A controller of a parallel power amplifier based on FPGA control

Abstract

The application provides a controller of a parallel power amplifier based on FPGA control, which comprises an input buffer circuit, a voltage controller, an FPGA controller, a digital PWM generator and a filter circuit; the input buffer circuit receives and processes an input signal, so as to ensure the stability of the frequency response of the input signal; the voltage controller adopts a negative feedback control mode, so as to realize constant voltage driving of a power amplifier system; the FPGA controller receives a current feedback signal output by the filter circuit and a voltage signal output by the voltage controller, and outputs a PWM pulse wave, so as to drive the power amplifier system.

Description

Technical Field

[0001] This invention belongs to the field of vibration table testing equipment, specifically relating to a controller for a parallel power amplifier based on FPGA control. Background Technology

[0002] Switching power amplifiers, due to their high efficiency and high power density, are gradually replacing traditional linear amplifiers in fields such as vibration testing and audio amplification. When driving an electric vibration table, the power amplifier must have low output impedance, a wide frequency range, and the ability to operate normally with inductive loads. Compared to the limitations of traditional MOSFET power amplifiers (which cannot provide high power) and IGBT power amplifiers (which cannot operate at high frequencies), the emergence of third-generation semiconductor SiC MOSFETs has become an ideal switching device for high-temperature, high-frequency, radiation-resistant, and high-power applications. However, due to the lack of development and application of SiC MOSFETs in power amplifier systems, existing high-power switching amplifier control technologies suffer from numerous problems, including poor parallel current sharing control accuracy, slow dynamic response, imperfect protection mechanisms, difficulties in synchronizing multiple modules, and electromagnetic interference. Summary of the Invention

[0003] The technical problem solved by this invention is to overcome the shortcomings of existing control technologies for switching power amplifiers and provide a controller for a parallel power amplifier based on FPGA control, which can improve the current sharing accuracy, dynamic response speed, reliability and scalability of the parallel power amplifier system.

[0004] This invention provides a controller for a parallel power amplifier based on FPGA control, including an input buffer circuit, a voltage controller, an FPGA controller, a digital PWM generator, and a filter circuit. The input buffer circuit receives and processes the input signal to ensure the stability of the input signal frequency response. The voltage controller adopts a negative feedback control method to achieve constant voltage drive of the power amplifier system. The FPGA controller receives the current feedback signal output by the filter circuit and the voltage signal output by the voltage controller, and outputs a PWM pulse wave to drive the power amplifier system.

[0005] Furthermore, it also includes a parallel synchronization circuit and a real-time protection circuit; the parallel synchronization circuit is used to ensure that the PWM pulse waves of multiple parallel power amplifier modules are in phase and frequency; the real-time protection circuit is used to quickly respond to fault signals and shut down the drive signal of the power amplifier system.

[0006] Furthermore, the power amplifier system adopts a modular parallel architecture, consisting of several power amplifier modules connected in parallel, and each power amplifier module is an independent unit.

[0007] Furthermore, the FPGA controller includes a current controller and a digital PWM generator; the current controller includes an A / D converter and a PID controller; the A / D converter converts the current feedback signal output by the filter circuit and the voltage signal output by the voltage controller into digital signals; the PID controller processes the digital signal output by the A / D converter and outputs the carrier signal required for PWM modulation; the digital PWM generator compares the carrier signal required for PWM modulation with the triangular carrier signal in the FPGA controller and outputs a PWM pulse wave to drive the power amplifier system.

[0008] Furthermore, the current controller converts the current feedback signal output by the filter circuit and the voltage signal output by the voltage controller into digital signals and compares them, thereby realizing closed-loop control of the output current of different power amplifier modules and ensuring the balance of the output current of different power amplifier modules.

[0009] Furthermore, the software program of the FPGA controller is set with a dead time for real-time detection of faults in the power amplifier system; upon receiving the fault information, the real-time protection circuit shuts off the PWM pulse wave output.

[0010] Furthermore, the filtering circuit converts the switching signal output by the power amplifier system into an AC signal for load control.

[0011] The advantages of this invention compared to the prior art are as follows: a) This invention provides a controller for a parallel power amplifier based on FPGA control. By designing a current controller, closed-loop control of the output current of different power amplifier modules is realized, ensuring the balance of the output current of different power amplifier modules.

