Motor PWM Frequency Switching for Reverse Rotation Control
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Solution Overview
Problem
Conventional motor control methods face malfunctions due to the use of PWM control signals with a duty of 5% for both forward and reverse rotational driving, limiting the degree of freedom in motor control.
Innovation Solution
Implementing a first control signal with a frequency of 10 kHz to 30 kHz for forward rotation and a second control signal with a frequency of 8 Hz to 12 Hz for reverse rotation, utilizing pulse width modulation (PWM) signals with different frequencies to enhance control flexibility and prevent malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If PWM control signals with a duty of 5% are used for both forward and reverse rotational driving, then the control method is simple, but malfunctions occur and the degree of freedom of control is limited
Solution Approach 1:
The patent changes the frequency parameter of the PWM control signal to differentiate between forward and reverse rotation commands. The first control signal operates at 10 kHz to 30 kHz for forward rotation, while the second control signal operates at 8 Hz to 12 Hz for reverse rotation. This parameter differentiation eliminates the malfunction issue that occurred when both directions used identical 5% duty cycle signals, while maintaining control simplicity.
2Adaptability or versatility
If PWM control signals with a duty of 5% are used for both forward and reverse rotational driving, then the control structure is unified, but the degree of freedom of control is limited
Solution Approach 1:
The patent uses frequency as a distinguishing parameter for control signals. The microcomputer generates first control signals at 10 kHz to 30 kHz for forward rotation and second control signals at 8 Hz to 12 Hz for reverse rotation. This approach provides control flexibility and adaptability for different rotation directions while keeping the control structure unified, as both signals are still PWM signals processed through the same inverter circuit without requiring additional wiring or hardware changes.
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
Enhances motor control freedom by preventing erroneous recognition and malfunctions through distinct frequency-based PWM signals, allowing seamless switching between forward and reverse rotational directions without additional wiring.
Implementation Method 1
a first control signal that is a pulse width modulation signal and a second control signal that is a pulse width modulation signal of a different frequency from the first control signal are received
Data Source
AI summary
A motor control method includes driving a motor in a forward rotational direction at a rotational speed corresponding to a duty cycle range of a first control signal that is a pulse width modulation signal, and when the rotational direction and the rotational speed of the motor correspond to that when the motor is not rotating and a second control signal that is a pulse width modulation signal having a frequency different from a frequency of the first control signal is received, driving the motor in a reverse rotational direction. Thus, the method controls the motor by switching the rotational direction of the motor between the forward rotational direction and the reverse rotational direction with a high degree of freedom to reduce or prevent malfunctioning.