Direct current power supply

Abstract

The invention discloses a direct current power supply, which comprises a rectifying unit, an inverter unit, an output rectifying unit, a detection unit and a DSP processor, wherein the detection unit is arranged at the downstream of the output rectifying unit to detect a voltage transmitted by an output filter unit to a load and transmits a detected value to the DSP processor; and the DSP processor is arranged between the detection unit and the inverter unit to output a corresponding PWM control signal according to the detected value of the voltage of the load and an expected value input in advance of the load to the inverter unit to control the on and off of a switch element in the inverter unit and to adjust the dutyfactor of the switch element in the inverter unit to adjust the output voltage of the inverter unit to allow to the detected value of the load to approach the expected value of the voltage of the load. The output voltage of the direct current power supply is high in quality and small in harmonic content and interference, so the direct current power supply meets the electricity use requirements of precise instruments and effectively avoids damages to the precise instruments caused by power supply quality.

Description

technical field [0001] The present invention relates to the field of electronic technology, in particular to a DC power supply. Background technique [0002] As we all know, some precision instruments are often set or configured in semiconductor equipment, such as high vacuum gauges and mass flow meters (MFC, Mass Flow Controller). These precision instruments are usually powered by a DC power source. At present, DC power supply can be divided into linear power supply and switching power supply according to its basic working principle. [0003] Among them, such as figure 1 As shown, the linear power supply mainly includes a power frequency transformer, an output rectification filter, a control circuit (not shown in the figure) and a protection circuit (not shown in the figure). Usually, the working process of a linear power supply is as follows: the input AC power is first transformed by a power frequency transformer, and then rectified and filtered by an output rectifier ...

AI Technical Summary

Problems solved by technology

However, in practical applications, it has such disadvantages: first, due to the large size of the filter capacitor and transformer in the rectifier circuit, the entire power supply is bulky and heavy; second, the voltage feedback circuit in the linear power supply usually works In the linear state, there is a certain voltage drop on the adjustment tube, which leads to a certain power consumption. Especially when outputting a large operating current, the power consumption of the adjustment tube is usually large, resulting in low conversion efficiency and high power consumption. Resulting in more heat generated, which requires the installation of a large heat sink

[0011] In practical applications, although this kind of DC power supply can reduce the ripple and improve the quality of the output voltage, it still has such shortcomings: that is, the DC power supply provided by the prior art adopts an open-loop control method, That is to say, the signal flows in one direction. Specifically, the power signal is directly output to loads such as precision instruments after being input to the rectifier circuit --- converter --- output rectifier circuit --- output filter circuit

However, each link in the above-mentioned open-loop control process may generate power loss, especially the power loss of the filter circuit itself. Therefore, controlling the output of the DC power supply only according to the pre-input expected value will lead to the loss of the DC power supply. There is a large deviation between the actual output value and its expected value, in other words, there will be a large deviation between the voltage output to the load such as a precision instrument and its expected value, so that the DC power supply still has a large ripple, and the output The voltage accuracy is low, which will affect the work of the load because the expected working voltage cannot be obtained, and even cause damage to the load

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