阅读说明：本技术 一种大功率射频功率源输出功率线性控制系统和方法 (High-power radio frequency power source output power linear control system and method ) 是由 舒先来 刘智民 谢亚红 蒋才超 潘军军 陈世勇 刘胜 崔庆龙 谢远来 于 2021-06-29 设计创作，主要内容包括：本发明涉及一种大功率射频功率源输出功率线性控制系统和方法,所述系统包括射频信号产生单元、射频功放模块组、功率合成单元、控制信号源、信号处理单元、功率控制单元；射频功放模块组的每个射频功放模块连接至功率合成单元中功率合成变压器的初级；功率合成单元对各个射频功放模块的功率进行合成输出；控制信号源是给定的用于控制输出功率的模拟电压信号；所述功率控制单元根据信号处理单元得到的数字信号,通过协同调整功率模块数量以及供电单元电压控制射频功放模块组的功率输出。本发明实现了模拟信号对射频功率源输出功率的线性控制,保证了输出功率的线性叠加,从根本上解决了功率调节精度下降的问题,提高了在高功率输出条件下的功率调节精度。(The invention relates to a high-power radio frequency power source output power linear control system and a method, wherein the system comprises a radio frequency signal generating unit, a radio frequency power amplifier module group, a power synthesizing unit, a control signal source, a signal processing unit and a power control unit; each radio frequency power amplifier module of the radio frequency power amplifier module group is connected to the primary of a power synthesis transformer in the power synthesis unit; the power synthesis unit synthesizes and outputs the power of each radio frequency power amplification module; the control signal source is a given analog voltage signal for controlling the output power; and the power control unit controls the power output of the radio frequency power amplifier module group by cooperatively adjusting the number of the power modules and the voltage of the power supply unit according to the digital signal obtained by the signal processing unit. The invention realizes the linear control of the output power of the radio frequency power source by the analog signal, ensures the linear superposition of the output power, fundamentally solves the problem of the reduction of the power regulation precision and improves the power regulation precision under the condition of high power output.)

1. A high-power radio frequency power source output power linear control system is used for realizing the linear control of the output power of a radio frequency power source by analog signals, and is characterized in that: the system comprises a radio frequency signal generating unit, a radio frequency power amplifier module group, a power synthesizing unit, a control signal source, a signal processing unit and a power control unit;

the radio frequency signal generating unit is a high-power all-solid-state radio frequency power source radio frequency channel, and a radio frequency signal generated by the radio frequency channel is used as an input signal of the radio frequency power amplifier module group;

the radio frequency power amplifier module group comprises a plurality of identical radio frequency power amplifier modules, each radio frequency power amplifier module generates corresponding radio frequency power according to the change of load equivalent impedance of the radio frequency power amplifier module, and the on or off of the radio frequency power amplifier module can be determined through a control signal; each radio frequency power amplifier module is connected to the primary of a power synthesis transformer in the power synthesis unit;

the power synthesis unit synthesizes and outputs the power of each radio frequency power amplifier module by using a power synthesis transformer, and is provided with a corresponding impedance matching and filtering circuit;

the control signal source is a given analog voltage signal for controlling output power;

the signal processing unit is used for preprocessing an input control signal and outputting a digital signal;

and the power control unit controls the power output of the radio frequency power amplifier module group by cooperatively adjusting the number of the power modules and the voltage of the power supply unit according to the digital signal obtained by the signal processing unit.

2. The linear control system for output power of high power rf power source as claimed in claim 1, wherein: the signal processing unit comprises a voltage conversion circuit and a digital-to-analog conversion circuit, wherein:

the voltage conversion circuit converts the signal into a voltage domain required by the AD conversion module;

the digital-to-analog conversion circuit converts the analog control signal into a digital signal.

3. The linear control system for output power of high power rf power source as claimed in claim 1, wherein: the power control unit comprises an enabling unit and a power supply unit, and enables and adjusts the power supply according to the digital signal obtained by the signal processing unit, wherein:

the enabling unit controls the on-off of each radio frequency power amplifier module according to the number of the radio frequency power amplifier modules needing to be opened currently;

the power supply unit adjusts the continuous adjustable direct current power supply for supplying power to each radio frequency power amplifier module to adjust the output power of the modules.

4. The linear control system for output power of high power RF power source as claimed in claim 3, wherein: the enabling unit is realized by adopting a scheme of controller I/O expansion, I2C communication is adopted, and a plurality of I/O expansion chips are mounted on an I/O bus.

5. The linear control system for output power of high power RF power source as claimed in claim 3, wherein: the power supply unit needs to realize power control of the radio frequency power amplifier module: and adjusting the output voltage of the power supply according to the number of the opening modules, wherein the voltage control adopts various modes including a USB (universal serial bus), a CAN (controller area network) bus, a digital I/O (input/output) port, a GPIB (general purpose interface bus) and an analog quantity.

6. A method for linear control of output power of a high power rf power source using the system of any one of claims 1-5, characterized by: the power control circuit performs enabling control and power supply voltage adjustment of the number of the radio frequency power amplifier modules according to the digital signals obtained by the signal processing unit to realize power linear control, and the method specifically comprises the following steps:

(1) confirming rated output power of radio frequency power sourceRate P₀And the number N of the radio frequency power amplifier modules which are opened under the rated output power₀；

(2) According to P₀And N₀Obtaining the power P generated by each radio frequency power amplifier module under the rated power;

(3) obtaining corresponding output power P according to the digital signal obtained by the signal processing unit_m；

(4) According to the formula:

calculating to obtain the number m of the radio frequency power amplification modules to be opened;

(5) according to the formula:

calculating to obtain a power supply voltage U of the radio frequency power amplifier module, wherein n is the ratio of the primary turns to the secondary turns of the synthetic transformer, and R is the equivalent load of the synthetic transformer;

(6) and the power control module is used for realizing power linear control by coordinating and adjusting the power amplifier module number m and the power supply voltage U of the radio frequency power amplifier module based on the calculation.

7. The method for linearly controlling the output power of a high power RF power source as claimed in claim 6, wherein: and realizing the enabling control of the plurality of radio frequency power amplifier modules by utilizing the I/O expansion method of the controller.

8. The method for linearly controlling the output power of a high power RF power source as claimed in claim 6, wherein: by arranging the second radio frequency power amplifier module group, more power levels are expanded, so that the power regulation continuity is increased, and the quantization distortion is reduced; the second radio frequency power amplifier module group is also composed of a plurality of same radio frequency power amplifier modules, the power parameter of a single radio frequency power amplifier module is smaller than that of the first radio frequency power amplifier module group, the power parameter is 1/N of P, and N is larger than 1.

Technical Field

The invention is applied to the field of radio frequency negative ion source neutral beam injectors, and particularly relates to a high-power radio frequency power source output power linear control system and method.

Background

The radio frequency negative ion source neutral beam injector needs a high-power radio frequency power source to provide radio frequency power for a driving coil in an inductive coupling mode to generate plasma. The radio frequency power source applied to the field needs to have the characteristics of high power output, high linearity and high precision, in order to obtain enough radio frequency power, the prior art utilizes a power synthesis transformer to perform power superposition output on a plurality of radio frequency power amplification modules, and the voltage superposed on the secondary side of each radio frequency power amplification module is fixed. Research shows that the output power and the number of the opened radio frequency power amplifier modules are in a quadratic growth relationship due to the design. Therefore, in order to realize the linear control of the output power, the nonlinear compensation is needed under the condition of having enough radio frequency power source power levels, namely, the inverse function relation of the analog control signal relative to the number of the radio frequency power amplifier modules is set, so that the linear correspondence of the analog control signal and the radio frequency output power is realized.

