Alternating current variable frequency random pulse width modulation method, system, device and medium

Abstract

The invention relates to an alternating-current variable-frequency random pulse width modulation method, system and device and a medium. The method comprises the following steps: generating a first pseudo-random binary sequence and a second pseudo-random binary sequence by using two linear feedback shift registers; a digital module is designed, the digital module is a derived clock generator, and the derived clock generator comprises a triangular carrier generator, a sine carrier generator and an arcsine carrier generator; according to the first basic frequency f1 = 2kHz, the second basic frequency f2 = 4kHz, the third basic frequency f3 = 3kHz, the first pseudo-random binary sequence and the second pseudo-random binary sequence, calculating a random frequency by using a preset carrier frequency formula; according to the random frequency and a digital module, clock signals with the frequencies of 400 kHz, 300 kHz and 200 kHz are obtained; generating a carrier signal with a random frequency by combining a triangular carrier generator, a sine carrier generator and an arcsine carrier generator according to the clock signal; a carrier signal with a random frequency is applied to a generation process of alternating-current variable-frequency random pulse width modulation, and random pulse width modulation control is realized.

Description

Technical Field

[0001] The invention relates to an AC variable frequency random pulse width modulation method, system, equipment and medium, and belongs to the fields of communication engineering and power conversion. Background Art

[0002] PWM (Pulse Width Modulation) is a commonly used modulation technology that simulates the waveform of an analog signal by changing the width of a pulse. In the field of power electronics, PWM technology is widely used in inverters, motor control and other occasions. However, traditional PWM technology has problems such as high harmonic content and uneven spectrum distribution, which will have an adverse effect on the operating efficiency and noise level of the motor.

[0003] Linear Feedback Shift Register (LFSR) is a pseudo-random number generator that uses a linear feedback function to generate a pseudo-random sequence. AC-Variable Frequency Random Pulse Width Modulation is a pulse width modulation technique that first uses LFSR to generate a carrier with a random frequency. Specifically, the pseudo-random sequence generated by the LFSR is used to control the clock frequency of the carrier generator to generate a carrier with a random frequency. These carriers are used to compare with the modulating signal to generate a PWM waveform.

[0004] Traditional PWM methods, such as SPWM, are prone to harmonic problems because the carrier signal is fixed. These harmonics may cause adverse effects on the motor and the power grid, such as vibration, noise, and power loss.

[0005] Prior art, such as the Chinese patent number "CN114401052B", discloses a 5-level RF-PWM modulation method and modulator. The method includes the following steps: using an amplitude-phase separation algorithm to decompose the I signal and Q signal in the baseband signal into a normalized amplitude signal and a phase signal; generating a first reference signal and a second reference signal according to the RF carrier frequency and the phase signal; generating a threshold signal according to the amplitude signal; comparing the first reference signal with the threshold signal to generate a first 3-level RF pulse width modulation signal; comparing the second reference signal with the threshold signal to generate a second 3-level RF pulse width modulation signal; the first 3-level RF pulse width modulation signal and the second 3-level RF pulse width modulation signal have equal pulse widths; linearly superimposing the first reference signal and the second reference signal to obtain a 5-level RF pulse width signal.

[0006] The problems with the above-mentioned prior art are that it involves amplitude-phase separation algorithms, generation of threshold signals, etc., the overall implementation is relatively complex, and the implementation and debugging of the algorithms are difficult. When processing specific signals, it may be sensitive to the amplitude and phase changes of the input signal, which limits the system's adaptability to different types of signals. Amplitude-phase separation may introduce additional signal interference or distortion, especially under low signal-to-noise ratio conditions (such as in complex environments). Summary of the invention

[0007] In order to solve the above problems existing in the prior art, the present invention proposes an AC variable frequency random pulse width modulation method, system, device and medium.

[0008] The technical solution of the present invention is as follows:

[0009] In one aspect, the present invention provides an AC variable frequency random pulse width modulation method, comprising the following steps:

[0010] generating a first pseudo-random binary sequence and a second pseudo-random binary sequence using two linear feedback shift registers;

[0011] Designing a digital module, wherein the digital module is a derived clock generator, and the derived clock generator includes a triangular carrier generator, a sine carrier generator, and an arcsine carrier generator; wherein the triangular carrier generator is designed with an up-down counter, and the sine carrier generator and the arcsine carrier generator are designed to be sequentially executed with a preset sampling rate;

[0012] The random frequency is calculated by using a preset carrier frequency formula through a first base frequency f1=2kHz, a second base frequency f2=4kHz, a third base frequency f3=3kHz, a first pseudo-random binary sequence and a second pseudo-random binary sequence;

[0013] According to the random frequency and digital module, clock signals with frequencies of 400kHz, 300kHz and 200kHz are obtained;

[0014] A carrier signal of random frequency is generated by combining a triangular carrier generator, a sine carrier generator and an inverse sine carrier generator according to a clock signal;

[0015] The random frequency carrier signal is applied to the generation process of AC variable frequency random pulse width modulation to realize random pulse width modulation control.

[0016] As a preferred implementation, the preset carrier frequency formula is:

[0017] fr=PRBS1×PRBS2×f1+PRBS1×PRBS2×f2+PRBS1×PRBS2×f3;

[0018] Wherein, PRBS1 represents a first pseudo-random binary sequence, PRBS2 represents a second pseudo-random binary sequence, and fr represents a random frequency.

[0019] As a preferred implementation, the triangular carrier generator, the sine carrier generator and the arcsine carrier generator are simulated and verified by using a digital design simulation tool.

[0020] As a preferred embodiment, the step of evaluating the performance of the carrier signal generating the random frequency is also included:

[0021] Including evaluation indicators harmonic spreading factor HSF and power spectral density PSD;

[0022] Among them, HSF is calculated through the concept of statistical deviation to evaluate the harmonic diffusion effect of random pulse width modulation; PSD monitors the motor condition through vibration analysis;

[0023]

[0024] Among them, H j is the amplitude of the jth harmonic, and H0 is the average value of all N-1 harmonics.

[0025] On the other hand, the present invention also provides an AC variable frequency random pulse width modulation system, comprising:

[0026] Pseudo-random binary sequence module: using two linear feedback shift registers to generate a first pseudo-random binary sequence and a second pseudo-random binary sequence;

[0027] Digital module: Design a digital module, which is a derived clock generator, and the derived clock generator includes a triangular carrier generator, a sine carrier generator, and an arcsine carrier generator; wherein the triangular carrier generator is designed with an up-down counter, and the sine carrier generator and the arcsine carrier generator are designed to be executed sequentially with a preset sampling rate;

[0028] Random frequency generation module: calculates the random frequency by using the first basic frequency f1=2kHz, the second basic frequency f2=4kHz, the third basic frequency f3=3kHz, the first pseudo-random binary sequence and the second pseudo-random binary sequence, using a preset carrier frequency formula;

[0029] Clock signal generation module: According to the random frequency and digital module, clock signals with frequencies of 400kHz, 300kHz and 200kHz are obtained;

[0030] Random frequency carrier signal generation module: generates a random frequency carrier signal by combining a triangular carrier generator, a sine carrier generator and an inverse sine carrier generator according to a clock signal;

[0031] Modulation module: applies the carrier signal of random frequency to the generation process of AC variable frequency random pulse width modulation to realize random pulse width modulation control.

[0032] In yet another aspect, the present invention further provides an electronic device having a computer program stored thereon, wherein when the computer program is executed by a processor, the AC variable frequency random pulse width modulation method as described in any embodiment of the present invention is implemented.

[0033] On the other hand, the present invention also provides a computer-readable storage medium for storing one or more programs, which, when executed by the one or more processors, enables the one or more processors to implement the AC variable frequency random pulse width modulation method as described in any embodiment of the present invention.

