Requirements for the use of module power supplies in high-voltage power supplies

When designing a high-voltage power supply, it is usually necessary to go through two or more stages of voltage stabilization from the ordinary power supply system to meet the output requirements. And also need to consider power isolation, volume, heat dissipation, reliability and other issues. The range of high-voltage power supply using the module power supply is: filter power conversion circuit, control part (low voltage), high-voltage part generally does not use commercially available high-voltage module power supply, but should be specially designed according to the requirements of transmitter usage parameters.

1. Analysis of power supply input and control circuit

The power input of the high-voltage power supply is composed of two parts, one part is AC power supply, which is usually generated by an on-board or on-board generator. It is usually 400 Hz or 50 Hz, and the voltage is about 115 V or 220 V. The medium and small power high-voltage power supply selects single-phase power supply, and the high-power high-voltage power supply selects three-phase power supply. The other part is the low-voltage DC power supply, which is mainly used for the control part of the high-voltage power supply, such as ±5 V, ±15 V, ±27 V and so on. Generally, the current is small and the power is not high.

In the actual system, the high-voltage power supply obtains power from the system, the AC power supply provides the power source, and the low-voltage DC power supply provides the control use. For the sake of grounding safety, the system usually connects the digital ground, analog ground, cable shielding layer and the chassis ground, and even some low-voltage DC power supply loops are directly connected to the shielding layer or ground. The PWM control part of the high-voltage power supply should be compared with the high-voltage feedback voltage. The required low-voltage DC power supply often needs to be powered separately, and its return line cannot be grounded for isolation. In this way, the low-voltage DC power supply of the system cannot meet the requirements in this case, and the high-voltage power supply cannot use the power supply of the system. Instead, an appropriate DC/DC module power supply must be used in the high-voltage power supply to generate the required isolated low-voltage DC power supply.

2. Analysis of filtering and power conversion circuits

The stability of the high-voltage power supply has high requirements, and the output is often multi-channel power supply, and often the first-level voltage stabilizer cannot meet the stability requirements of the high-voltage power supply well.

During power conversion, the DC power needs to be inverted into high-frequency AC power and sent to the high-voltage transformer. After the AC input is rectified and filtered, the voltage stabilizer module power supply is used to provide DC/DC conversion, which becomes a first-level voltage stabilizer, and then the high-frequency AC power is inverted and sent to the high-voltage transformer for boosting and stabilizing, that is, the second-level voltage stabilizer . In this way, from the ordinary power supply system through two or more stages of voltage stabilization to meet the output requirements.

In addition, the rectification and filtering of the AC input can also be selected with appropriate AC/DC module power supply, filtering or power factor compensation modules and so on.

3. Requirements for use

The module power supply used by the transmitter high-voltage power supply must meet the requirements of the national military standard.

The module power supply must meet the corresponding requirements of high-voltage power supply installation, volume, heat dissipation and weight in terms of appearance and structure, and can withstand the strict environmental stress test of the system.