The Difference Between PWM and Frequency

The difference between PWN and Frequency in a speed controller!

The human ear can hear a wide range of frequencies, from about 20 Hz to 20,000 Hz, with the range decreasing as we age. Young adults typically have a hearing range of 20 Hz to 20,000 Hz, while older adults may only be able to hear frequencies up to around 14,000 Hz. This is why younger people are more likely to hear the whine of a motor operating at high frequencies, while older people may not be able to hear it.

The whine of a motor, also known as "motor whine" or "motor noise," is a high-pitched sound that is caused by the vibration of the motor's components. It is typically caused by the interaction of the magnetic fields within the motor and the current flowing through the windings. As the frequency of the electrical power supplied to the motor increases, the whine of the motor also increases. The frequency at which the whine becomes audible varies depending on the design of the motor, but it is usually in the range of 20,000 Hz to 30,000 Hz.

It's worth noting that the whine of a motor can be reduced by using a technique called "frequency shaping" which is a method of controlling the frequency of the electrical power supplied to the motor. This technique involves shaping the frequency spectrum of the electrical power supplied to the motor in order to reduce the whine of the motor. It can be used in combination with PWM or frequency control.

In summary, the human ear can hear a wide range of frequencies but as we age, the range decreases. Younger people are more likely to hear the whine of a motor operating at high frequencies, while older people may not be able to hear it. The whine of a motor is caused by the vibration of the motor's components and is typically caused by the interaction of the magnetic fields within the motor and the current flowing through the windings. It can be reduced by using techniques like frequency shaping.

Using Pulse Width Modulation (PWM) and frequency control together in a motor controller can provide a number of benefits.

PWM is a method of controlling the speed of a DC motor by rapidly switching the voltage on and off at a high frequency. The duty cycle, or the proportion of the time that the voltage is on versus off, determines the average voltage applied to the motor. By changing the duty cycle, the speed of the motor can be adjusted.

Frequency control, on the other hand, is a method of controlling the speed of a DC motor by adjusting the frequency of the electrical power supplied to the motor. The speed of the motor is directly proportional to the frequency of the power supplied to the motor. By adjusting the frequency, the speed of the motor can be precisely controlled.

When used together, PWM and frequency control can provide a more precise control over the motor's speed and torque. PWM can be used to adjust the speed of the motor, while frequency control can be used to control the torque. By adjusting both the duty cycle and the frequency, the motor can be fine-tuned to the specific requirements of the application.

For example, in a conveyor belt system, PWM can be used to adjust the speed of the belt to match the rate of production, while frequency control can be used to maintain a constant torque on the motor, even as the load on the motor changes. This allows for a more efficient and precise control of the conveyor belt system.

In precision control applications such as robotics or CNC machines, PWM can be used to control the speed of the motor while frequency control can be used to control the torque. This allows the motor to run at specific speeds while maintaining a consistent torque output, ensuring accurate movement and positioning of the robotic arm or machine tool.

Another benefit of using PWM and frequency control together is that they can help to reduce the noise generated by the motor. By using PWM to control the speed of the motor and frequency control to control the torque, the motor can be run at lower speeds, which can result in a reduction of the mechanical noise generated by the motor.

In summary, using PWM and frequency control together in a motor controller can provide a more precise control over the motor's speed and torque, improve the efficiency and performance of the motor in certain situations, and reduce the noise generated by the motor. It allows for a fine-tuning of the motor to the specific requirements of the application, resulting in a more efficient, reliable, and quiet operation.