A Class-E amplifier multi-channel direct power synthesis circuit based on a resonant network

Abstract

The present invention discloses a multi-channel direct power combining circuit for class-E amplifier based on a resonant network. First, the AC component and high-order harmonics of the input current are removed by a voltage regulation unit, and at the same time, the switching tube is made to operate under ZVS conditions by the method of connecting a parallel capacitor to the switching tube. Then, the input current is shaped and filtered through an LC series resonant circuit to make the output sinusoidal. Next, an improved class-E power amplifier circuit is formed by combining a single-channel voltage regulation unit and a single-channel LC resonant unit, which is the implementation process of a single-channel class-E power amplifier. Finally, multiple single-channel class-E power amplifiers are connected in parallel through a power combining unit to finally realize the combined amplification of power.

Description

Technical Field

[0001] The present invention belongs to the technical field of radio frequency power supplies, and more specifically, relates to a multi-channel direct power combining circuit of class-E amplifiers based on a resonant network. Background Art

[0002] When radio frequency power supplies are in practical applications, it is required that the radio frequency power supply system has a high operating frequency, a strong power output, and can drive a load within a certain range of variations. As a high-efficiency power amplifier, the class-E power amplifier has the advantages of low energy consumption, simple structure, strong designability, and high practicality. The class-E amplifier is mainly designed based on the principle that the current and voltage of the switching transistor do not appear simultaneously.

[0003] Although the class-E power amplifier has high efficiency and a simple structure, its single-channel output power is not high. In order to increase the output power of the radio frequency power supply system, a certain power combining method is adopted to achieve the combination of multi-channel power outputs. Currently, the output combination of traditional class-E power amplifiers mainly uses transformers.

[0004] As Figure 1 shown, one type of traditional power combining is a power combining method based on voltage. The outputs of two class-E power amplifiers with equal amplitudes and a phase difference of half a cycle are connected to the corresponding ports of two balun transformers, thereby achieving the combination of the outputs. The total output voltage amplitude of this power combining circuit is 4 times that of the single-channel input voltage, and the output current is 0.5 times that of the single-channel input. Assuming that the single-channel output impedance is all R L , then after combination, the output circuit impedance should be modified to 8R of the original value L .

[0005] As Figure 2 shown, another type of traditional power combining is a power combining method based on current. This method increases the output power level by amplifying the output current amount. The circuit used in this method uses a single balun transformer to connect the outputs of two class-E amplifiers, such that the output voltage of the combining circuit is the same as the single-channel output voltage, the output current is twice the corresponding value, and the output impedance should be modified to 0.5R of the corresponding single-channel impedance L .

[0006] In summary, compared with the two traditional power combining circuits and the multi-channel direct power combining circuit of class-E amplifiers based on a resonant network of the present invention, as shown in Table 1:

[0007] Synthesis technology Number of synthesizable paths Output voltage Output current Impedance relationship Based on voltage <![CDATA[2 n road]]> <![CDATA[4 n times]]> <![CDATA[1 / 2 n times]]> <![CDATA[8 n > Based on current <![CDATA[2 n road]]> 1 times <![CDATA[2 n times]]> <![CDATA[1 / 2 n times]]>

[0008] Table 1

[0009] As can be seen from the table, the traditional methods can only combine 2 n channels, and cannot combine signals of any number of channels, especially the combination of odd-numbered channel signals such as 3, 5, 7, etc. Summary of the Invention

[0010] The object of the present invention is to overcome the deficiencies of the prior art and provide a multi-channel direct power synthesis circuit for class-E amplifiers based on a resonant network. By replacing the transformer with an LC resonant unit, power synthesis of class-E power amplifiers with any number of channels can be achieved without adding a transformer.

[0011] To achieve the above object of the invention, a multi-channel direct power synthesis circuit for class-E amplifiers based on a resonant network of the present invention is characterized by comprising: a voltage regulation module, an LC resonance module, and a power synthesis unit;

[0012] The input end of the voltage regulation module is connected to the power supply V, and the output end is connected to the LC resonance module; the voltage regulation module is composed of n parallel voltage regulation units, and each voltage regulation unit specifically includes a choke coil L f , a switching tube circuit, and an LC series resonance circuit; the switching tube circuit is composed of a switching tube S and a capacitor C p connected in parallel therewith; the LC series resonance circuit is composed of a capacitor C s and an inductor L s connected in series;

