AN 973: Three-phase Boost Bidirectional AC/DC Converter for Electric Vehicle (EV) Charging
ID
733436
Date
6/23/2022
Public
1. Three-phase Boost Bidirectional AC/DC Converter for Electric Vehicle (EV) Charging Design Example Overview
2. Downloading and Installing the Design Example
3. Model Description
4. FPGA Resource Use Comparison
5. Locating Top-level VHDL Wrapper
6. Generating HDL Code with MATLAB and HDL Coder
7. Simulink Simulation Results
8. Document Revision History for AN 973: Three-phase Boost Bidirectional AC/DC Converter for EV Charging
3.2.2.3. Output Capacitor
In this model, there is a subblock to emulate the output capacitor or DC-link capacitor, for which you must consider an acceptable output voltage ripple. In the continuous-time domain, you can use the following standard electronics formula to obtain the capacitor value:
Where:
- ΔV = 0.5 V, which is the acceptable output voltage ripple.
- 1 x 10-5s is the inverse of the switching frequency.
- 125 A is the maximum output current.
The voltage across the output capacitor (VDC ) is the integral of the current flowing into it as follows:
The inductor and switch models calculate the high side current, which is a split between the output capacitor (IC ) and load resistor (ILOAD ). Although VC is controlled to a DC voltage, the voltage on the capacitor terminals is relative to the ground (VDC_P and VDC_N ) switches up and down with the PWM of the switches. The calculation of VDC_P and VDC_N depends on the state of the PWM signals (0 or 1).
Then, calculate VDC_P using: