A method for generating SPWM waveforms, a waveform generator, and an inverter system

Abstract

The application discloses a SPWM waveform generation method. The method comprises the following steps: obtaining parameters of a plurality of preset angles, wherein the parameters comprise B value and A value; calculating high and low level sending times and delay time corresponding to the plurality of preset angles according to the parameters; and sending control signals to an inverter circuit according to the high and low level sending times and the delay time. In the calculation step, the parameter value Y is calculated by using a formula Y=B+A*SIN(Φ), wherein Φ is the preset angle; the high level sending time N_high and the low level sending time N_low are calculated according to the Y value; and the high level delay time and the low level delay time are calculated. The application simplifies the circuit structure, does not need a carrier wave and a modulation wave comparison circuit, and reduces the system complexity and cost; the SPWM waveform can be generated by pre-storing parameters and simple calculation, the command is sent in a fixed cycle and delay compensation is carried out, and the sine characteristic and accurate control of the waveform are ensured.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to an SPWM waveform generation method, an SPWM waveform generator, and an inverter system. Background Technology

[0002] In modern power electronic systems, inverters are key devices for converting direct current (DC) to alternating current (AC). The performance of the inverter directly affects the efficiency and output quality of the entire system. Currently, sinusoidal pulse width modulation (SPWM) technology is widely used in inverter control to generate high-quality sinusoidal output.

[0003] Traditional SPWM technology typically requires real-time comparison of the carrier and modulated waveforms, which necessitates complex hardware circuitry and precise analog signal processing. This not only increases system complexity and cost but can also introduce noise and distortion, affecting the quality of the output waveform.

[0004] Furthermore, existing SPWM implementations often rely on high-performance digital signal processors (DSPs) or complex application-specific integrated circuits (ASICs), which limits the system's flexibility and makes it difficult to quickly adjust and optimize for different application scenarios.

[0005] In practical applications, inverter systems also face the challenge of electromagnetic interference. Traditional control signal transmission methods are easily affected by external electromagnetic interference, leading to decreased control accuracy and even potential system malfunctions.

[0006] These issues have resulted in shortcomings in existing SPWM technology in terms of simplicity of implementation, cost-effectiveness, and anti-interference capability, limiting the performance and reliability of inverter systems in various application scenarios. Summary of the Invention

[0007] The purpose of this invention is to provide an SPWM waveform generation method, an SPWM waveform generator, and an inverter system to solve the problems of complex SPWM waveform generation circuit structure and high cost in the prior art.

[0008] To achieve the above objectives, the present invention provides an SPWM waveform generation method, comprising the following steps:

[0009] The system acquires parameters for multiple preset angles, including B and A values; calculates the number of high and low level transmissions and the delay time corresponding to the multiple preset angles based on the parameters; and sends control signals to the inverter circuit based on the number of high and low level transmissions and the delay time.

[0010] Further, the steps of calculating the number of high and low level transmissions and the delay time based on the parameters include: calculating the parameter value Y using the formula Y = B + A * SIN(Φ), where Φ is a preset angle; calculating the number of high level transmissions N_high and the number of low level transmissions N_low based on the Y value; calculating the number of high level transmissions N_high = Y / 90; and calculating the number of low level transmissions N_low = 400 - N_high.

[0011] Specifically, the step of calculating the delay time includes: calculating the high-level delay time = (N_high - floor(N_high)) * fixed period; calculating the low-level delay time = (N_low - floor(N_low)) * fixed period; where floor represents the floor function.

[0012] Furthermore, the method also includes the step of: when the calculated number of transmissions is less than a preset threshold, setting the number of transmissions to the preset threshold and increasing the delay time accordingly.

[0013] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described SPWM waveform generation method.

[0014] The present invention also provides an SPWM waveform generator, comprising:

[0015] The parameter acquisition module is used to acquire parameters for multiple preset angles, including B values ​​and A values.

[0016] The calculation module is used to calculate the number of high and low level transmissions and the delay time corresponding to multiple preset angles based on the parameters;

[0017] The signal transmission module is used to send control signals to the inverter circuit according to the number of high and low level transmissions and the delay time.

[0018] Furthermore, the computing module is specifically used for:

[0019] The parameter value Y is calculated using the formula Y = B + A * SIN(Φ), where Φ is a preset angle;

[0020] Calculate the number of high-level transmissions and the number of low-level transmissions based on the Y value;

[0021] Calculate the high-level delay time = (N_high - floor(N_high)) * fixed period;

[0022] Calculate the low-level delay time = (N_low - floor(N_low)) * fixed period;

[0023] Calculate the number of high-level transmissions N_high = Y / 90; calculate the number of low-level transmissions N_low = 400 - N_high;

[0024] Where floor represents the floor function, N_high represents the number of high-level transmissions, and N_low represents the number of low-level transmissions.

[0025] Furthermore, the computing module is also used for:

[0026] When the calculated number of transmissions is less than the preset threshold, the number of transmissions is set to the preset threshold, and the delay time is increased accordingly.

[0027] In addition, the SPWM waveform generator also includes a clock module for providing a clock signal with a fixed period to the signal transmission module.

[0028] The present invention also provides an inverter system, comprising: the aforementioned SPWM waveform generator; a microcontroller connected to the SPWM waveform generator; and an inverter circuit connected to the microcontroller, configured to receive control signals sent by the SPWM waveform generator through the microcontroller and perform inverter operations according to the control signals.

[0029] The SPWM waveform generation method, SPWM waveform generator, and inverter system provided by this invention can generate SPWM waveforms through pre-stored parameters and simple calculations, eliminating the need for complex carrier and modulation wave comparison circuits, greatly simplifying the circuit structure and reducing system complexity and cost. Simultaneously, by employing fixed-period control signal transmission and delay compensation, the sinusoidal characteristics of the waveform and precise control are ensured. When the number of transmissions is less than a preset threshold, the stability of the control signal is further ensured by setting a minimum number of transmissions and increasing the delay time.

[0030] Furthermore, the SPWM waveform generator of this invention uses fiber optic transmission for control signals, significantly improving the system's electromagnetic interference resistance and making it suitable for harsh electromagnetic environments. Flexible control via a microcontroller allows for rapid adjustment of system parameters according to different application requirements, enhancing the system's flexibility and adaptability. The integrated design of the inverter system simplifies the overall structure, making it easy to implement and maintain, while ensuring high-quality output waveforms, effectively reducing harmonic content, and improving system efficiency. Attached Figure Description

[0031] Figure 1 This is a flowchart of an SPWM waveform generation method according to an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the SPWM waveform period in one embodiment of the present invention;

[0033] Figure 3 This is a block diagram of an SPWM waveform generator structure according to an embodiment of the present invention;

[0034] Figure 4 This is a block diagram of an inverter system structure according to an embodiment of the present invention.

[0035] In the diagram: 1. Parameter storage module, 2. Calculation module, 3. Signal transmission module, 4. Clock module. Detailed Implementation

[0036] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the described embodiments are only used to explain the technical principles of the present invention and are not intended to limit its scope of protection. Those skilled in the art should understand that various transformations, modifications, or equivalent substitutions can be made to these embodiments without departing from the spirit and scope of the present invention. All such transformations, modifications, or equivalent substitutions should be considered to fall within the scope of protection defined by the claims of the present invention.

[0037] like Figure 1 As shown, the present invention provides an SPWM waveform generation method, comprising the following steps:

[0038] S1: Obtain parameters for multiple preset angles. These parameters include B and A values, which are pre-stored in a parameter storage module. In this embodiment, 10 key angle points are selected: 0°, 36°, 72°, 108°, 144°, 180°, 216°, 252°, 288°, and 324°. The B and A values ​​corresponding to each angle point are obtained through experimental optimization and stored in the parameter storage module. For this embodiment, both A and B values ​​are set to 18000. This selection simplifies the calculation process while ensuring the symmetry and accuracy of the SPWM waveform.

[0039] It is worth noting that the present invention is not limited to the specific embodiments described above. In other possible implementations, the system can be adjusted and optimized in various ways according to actual needs. For example, the values ​​of A and B can be dynamically adjusted to adapt to different load conditions or output requirements, thereby optimizing the output of the SPWM waveform in real time. Another possible variation is to use different values ​​of A and B, such as A value of 18000 and B value of 19000, which can generate an SPWM waveform with a specific bias.

[0040] S2: Calculate the number of high and low level transmissions and the delay time corresponding to multiple preset angles based on the parameters. The specific calculation process is as follows:

[0041] a) The parameter value Y is calculated using the formula Y=B+A*SIN(Φ), where Φ is the preset angle.

