CN-122026927-A - Low-frequency high-power transmitter

Abstract

A low-frequency high-power transmitter comprises N controllable high-voltage direct-current power supplies, N inversion modules, a tuning unit and an antenna, wherein each controllable high-voltage direct-current power supply is a power supply conversion device isolated from the input of mains supply, direct-current voltage output ends of the N controllable high-voltage direct-current power supplies are respectively connected with direct-current input ends of the N inversion modules, bipolar symmetrical square wave output ends of the N inversion modules are sequentially cascaded and then are connected with the input ends of the tuning unit, the output ends of the tuning unit are connected with the antenna, and the phase difference pi/N of excitation signals of the N inversion modules is larger than 1 natural number. According to the invention, bipolar symmetrical square waves output by N inversion modules with the phase difference pi/N of the excitation signal are overlapped to obtain a bipolar symmetrical stepped waveform with 2N-1 levels, so that the odd harmonic content of the transmission signal is greatly reduced, and the output quality of the low-frequency high-power transmitter is effectively improved.

Inventors

• ZHANG CHAO
• GE PENG
• GENG XIAOJIAO
• MA XUFENG
• YANG MAN
• LIU MENG
• SU YANSHENG
• JI SHAOKAI
• LI QIAN
• GAO DONGYAO

Assignees

• 石家庄国耀电子科技有限公司

Dates

Publication Date

20260512

Application Date

20251217

Claims (6)

1. 1. A low-frequency high-power transmitter is characterized by comprising N controllable high-voltage direct-current power supplies, N inversion modules, a tuning unit (TX) and An antenna (An), wherein each controllable high-voltage direct-current power supply is a power supply conversion device isolated from mains supply input, direct-current voltage output ends of the N controllable high-voltage direct-current power supplies are respectively connected with direct-current input ends of the N inversion modules, bipolar symmetrical square wave output ends of the N inversion modules are connected with An input end of the tuning unit (TX) after being sequentially cascaded, an output end of the tuning unit (TX) is connected with the antenna (An), and phases of excitation signals of the N inversion modules are sequentially different by pi/N, wherein N is a natural number greater than 1.
2. 2. The low-frequency high-power transmitter according to claim 1, wherein each inverter module comprises four power switching tubes and four driving circuits, drains of the first power switching tube (Q1) and the third power switching tube (Q3) are connected with a power supply positive electrode, drains of the second power switching tube (Q2) and the fourth power switching tube (Q4) are respectively connected with sources of the first power switching tube (Q1) and the third power switching tube (Q3), sources of the second power switching tube (Q2) and the fourth power switching tube (Q4) are connected with a power supply negative electrode, gates of the four power switching tubes are respectively connected with output ends of the four driving circuits, and a voltage signal between sources of the first power switching tube (Q1) and the third power switching tube (Q3) is an output signal of the inverter module.
3. 3. The low-frequency high-power transmitter according to claim 2, wherein the excitation signals of the four driving circuits of each inversion module are provided by a control unit, the input ports of the control unit are connected with the excitation signals, and the excitation signal input ends of the four driving circuits are respectively connected with different output ports of the control unit.
4. 4. The low-frequency high-power transmitter according to claim 3, wherein the bipolar symmetrical square wave output ends of the N inversion modules are sequentially cascaded in such a way that the source electrode of the first power switch tube (Q1) of the first inversion module (NB 1) and the source electrode of the third power switch tube (Q3) of the N inversion module (NBN) are connected with the input end of the tuning unit (TX), and for any two adjacent inversion modules, the source electrode of the third power switch tube (Q3) of the former inversion module is connected with the source electrode of the first power switch tube (Q1) of the latter inversion module.
5. 5. The low-frequency high-power transmitter according to claim 4, wherein the controllable high-voltage direct-current power supply comprises a three-phase active power factor correction circuit and a switching power supply, the input end of the three-phase active power factor correction circuit is connected with three-phase mains supply, the output end of the three-phase active power factor correction circuit is connected with the input end of the switching power supply, and the power switching tube of the switching power supply and the four power switching tubes of the inversion module are silicon carbide MOS tubes.
6. 6. A low frequency high power transmitter according to any of claims 1-5, wherein the duty cycle of the excitation signal of the inverter module is 50%.

