Customer question: How can the customer choose the correct voltage capacitance value of the capacitor to derate the surge voltage in the working circuit when designing a circuit?
Our solution: When selecting the rated voltage of the electrolytic capacitor, select a capacitor whose voltage is greater than 1.25 times the maximum bus voltage; under the rated working condition of the system, the bus voltage fluctuation does not exceed plus or minus 5%, so we can calculate the capacitance capacity. The ripple current does not exceed 85% of the rated value. The self-heating temperature of aluminum electrolytic capacitors is generally required to not exceed 5 degrees Celsius. Based on the system life, capacitors that are more durable and have a longer life in harsh environments are selected.
