It uses (n + 5) keys and only 1 capacitor to balancen cells. It is one of the most common charge-shuttling techniques and is also called fly capacitor. In this method, the capacitor charges from the cell with the highest voltage and discharges in the cell with the lowest voltage according to the selection. Although this method provides balancing in a short time, it requires many keys. Uses a simple control strategy.
With the help of a bi direction converter connected to the SSC system, the batteries are charged and discharged through the capacitor.
- There are 9 batteries inside each module (n + 5).
- These switches are a structure consisting of 2 N-channel mosfet’s called bi-directional structures. This structure is briefly made in a controlled way of current flow in both streams.
- Parallel single capacitor to ensure the need for balancing and smoothness.
- All the switches in the circuit are driven by the PWM signal.
- Selection of high and low energy batteries after determining the Pwm signal.
- For the low energy charge charge, 90% is selected as shown.
- For the discharge of the high energy battery, 10% is selected as shown.
The structure allows current to flow in both directions. The direction of the current is determined according to the voltage differences at the two ends. N-channel is a combination of two mosfets. "IRFB3806PBF" can be used as Mosfet. All switches, except the converter key in the topology, are bi-directional.
It has been used to support and isolate batteries’ charge and discharge. In line with the information received from the microcontrollers, the switches of the low voltage battery are activated and brought to the converter boost position. The opposite of the same process, with the activation of the high voltage battery, the converter is placed in the buck position and the battery is charged.
- Module 1 values:%20, %40, %80, %20 SOC for cell 1, 2, 3 and 4 respectively.
There are a total of 4 batteries in 1 module. The simulation time of each battery had to be limited to 30 minutes. The total simulation time for 1 Module took 2 hours. This is because the batteries need to be balanced individually.
Let’s first look at the SOC comparisons.
Comparison of volt values.
