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·DC Power Supply

DC Power supply is also known as DC-DC power supply regulator. It is mostly a supply voltage of AC voltage, when the AC supply voltage of the voltage or output load resistance changes, the regulator output voltage can be directly maintain stability. Regulator parameters are voltage stability, ripple coefficient and response speed. The former indicated that the changes in input voltage output voltage. Ripple coefficient indicated that, under nominal working conditions, the output voltage is the AC component of the size; the latter indicated that dramatic changes in input voltage or load when the voltage is back to normal time. DC power supply is divided into sub-continuous conduction type and switching categories. The former is transformed from the frequency to single or three phase AC voltage change to the appropriate value, and then through the rectifier, filter, access to stable DC power supply, and then be stabilized by the regulator circuit voltage (or current). This power supply circuit simple, ripple is small, interfere with each other small, but bulky, consumables and more efficiency is low (often less than 40% to 60%). The latter is to change the adjustment element (or switch) on-off time to regulate the output voltage to achieve the regulation. Such power consumption is small, efficiency is about 85%, but the drawback is that the ripple big mutual interference. Therefore, it get rapid development since the 80’s. From the work it can be divided into: ① controlled rectifier. To adjust the output voltage by changing the thyristor conduction time. ② chopper. DC voltage input is unstable, in order to change the circuit switch-off than to be a one-way pulsating DC, and then by post-filtering to ensure a stable DC voltage. ③ converter type. DC voltage instability are first converted into high-frequency AC inverter, through converter and then through the transformer, rectifier, filtered, from the proceeds of the new DC output voltage sampling, control inverter operating frequency again,, reaching a stable DC output voltage purposes.