Due to the quadratic increase relationship between the radio frequency output power and the radio frequency power amplifier modules, the output power increase caused by adding one more radio frequency power amplifier module increases with the increase of the number of the opened radio frequency power amplifier modules, which leads to the power regulation precision of the radio frequency power amplifier modules to be in a descending trend with the increase of the radio frequency power. The rf power sources used in neutral beam implanters typically operate at high power while desirably possessing high power regulation accuracy. However, the quadratic relation increase achieves higher accuracy at lower power and lower accuracy at higher power than the linear increase mode in which the adjustment accuracy is fixed.

In the above-described power control method, linear control of the output power is achieved by a form of nonlinear compensation, in such a manner that the nature of power adjustment is not changed, and the characteristic that the accuracy of output power adjustment is degraded is not improved.

Disclosure of Invention

In order to overcome the defect that the power regulation precision of the existing radio frequency power source is in a descending trend along with the increase of the radio frequency output power, the invention provides an output power linear control system and method, which can be used for realizing the linear superposition of the output power so as to obtain higher power regulation precision and realize the linear control of the control signal on the output power of the high-power radio frequency power source.

The technical scheme of the invention is as follows: a high-power radio frequency power source output power linear control system is used for realizing the linear control of analog signals to the radio frequency power source output power, and comprises a radio frequency signal generating unit, a radio frequency power amplifier module group, a power synthesizing unit, a control signal source, a signal processing unit and a power control unit;

the radio frequency signal generating unit is a high-power all-solid-state radio frequency power source radio frequency channel, and a radio frequency signal generated by the radio frequency channel is used as an input signal of the radio frequency power amplifier module group;

the radio frequency power amplifier module group comprises a plurality of identical radio frequency power amplifier modules, each radio frequency power amplifier module generates corresponding radio frequency power according to the change of load equivalent impedance of the radio frequency power amplifier module, and the on or off of the radio frequency power amplifier module can be determined through a control signal; each radio frequency power amplifier module is connected to the primary of a power synthesis transformer in the power synthesis unit;

the power synthesis unit synthesizes and outputs the power of each radio frequency power amplifier module by using a power synthesis transformer, and is provided with a corresponding impedance matching and filtering circuit;

the control signal source is a given analog voltage signal for controlling output power;

the signal processing unit is used for preprocessing an input control signal and outputting a digital signal;

and the power control unit controls the power output of the radio frequency power amplifier module group by cooperatively adjusting the number of the power modules and the voltage of the power supply unit according to the digital signal obtained by the signal processing unit.

Further, the signal processing unit includes a voltage conversion circuit and a digital-to-analog conversion circuit, wherein:

the voltage conversion circuit converts the signal into a voltage domain required by the AD conversion module;

the digital-to-analog conversion circuit converts the analog control signal into a digital signal.

Further, the power control unit includes an enabling unit and a power supply unit, and performs enabling and power supply adjustment according to the digital signal obtained by the signal processing unit, wherein:

the enabling unit controls the on-off of each radio frequency power amplifier module according to the number of the radio frequency power amplifier modules needing to be opened currently;

the power supply unit adjusts the continuous adjustable direct current power supply for supplying power to each radio frequency power amplifier module to adjust the output power of the modules.

Furthermore, the enabling unit is implemented by adopting a scheme of controller I/O expansion, I2C communication is adopted, and a plurality of I/O expansion chips are mounted on an I/O bus.

Further, the power supply unit needs to control the power supply of the rf power amplifier module: and adjusting the output voltage of the power supply according to the number of the opening modules, wherein the voltage control adopts various modes including a USB (universal serial bus), a CAN (controller area network) bus, a digital I/O (input/output) port, a GPIB (general purpose interface bus) and an analog quantity.

