The average voltage across the motor also changes accordingly. It can be seen from the above formula that changing the ratio of the switch-on time ton to the switching period T, that is, changing the duty cycle of the pulse. T: Short time period when the switch is on.ton: The time when the switch is turned on each time.The voltage waveform obtained at both ends of the motor is shown in Figure 2, and the average voltage Uav can be expressed by the following formula: At this time, the motor current continues to flow through the freewheeling diode VD. But the energy stored in the armature inductance during the switch S is on. When the switch S is off, the power supply Us is interrupted to provide electrical energy to the motor.
When S is connected, the power supply Us is applied to both ends of the motor through the switch S, the power supply provides energy to the motor, and the motor stores energy. The controllable switch S is repeatedly turned on and off at certain time intervals. The schematic diagram of PWM control is shown in Figure 1. Therefore, this device is also called a "switch drive device." By changing the "duty cycle" of the voltage on the armature of the DC servo motor, the average voltage can be changed to control the motor speed. Then, change the length of the "on" and "off" time in a cycle as needed. The PWM speed control device uses the switching characteristics of high-power transistors to modulate a fixed-voltage DC power supply, and switches on and off at a fixed frequency. III Working Principle of DC Household WM Speed Control System Therefore, the DC motor is widely used in speed control.Įspecially with the development of computers in the field of human control and the development of high switching frequency, fully controlled second-generation power semiconductor devices (GTR, GTO, MOS inkstone T, IGBT, etc.), the pulse width modulation (PWM) DC speed control system is in It is more and more commonly used in speed control.
#L298n motor driver arduino code software#
V Software Implementation of PWM Speed Regulationįor a long time, because DC motors have the following characteristics:
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