I have an application where I need to charge a massive capacitive load (high ESR, high self discharge, unknown capacitance but >5 farad) to roughly +1.5V and then discharge it to roughly -1.5V. The switching frequency is roughly once every 10 minutes. Fully characterizing the load requires testing at both constant current and constant voltage. The early prototypes pull 3-5 amps for a short time when connected directly to a 40A 1.2V supply, but the full scale units might be 10X larger. I am trying to measure voltage and current while the load runs for multiple charge/discharge cycles to test different active materials used in constructing the capacitor. Some experiments run for multiple days, so automated data collection is definitely required. I am using two INA219 current sense modules with an Arduino writing data to an SD card.
Currently I am using two high current lab power supplies and switching between them with a DPDT mechanical relay configured as a sort-of H-Bridge. This gives me (manual) control of voltage setpoints and current limits in either direction. This setup works except during the time when the capacitor is providing power to the supply, which causes the supplies to lose control of the load and interferes with the data collected during the switching transient. I know that an active load would dissipate this power but I don't want to purchase additional lab equipment and bodge together some nightmare of relays and control to switch them in and out at the appropriate times. I have seen a few four quadrant power supplies, which seems like a good starting place, but the ones I have seen don't offer automated sequencing with separate current limits and voltage controls.
I am a chemical engineer but I know my way around basic electronics. I have been looking at the LT8714 four quadrant synchronous controller which seems to be pretty close to what I need, but I would have to implement some kind of configurable current limits for some tests. If it is worthwhile I could dive into the data sheet and figure it out but it would take me a long time to brush up on KiCad and SPICE to get something implemented.
My questions are as follows:
-> Is a four quadrant supply the right piece of equipment to build my testing apparatus around or is there a better method?
->Does anyone have knowledge of a vendor that makes an integrated unit that can address all 4 quadrants with optional current limiting and high current (>20A preferred) output?
-> Should I just bite the bullet and start designing something custom?
Currently I am using two high current lab power supplies and switching between them with a DPDT mechanical relay configured as a sort-of H-Bridge. This gives me (manual) control of voltage setpoints and current limits in either direction. This setup works except during the time when the capacitor is providing power to the supply, which causes the supplies to lose control of the load and interferes with the data collected during the switching transient. I know that an active load would dissipate this power but I don't want to purchase additional lab equipment and bodge together some nightmare of relays and control to switch them in and out at the appropriate times. I have seen a few four quadrant power supplies, which seems like a good starting place, but the ones I have seen don't offer automated sequencing with separate current limits and voltage controls.
I am a chemical engineer but I know my way around basic electronics. I have been looking at the LT8714 four quadrant synchronous controller which seems to be pretty close to what I need, but I would have to implement some kind of configurable current limits for some tests. If it is worthwhile I could dive into the data sheet and figure it out but it would take me a long time to brush up on KiCad and SPICE to get something implemented.
My questions are as follows:
-> Is a four quadrant supply the right piece of equipment to build my testing apparatus around or is there a better method?
->Does anyone have knowledge of a vendor that makes an integrated unit that can address all 4 quadrants with optional current limiting and high current (>20A preferred) output?
-> Should I just bite the bullet and start designing something custom?
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