[0012] b) This invention provides a controller for a parallel power amplifier based on FPGA control. By designing a digital PWM generator and a real-time protection circuit, it realizes PWM pulse wave generation and integrated hardware protection logic.

[0013] c) This invention provides a controller for a parallel power amplifier based on FPGA control, and proposes a high-performance, high-reliability parallel architecture for a power amplifier system suitable for any vibration table. Attached Figure Description

[0014] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a block diagram of a switching power amplifier according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a switching power amplifier system according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a parallel structure of multiple power amplifier modules according to an embodiment of the present invention. Detailed Implementation

[0015] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0016] Example 1 This invention provides a controller for a parallel power amplifier based on FPGA control, including an input buffer circuit, a voltage controller, an FPGA controller, a digital PWM generator, and a filter circuit. The input buffer circuit receives and processes the input signal to ensure the stability of the input signal frequency response. The voltage controller adopts a negative feedback control method to achieve constant voltage drive of the power amplifier system. The FPGA controller receives the current feedback signal output from the filter circuit and the voltage signal output from the voltage controller, and outputs a PWM pulse wave to drive the power amplifier system.

[0017] It also includes a parallel synchronization circuit and a real-time protection circuit; the parallel synchronization circuit is used to ensure that the PWM pulse waves of multiple parallel power amplifier modules are in phase and frequency; the real-time protection circuit is used to quickly respond to fault signals and shut down the drive signal of the power amplifier system.

[0018] The power amplifier system adopts a modular parallel architecture, consisting of several power amplifier modules connected in parallel, and each power amplifier module is an independent unit.

[0019] The FPGA controller includes a current controller and a digital PWM generator; the current controller includes an A / D converter and a PID controller; the A / D converter converts the current feedback signal output from the filter circuit and the voltage signal output from the voltage controller into digital signals; the PID controller processes the digital signal output from the A / D converter and outputs the carrier signal required for PWM modulation; the digital PWM generator compares the carrier signal required for PWM modulation with the triangular carrier signal in the FPGA controller and outputs a PWM pulse wave to drive the power amplifier system.

[0020] The current controller converts the current feedback signal output by the filter circuit and the voltage signal output by the voltage controller into digital signals and compares them, thereby realizing closed-loop control of the output current of different power amplifier modules and ensuring the balance of the output current of different power amplifier modules.

[0021] The FPGA controller's software program is configured with a dead time to detect faults in the power amplifier system in real time; the real-time protection circuit receives fault information and shuts off the PWM pulse wave output.

[0022] The filter circuit converts the switching signal output by the power amplifier system into an AC signal for load control.

[0023] Example 2 (1) Modular parallel architecture: The power amplifier system consists of at least one power amplifier module connected in parallel, supporting no less than 18 modules connected in parallel, with a total output power of 2000kVA, and each module is an independent unit.

[0024] (2) Digital Current Inner Loop Controller: A high-speed AD converter is used to synchronously sample the input voltage signal and output current signal of each module. The sampled data is sent to the digital controller FPGA for processing. After processing by the PID algorithm, the controller generates the switching signal required for high-frequency PWM modulation, and compares the output voltage feedback signal with the input voltage through LC filtering, realizing fast closed-loop control of current and laying the foundation for high-precision current sharing.

[0025] (3) FPGA-based integrated digital PWM and protection logic: A triangular carrier with stable frequency and high linearity is generated in the FPGA. This carrier is compared with the signal output by the current controller to generate a PWM pulse with adjustable duty cycle to drive the SiC MOSFET. In order to realize multiple hardware protection functions, a dead time is set in the software program to prevent the SiC MOSFET from shooting up and down. After the power amplifier is powered on, the software detects and eliminates the excessively narrow pulse that will cause the SiC MOSFET switching loss to increase dramatically. For faults such as overcurrent, overtemperature and loss of synchronization generated by the system, it can respond quickly and shut down the drive within microseconds.

[0026] (4) Synchronization and Current Sharing Mechanism: Each parallel module receives a unified 150kHz square wave synchronization clock signal through a synchronization signal interface to ensure that the PWM carriers of all modules are in phase and frequency. Combined with digital current loop control, accurate current sharing with an output current error of no more than 1% between modules is achieved.

