CN104467467A - Scheme for converting microwave energy into direct current during large dynamics - Google Patents

Abstract

The invention discloses a high-efficiency rectification circuit scheme for converting microwave energy into direct current in the process of working under large dynamic power input to overcome the detects that in the prior art, during large dynamic power input, a match circuit is high in design difficulty, low in rectification efficiency and the like. According to the technical scheme, the rectification circuit scheme is characterized by being composed of multiple levels of rectification circuits; each level of rectification circuit is composed of a circulator, a rectifier diode array and a filter circuit; the different levels of rectification circuits can be arranged according to different magnitudes of input power and dynamics. According to one-way channels of the circulators and the characteristic that inversion has high isolation, the scheme that the circulators are applied to the multi-level microwave rectification circuits is put forward for the first time; reflective waves generated by a circuit mismatch is recovered to the next level of circuit by utilizing the characteristic of the one-way channels of the circulators so that rectification can be performed again. According to the scheme, the defects that due to non-linear characteristics of the rectifier diodes, the rectifier diodes present different impedance characteristics during different power inputs, and then an impedance mismatch is caused are overcome; besides, the rectification match circuits are greatly simplified, and high rectification efficiency under the large dynamic power input condition is guaranteed.

Description

A large dynamic microwave energy conversion scheme

technical field

The invention relates to the technical field of microwave transmission energy, in particular to microwave rectifier circuit technology

Background technique

Microwave energy transmission has become an important research direction in the field of new energy. Microwave energy transmission can realize wireless transmission of energy by using microwave as a carrier. Microwave energy transmission technology can be used to realize energy transmission between space solar power stations and ground receiving stations. It can also be used In the field of power supply to space vehicles. As an important part of microwave energy transmission, the rectifier circuit will directly affect the efficiency of the entire microwave energy transmission system. However, the existing technological innovations on the rectifier circuit are almost all aimed at improving the power capacity and improving the rectification efficiency under a certain fixed working state. However, there is no effective way to improve rectification efficiency under large dynamic power input. In the existing rectifier circuit, a matching circuit is required between the rectifier diode and the signal input terminal. The matching circuit matches the input impedance of the diode to 50 ohms at a specific input power to match the signal source so that the reflection is reduced and more energy is fed into the circuit. To improve rectification efficiency. Under a specific input power, although this method can obtain better return loss, since the diode in the rectifier circuit is a nonlinear element, it presents different impedance characteristics under different power input and different operating frequencies. It is difficult to ensure that the matching circuit of a single rectification circuit achieves impedance matching, let alone solve the problem of return loss caused by impedance mismatch when large dynamic power is input. The echo not only wastes a lot of energy and greatly reduces the efficiency of the entire microwave energy transmission system, but if the generated reflected wave is transmitted back to the receiving end and radiated out through the receiving antenna, it will cause serious secondary radiation problems.

Contents of the invention

The main problem to be solved by the present invention is to provide a solution for converting large dynamic microwave energy into direct current, which is suitable for rectifier circuits with different power inputs, in view of the shortcomings of existing rectifier circuits such as complex matching circuit structures. In the traditional rectifier circuit, different impedance characteristics are presented under different power input and different operating frequencies. It is difficult to ensure that the matching circuit of a single rectifier circuit achieves impedance matching, and the receiving circuit part will generate reflected waves due to impedance mismatch, resulting in energy loss. , affecting the rectification efficiency, the multi-stage rectification circuit based on the circulator introduced in the present invention performs secondary rectification on the reflected wave generated by impedance mismatch, which not only solves the problem of secondary radiation of the reflected wave, but also fully recovers the reflected wave to improve rectification efficiency.

The present invention solves described technical problem, and the technical solution that adopts is:

The circulator is connected to the receiving end. The circulator is a multi-port device, in which the transmission of electromagnetic waves can only circulate in one direction, and the opposite direction has high isolation. As shown in Figure 1, port ① of the circulator is used as the input terminal, port ② is the input terminal of the first stage, this terminal is connected to the rectifier circuit, and port ③ is connected to the second stage rectifier circuit. Different stages can be set according to different circuit requirements. When the number of stages is increased, the circulator port ③ can be connected to the next circulator, and connected to the rectifier circuit and the next rectifier circuit in turn.

According to the working principle of the circulator, the present invention utilizes the one-way channel characteristic of the circulator, and proposes to use the circulator in the rectification circuit for the first time. A large part of the reason for the low rectification efficiency in traditional rectification circuits is that the incoming energy cannot be fully utilized. In traditional technology, when the rectifier circuit receives different power signals, due to the nonlinear characteristics of the diode, the rectifier circuit will inevitably generate reflected waves due to impedance mismatch due to power changes. In the traditional rectifier circuit, the reflected waves are directly transmitted to the input Re-radiation at the end will affect the efficiency of the entire rectification system. Even if some existing technologies connect filters to the front end of the diode, they cannot isolate the reflected waves, let alone make full use of them, resulting in energy waste. In the present invention, the access of the circulator can not only effectively suppress the occurrence of this phenomenon, but also recover the transmitted wave to the next port of the circulator for secondary rectification, which can not only change the reflected wave and higher harmonic The impact on the entire circuit can improve the utilization rate of energy and the conversion rate of the rectifier circuit.

The present invention has strong transformability. A new multi-stage rectifier circuit proposed by the present invention can meet different circuit requirements. When the circuit is in the state of low power and small dynamic input, only one circulator can be selected, and only one-stage circuit can be used to connect to the matching circuit. High-efficiency rectification can be realized with a simple structure. When the circuit needs to work in a high-power state, several circulators can be selected to design different stages to improve the upper power limit and rectification efficiency of the circuit. And different numbers of circulators are connected according to different circuit requirements.

