• Vishnupriya murugesan

Open Loop Speed Control of BLDC motor using Snetly





Open Loop Speed Control of BLDC motor using Snetly


Hi viewers

welcome to LMS solution

Today we are going to see about the open loop speed control of BLDC motor by using Snetly modular real-time system the application engineering Mr Iyappan from snetly modular real system going to be explain the concept let's see the demonstration!


Hi everyone today we are going to see about the open loop speed control of brushless dc motor with our real-time modular based controller snetly this is the hardware unit of snetly where i'll connect our interfacing digital input and digital output and analog signal area and this will be the inbuilt gate drive circuit of digital output 0 to 15 volt level an interfacing part and programming for this one here we are connecting three phase brushless dc motor and the feedback from the motor hall signals three signal will be connected to the digital input pin and the power supply has been taken from the snetly HALL-A HALL-B HALL-C with a phase shift of 120 degree in the motor configuration


This will be current sensor measurement port we are measuring three phase current of the brushless motor and this will be our three phase voltage source inverter power module two level inverter this has been directly connected to the power semiconductor switches since we have an in-built gate drive circuits and for our power supply we are using dc 24 volt since motor is 24 volt brushless motor and here we have developed the model level design to run a motor in an open loop speed control since it is a brushless dc motor it is a sensor based motor first we require sets of feedback based on the sets of feedback we need to configure the gate signal of voltage source inverter module and here we are using configurable lookup table to configure the gate signal for a gate signal top and bottom of each leg we are giving simple square pulse with a variable duty control and for the speed measurement we are just using one of the speed feedback from the encoder and we need to configure number of PPR in the motor here the number of PPR of this motor is four so we are configuring it four and directly we are measuring the rpm revolution per minute and here we are using a dead time controller for each leg we need a dead time and we need to configure the dead time value in microseconds here i am configured one micro second just apply register back to schematic


This model we are generating totally six gate signal for each lookup table we will get two gate signal nothing but the six step commutation 120 degree mode of operation so we are directly connecting to the digital output pin with the inbuilt gate drive circuit and it will be giving 0 to 15 volt output where you can connect your direct igbts and mosfet so no need of external gate drive circuits this part will be your analog input where you can measure a three Phase current waveform of your brushless dc motor first three signals we are using in this application we have current rating of +- 20 amps and even we have voltage sensor signals we need to configure just offset and gain value of particular signal which we are using in our application here we are using three current measurement and in this end we have the typical gain value as well as offset values after creating a model level design you can directly connect your hardware and then click on run button by simply varying the duty control you can observe your motor starts running once motor starts running here you will get the feedback HALL sensor feedback the three sensor feedback at the phase shift of 120 degree has been shown in the waveform and sixth gate signal has been shown in the logic analyzer and the current waveform of R-phase of Brushless dc motor and Y-Phase and B-Phase you can observe here the current waveform is 120 mode operating.


Simply changing the knop value or duty cycle of pulse width will be increasing so the motor speed will be increased here you can observe the motor speed in rpm 1750 since it is open loop control by simply varying the duty control speed will be vary this is the current waveform by simply applying load to the motor you can observe the live current waveform has been increasing simply applying load to the motor the current rating has been increasing that's all for today's video thanks for watching


Thanks to Mr.Iyappan for wonderful demonstration on open loop speed control of brushless dc motor by using snetly kindly subscribe snetly youtube channel as well as lms solution for more info kindly go to this website snetly.in and then you can contact directly the application engineer and sales person to know about more on snetly thank you

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