[0027] (5) Excellent electromagnetic compatibility: Through optimized PCB layout, filter circuit design and digital control technology, SiCMOSFET high power amplifier system has excellent EMC characteristics.

[0028] Example 3 A controller design for a high-power parallel SiC MOSFET power amplifier based on FPGA control includes an input buffer circuit, a voltage control loop, a digital current control loop, a digital PWM generator, a drive circuit, a SiC MOSFET switching circuit, a low-pass filter circuit, and a parallel control unit.

[0029] (1) Signal buffer circuit: The input analog signal is processed by the input buffer circuit to ensure a flat frequency response.

[0030] (2) Voltage control loop circuit: Deep voltage negative feedback is adopted to make the amplifier present low output impedance, realize constant voltage drive, and suppress the influence of power grid fluctuations and load changes.

[0031] (3) Digital current control loop circuit: The output current of each module is sampled and digitally processed at high speed to generate a current feedback signal. After being compared with the signal generated by the voltage control loop, it enters the current PID algorithm controller to generate a carrier signal for modulating PWM.

[0032] (4) Digital PWM generator: After comparing the carrier signal with the triangular carrier generated in the FPGA with stable frequency and high linearity, a PWM pulse wave with dead time is generated.

[0033] (5) Parallel synchronization circuit: Distribute a synchronization clock signal to all parallel modules to ensure that the PWM generators of each module work synchronously.

[0034] (6) Real-time protection: The FPGA continuously monitors the SiC MOSFET status, heat sink temperature, output current and synchronization signal. Once a fault is detected (such as overcurrent, overtemperature, or loss of synchronization), the PWM output is immediately shut down.

[0035] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A controller for a parallel power amplifier based on FPGA control, characterized in that, It includes an input buffer circuit, a voltage controller, an FPGA controller, a digital PWM generator, and a filter circuit. The input buffer circuit receives and processes the input signal to ensure the stability of the input signal frequency response. The voltage controller adopts a negative feedback control method to achieve constant voltage drive of the power amplifier system. The FPGA controller receives the current feedback signal output by the filter circuit and the voltage signal output by the voltage controller, and outputs a PWM pulse wave to drive the power amplifier system.

2. The controller for the FPGA-controlled parallel power amplifier according to claim 1, characterized in that, It also includes a parallel synchronization circuit and a real-time protection circuit; the parallel synchronization circuit is used to ensure that the PWM pulse waves of multiple parallel power amplifier modules are in phase and frequency; the real-time protection circuit is used to quickly respond to fault signals and shut down the drive signal of the power amplifier system.

3. The controller for the FPGA-controlled parallel power amplifier according to any one of claims 1 or 2, characterized in that, The power amplifier system adopts a modular parallel architecture, consisting of several power amplifier modules connected in parallel, and each power amplifier module is an independent unit.

4. The controller for the FPGA-based parallel power amplifier according to claim 1, characterized in that, The FPGA controller includes a current controller and a digital PWM generator; the current controller includes an A / D converter and a PID controller; the A / D converter converts the current feedback signal output by the filter circuit and the voltage signal output by the voltage controller into digital signals; the PID controller processes the digital signal output by the A / D converter and outputs the carrier signal required for PWM modulation; the digital PWM generator compares the carrier signal required for PWM modulation with the triangular carrier signal in the FPGA controller and outputs a PWM pulse wave to drive the power amplifier system.

5. The controller for the FPGA-based parallel power amplifier according to claim 4, characterized in that, The current controller converts the current feedback signal output by the filter circuit and the voltage signal output by the voltage controller into digital signals and compares them, thereby realizing closed-loop control of the output current of different power amplifier modules and ensuring the balance of the output current of different power amplifier modules.

6. The controller for the FPGA-based parallel power amplifier according to claim 2, characterized in that, The FPGA controller's software program is configured with a dead time for real-time detection of faults in the power amplifier system; the real-time protection circuit receives fault information and shuts off the PWM pulse wave output.

7. The controller for a parallel power amplifier based on FPGA control according to any one of claims 1 or 5, characterized in that, The filtering circuit converts the switching signal output by the power amplifier system into an AC signal for load control.

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