A wide-range radio frequency power conversion system based on asymmetric hybrid structure and hybrid modulation

Abstract

This invention discloses a wide-range radio frequency power conversion system based on an asymmetric hybrid structure and hybrid modulation. It adopts an input parallel, output series architecture, consisting of a main power regulation module and several auxiliary power modules. The main power regulation module includes a front-stage Buck-Boost converter and a rear-stage dual-parallel full-bridge resonant unit, possessing fine voltage and phase adjustment capabilities. The auxiliary power modules are simplified full-bridge units, responsible only for discrete power switching. The system employs a hybrid modulation strategy, utilizing phase-shift control of the main power module in the low-power range, DC bus voltage regulation of the main power module in the medium-power range, and full-bridge / bypass mode switching of the auxiliary power modules in the high-power range, achieving smooth and continuous adjustment from zero to rated power. This architecture, through optimized design of resonant network parameters and utilization of the internal resonant circulating current generated by the main module in phase-shift state, ensures zero-voltage switching (ZVS) operation across the entire range, significantly reducing system hardware costs and control complexity while significantly improving system efficiency in power back-off state.

Description

Technical Field

[0001] This invention belongs to the field of power electronics and radio frequency power conversion technology, and more specifically, relates to a wide-range radio frequency power conversion system based on asymmetric hybrid structure and hybrid modulation. Background Technology

[0002] In fields such as semiconductor manufacturing (e.g., plasma etching, thin film deposition) and wireless power transmission, radio frequency (RF) power supplies not only need to provide high-frequency, high-power output, but also need to adapt to dynamically changing nonlinear loads and have a wide range of power regulation capabilities (e.g., 10:1 or even wider).

[0003] Existing technical solutions mainly include:

[0004] Frequency modulation: This method adjusts power by changing the switching frequency and utilizing the impedance characteristics of a resonant network. However, this can cause the frequency to deviate from industry standards (such as 13.56MHz and its harmonics) and increase the difficulty of EMI filter design.

[0005] DC-link Voltage Control: This method regulates the voltage via the upstream DC-DC converter. However, this increases system complexity, and at low voltage outputs, the downstream inverter often struggles to maintain soft switching, leading to decreased efficiency.

[0006] Chireix Outphasing phase control: This method synthesizes the output by using the phase difference of two constant amplitude vectors. It is highly efficient at medium to high power, but severe reactive circulating currents occur during deep power back-off (low power) or large-angle phase shifts, leading to a significant deterioration in efficiency.

[0007] Furthermore, traditional modular power supplies typically employ a symmetrical structure, meaning all modules have identical structures (each containing a complete DC-DC converter and resonant network). While this approach offers good scalability, in high-power scenarios, the excessive number of resonant components and control circuitry significantly increases size and cost.

[0008] Therefore, there is an urgent need for a new RF power supply architecture that can reduce hardware costs, achieve wide-range efficient regulation and full-range zero-voltage switching (ZVS), and stably output high-quality RF power under dynamic load and high-frequency conditions, while improving energy efficiency and system reliability to meet the needs of next-generation high-end industrial equipment and application scenarios. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and provide a wide-range radio frequency power conversion system based on asymmetric hybrid structure and hybrid modulation. By using an asymmetric combination of "main power adjustment module + auxiliary power module" and a hybrid modulation strategy of continuous voltage / phase adjustment and discrete module switching, a high-efficiency and low-cost wide-range power output is achieved.

[0010] To achieve the above-mentioned objectives, the present invention provides a wide-range radio frequency power conversion system based on an asymmetric hybrid structure and hybrid modulation, characterized in that it includes: a DC input source, a main power regulation module, an auxiliary power output module, and a power combining and output network;

[0011] The DC input source is used to provide DC energy to the system. The main power regulation module and all auxiliary power output modules are connected in parallel to the DC input source on the DC input side.

[0012] The main power regulation module includes a front-end Buck-Boost converter, an intermediate DC bus capacitor, a rear-end dual parallel full-bridge inverter unit, and a series resonant network; it is used to provide continuous voltage and phase regulation for the system.

[0013] The front-stage Buck-Boost converter consists of two front-stage voltage regulating bridge arms composed of four switching transistors. Switches Q1 and Q2 form the left front-stage voltage regulating bridge arm, and switches Q3 and Q4 form the right front-stage voltage regulating bridge arm, which also includes an energy storage inductor. One end of the energy storage inductor is connected to the midpoint of the left front-stage voltage regulating bridge arm, and the other end is connected to the midpoint of the right front-stage voltage regulating bridge arm. The output of the front-stage Buck-Boost converter is connected to the intermediate DC bus capacitor to regulate the intermediate DC bus voltage.

[0014] The subsequent dual-parallel full-bridge inverter unit contains two parallel full-bridge inverter units, forming a total of four main inverter bridge arms, which are connected in parallel across the two ends of the intermediate DC bus capacitor.

[0015] The series resonant network consists of four independent resonant branches, each containing a series resonant capacitor and a resonant inductor. The input of each resonant branch is connected to the midpoint of the four main inverter bridge arms, and its outputs are connected in parallel to the two ends of the primary winding of the main high-frequency transformer in the power combining and output network.

[0016] The auxiliary power output module includes multiple parallel full-bridge inverter units. Each single full-bridge inverter unit consists of four switching transistors forming two auxiliary inverter bridge arms, which are used to provide discrete voltage gain to the system when switching between full-bridge mode and bypass mode.

[0017] The power combining and output network includes a main high-frequency transformer, multiple auxiliary high-frequency transformers, and an output filter network.

[0018] In this system, each full-bridge inverter unit in the auxiliary power output module is connected to an auxiliary high-frequency transformer. The primary winding of the auxiliary high-frequency transformer is connected between the midpoints of the two auxiliary inverter bridge arms. The secondary winding of the main high-frequency transformer is connected in series with the secondary windings of all the auxiliary high-frequency transformers to form an AC output link for superimposing and synthesizing the output voltage. Finally, the two ends of the AC output link are connected to the input of the output filter network, and the output of the output filter network is connected to the load.

[0019] The objective of this invention is achieved as follows:

[0020] This invention discloses a wide-range radio frequency power conversion system based on an asymmetric hybrid structure and hybrid modulation. It employs an input parallel, output series architecture, consisting of a main power regulation module and several auxiliary power modules. The main power regulation module includes a front-stage Buck-Boost converter and a rear-stage dual-parallel full-bridge resonant unit, providing fine voltage and phase adjustment capabilities. The auxiliary power modules are simplified full-bridge units, responsible only for discrete power switching. The system uses a hybrid modulation strategy: in the low-power range, it utilizes phase-shift control of the main power module; in the medium-power range, it utilizes DC bus voltage regulation of the main power module; and in the high-power range, it combines full-bridge / bypass mode switching of the auxiliary power modules, achieving smooth and continuous adjustment from zero to rated power. This architecture, through optimized design of resonant network parameters and utilization of the internal resonant circulating current generated by the main module in phase-shift state, ensures zero-voltage switching (ZVS) operation across the entire range, significantly reducing system hardware costs and control complexity while substantially improving system efficiency in power back-off states.

[0021] Meanwhile, the wide-range radio frequency power conversion system based on asymmetric hybrid structure and hybrid modulation of the present invention also has the following beneficial effects:

[0022] (1) Novel topology and significantly reduced hardware cost: An asymmetric hybrid architecture of main and auxiliary modules is adopted. Only the main module contains the pre-stage voltage regulation circuit and resonant network, while the auxiliary module is simplified to a single full-bridge structure (eliminating the pre-stage DC-DC and independent resonant components). While ensuring high power output, the number of high-frequency components and control circuits is greatly reduced, effectively reducing the system size and hardware cost.

[0023] (2) Hybrid modulation strategy to achieve wide-range smooth adjustment: The continuous adjustment of the main module (phase shift / bus voltage regulation) is innovatively integrated with the discrete phase switching of the auxiliary module. By introducing feedforward control to dynamically compensate for voltage step at the moment of module switching, seamless, smooth and continuous adjustment of load output power from zero to rated power is achieved.