Description of drawings

Fig. 1 is the schematic diagram of the scheme of converting large dynamic microwave energy into direct current of the present invention

Fig. 2 is the schematic diagram of the circuit applicable to lower power and input frequency variation of the present invention

Fig. 3 is the principle diagram of the multi-stage rectification circuit suitable for high power and large dynamic input of the present invention

Detailed ways

The working principle and connection structure of the present invention will be described in detail below in conjunction with the accompanying drawings and specific examples.

Implementation example 1

This example is an illustration of the application of the invention as it applies to lower power, varying input frequencies. When the input power is low and the input frequency changes, only one circulator, several rectifier diodes, and several filter capacitors are needed to form a rectification circuit with simple structure and high efficiency.

As shown in Figure 2, this example combines the large dynamic input energy recovery rectification technical solution of the present invention with the traditional rectification circuit, which saves the matching circuit part of the rectification system, and can improve the defects of the traditional rectification circuit with complex structure and low efficiency. This circuit adopts a circulator, a rectifier diode array composed of four diodes and a rectifier circuit in series with two diodes. When the current is rectified by the first-stage rectifier circuit, the port ③ of the circulator recovers the reflected wave for secondary rectification. . This circuit not only prevents the reflected wave from flowing back to the input end without the need of a matching circuit, but also recovers the reflected wave to the rectification circuit connected to the next port of the circulator for further full rectification.

Implementation example 2

This example is a concrete introduction of applying the present invention to higher power input. As shown in FIG. 3 , it is a schematic diagram of the rectification circuit of the present invention applied to multi-stage energy recovery with large dynamic input, which includes a circulator, rectifier diode arrays at various levels, and also includes a filter circuit and a DC load. This example takes a three-port circulator as an example, and the number of stages is selected as three for introduction.

The first-stage rectification circuit includes a circulator M1, a rectification diode array D1 and filter capacitors C1 and C2. Since the first-stage circuit is required to be able to withstand higher power input, the selected diode array contains eight diodes. At this time, the highest power that the branch circuit can withstand is eight times that of a single diode. When receiving high-power AC signals After the AC signal passes through the diode array D1, most of the AC power is converted into DC power, and some high-order harmonics are filtered out by the filter capacitor C2. The reflected wave caused by the nonlinearity of the diode will be input to the next stage circuit for secondary rectification. The function of the filter capacitor C1 is to isolate the direct current and prevent the direct current rectified by the diode from entering the circulator M1.

The second-stage rectification circuit includes a circulator M2, a rectification diode array D2, and filter capacitors C3 and C4. This stage circuit is a second stage rectification circuit, so only a diode array composed of 4 diodes is required for rectification. After receiving the current signal from the first-stage circuit, the circulator M2 transmits it to port ② and connects to the second-stage rectification circuit for rectification. The high-order harmonics generated by this stage are filtered by the filter capacitor C4, and finally the reflected waves generated in this stage are transmitted to the next stage of rectification circuit. The function of the filter capacitor C3 is to isolate the direct current and prevent the direct current rectified by the diode from entering the circulator M2.

The third-stage rectification circuit includes a circulator M3, a rectification diode array D3, and filter circuits C5 and C6. After the first two stages of circuits, the unrectified signal is not strong. Two diode arrays can be used in this stage to achieve full rectification. After rectification, a stable DC signal can be obtained by filtering through the filter capacitor C6. The third port of the circulator M3 is connected to a single diode D4 and a filter capacitor C8 for final energy rectification and rectification, and finally the rectified DC power of each stage is sent in parallel to the DC load. The function of the filter capacitors C5 and C7 is to isolate the direct current and prevent the direct current rectified by the diode from entering the circulator.

The above examples are only to illustrate the idea of the present invention, and the number of rectification stages can also be increased or decreased according to specific circuit operating conditions, and the number of diodes in the rectifier diode can be increased or decreased.

Claims (6)

1. A large dynamic microwave energy conversion to direct current scheme is a multi-stage energy rectification recovery scheme, characterized in that the scheme is composed of multi-stage energy recovery rectification circuits, and each stage rectification circuit converts the impedance of the previous stage circuit The energy of the reflected wave caused by the mismatch is recovered and rectified again. 2. The multi-stage energy rectification and recovery scheme according to claim 1, characterized in that, the energy recovery circuit scheme of this level is composed of N-level branch rectification circuits. N is determined by the size of the input power and the dynamic range, the greater the power input or the greater the power dynamics, the greater the N should be (N≥1). 3. The branch rectification circuit according to claim 2, wherein each stage of rectification circuit is composed of a circulator, a rectification diode array, and a filter circuit. 4. The rectifier circuit according to claim 3, wherein the circulator is a three-port unidirectional transmission device, and any one of the three ports can be selected as the initial port ①, and the ports are sequentially along the transmission direction ②, ③, the transmission direction of the circulator is along the fixed direction ①→②→③→①. The circulator is set at the input end of each stage circuit, and the port ① is connected with the input end, the port ② is connected with the rectification circuit, and the port ③ is connected with the input end of the secondary rectification circuit. 5. The rectifying circuit according to claim 3, wherein, in the rectifying diode array, the number of rectifying diodes in each stage circuit is different, and the number of diodes in each stage of rectifying diode array is set according to different power inputs, and The number of diodes decreases step by step. 6. The scheme for converting large dynamic microwave energy into DC according to claim 1, characterized in that, each stage of the multi-stage circuit has a DC output, and the output terminal connects the DC outputs of N stages in parallel and transmits them to the load.