[0034] The present invention has the following beneficial effects:

[0035] The present invention uses a pseudo-random binary sequence generated by two linear feedback shift registers (LFSRs) to provide good randomness. This randomness is of great significance in the fields of encryption, modulation and signal processing, and can improve the security of the system. By adjusting different basic frequencies (f1, f2, f3), multiple frequency signals can be flexibly generated. This flexibility adapts to the needs of various application environments and enhances the versatility of the system. AC variable frequency random pulse width modulation is achieved through a carrier signal with a random frequency. This unique modulation method can effectively reduce the electromagnetic interference of the system and enhance the robustness of the signal, especially in power electronics and motor drive applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a flowchart for implementing the method. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be understood that the step numbers used in this document are only for convenience of description and are not intended to limit the order in which the steps are executed.

[0039] It should be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0040] The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0041] The term "and / or" means and includes any and all possible combinations of one or more of the associated listed items.

[0042] Embodiment 1:

[0043] See also Figure 1 The present invention provides an AC variable frequency random pulse width modulation method, comprising the following steps:

[0044] Two linear feedback shift registers are used to generate a first pseudo-random binary sequence and a second pseudo-random binary sequence; the pseudo-random binary sequence generated by two linear feedback shift registers (LFSR) can provide good randomness. This randomness is of great significance in the fields of encryption, modulation and signal processing, and can improve the security of the system.

[0045] Designing a digital module, wherein the digital module is a derived clock generator, and the derived clock generator includes a triangular carrier generator, a sine carrier generator, and an arcsine carrier generator; wherein the triangular carrier generator is designed with an up-down counter, and the sine carrier generator and the arcsine carrier generator are designed to be sequentially executed with a preset sampling rate;

[0046] The random frequency is calculated using a preset carrier frequency formula using the first basic frequency f1=2kHz, the second basic frequency f2=4kHz, the third basic frequency f3=3kHz, the first pseudo-random binary sequence and the second pseudo-random binary sequence; by adjusting different basic frequencies (f1, f2, f3), a variety of frequency signals can be flexibly generated, and this flexibility adapts to the needs of various application environments and enhances the versatility of the system.

[0047] According to the random frequency and digital module, clock signals with frequencies of 400kHz, 300kHz and 200kHz are obtained;

[0048] According to the clock signal, a triangular carrier generator, a sine carrier generator and an inverse sine carrier generator are combined to generate a carrier signal with a random frequency. The AC variable frequency random pulse width modulation is realized through the random frequency carrier signal. This unique modulation method can effectively reduce the electromagnetic interference of the system and enhance the robustness of the signal, especially in power electronics and motor drive applications.

[0049] The random frequency carrier signal is applied to the generation process of AC variable frequency random pulse width modulation to realize random pulse width modulation control.

[0050] As a preferred implementation, the preset carrier frequency formula is:

[0051] fr=PRBS1×PRBS2×f1+PRBS1×PRBS2×f2+PRBS1×PRBS2×f3;

[0052] Wherein, PRBS1 represents a first pseudo-random binary sequence, PRBS2 represents a second pseudo-random binary sequence, and fr represents a random frequency.

[0053] As a preferred implementation, the triangular carrier generator, the sine carrier generator and the arcsine carrier generator are simulated and verified by using a digital design simulation tool.

[0054] The co-simulation created is a time saving technique to describe hybrid simulation. Two simulators and a synthesizer were used to accomplish this work. ModelsimSE 6.3f was used for digital block design simulation. MATLAB 7.1.0 (2010a) -Simulink tool integrated the three-phase inverter design modeling, analysis tools (FFT-Powergui, Power Spectral Density Oscilloscope) and interface tools. Functional verification done by RTL based test bench was also incorporated into the Modelsim VHDL design. A 50 MHz system clock was used for all VHDL design blocks. Active high reset was used for system design deactivation. The workspace is the area where data between the two simulators is stored. The HDL co-simulation tool is a powerful tool which was used as an interface between the design and analysis environment. The scope of the real-time implementation was analyzed by using Xilinx Project Navigation Tool (ISE Design Suite 14.5) in combination with comprehensive behavioral analysis.

