Problem: Control a High Power DC Motor(220 Volt)

[sabri]

220 dc motor

I want control a industrial 220Volt DC motor with microcontroler such as PIC16F877
with PWM(Pulse Width Modulation) method.
I programed the microcontroler to construct pulses with 2-99 percent
duty cycle ,but i do not know , how trigger the high power DC motor with
Optoisolator & Triac.
Please help me ,How i can do that?

 

[IanP]

TRIACS ARE GOOD FOR AC VOLTAGE ONLY as you need zero-crossing or zero-current to turn them off.
For DC HV applications you will need power transistors.
You can use some of them connected in paralle from negative pol with your motor connected to positivel and base(s) controled trough opto-isolator(s).
But the best solution is a bridge based on PNP and NPN power transisstors and again their bases will be controlled with opto-isolators. Alternatively you can select NMOS and PMOS transistors with very low open-channel resistance.
In the bridge configuration you will be able to operate at full 200Vdc and you will be able to change direction...full control, including speed (PWM).

 

[nicleo]

I assume the 'high power' of the DC motor is 'DC power supply'. If it's DC power supply, probably you could use MOSFET or IGBT to replace the Triac. Can you have that option?

 

[sabri]

I want use TRIACs ,because TRIACs are used for high power control.
Can I use Power transistors for high power control (e.g. 220Volts & 10Amps)?
In the PWM method Freq of pulses is 100-1000 Hz .
Can I use the Power Transistore for construct PWM pulses, In this range of frequencies ?

Thank You

 

[picotube]

I want use TRIACs ,because TRIACs are used for high power control.
Can I use Power transistors for high power control (e.g. 220Volts & 10Amps)?
In the PWM method Freq of pulses is 100-1000 Hz .
Can I use the Power Transistore for construct PWM pulses, In this range of frequencies ?

You may consider power transistors (e.g. power BJT, power mosfet, and IGBT). Three of them have no problem to handle 220V/10A. They can be used for switching up to few kHz. Power mosfet and IGBT have higher switching frequency capability. I used IGBTs before, and the IGBTs (frm Semikron) were rated as 600V/200A and 600V/300A. These IGBTs can be switched up to 20kHz. So, I think they are more than enough for your application.

 

[sabri]

Use of transistors is a good idea.
Can you send me a schematic circuit of that?

 

[Colbhaidh]

Here is an IRF application note for 3 phase AC motors. Should be useful for single phase also.

 

[nicleo]

Use of transistors is a good idea.
Can you send me a schematic circuit of that?

Would you please advise the block diagram of your dc motor circuit is as the one shown attachment? If NOT, pls send us the block diagram of your design.

Besides, sorry to ask this, but I wish to confirm before I proceed ... Do you want the TRIAC/Transistor to be the 'switching devices/transistor' (see figure), or to be the 'main switch' (see figure). Pls update.