（1) Advantages of power adapter
Power adapter is a static frequency conversion power supply composed of power semiconductor components. It is a static frequency conversion technology that converts power frequency (50Hz) into intermediate frequency (400Hz ~ 200kHz) through thyristor. It has two frequency conversion modes: AC-DC-AC frequency conversion and AC-AC frequency conversion. Compared with the traditional power generator set, it has the advantages of flexible control mode, large output power, high efficiency, convenient changing operation frequency, low noise, small volume, light weight, simple installation and easy operation and maintenance. It has been widely used in building materials, metallurgy, national defense, railway, petroleum and other industries. The power adapter has high efficiency and variable frequency. The main technologies and advantages of modern power adapter are as follows.
(2) The starting mode of modern power adapter adopts the sweep frequency zero voltage soft start mode in the form of other excitation to self excitation. In the whole starting process, the frequency regulation system and current and voltage regulation closed-loop system track the change of load at all times to realize the ideal soft start. This starting mode has little impact on the thyristor, which is conducive to prolonging the service life of the thyristor. At the same time, it has the advantages of easy start under light and heavy load, Especially when the steel-making furnace is full and cold, it can be easily started.
(3) The control circuit of modern power adapter adopts microprocessor constant power control circuit and inverter Ф The angle automatic adjustment circuit can automatically monitor the changes of voltage, current and frequency at any time during operation, judge the change of load, automatically adjust the matching of load impedance and constant power output, so as to achieve the purpose of time saving, power saving and improving power factor. It has obvious energy saving and less power grid pollution.
(4) The control circuit of modern power adapter is designed by CPLD software. Its program input is completed by computer. It has high pulse accuracy, anti-interference, fast response speed, convenient debugging, and has multiple protection functions such as current cut-off, voltage cut-off, overcurrent, overvoltage, undervoltage and lack of power. Because each circuit component always works within the safe range, the service life of power adapter is greatly improved.
(5) The modern power adapter can automatically judge the phase sequence of three-phase incoming line without distinguishing the phase sequence of a, B and C. the debugging is very convenient.
(6) The circuit boards of modern power adapters are all made by wave crest automatic welding, without false welding. All kinds of regulation systems adopt contactless electronic regulation, with no fault points, extremely low failure rate and extremely convenient operation.
(7) Classification of power adapters
Power adapter can be divided into current type and voltage type according to different filters. The current mode is filtered by DC smoothing reactor, which can obtain relatively straight DC current. The load current is rectangular wave, and the load voltage is approximately sine wave; The voltage type adopts capacitor filtering to obtain a relatively straight DC voltage. The voltage at both ends of the load is a rectangular wave, and the load power supply is approximately a sine wave.
According to the load resonance mode, the power adapter can be divided into parallel resonance type, series resonance type and series parallel resonance type. Current mode is commonly used in parallel and series parallel resonant inverter circuits; Voltage source is mostly used in series resonant inverter circuit.
Post time: Apr-13-2022