[0055] As a preferred embodiment, the step of evaluating the performance of the carrier signal generating the random frequency is also included:

[0056] Including evaluation indicators harmonic spreading factor HSF and power spectral density PSD;

[0057] Among them, HSF is calculated through the concept of statistical deviation to evaluate the harmonic diffusion effect of random pulse width modulation; PSD monitors the motor condition through vibration analysis;

[0058]

[0059] Among them, H j is the amplitude of the jth harmonic, H0 is the average value of all N-1 harmonics;

[0060] The calculation method of H0 is:

[0061]

[0062] Embodiment 2:

[0063] The present invention also provides an AC variable frequency random pulse width modulation system, comprising:

[0064] Pseudo-random binary sequence module: using two linear feedback shift registers to generate a first pseudo-random binary sequence and a second pseudo-random binary sequence;

[0065] Digital module: Design a digital module, which is a derived clock generator, and the derived clock generator includes a triangular carrier generator, a sine carrier generator, and an arcsine carrier generator; wherein the triangular carrier generator is designed with an up-down counter, and the sine carrier generator and the arcsine carrier generator are designed to be executed sequentially with a preset sampling rate;

[0066] Random frequency generation module: calculates the random frequency by using the first basic frequency f1=2kHz, the second basic frequency f2=4kHz, the third basic frequency f3=3kHz, the first pseudo-random binary sequence and the second pseudo-random binary sequence, using a preset carrier frequency formula;

[0067] Clock signal generation module: According to the random frequency and digital module, clock signals with frequencies of 400kHz, 300kHz and 200kHz are obtained;

[0068] Random frequency carrier signal generation module: generates a random frequency carrier signal by combining a triangular carrier generator, a sine carrier generator and an inverse sine carrier generator according to a clock signal;

[0069] Modulation module: applies the carrier signal of random frequency to the generation process of AC variable frequency random pulse width modulation to realize random pulse width modulation control.

[0070] Embodiment three:

[0071] This embodiment provides an electronic device having a computer program stored thereon. When the computer program is executed by a processor, the AC variable frequency random pulse width modulation method as described in any embodiment of the present invention is implemented.

[0072] Embodiment 4:

[0073] This embodiment provides a computer-readable storage medium for storing one or more programs. When the one or more programs are executed by the one or more processors, the one or more processors implement the AC variable frequency random pulse width modulation method as described in any embodiment of the present invention.

[0074] In the embodiments of the present application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, c can be single or multiple.

[0075] Those of ordinary skill in the art will appreciate that the various units and algorithm steps described in the embodiments disclosed herein can be implemented in a combination of electronic hardware, computer software, and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0076] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0077] In several embodiments provided in the present application, if any function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory; hereinafter referred to as: ROM), random access memory (Random Access Memory; hereinafter referred to as: RAM), disk or optical disk and other media that can store program codes.

[0078] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An AC variable frequency random pulse width modulation method, characterized in that: The following steps are involved: generating a first pseudo-random binary sequence and a second pseudo-random binary sequence using two linear feedback shift registers; Designing a digital module, wherein the digital module is a derived clock generator, and the derived clock generator includes a triangular carrier generator, a sine carrier generator, and an arcsine carrier generator; wherein the triangular carrier generator is designed with an up-down counter, and the sine carrier generator and the arcsine carrier generator are designed to be sequentially executed with a preset sampling rate; The random frequency is calculated by using a preset carrier frequency formula through a first base frequency f1=2kHz, a second base frequency f2=4kHz, a third base frequency f3=3kHz, a first pseudo-random binary sequence and a second pseudo-random binary sequence; According to the random frequency and digital module, clock signals with frequencies of 400kHz, 300kHz and 200kHz are obtained; A carrier signal of random frequency is generated by combining a triangular carrier generator, a sine carrier generator and an inverse sine carrier generator according to a clock signal; The random frequency carrier signal is applied to the generation process of AC variable frequency random pulse width modulation to realize random pulse width modulation control.

