PI controller oscillating error signal

Hi, I am simulating the current control for grid connected inverter using SIMULINK. The closed loop model seems to be working fine but the PI controller error signal is oscillating between a high range (-500 to 500) because of which my signals dont reach a steady state. I have already tuned the PI controller to exact values. The high range of error is at the best tuning parameters possible. I am using space vector modulation for PWM. The same model works superbly when I use Sinusoidal PWM.