Hi Guys,
This one might interest some of you.
The last year or so I've been working on a 500kW variable pitch wind turbine (restricted through settings to 250kW). This is a little unusual in that the turbine is designed to be grid connected but I have made a system to allow it to self excite and therefore run as an island generator. To date the system has been running off and on.
My PLC is a AB micrologix 1400. I am using a PID control loop to monitor the RPM of the generator(4 pole 50hz 1500rpm asynchronous motor) and adjust the load applied to stabilise the speed. The operating range of the turbine means I only have a tolerance of +- 100rpm on the generator otherwise the turbine's standard control system will fault on over-speed or under-speed.
In relatively constant wind I have the system fairly stable and it will operate well without stopping. The turbine will run at approx +- 40rpm. In gusty winds the system isn't too bad taking a very strong gust to overcome the control system. In higher winds (above 13m/s) the system can't run as the turbine is trying to restrict it's output by pitching the blades which causes a slow oscillation in my control system.
The parameters I have in my control loop are:
Kc = 3.6
Ki = 0.03
Kd = 0.00
Loop update 0.01.
Is it possible to tune a PID to be reactive in massively varying conditions? As you can imagine the rate of change of wind speed varies considerably and sometimes dramatically.
I'm quite new to PID control and have got the setting by trial and error. I find that if I apply a Kd it sends the system out of control but I'm really struggling to get a stable rpm with just Kc and Ki. Can anyone offer any help / advice on this or even tuning PID loops in general?
Thanks
Jonny
This one might interest some of you.
The last year or so I've been working on a 500kW variable pitch wind turbine (restricted through settings to 250kW). This is a little unusual in that the turbine is designed to be grid connected but I have made a system to allow it to self excite and therefore run as an island generator. To date the system has been running off and on.
My PLC is a AB micrologix 1400. I am using a PID control loop to monitor the RPM of the generator(4 pole 50hz 1500rpm asynchronous motor) and adjust the load applied to stabilise the speed. The operating range of the turbine means I only have a tolerance of +- 100rpm on the generator otherwise the turbine's standard control system will fault on over-speed or under-speed.
In relatively constant wind I have the system fairly stable and it will operate well without stopping. The turbine will run at approx +- 40rpm. In gusty winds the system isn't too bad taking a very strong gust to overcome the control system. In higher winds (above 13m/s) the system can't run as the turbine is trying to restrict it's output by pitching the blades which causes a slow oscillation in my control system.
The parameters I have in my control loop are:
Kc = 3.6
Ki = 0.03
Kd = 0.00
Loop update 0.01.
Is it possible to tune a PID to be reactive in massively varying conditions? As you can imagine the rate of change of wind speed varies considerably and sometimes dramatically.
I'm quite new to PID control and have got the setting by trial and error. I find that if I apply a Kd it sends the system out of control but I'm really struggling to get a stable rpm with just Kc and Ki. Can anyone offer any help / advice on this or even tuning PID loops in general?
Thanks
Jonny