The following page will describe a three-phase two-level inverter for grid-connected vehicle applications. As mentioned on the home page couple use cases of a grid connected inverters involve powering commercial equipment when the primary power supply has been compromised, as well as providing power to a residential space until the primary source can be reestablished.
The following design parameters have been altered in order to increase power factor, reduce EMI levles, and minimize THD.
-Lower Switching Frequency to reduce EMI Level
-Multi-Level Inverter which better mimics a sinusoidal wave and reduces THD
-LCL Filter to smooth out current and increase power factor
-Tuned PID controllers that command accurate control schemes and minimize losses
-MOSFETs with a low RDS ON to minimize switching losses
Model Parameters
Three-phase grid voltage = 480 Vrms
Fundamental frequency: 60 Hz
GCI Topology: Three-Phase Two-Level Inverter
DC-link voltage: 800 V
Switching frequency: 10 kHz
Sampling frequency: 2 MHz
Phase A angle at 0 degree
Filter configuration – LCL filter
PWM Scheme – Sinusoidal SVPWM
Block Diagram
Below is a diagram of the full-scale grid connected inverter. Similar to the diagram above there are several key features within the Grid Connected Inverter which allow it to
Full Scale Model of Grid Connected Inverter
First we will look at the inverter topology, and the A/C output before and after a passive component filter has been added to reduce switching noise. As seen in the by both the inverter topology and the stepped output waveform, this inverter has a multilevel modular theme which allows it to better replicate a sinusoidal wave.
dsaffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
FET Electrical Properties
As discussed before
LCL Filter
In the below output diagram a comparison is made between the inverter current before and after a LCL filter was added to the circuit.
Inverter Output compared with Grid
As seen in the by both the inverter topology and the stepped output waveform, this inverter has a multilevel modular theme which allows it to better replicate a sinusoidal wave.