2:
The patent replaces the passive resistor-based voltage division mechanism with an active transistor-based voltage regulation system. This substitution enables dynamic control of voltage and motor speed through electronic switching, overcoming the limitations of fixed resistor ratios.
2Power
If current flows through the resistor or power switching device, then voltage can be controlled, but a lot of power is consumed, lowering power efficiency
Solution Approach 1:
The patent employs periodic switching of the transistor between conduction and cutoff states. During the conduction period, current flows through the motor; during the cutoff period, no current flows. This periodic action reduces average power consumption while maintaining voltage control capability.
Solution Approach 2:
The patent transitions from static resistor-based voltage division to dynamic transistor-based voltage control. The transistor's conduction state can be dynamically adjusted based on required motor speed, optimizing power consumption at different operating points rather than continuously dissipating power through a resistor.
3Use of energy by moving object
If the voltage VIN2 is low, then the load current is smaller, but the amount by which the voltage is lowered is below expected value, limiting speed adjustment
Solution Approach 1:
The patent implements a control mechanism where the control unit monitors the voltage VIN2 and adjusts the transistor's conduction accordingly. This feedback loop ensures that the voltage is lowered to the expected value even when load current is small, achieving the desired speed reduction.
Solution Approach 2:
The control unit proactively adjusts the transistor's conduction state before the motor speed deviates from the desired value. By anticipating the need for speed adjustment and pre-regulating the voltage, the system maintains accurate speed control across the entire operating range.
Data Source
AI summary
A motor driving circuit for adjusting speed of the motor by changing output voltage is disclosed. One end of the motor is coupled to a variable voltage source. The motor driving circuit includes a motor-driving unit, a control unit and a determining unit. The motor-driving unit includes a first end coupled to another end of the motor, a second end coupled to a ground and a third end, and is utilized for driving the motor. The control unit is utilized for controlling the voltage between the first end and the third end of the motor-driving unit. The determining unit is coupled between the variable voltage source and the control unit, and is utilized for controlling the control unit to adjust the voltage between the first end and the third end of the motor-driving unit according to magnitude of the voltage of the variable voltage source.