[0024] (3) Full load range soft switching (ZVS) improves light load efficiency: The system cleverly utilizes the internal resonant circulating current generated by the main module in the phase-shift state through the optimized design of the resonant network parameters, ensuring that all switching transistors can meet the charging and discharging requirements and achieve zero voltage switching at different power levels (especially in the deep power back-off state), thus completely solving the problem of the deterioration of light load efficiency of traditional phase-shift RF power supplies.

[0025] (4) High reliability and fault tolerance: Based on the input parallel output series (IPOS) architecture, the system naturally has excellent power scalability and fault tolerance. When the power devices of some auxiliary modules fail due to short circuit or open circuit, the system does not need to be shut down for reconstruction and can still maintain stable operation with derating through the remaining modules. Attached Figure Description

[0026] Figure 1 This is a structural diagram of a wide-range radio frequency power conversion system based on asymmetric hybrid structure and hybrid modulation according to the present invention.

[0027] Figure 2 The simplified equivalent circuit diagram of a wide-range RF power conversion system.

[0028] Figure 3 Typical waveforms for each module of a wide-range RF power conversion system.

[0029] Figure 4 This is a schematic diagram illustrating how the system output voltage changes with the operating state under a hybrid modulation strategy.

[0030] Figure 5 This is a design flowchart for a wide-range RF power conversion system. Detailed Implementation

[0031] The specific embodiments of the present invention will now be described with reference to the accompanying drawings to enable those skilled in the art to better understand the invention. It should be particularly noted that in the following description, detailed descriptions of known functions and designs that might obscure the main content of the invention will be omitted here.

[0032] Example

[0033] In this embodiment, as Figure 1 As shown, the present invention discloses a wide-range radio frequency power conversion system based on asymmetric hybrid structure and hybrid modulation, comprising: a DC input source, a main power regulation module, an auxiliary power output module, and a power combining and output network;

[0034] The DC input source is used to provide DC energy to the system, and the main power regulation module and the auxiliary power output module are connected in parallel to the DC input source on the DC input side.

[0035] like Figure 1 As shown, the main power regulation module includes a front-end Buck-Boost converter, an intermediate DC bus capacitor, a rear-end dual parallel full-bridge inverter unit, and a series resonant network; it is used to provide continuous voltage and phase regulation for the system.

[0036] The front-end Buck-Boost converter consists of two front-end voltage regulating bridge arms composed of four switching transistors, such as... Figure 1 As shown, Q1 and Q2 form the left front-stage voltage regulating bridge arm, and Q3 and Q4 form the right front-stage voltage regulating bridge arm, and include an energy storage inductor; one end of the energy storage inductor is connected to the midpoint of the left front-stage voltage regulating bridge arm, and the other end is connected to the midpoint of the right front-stage voltage regulating bridge arm; the output of the front-stage Buck-Boost converter is connected to the intermediate DC bus capacitor to regulate the intermediate DC bus voltage; the rear-stage dual parallel full-bridge inverter unit contains two parallel full-bridge inverter units, forming a total of four main inverter bridge arms, which are connected in parallel across the intermediate DC bus capacitor;

[0037] The series resonant network consists of four independent resonant branches, each containing a series resonant capacitor and a resonant inductor. The input of each resonant branch is connected to the midpoint of the four inverter bridge arms, and its outputs are connected in parallel to each other and then connected to the two ends of the primary winding of the main high-frequency transformer in the power combining and output network.

[0038] like Figure 1 As shown, the auxiliary power output module includes multiple parallel full-bridge inverter units. Each full-bridge inverter unit consists of four switching transistors forming two auxiliary inverter bridge arms, which are used to provide discrete voltage gain to the system when switching between full-bridge mode and bypass mode.

[0039] In this embodiment, the number of full-bridge inverter units in the auxiliary power output module can be configured according to the actual power demand. The larger the power demand, the larger the value of m, but it must be guaranteed to include at least one full-bridge inverter unit.

[0040] In addition, the full-bridge inverter unit in the auxiliary power output module has two operating modes, and in both modes, high-frequency resonance is not performed; only the fundamental frequency energy is transmitted. The two operating modes are as follows:

[0041] Full-bridge mode (FB): The four switches of the two auxiliary inverter bridge arms are turned on alternately, and the output is a square wave voltage with a fixed amplitude.