[0013] Among them, the power supply V inputs the input current to the voltage regulation module through the choke coil L f , filters out the radio frequency current part in the input current through the choke coil L f , and then inputs the current to the collector of the switching tube. With the help of the parallel capacitor C p , the switching tube is enabled to operate under the zero voltage switching (ZVS) condition, and then the current is input to the LC series resonance circuit to realize shaping and filtering of the input current, so that the output is sinusoidal;

[0014] The input end of the LC resonance module is connected to the LC series resonance circuit in the voltage regulation module, and the output end is connected to the power synthesis unit; the LC resonance module is composed of n parallel LC resonance units, and each LC resonance unit further includes inductors L ext , L COM connected in series and a capacitor C COM ; a single-channel voltage regulation unit and a single-channel LC resonance unit form an improved class-E power amplification circuit;

[0015] The power synthesis unit is connected to a pure resistance load R L or a load equivalent to a pure resistance load R at the switching frequency point composed of a resistor, a capacitor, and an inductor network L ; its input end is connected to the output of a multi-channel improved class-E power synthesis circuit, and then is combined and amplified through the power synthesis unit for output.

[0016] The object of the present invention is achieved as follows:

[0017] The multi-channel direct power synthesis circuit of the class-E amplifier based on the resonant network of the present invention first eliminates the AC components and high-order harmonics of the input current through the voltage regulation unit, and at the same time makes the switching tube work under the ZVS condition by the method of connecting a parallel capacitor to the switching tube. Then, the input current is shaped and filtered through the LC series resonant circuit to make the output sinusoidal. Next, an improved class-E power amplifier circuit is formed by combining a single-channel voltage regulation unit and a single-channel LC resonant unit, which is the implementation process of the single-channel class-E power amplifier. Finally, multiple single-channel class-E power amplifiers are connected in parallel through the power synthesis unit to finally realize the synthesis and amplification of power.

[0018] At the same time, the multi-channel direct power synthesis circuit of the class-E power amplifier based on the resonant network of the present invention also has the following beneficial effects.

[0019] (1) Compared with the traditional power synthesis method, the present invention cancels the transformer in the traditional class-E power amplifier and replaces the transformer with the LC resonant unit, reducing the loss of the circuit.

[0020] (2) The power synthesis unit uses the LC resonant unit to form an improved class-E power amplifier circuit, so that when multiple class-E power synthesis circuits are connected in parallel, the mutual influence of the additional inductors of the class-E power amplifier (destroying the soft-switching working condition of the class-E power amplifier) can be offset, and the parallel connection of any number of class-E power amplifier circuits can be realized.

[0021] (3) An LC resonant circuit unit is added to the synthesis circuit, and the load end can be grounded. When n parallel improved class-E power synthesis circuits are connected in parallel, the load voltage is still equal to the single-channel voltage, its voltage remains unchanged, and the current increases. For the single-channel improved class-E power synthesis circuit, the load resistance is reduced.

[0022] (4) With the help of the parallel capacitor, the switching tube works under the zero-voltage switching (ZVS) condition. The working principle is as follows: Before the switching tube is turned off, it is in the conducting state, its current is i s , and the voltage is 0. When the switching tube is turned off, its current i s gradually decreases until it becomes 0. During this process, the voltage of the parallel capacitor C p does not change suddenly and still remains 0 until the switching tube is completely turned off. The input current charges the parallel capacitor, causing its voltage to rise. Therefore, the voltage and current of the switching tube do not appear simultaneously, reducing the loss of the switching tube and realizing the high-efficiency operation of the class-E power amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a traditional power synthesis circuit diagram based on voltage;

[0024] Figure 2 is a traditional power combining circuit diagram based on current;

[0025] Figure 3 is the schematic diagram of the Class - E amplifier multi - path direct power combining circuit based on the resonant network of the present invention;

[0026] Figure 4 is the circuit diagram of the 3 - path direct power combining of the Class - E amplifier based on the resonant network of the present invention. Detailed implementation manners

[0027] The following describes the detailed implementation manners of the present invention with reference to the accompanying drawings so that those skilled in the art can better understand the present invention. It should be particularly noted that in the following description, when the detailed description of known functions and designs may dilute the main content of the present invention, these descriptions will be omitted here.

[0028] Embodiment

[0029] Figure 3 is the circuit diagram of the 3 - path direct power combining of the Class - E amplifier based on the resonant network of the present invention.