According to another aspect of the present invention, a method for performing linear control on output power of a high-power rf power source by using the above system is provided, in which a power control circuit performs enable control of the number of rf power amplification modules and power supply voltage adjustment according to a digital signal obtained by a signal processing unit, so as to implement linear control on power, and specifically includes the following steps:

(1) confirming rated output power P of radio frequency power source₀And the number N of the radio frequency power amplifier modules which are opened under the rated output power₀；

(2) According to P₀And N₀Obtaining the power P generated by each radio frequency power amplifier module under the rated power;

(3) obtaining corresponding output power P according to the digital signal obtained by the signal processing unit_m；

(4) According to the formula:

calculating to obtain the number m of the radio frequency power amplification modules to be opened;

(5) according to the formula:

calculating to obtain a power supply voltage U of the radio frequency power amplifier module, wherein n is the ratio of the primary turns to the secondary turns of the synthetic transformer, and R is the equivalent load of the synthetic transformer;

(6) and the power control module is used for realizing power linear control by coordinating and adjusting the power amplifier module number m and the power supply voltage U of the radio frequency power amplifier module based on the calculation.

Furthermore, the enabling control of the plurality of radio frequency power amplifier modules is realized by utilizing a controller I/O expansion method.

Furthermore, a second radio frequency power amplifier module group is arranged, so that more power levels are expanded, the power adjustment continuity is improved, and the quantization distortion is reduced; the second radio frequency power amplifier module group is also composed of a plurality of same radio frequency power amplifier modules, the power parameter of a single radio frequency power amplifier module is smaller than that of the first radio frequency power amplifier module group, the power parameter is 1/N of P, and N is larger than 1.

Compared with the prior art, the invention has the following beneficial effects:

the invention realizes the linear superposition of the output power of the radio frequency power source by adjusting the number of the switched-on radio frequency power amplification modules and the power supply voltage of the modules, fundamentally solves the problem of the reduction of the adjustment precision of the radio frequency power and improves the power adjustment precision under the condition of high power output.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a schematic diagram of an output power linear control system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a power combining circuit;

FIG. 3 is a flow chart illustrating a power control unit rate control method according to an embodiment of the present invention;

fig. 4 is a schematic diagram illustrating an enabling control of the rf power amplifier module according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments, and all other embodiments obtained by a person skilled in the art based on the embodiments of the present invention belong to the protection scope of the present invention without creative efforts.

As shown in fig. 1, the system is a linear control system for output power of a high-power rf power source, and the system includes a control signal source, a signal processing unit, a power control unit, an rf signal generating unit, an rf power amplifier module, and a power synthesizing unit;

specifically, as shown in fig. 1, the control signal emitted by the control signal source is a given analog voltage signal for controlling the output power; the signal processing unit is used for preprocessing an input control signal and outputting a digital signal;

the power control unit controls the power output of the radio frequency power amplifier module group according to the digital signal obtained by the signal processing unit;

the radio frequency signal generating unit is a high-power all-solid-state radio frequency power source radio frequency channel, and the radio frequency signal generated by the radio frequency channel is an input signal of the radio frequency power amplifier module group; the radio frequency power amplifier module group consists of a plurality of identical radio frequency power amplifier modules, and each radio frequency power amplifier module is connected to the primary side of a power synthesis transformer in the power synthesis unit; the power synthesis unit synthesizes and outputs the power of each radio frequency power amplification module by using a power synthesis transformer, is a power output device of a radio frequency power source, and is provided with a corresponding impedance matching and filtering circuit.

According to one embodiment of the invention, linear control of the radio frequency output power of 0-100kW is realized by using an analog quantity control signal of 0-10V. Firstly, an input analog control signal needs to be preprocessed through a signal processing unit and a digital signal is output, a power control unit can adjust the number of the opened radio frequency power amplification modules and the module power supply voltage according to the digital signal obtained by the signal processing unit, and finally, a power synthesis unit synthesizes and outputs the output power of each radio frequency power amplification module.

For example, a commonly used rf power amplifier module employs a bridge amplifier circuit, the on/off states of four bridge arms of the bridge amplifier circuit are controlled by field effect transistors respectively, and the conduction of the field effect transistors is controlled by rf signals, wherein the field effect transistors on the diagonal bridge arms are controlled by the same rf signal, and the phases of two rf signals are different by 180 degrees. The field effect transistors on the diagonal bridge arms are simultaneously switched on, one group of field effect transistors is switched on while the other group of field effect transistors is switched off, the circuit works in a full-bridge mode, the output voltage of the radio frequency power amplifier module is bipolar square waves, and the amplitude of the output voltage is the power supply voltage V of the radio frequency power amplifier module. Meanwhile, the output of the radio frequency power amplification module is controlled by an enabling signal, and the high and low levels correspond to whether the module outputs or not.