[0042] Bypass mode (BP): The upper transistors of the two auxiliary inverter bridge arms are turned off simultaneously, while the lower transistors are continuously turned on. At this time, the output voltage is zero. This mode provides a freewheeling path for the system current on the AC output link, while avoiding the module operating in a half-bridge state with single-sided switching action, thus preventing the generation of DC bias voltage at the output.

[0043] like Figure 1 As shown, the power combining and output network includes a main high-frequency transformer, multiple auxiliary high-frequency transformers, and an output filter network;

[0044] In this module, each full-bridge inverter unit in the auxiliary power output module is connected to an auxiliary high-frequency transformer, and the primary winding of the auxiliary high-frequency transformer is connected between the midpoints of the two auxiliary inverter bridge arms.

[0045] The secondary winding of the main high-frequency transformer is connected in series with the secondary windings of all auxiliary high-frequency transformers to form an AC output link for superimposing and synthesizing the output voltage. Finally, the two ends of the AC output link are connected to the input of the output filter network, and the output of the output filter network is connected to the load.

[0046] In this embodiment, the output filtering network is a T-type low-pass filter, which consists of a first filter inductor and a second filter inductor connected in series and a filter capacitor connected in parallel. It is used to filter out high-order harmonics and output sinusoidal radio frequency power to the load.

[0047] In this embodiment, the operating state of the wide-range RF power conversion system is dynamically changed according to changes in power demand, and the power regulation process is divided into the following stages:

[0048] When the wide-range RF power conversion system operates in a low-power state, all full-bridge inverter units in the control auxiliary power output module operate in bypass mode; the intermediate DC bus voltage ratio of the front-stage Buck-Boost converter of the main power regulation module is fixed, and phase-shift control is performed only by the rear-stage dual parallel full-bridge inverter units.

[0049] In this embodiment, the phase shift angle θ of the subsequent dual-parallel full-bridge inverter unit is based on the target power requirement P. ref With the main module's maximum output power P max The ratio is used for dynamic feedforward calculation: when the target power demand P ref = P max When the phase shift angle θ is set to 0; when the target power demand P ref < P max At that time, the continuous adjustment of the phase shift angle θ satisfies the following relationship: .

[0050] When the wide-range RF power conversion system is operating in the medium power state, all full-bridge inverter units in the control auxiliary power output module are kept in bypass mode, and the phase shift angle of the main regulation module is fixed at 0°. The intermediate DC bus voltage ratio is changed by adjusting the duty cycle of the switching transistors of the front-stage Buck-Boost converter, thereby achieving linear and continuous regulation of the output power.

[0051] When the wide-range RF power conversion system operates at high power, one or more full-bridge inverter units in the auxiliary power output module are sequentially switched from bypass mode to full-bridge mode according to the power increase demand. This utilizes the discrete voltage steps provided by the auxiliary power output module to increase the output power. Simultaneously, at the instant of mode switching, the system synchronously reduces the output voltage of the main power regulation module through feedforward control (by increasing the phase shift angle or reducing the bus voltage ratio) to precisely offset the auxiliary voltage step, thereby eliminating the voltage surge caused by module switching and achieving a seamless and smooth transition of total output power.

[0052] Figure 2 To demonstrate the simplified equivalent circuit model of the system for theoretical analysis and parameter design, a simplified equivalent circuit model is presented. In this model, the dual-parallel full-bridge inverters of the main regulating module and the full-bridge inverters of each auxiliary module are equivalent to controlled AC voltage sources Vp1 to Vp2. The resonant network of the main module is simplified to an equivalent inductance Lr and a capacitor Cr. The turns ratio of all transformers is uniformly set to N in the model, and the secondary-side filter inductance Lf1 and the secondary-side leakage inductance of all transformers are combined and represented as the equivalent inductance Leq_f1. At the same time, the load RL and filter parameters are converted to the primary side to form the equivalent impedance Rref. This model is used to analyze the load characteristics of each module under different modulation states and the soft-switching implementation conditions.