[0042] b) Calculate the number of high-level transmissions N_high and the number of low-level transmissions N_low based on the Y value. The calculation formula is:

[0043] N_high = Y / 90

[0044] N_low = 400 - N_high

[0045] Table 1. Key Angles and Number of High and Low Level Transmissions for SPWM Waveform Generation

[0046] angle B A 0° 200 200 36° 317 82 72° 390 10 108° 390 10 144° 317 82 180° 200 200 216° 82 317 252° 9 390 288° 9 390 324° 82 317

[0047] c) Calculate the high-level delay time and the low-level delay time:

[0048] High-level delay time = (N_high - floor(N_high)) * fixed period

[0049] Low-level delay time = (N_low - floor(N_low)) * fixed period

[0050] Here, floor represents the floor function, and in one specific embodiment, the fixed period is 5 μs. In another embodiment, the fixed period is an adjustable period, which can be adjusted from 0.5 microseconds (μs) to 20 microseconds (μs).

[0051] S3: Send control signals to the inverter circuit according to the number of high and low level transmissions and the delay time. For example... Figure 2 As shown, in a complete SPWM waveform cycle, high and low levels alternate, the duration of each level is determined by the number of transmissions, and there is a delay after each level ends.

[0052] Specifically, taking a 36° angle as an example:

[0053] S1: B = 18000, A = 18000;

[0054] S2:Y=18000+18000*SIN(36*π / 180)≈28580.68;

[0055] N_high=28580.68 / 90≈317.56;

[0056] N_low = 400 - 317.56 = 82.44;

[0057] S3: Actual number of high-level transmissions = floor(317.56) = 317;

[0058] High-level delay time = (317.56-317)*250≈140ns;

[0059] The actual number of low-level transmissions = floor(82.44) = 82;

[0060] Low-level delay time = (82.44-82)*250≈110ns.

[0061] In practical applications, when the calculated number of transmissions is less than a preset threshold (e.g., 10), the number of transmissions is set to the preset threshold, and the delay time is increased accordingly to ensure the stability of the control signal.

[0062] The described SPWM waveform generation method can generate SPWM waveforms through pre-stored parameters and simple calculations, eliminating the need for complex carrier and modulation wave comparison circuits and greatly simplifying the circuit structure. Simultaneously, by sending control signals at fixed periods and performing delay compensation, the sinusoidal characteristics of the waveform and precise control are ensured.

[0063] The SPWM waveform generation method of the present invention has the following beneficial effects:

[0064] 1. It simplifies the circuit structure, eliminating the need for carrier and modulation wave comparison circuits, thus reducing system complexity and cost.

[0065] 2. SPWM waveforms can be generated by pre-stored parameters and simple calculations, which improves the system's response speed and efficiency.

[0066] 3. By using a fixed-period command sending method and performing delay compensation, the sinusoidal characteristics of the waveform and precise control are ensured.

[0067] 4. The system can be flexibly adapted to different application scenarios by adjusting the pre-stored parameters, which improves the system's flexibility and adaptability.

[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0069] The present invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the above-described SPWM waveform generation method. The computer-readable storage medium may be a non-volatile memory such as flash memory, EEPROM, EPROM, or ROM, or a volatile memory such as RAM. The computer program may be written in programming languages ​​such as C or assembly language; its specific implementation is a matter of common practice for those skilled in the art and will not be elaborated further.

[0070] The present invention also provides an SPWM waveform generator, such as Figure 3As shown, the SPWM waveform generator of the present invention includes:

[0071] Parameter storage module 1 is used to store parameters for multiple preset angles. Parameter storage module 1 can be an EEPROM or Flash memory, used to store parameters such as B value and A value.

[0072] Calculation module 2 is used to calculate the number of high and low level transmissions and the delay time corresponding to multiple preset angles based on the parameters. Calculation module 2 can be a microcontroller or FPGA, used to execute the calculation steps in the above-described SPWM waveform generation method.

[0073] The signal transmission module 3 is used to send control signals to the inverter circuit according to the number of high and low level transmissions and the delay time. The signal transmission module 3 includes an optical fiber transmission unit 6, which is used to convert electrical signals into optical signals and transmit them through optical fibers to improve the anti-electromagnetic interference capability.

[0074] Clock module 4 is used to provide a clock signal with a fixed period to the signal transmission module 3. Clock module 4 can be a crystal oscillator circuit or a PLL circuit, used to generate a stable clock signal to ensure the accurate transmission period of the control signal.