Illustratively, the signal processing unit comprises a voltage conversion circuit, a digital-to-analog conversion circuit and other functional circuits. The voltage conversion circuit is mainly used for matching a control signal with a voltage domain of an AD conversion chip, the scheme adopts a digital-to-analog conversion chip with the voltage domain of 5V, the control signal needs to be reduced by half, and a signal output by the voltage conversion circuit directly enters the AD conversion chip through an overvoltage clamping circuit, so that the output resistance of the voltage conversion circuit needs to be as small as possible, and an operational amplifier circuit is proposed to realize the voltage conversion circuit instead of a divider resistance scheme; the digital-to-analog conversion circuit converts the analog signal into a digital signal, and the digital signal directly corresponds to the power linearity; other functional circuits are designed for different use occasions, such as a filter circuit designed under a high-power radio frequency working environment, and a closed-loop feedback circuit designed for responding to power misalignment caused by load equivalent impedance change.

Illustratively, the power control unit includes a radio frequency power amplifier module enabling unit and a power supply unit, and is configured to implement the radio frequency power amplifier module enabling and the radio frequency power amplifier module power supply voltage adjustment, and implement the linear power control through the cooperative adjustment. The enabling of the radio frequency power amplifier modules means that the power control unit controls a corresponding number of radio frequency power amplifier modules to work according to the digital signals obtained by the signal processing unit, so that the power synthesis transformer can output corresponding power; the power supply adjustment of the radio frequency power amplifier module refers to the power control unit adjusting the power supply voltage of the radio frequency power amplifier module according to the digital signal obtained by the signal processing unit, and the adjustment of the output power of the module is realized by adjusting the voltage, so that the linear superposition of the output power is ensured.

A conventional power synthesis method is to synthesize power by using power synthesis transformers, the power synthesis principle of which is shown in fig. 2, in which a primary side of each transformer is connected to a radio frequency power amplifier module, and the transformers synthesize power loaded on the primary side and output the power on a secondary side. The transformer equivalent load comprises a transformer impedance and a real load, in order to realize maximum power transmission, the impedance matching circuit ensures that the load impedance is equal to the transformer impedance, so that half of the impedance is lost on the internal resistance of the synthetic transformer, which is inevitable, and according to the diagram, the transformer equivalent load impedance is R.

The power of the radio frequency power amplifier modules can only be accumulated by utilizing the power synthesis transformer, and for a single module, the number of the switched-on radio frequency power amplifier modules is different, and the output power is also different, so that the linear control of the output power cannot be realized only by adjusting the number of the switched-on modules. The existing method utilizes a power control circuit to carry out nonlinear compensation, and the method still has certain defects in precision; in order to realize the linear control of the power, the improved scheme of the invention adopts the power control unit to perform linear output control, which is described as follows.

Illustratively, FIG. 3 illustrates the main power control logic of the power control unit of the present invention, wherein the power rating P is₀For the design index of the power source, the digital signal is the result obtained by the signal processing unit according to the conversion of the control signal, and after the current number m of the radio frequency power amplifier modules and the module power supply voltage U are obtained, the number N of the modules under the rated power can be performed in reverse₀And (4) adjusting. According to the digital signal obtained by the signal processing unit, the number m of the radio frequency power amplifier modules which should be opened currently and the module power supply voltage U can be confirmed according to the following steps:

(1) the rated output power of the radio frequency power source is 100kW, and the number of the radio frequency power amplifier modules which are opened under the rated output power is 160;

(2) the power P generated by each radio frequency power amplifier module can be calculated to be 625W;