[0053] Figure 3 This section presents typical drive timings and voltage / current waveforms for key units in the system under different operating modes. Figure 3 (a) The working state of the front-end Buck-Boost converter of the main power regulation module is described. The inductor current iLb is adjusted by controlling the duty cycle of the switching transistor, and the current ripple is used to ensure that the ZVS condition is met at the moment of switching transistor turn-off. Figure 3 (b) shows the waveform when phase-shift control is used in the back stage of the main power regulation module. By adjusting the phase difference θ between the two sets of half-bridge drive signals, the fundamental amplitude of the synthesized output voltage Vp1 is changed to achieve power fine-tuning. Figure 3 (c) shows the waveform of the auxiliary power output module in full-bridge mode. Its switching transistor generates a standard square wave voltage Vpi, and the output current lags behind the voltage, indicating that the system achieves efficient energy transfer through the resonant current of the main power regulation module and the loop current.

[0054] Figure 4A three-dimensional trajectory diagram of the system output voltage as a function of control variables visually illustrates the execution path of the hybrid modulation strategy. This strategy divides the operating range into three stages: In the low-power region (blue area), the system operates along the "Change θ" path, with the auxiliary power output module bypassed and the main power regulation module voltage ratio λ fixed. Only the phase shift angle θ is adjusted from 180° to 0° to achieve power initiation. In the medium-power region (green area), the system operates along the "Change λ" path, with θ fixed at 0°. λ is adjusted to linearly increase the main power regulation module voltage to its peak value. In the high-power region (red trajectory), when higher power is required, the system activates the auxiliary module and instantly reverts the control variable (λ or θ) of the main power regulation module, causing the total output voltage to smoothly rise to the rated power along the red curve. This ensures wide-range adjustment while eliminating voltage spikes caused by module switching.

[0055] Figure 5 The flowchart of the engineering design of the system of this invention is shown, covering the complete steps from indicator definition to strategy implementation. The design process first requires clarifying the core indicators of the system, such as rated power, operating frequency, and load impedance; then, the transformer turns ratio N and the maximum number of modules m are determined to meet the power level requirements; based on this, the series resonant network L of the main power regulation module is calculated according to the maximum output power and ZVS soft switching conditions. r and C r The value is then determined; next, based on the harmonic attenuation requirements and impedance matching principle, the low-pass filter L is selected. f and C f The parameters are determined; finally, based on the system power transmission characteristic curve, the specific modulation strategy and switching point of each power segment are determined, and the overall optimization design of the system parameters is completed.

[0056] Although the illustrative specific embodiments of the present invention have been described above to enable those skilled in the art to understand the invention, it should be understood that the invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of the present invention are protected.

Claims

1. A wide-range radio frequency power conversion system based on asymmetric hybrid structure and hybrid modulation, characterized in that, include: DC input source, main power regulation module, auxiliary power output module, and power combining and output network; The DC input source is used to provide DC energy to the system. The main power regulation module and all auxiliary power output modules are connected in parallel to the DC input source on the DC input side. The main power regulation module includes a front-end Buck-Boost converter, an intermediate DC bus capacitor, a rear-end dual parallel full-bridge inverter unit, and a series resonant network; it is used to provide continuous voltage and phase regulation for the system. The front-stage Buck-Boost converter consists of two front-stage voltage regulating bridge arms composed of four switching transistors. Switches Q1 and Q2 form the left front-stage voltage regulating bridge arm, and switches Q3 and Q4 form the right front-stage voltage regulating bridge arm, which also includes an energy storage inductor. One end of the energy storage inductor is connected to the midpoint of the left front-stage voltage regulating bridge arm, and the other end is connected to the midpoint of the right front-stage voltage regulating bridge arm. The output of the front-stage Buck-Boost converter is connected to the intermediate DC bus capacitor to regulate the intermediate DC bus voltage. The subsequent dual-parallel full-bridge inverter unit contains two parallel full-bridge inverter units, forming a total of four main inverter bridge arms, which are connected in parallel across the two ends of the intermediate DC bus capacitor. The series resonant network consists of four independent resonant branches, each containing a series resonant capacitor and a resonant inductor. The input of each resonant branch is connected to the midpoint of the four main inverter bridge arms, and its outputs are connected in parallel to the two ends of the primary winding of the main high-frequency transformer in the power combining and output network. The auxiliary power output module includes multiple parallel full-bridge inverter units. Each single full-bridge inverter unit consists of four switching transistors forming two auxiliary inverter bridge arms, which are used to provide discrete voltage gain to the system when switching between full-bridge mode and bypass mode. The power combining and output network includes a main high-frequency transformer, multiple auxiliary high-frequency transformers, and an output filter network. In this system, each full-bridge inverter unit in the auxiliary power output module is connected to an auxiliary high-frequency transformer. The primary winding of the auxiliary high-frequency transformer is connected between the midpoints of the two auxiliary inverter bridge arms. The secondary winding of the main high-frequency transformer is connected in series with the secondary windings of all the auxiliary high-frequency transformers to form an AC output link for superimposing and synthesizing the output voltage. Finally, the two ends of the AC output link are connected to the input of the output filter network, and the output of the output filter network is connected to the load.