Description

Low-frequency high-power transmitter Technical Field The invention relates to a high-power low-frequency transmitter with few odd harmonics and high output quality, belonging to the technical field of communication. Background Along with the high-speed development of national defense technology, the field of transmitters is also developed in a long-term manner under the background of the integration of military and civil engineering. The types of transmitters are numerous, in which the low frequency long wave transmitters have wavelengths of the order of kilometers, frequencies in the range of tens of kilohertz to hundreds of kilohertz, the carrier wave is a sine wave, the carrier wave amplitude is 1 kilovolt to tens of kilovolts, and the low-frequency transmitter has the advantages of stable signal propagation, strong diffraction capacity, strong anti-interference capacity, good penetrating capacity and the like. The schematic block diagram of the traditional low-frequency transmitter is shown in fig. 1, and the low-frequency transmitter consists of a controllable high-voltage direct-current power supply, an excitation signal, a power amplification module, a tuning unit and an antenna, wherein the excitation signal is a control signal of the transmitter, a high-frequency switching power supply is arranged in the controllable high-voltage direct-current power supply and converts commercial power into high-quality direct-current high voltage, the power amplification module amplifies the power of the excitation signal, and the tuning unit is used for adjusting the power amplification output to be matched with the antenna (impedance). The working principle of the traditional high-power transmitter is that commercial power input is converted into a controllable high-voltage direct-current power supply through power, the power amplification module is powered, an excitation signal (sine wave signal of 30 KHz-300 KHz) is controlled by a power driving circuit in the power amplification module to carry out power amplification on the excitation signal, the voltage of the excitation signal reaches a certain amplitude, then the excitation signal is connected with a tuning unit, the power signal is matched with the impedance of an antenna through adjusting parameters of the tuning unit, and a communication signal is transmitted through the antenna. The conversion efficiency of the controllable high-voltage direct current power supply and the power amplifier module is a key factor for determining the working efficiency of the low-frequency transmitter, and the controllable high-voltage direct current power supply is realized by a high-frequency switch power supply mode at the present stage. The topology forms of the high-frequency switching power supply are numerous, the hard switch comprises a forward topology, a push-pull topology, a half-bridge (full-bridge) topology and the like, the soft switch topology comprises a phase-shifting full-bridge soft switch topology, an LLC half-bridge (full-bridge) topology and the like, and the soft switch topology is mostly adopted in the power conversion of the controllable high-voltage direct-current power supply. Along with the development of material science, the main power device of the controllable high-voltage direct-current power supply adopts novel power switch tubes such as silicon carbide MOS, gallium nitride MOS and the like, and the novel power switch tubes have the advantages of low on-resistance, high switching speed, simple driving, short reverse recovery time of a body diode and the like, so that the controllable high-voltage direct-current power supply realizes high frequency, miniaturization and high conversion efficiency. The voltage level of the controllable high-voltage direct current power supply of the low-frequency transmitter is higher and reaches several kilovolts, so that the design of the controllable high-voltage direct current power supply is complex, the power device is difficult to select, and the safety protection level is higher in requirement of high-voltage output. In addition, the conversion efficiency of the power amplifier module is lower, and in a high-power transmitter, the power loss of the power amplifier module needs to increase the heat treatment capacity of the transmitter, such as forced air cooling heat dissipation, liquid cooling heat dissipation and the like, so that the size of the low-frequency transmitter is larger. The Chinese patent application No. CN201320009579.9 discloses a very low frequency high power transmitter, which comprises a plurality of unit inverter bridges connected in series, wherein the output of the unit inverter bridges connected in series is connected to a very low frequency antenna through a tuning matching network, and the unit inverter bridges comprise a plurality of insulated gate bipolar transistors IGBT. The very low frequency high power transmitter has the advantages of small volume, large power, relia