MATLAB: Duty cycle Matlab funciton is Simulink. Error! -Undefined function or variable ‘duty_cycle’. The first assignment to a local variable determines its class.

dutycycleerrorsimulink

Hi,
I want to make a function which would vary the duty cycler of a converter to get 400V output.
UNfortunately I am getting the error: Undefined function or variable 'duty_cycle'. The first assignment to a local variable determines its class.
This is my code. can you tell me what I should do?
function duty_cycle = dutycycle(Voltage_grid,past_duty)
duty_cycle_=0
if Voltage_grid>400
duty_cycle=duty_cycle-0.1
end
if Voltage_grid<400
duty_cycle=duty_cycle+0.1
end
if Voltage_grid==400
duty_cycle=past_duty
end
end

Best Answer

Two comments.
  1. Feed the "duty_cycle" to a "unit delay" block and then connect it to "past_duty".
  2. The first line inside your MATLAB Function should be "duty_cycle=past_duty;"
This way, you'll be able to regulate the voltage.
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