2. The wide-range radio frequency power conversion system based on asymmetric hybrid structure and hybrid modulation according to claim 1, characterized in that, The parameters of the series resonant network in the main power regulation module are designed based on the minimum equivalent load impedance when all modules are in operation, ensuring that the resonant circuit exhibits inductive behavior under any operating state and meets the requirements of zero-voltage switching soft-switching operation of the switching transistor.

3. The wide-range radio frequency power conversion system based on asymmetric hybrid structure and hybrid modulation according to claim 1, characterized in that, The auxiliary power output module contains at least one full-bridge inverter unit.

4. The wide-range radio frequency power conversion system based on asymmetric hybrid structure and hybrid modulation according to claim 1, characterized in that, The full-bridge inverter unit in the auxiliary power output module has two operating modes, and in both modes, high-frequency resonance is not performed; only fundamental frequency energy is transmitted. The two operating modes are as follows: Full-bridge mode: The four switches of the two auxiliary inverter bridge arms are turned on alternately, outputting a square wave voltage with a fixed amplitude; Bypass mode: The upper transistors of the two auxiliary inverter bridge arms are turned off simultaneously, while the lower transistors are continuously turned on. At this time, the output voltage is zero, providing a freewheeling path for the system current on the AC output link. This also avoids the module operating in a half-bridge state with single-sided switching action, preventing the generation of DC bias voltage at the output.

5. The wide-range radio frequency power conversion system based on asymmetric hybrid structure and hybrid modulation according to claim 1, characterized in that, The wide-range radio frequency power conversion system includes three operating states: low power, medium power, and high power. When the wide-range RF power conversion system is operating in a low-power state, all full-bridge inverter units in the control auxiliary power output module are operated in bypass mode; the intermediate DC bus voltage ratio of the front-stage Buck-Boost converter of the main power regulation module is fixed, and phase-shift control is performed only by the rear-stage dual parallel full-bridge inverter units; When the wide-range RF power conversion system is operating in the medium power state, all full-bridge inverter units in the auxiliary power output module are kept in bypass mode, and the phase shift angle of the main power regulation module is fixed at 0°. The intermediate DC bus voltage ratio is changed by adjusting the duty cycle of the switching transistors of the front-stage Buck-Boost converter, thereby achieving linear and continuous regulation of the output power. When the wide-range RF power conversion system operates in a high-power state, according to the power increase demand, one or more full-bridge inverter units in the auxiliary power output module are sequentially switched from bypass mode to full-bridge mode, using the discrete voltage steps provided by the auxiliary power output module to increase the output power. At the same time, at the instant of mode switching, the system synchronously reduces the output voltage of the main power regulation module through feedforward control to offset the discrete voltage steps, thereby eliminating the voltage surge caused by the mode switching of the auxiliary power output module and achieving a seamless and smooth transition of the total output power.

6. The wide-range radio frequency power conversion system based on asymmetric hybrid structure and hybrid modulation according to claim 1, characterized in that, The phase shift angle θ of the subsequent dual-parallel full-bridge inverter unit is based on the target power requirement P. ref With the main module's maximum output power P max The ratio is used for dynamic feedforward calculation: when the target power demand P ref = P max When the phase shift angle θ is set to 0; when the target power demand P ref < P max At that time, the continuous adjustment of the phase shift angle θ satisfies the following relationship: .

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