Newbie starter - AC generator circuit in Simulink

Hello everybody.

I'm a new starter to Matlab and Simulink, and I'm trying to create a basic electrical circuit in Simulink. It's comprised of a 'Synchronous Machine SI Fundamental' block, using 'Preset Model 05: 50hZ 400V 60kVA 1500RPM', and feeds a 'Three-Phase Parallel RLC Load' block, with parameters of 400V P-P, 10KW, +7.5kVAr and -5.0kVAr. I have a constant block of 100*pi (for 1500 rpm) connected to the PM input, and another constant of 3.212 connected to the Vf input of the generator, to provide speed and field voltage respectively. From the 'm' terminal I have a Bus Selector with 9 parameters selected, which then feed a 9-input scope. These inputs are:

Electrical power, Rotor speed, Field current, Output active power, Output reactive power, is_A, is_B, is_C, Load angle.

When I run the simulation the graphs in the scope display low electrical power, negative rotor speed, low output active power, massive output reactive power and a load angle that oscillates between +200 and -200 degrees. Additionally, nothing seems to happen for the first 55 seconds of the simulation, then from 55 to 60 seconds (when the simulation stops) I have activity.

I'd like some tips on how to correct this. My intent upon getting this going is to replace the Vf constant with a control system (PID or otherwise) to act as an automatic voltage regulator, and modify the model to simulate faults and changes in load. First things first though.

I don't know if models can be posted on here. If they can, could someone tell me how and I'll put it up for people to have a look at? I've tried to attach a picture of the circuit. I've also tried to attach some pictures of the scope displays. I'd also like to know how to slow down the simulation, if that's possible?

Thanks in advance!

Answer 1

[Sabin]

Mechanical power at the machine's shaft, in W. In generator mode, this input can be a positive constant or function or the output of a prime mover block. In motor mode, this input is usually a negative constant or function. The input to Pm is set to 100*pi= 314.1593 which matches the graphs.

“Nothing seems to happen for the first 55 seconds of the simulation” because in the Scope Logging the ‘Limit data points to last’ is on and the value there is probably the default 5000. Switching off the ‘Limit data points to last’ will sort this aspect.