(3) when the analog signal given by the control signal is 5V, the digital signal generated by the signal processing unit is 0x7FFF, and the power P should be output currently_mComprises the following steps:

(4) then according to the formula:

the number m of the radio frequency power amplification modules which should be opened at present can be obtained as 80;

(5) then according to the formula:

the turn ratio n of the primary coil to the secondary coil is equal to 15, and the equivalent load R of the transformer is equal to 20 omega, so that U is approximately equal to 294.52V;

(6) and the power control module is used for realizing power linear control by coordinating and adjusting the power amplifier module number m and the power supply voltage U of the radio frequency power amplifier module based on the calculation.

The above results are verified, the radio frequency power amplifier module is taken as a research object, and the equivalent impedance R is known according to the schematic diagram of FIG. 4 when the number of the open modules is m_mComprises the following steps:

substituting n-15, R-20 Ω, and m-80 into the above formula yields R_mThe harmonic is removed and only the fundamental component is retained, 1250W of power generated by the current module can be obtained, the total power on the synthesis transformer is 100kW, the power directly loaded on the load impedance is 50kW, that is, 50kW of power output is realized under the conditions that m is 80V and U is 294.52V, and the power output corresponds to the control signal.

For example, the power control unit needs to design a dedicated power controller to implement the power control logic, and the controller may adopt a relatively common ARM single chip microcomputer STM 32. The power control unit needs to realize the enabling control of the radio frequency power amplifier module: in the above example, it is necessary to implement control over 160 rf power amplifier modules, and actually, the number of modules that may need to be controlled may be greater.

Fig. 4 is a schematic diagram of enabling control of a radio frequency power amplifier module, which is implemented by using an I/O expansion scheme of a controller, that is, I/O expansion is implemented by using an MCP23017, the MCP23017 uses I2C for communication, 16 modules can be mounted on each chip, and since an address line of the MCP23017 is 3 bits, 8 MCP23017 chips can be mounted on each I2C bus, so that 128I/O ports can be developed by using one I2C bus, enabling control of 128 radio frequency power amplifier modules is implemented, and more I/O ports can be developed by using a multi-path I2C interface, thereby implementing enabling control of more modules;

in addition, the power control unit needs to control the power supply of the rf power amplifier module: in the above example, when the number of open modules is 160, the voltage is 208.26V; when the number of the opening modules is 1, the voltage is 2634.3V, so that the output voltage is required to be continuously adjustable within 0-2634.3V, a direct current power supply with the rated power of 200kW is used as a power supply unit, and the voltage control CAN adopt various modes, such as USB, CAN bus, digital I/O port, GPIB, analog quantity and the like.

Illustratively, a second radio frequency power amplifier module group with smaller power parameters can be set, so that more power levels are expanded, and the purpose of improving the power regulation precision is achieved. Assuming that the output power of a single module of the first rf power amplifier module group is P, according to an alternative embodiment of the present invention, the smaller power parameter may be 1/N (N >1) of P, which is not limited in the present invention; meanwhile, the number of the second radio frequency power amplifier module groups is related to the power parameter selection, and the combined output power of the second radio frequency power amplifier module groups is (N-1) P/N. In the above case, the output power P of a single module of the first rf power amplifier module group is 625W, 1/10 (62.5W) of the output power P of a single module of the second rf power amplifier module group can be set, and the number of the rf power amplifier modules required by the second rf power amplifier module is 9, and the combined output power of the rf power amplifier modules is 0.9P, so that the original 625W power adjustment step length is reduced to 1/10. In this application, a dedicated power supply unit is required to be designed for the second power rf power amplifier module according to a similar logic. For example, for 160 identical rf power amplifier modules in the rf module group, each module outputs power P, and the adjustable power step is 161 steps (0, P,2P, …, 160P). By additionally setting 9 modules with power parameters of P/9, the power regulation amplitude can be reduced from P to P/9, and the power is increased in steps to 1610. The continuity of power adjustment can be greatly increased and quantization distortion can be reduced.

It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.