2. The AC variable frequency random pulse width modulation method according to claim 1, characterized in that: The preset carrier frequency formula is: fr=PRBS1×PRBS2×f1+PRBS1×PRBS2×f2+PRBS1×PRBS2×f3; Wherein, PRBS1 represents a first pseudo-random binary sequence, PRBS2 represents a second pseudo-random binary sequence, and fr represents a random frequency.

3. The AC variable frequency random pulse width modulation method according to claim 1, characterized in that: The triangular carrier generator, sine carrier generator and inverse sine carrier generator are simulated and verified by using a digital design simulation tool.

4. The AC variable frequency random pulse width modulation method according to claim 1, characterized in that: It also includes steps to evaluate the performance of generating a random frequency carrier signal: Including evaluation indicators harmonic spreading factor HSF and power spectral density PSD; Among them, HSF is calculated through the concept of statistical deviation to evaluate the harmonic diffusion effect of random pulse width modulation; PSD monitors the motor condition through vibration analysis; Among them, H j is the amplitude of the jth harmonic, H 0 is the average value of all N-1 harmonics.

5. An AC variable frequency random pulse width modulation system, characterized in that: include: Pseudo-random binary sequence module: using two linear feedback shift registers to generate a first pseudo-random binary sequence and a second pseudo-random binary sequence; Digital module: Design a digital module, which is a derived clock generator, and the derived clock generator includes a triangular carrier generator, a sine carrier generator, and an arcsine carrier generator; wherein the triangular carrier generator is designed with an up-down counter, and the sine carrier generator and the arcsine carrier generator are designed to be executed sequentially with a preset sampling rate; Random frequency generation module: calculates the random frequency by using the first basic frequency f1=2kHz, the second basic frequency f2=4kHz, the third basic frequency f3=3kHz, the first pseudo-random binary sequence and the second pseudo-random binary sequence, using a preset carrier frequency formula; Clock signal generation module: According to the random frequency and digital module, clock signals with frequencies of 400kHz, 300kHz and 200kHz are obtained; Random frequency carrier signal generation module: generates a random frequency carrier signal by combining a triangular carrier generator, a sine carrier generator and an inverse sine carrier generator according to a clock signal; Modulation module: applies the carrier signal of random frequency to the generation process of AC variable frequency random pulse width modulation to realize random pulse width modulation control.

6. The AC variable frequency random pulse width modulation system according to claim 1, characterized in that: The random frequency generation module presets the carrier frequency formula as follows: fr=PRBS1×PRBS2×f1+PRBS1×PRBS2×f2+PRBS1×PRBS2×f3; Wherein, PRBS1 represents a first pseudo-random binary sequence, PRBS2 represents a second pseudo-random binary sequence, and fr represents a random frequency.

7. The AC variable frequency random pulse width modulation system according to claim 1, characterized in that: The digital modules, the triangular carrier generator, the sine carrier generator and the inverse sine carrier generator, are simulated and verified by using a digital design simulation tool.

8. The AC variable frequency random pulse width modulation system according to claim 1, characterized in that: It also includes a performance evaluation module: steps for evaluating the performance of a carrier signal generating a random frequency: Including evaluation indicators harmonic spreading factor HSF and power spectral density PSD; Among them, HSF is calculated through the concept of statistical deviation to evaluate the harmonic diffusion effect of random pulse width modulation; PSD monitors the motor condition through vibration analysis; Among them, H j is the amplitude of the jth harmonic, and H0 is the average value of all N-1 harmonics.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the AC variable frequency random pulse width modulation method as described in any one of claims 1 to 4 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the AC variable frequency random pulse width modulation method as claimed in any one of claims 1 to 4 is implemented.

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