[0075] The calculation module 2 is specifically used for:

[0076] a) The parameter value Y is calculated using the formula Y=B+A*SIN(Φ), where Φ is a preset angle;

[0077] b) Calculate the number of high-level transmissions N_high and the number of low-level transmissions N_low based on the Y value;

[0078] c) Calculate the high-level delay time and the low-level delay time.

[0079] The specific implementation of these calculation steps is the same as described in the above SPWM waveform generation method.

[0080] The present invention also provides an inverter system, such as Figure 4 As shown, the inverter system of the present invention includes:

[0081] An SPWM waveform generator is used to generate SPWM control signals.

[0082] A microcontroller (MCU) is connected to the SPWM waveform generator. The microcontroller receives control signals transmitted by the SPWM waveform generator via optical fiber and controls the operation of the inverter circuit.

[0083] An inverter circuit, connected to the microcontroller, is used to receive control signals sent by the SPWM waveform generator through the microcontroller and perform inverter operations according to the control signals. The inverter circuit includes four power switching devices (such as IGBTs or MOSFETs) forming a full-bridge inverter circuit structure.

[0084] Output terminals A and B are connected to the output terminals of the inverter circuit to output the inverted AC power.

[0085] The DC power supply (CD) provides the DC input voltage to the inverter circuit.

[0086] The inverter system of the present invention has the following beneficial effects:

[0087] 1. The use of fiber optic transmission for control signals greatly improves the system's resistance to electromagnetic interference, making it suitable for harsh electromagnetic environments.

[0088] 2. Flexible control is achieved through a microcontroller, allowing for rapid adjustment of system parameters according to different application requirements.

[0089] 3. The structure is simple and easy to implement and maintain.

[0090] 4. The full-bridge inverter circuit structure can achieve high-efficiency DC to AC conversion.

[0091] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of generating SPWM waveforms, characterized by, The method comprises the following steps: obtaining parameters of a plurality of preset angles, the parameters comprising a B value and an A value; calculating high and low level sending times and delay times corresponding to the plurality of preset angles according to the parameters; the step of calculating the high and low level sending times and the delay times according to the parameters comprises: calculating a parameter value Y using a formula Y = B + A * SIN (Φ), wherein Φ is the preset angle; calculating a high level sending time N_high = Y / 90; calculating a low level sending time N_low = 400 - N_high; wherein N_high represents the high level sending time and N_low represents the low level sending time; the step of calculating the delay times comprises: calculating a high level delay time = (N_high - floor (N_high)) * fixed period; calculating a low level delay time = (N_low - floor (N_low)) * fixed period; wherein floor represents a floor function; sending control signals to an inverter circuit according to the high and low level sending times and the delay times.

2. The method of claim 1, wherein, The method further comprises the step of: when the calculated sending time is less than a preset threshold, setting the sending time to the preset threshold and correspondingly increasing the delay time.

3. A computer-readable storage medium, characterized in that, A computer program is stored on the computer program product, and the program is executed by a processor to implement the steps of the SPWM waveform generation method according to any one of claims 1 to 2.

4. A SPWM waveform generator characterized by, The computer program product comprises: a parameter obtaining module configured to obtain parameters of a plurality of preset angles, the parameters comprising a B value and an A value; a calculation module configured to calculate high and low level sending times and delay times corresponding to the plurality of preset angles according to the parameters; the calculation module is specifically configured to: calculate a parameter value Y using a formula Y = B + A * SIN (Φ), wherein Φ is the preset angle; calculate a high level sending time N_high = Y / 90; calculate a low level sending time N_low = 400 - N_high; calculate a high level delay time = (N_high - floor (N_high)) * fixed period; calculate a low level delay time = (N_low - floor (N_low)) * fixed period; wherein floor represents a floor function, N_high represents the high level sending time, and N_low represents the low level sending time; a signal sending module configured to send control signals to an inverter circuit according to the high and low level sending times and the delay times.

5. The SPWM waveform generator of claim 4, wherein, The calculation module is further configured to: when the calculated sending time is less than a preset threshold, set the sending time to the preset threshold and correspondingly increase the delay time.

6. The SPWM waveform generator of claim 4, wherein, The computer program product further comprises a clock module configured to provide a fixed period clock signal for the signal sending module.

7. An inverter system characterized by comprising: The computer program product comprises: an SPWM waveform generator according to any one of claims 4 to 6; a microcontroller connected to the SPWM waveform generator; an inverter circuit connected to the microcontroller, configured to receive control signals sent by the SPWM waveform generator through the microcontroller and perform inverter operation according to the control signals.

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