Power saving solution based on energy recycling

The development of modern electronics industry has promoted the development of power supply industry. Any electronic equipment cannot do without power supply of various precisions. Power converter can convert various voltages into voltages required by users, such as power transformer can convert the transmitted kilovolt high voltage AC power into normal city power; various chargers, as well as industrial and communication power supply modules, can convert AC or DC voltage into DC or AC voltage required by users. Such equipment is power converter that provides power conversion. Compared with signal-level converters, power converters have much greater power, ranging from a few watts to tens of kilowatts, and their work is accompanied by huge energy conversion.

In the production process of power supply equipment, routine testing and aging of power supply equipment is a necessary part of equipment inspection, which can improve the reliability of power supply equipment and reduce the rework and warranty costs of the factory. However, due to the aging of equipment, the power consumption cost of production is also increased. Usually, the routine aging of equipment is to connect the equipment to a simulated load for simulated work. Of course, energy is consumed on the simulated load, and this consumption is usually not optimally utilized. Based on the characteristics of power converters that convert electrical energy into different levels of electrical energy, this article proposes to achieve the recycling of most of the energy through energy feedback, thereby achieving the purpose of energy saving. How to save energy and reduce energy consumption is a goal that people have always pursued. Today, in the construction of a conservation-oriented society, the significance of energy saving and consumption reduction is even more important.

How it works

The power converter can process electrical energy into the required electrical energy. Its routine aging use only requires connecting a suitable resistance load or an electrical device with equivalent impedance to the output end of the power converter to ensure that it works under a certain load. As shown in Figure 1: The input voltage Vin is converted by the power converter to Vout and added to the resistance load. During routine operation, the power consumed by the power converter (loss during conversion is not calculated) is Po="Vout2"/R1.

Figure 1 Schematic diagram of converter operation

In this case, the consumed electrical energy is not utilized at all, but directly converted into heat energy and dissipated from the resistive load, which is a serious waste of electrical energy.

To achieve energy conservation and recycling, the main consideration is to make more reasonable use of the energy consumed in the resistance load. If the output voltage Vout can be restored to the input voltage Vin, the output electric energy is converted into the input electric energy, and the recycling of electric energy can be achieved, as shown in Figure 2: the resistance load R1 of the original converter is replaced by the converter 2 with equivalent input impedance, and the output of converter 2 is connected to the input of converter 1. Then the energy consumed by converter 2 with equivalent input impedance to R1 from the output end of converter 1 is converted to the input end of converter 1, and then to the input end of converter 2 through converter 1, realizing the recycling of energy. If there is no conversion loss in an ideal situation, the system can work in a self-circulating manner. Of course, this is impossible to achieve, so the consumption of the conversion process should be introduced in energy analysis.

Figure 2 Schematic diagram of converter energy cycle

The energy consumption in the above two working modes is analyzed as follows:

The first working mode is when there is no energy circulation, Pi is the input energy of the converter, Pw is the energy consumed by the converter during the conversion process, and Po is the output energy consumed by the converter on the resistive load. Assuming that the conversion efficiency of the converter is 80%, the energy consumed by the converter during the conversion process can be set to Pw=25%Po, then the overall total energy consumption is the input energy of the converter Pi=Po+Pw=1.25Po.

The second working mode is to introduce energy feedback, and the energy conversion is shown in Figure 3: converter 1 is a power converter that needs to be used routinely, converter 2 is a converter used for energy feedback, Pi is the input energy from the outside of the system to converter 1, Pw is the energy consumed during the conversion process of converter 1, Po is the energy that the power converter 1 should normally output for routine use, and it is also the input energy of converter 2; Pwf is the energy consumed during the conversion process of converter 2 used for energy feedback, and Pf is the energy fed back to the power converter 1 by converter 2.

Assume Power Converter 1 and converter 2 have conversion efficiencies of 80%, then converter 1 consumes the same energy as mode 1: Pw=25%Po, and converter 2 consumes the same energy as mode 1: Pw=25%Po. Based on the conversion efficiency of the converter, converter 2 consumes the same energy as mode 1: Pwf=20%Po. According to the law of conservation of energy, the total energy consumption is: Pi=Pw+Pwf=25%Po+20%Po=45%Po.

From the above two modes, the energy consumption analysis can conclude that when the working mode with energy feedback is used for routine aging, the energy consumed is only 0.45 of the working energy. Compared with routine aging without energy feedback, the total energy consumption is 1.25 times the working energy. Therefore, the routine aging use mode with energy feedback saves energy.

System Implementation

From the analysis of the above two working modes, it is possible to use energy feedback to form an energy circulation system to reduce energy consumption. The system operation can be illustrated in Figure 4, which includes three parts:

Figure 4 Schematic diagram of energy feedback system implementation

a) Power supply part, providing external excitation source for the system;

b) The converter part is a power supply device that needs routine aging, which converts the input power voltage into the required output voltage;

c) The energy feedback part can convert the output voltage of the converter into the input voltage of the converter.

The energy feedback part and the converter that needs routine trial form an energy circulation system. Under the stimulation of the external power supply, the system maintains rated power operation. According to the power formula P=U*I, U is stabilized by the power converter that is routinely aged. To ensure the rated power, it is necessary to ensure the output current I, that is, the energy feedback part is designed as a constant current circuit . Therefore, the equivalent control quantity that ensures the stable operation of the energy cycle under the rated power is the output current of the power converter that needs routine use.