[0030] In this embodiment, as Figure 1 shown, a multi - path direct power combining circuit of a Class - E amplifier based on a resonant network according to the present invention is characterized by comprising: a voltage regulation module, an LC resonance module, and a power combining unit;

[0031] The input end of the voltage regulation module is connected to the power supply V, and the output end is connected to the LC resonance module; the voltage regulation module is composed of n parallel - connected voltage regulation units, and each voltage regulation unit specifically includes a choke coil L f , a switching tube circuit, and an LC series resonance circuit; the switching tube circuit is composed of a switching tube S and a capacitor C p connected in parallel therewith; the LC series resonance circuit N1 is composed of a capacitor C s and an inductor L s connected in series;

[0032] Among them, the power supply V inputs the input current to the voltage regulation module through the choke coil L f , filters out the radio - frequency current part in the input current through the choke coil L f , and then inputs the current to the collector of the switching tube. With the help of the parallel - connected capacitor C p , the switching tube works under the ZVS condition, and then the current is input to the LC series resonance circuit to realize the shaping and filtering of the input current, so that the output is sinusoidal;

[0033] In this embodiment, the switching device preferably uses a gallium nitride switching device made of third-generation semiconductor materials. However, the present invention is not limited to the type of switching device, and other solid-state switching devices can also be used.

[0034] The input end of the LC resonance module is connected to the LC series resonance circuit in the voltage regulation module, and the output end is connected to the power combining unit; the LC resonance module is composed of n parallel LC resonance units, and each LC resonance unit N2 further includes a series-connected inductor L ext 、L COM and a capacitor C COM ; A single-channel voltage regulation unit and a single-channel LC resonance unit form an improved class-E power amplifier circuit;

[0035] In this embodiment, in order to meet the resonance requirements and the operating requirements of the class-E power amplifier, the device selection of the LC resonance unit N2 should meet the following conditions:

[0036] 1), The capacitor C COM resonates with the series-connected inductors L ext 、L COM at the switching frequency point of the voltage regulation unit, that is, it satisfies

[0037] 2) The capacitor C COM is connected in parallel with a pure resistance load R L , and then the network formed by being connected in series with the inductor L COM is equivalent to a pure resistance R eq at the switching frequency point. The equivalent impedance expressed from the N1 port looking towards the load end is: Z eq =R eq +jwL ext =R eq +j1.152 R eq ;

[0038] And the LC series resonance circuit satisfies the following conditions:

[0039] 1), The inductor L s and the capacitor C s resonate at the switching frequency point;

[0040] 2), The quality factor of the series network composed of the inductor L s , the capacitor C s and the equivalent pure resistance R eq is between 5 and 10.

[0041] The power combining unit is connected to a pure resistance load R L or a load equivalent to a pure resistance load R L at the switching frequency point and composed of a resistor, capacitor, and inductor network.; Its input terminal is connected to the output of a multi-channel improved class-E power combining circuit, and then is combined and amplified through a power combining unit for output.

[0042] In this embodiment, taking 3-way direct power combination as an example for analysis and explanation, as Figure 3 shown, the direct combination of the power of the class-E power amplifier is achieved by adding an LC resonance network, and this resonance network is connected between the inductor L ext and the load resistor R L . According to the superposition principle, when the first path is working, the inputs of the second and third paths are grounded. N3 and N4 in the second path and N5 and N6 in the third path are equivalent to the loads of the first path input. According to the circuit parameter design of the present invention, the L s , C s in the N3 and N5 circuits generate resonance, and the C COM and L ext , L COM in N4 and N6 generate resonance, thus eliminating the influence of the inductors of the second and third paths on the inductor and the load of the first path. At this time, the load voltage is V out1 , and the output current is i out1 ; when the second path is working, the inputs of the first and third paths are grounded. At this time, N1, N2, N3, and N4 in the input circuits of the first and second paths are equivalent to the loads of the second path input. At this time, the L s , C s in the N1 and N3 circuits generate resonance, and the C COM and L ext , L COM in the N2 and N4 circuits generate resonance. At this time, the load output voltage is V out2 , and the output current is i out2 ; similarly, it can be obtained that when the third path is working, its output load voltage is V out3 , and the output current is i out3 . Since the 3 paths of circuits are in parallel and their inputs are equal, the output voltage V out and the output current i out of the power combining circuit of the 3-way class-E power amplifier are respectively:

[0043] V out = V out1 = V out2 = V out3

[0044] i out = i out1 = i out2 = i out3

[0045] When wanting to combine and increase the number of paths of the class-E power amplifier, only need to adjust the L of the LC network of the increased path COMand C COM The connection point is connected to the original circuit. Since the load R increases with the increase in the number of circuits L The current increases by one path and the voltage remains unchanged. For the load resistance of a single-channel class-E power amplifier, it decreases. Here, the load resistance synthesis coefficient k is introduced. When the number of synthesized paths is 1, the load resistance is R L , when the number of paths increases to k, the load resistance is:

[0046] R kL = kR L k = 1, 2, …, n

[0047] Furthermore, since the present invention uses a resonant power grid to replace the traditional power synthesis using a balun transformer, one end of the load resistance can be directly grounded.

[0048] Finally, compared with two traditional power synthesis circuits and the class-E amplifier multi-channel direct power synthesis circuit based on a resonant network of the present invention, as shown in Table 2

[0049] Synthesis technology Number of synthesizable paths Output voltage Output current Based on voltage <![CDATA[2 n road]]> <![CDATA[4 n times]]> <![CDATA[1 / 2 n times]]> Based on current <![CDATA[2 n road]]> 1 times <![CDATA[2 n times]]> Based on the resonant network k paths 1 times k times

[0050] Table 2

[0051] It can be seen from the comparison in Table 2 that compared with the traditional power synthesis method which can only achieve power synthesis of 2 n paths, the power synthesis circuit of the present invention can achieve power synthesis of any number of paths. The multiple of the power synthesis output is proportional to the number of synthesized paths, and the selection of the load resistance is also more free.

[0052] Although the above describes the illustrative specific embodiments of the present invention for the understanding of those skilled in the art of the present technology, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art of the present technology, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions made using the concept of the present invention are within the scope of protection.

Claims

1. A class-E amplifier multi-channel direct power synthesis circuit based on a resonant network, characterized in that, including: a voltage regulation module, an LC resonance module and a power combining unit; The input end of the voltage regulation module is connected to the power supply V, and the output end is connected to the LC resonance module; the voltage regulation module is composed of n parallel-connected voltage regulation units, and each voltage regulation unit specifically includes a choke coil L f , a switching tube circuit and an LC series resonance circuit; The switching transistor circuit consists of a switching transistor S and a capacitor C connected in parallel therewith p ; The LC series resonance circuit consists of a capacitor C s and an inductor L s connected in series; Among them, the power supply V passes the input current through the choke coil L f and inputs it to the voltage regulation module. Through the choke coil L f the radio frequency current part in the input current is filtered out, and then the current is input to the collector of the switching transistor. With the help of the parallel capacitor C p the switching transistor is enabled to operate under the zero voltage switching (ZVS) condition, and then the current is input to the LC series resonance circuit to shape and filter the input current, so that the output is sinusoidal; The input end of the LC resonance module is connected to the LC series resonance circuit in the voltage regulation module, and the output end is connected to the power combining unit; the LC resonance module is composed of n parallel LC resonance units, and each LC resonance unit further includes inductors L ext , L COM and capacitor C COM ; The single-channel voltage regulation unit and the single-channel LC resonance unit form an improved class-E power amplifier circuit; The power combining unit is connected to a pure resistive load R L or a load equivalent to a pure resistive load R at the switching frequency point, which is composed of a resistor, a capacitor and an inductor network L ; its input terminal is connected to the outputs of multiple improved class-E power combining circuits, and then the power is combined and amplified by the power combining unit for output 2. The multi-channel direct power combining circuit of the class-E amplifier based on a resonant network according to claim 1, characterized in that, the LC resonance unit satisfies the following conditions: 1), capacitor C COM is in resonance with the series inductor L ext , L COM at the switching frequency point of the voltage regulating unit; 2) Capacitor C COM and the pure resistance load R L are in parallel, and then in series with the inductor L COM The network formed is equivalent to a pure resistance R at the switching frequency point eq .

3. The multi-channel direct power combining circuit of the class-E amplifier based on a resonant network according to claim 1, characterized in that, the LC series resonance circuit satisfies the following conditions: 1), Inductor L s and capacitor C s resonate at the switching frequency point; 2), Inductor L s , Capacitor C s and equivalent pure resistance R eq The quality factor of the series network composed of them is between 5 and 10.

4. The multi-channel direct power combining circuit of class-E amplifier based on resonant network according to claim 1, characterized in that, The pure resistive load R L has one end that can be directly grounded.

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