System and method for generating three-phase horn modulated wave by three-phase sinusoidal modulated wave

Abstract

The invention aims to provide a system and a method for generating a three-phase horn modulated wave from a three-phase sinusoidal modulated wave. The system comprises a three-path multiplier (1), an amplitude conversion module (2), a first summation module (3), a channel selection module (4), a second summation module (5) and a third summation module (6). The method comprises the following steps: a, generating an original sine wave signal by using a sine modulation wave generation system; b, performing equal amplitude transformation on the three-phase original sine wave signal by using an amplitude transformation module 2 to obtain a synthetic amplitude Uamp of the three-phase original signal; c, setting a proportionality coefficient Coe, and rectifying the original sine wave signal by using a multiplier (1); d, obtaining the content Ucom of the injected original signal by using a second summation module (5); and e, superposing the original sine wave signal and the content Ucom of the injected original signal obtained in the step d to obtain a horn modulation wave signal. The invention is applied to the technical field of power electronics.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular to a system and method for generating a three-phase ram horn modulation wave from a three-phase sinusoidal modulation wave. Background Art

[0002] In power electronics, when the modulation signal in three-phase SPWM inverter control is sinusoidal, the system output will exhibit a high content of low-order harmonics near the modulation frequency, such as the 3rd, 5th, and 7th harmonics. For the low-pass filter in the subsequent system main power circuit design, reducing the grid-connected current harmonics at the same power level requires increasing the LC filter circuit, which is detrimental to cost reduction and efficiency. Furthermore, SVPWM (vector pulse width modulation), a commonly used PWM modulation technique, uses vector-based time calculations to allocate the operating time of various components in the bridge circuit. This method can improve the current harmonics (THD) of the grid-connected inverter while effectively avoiding excessive costs. Compared to SPWM, the theoretical calculations of SVPWM based on a sinusoidal signal input are more complex. While the cost of the physical components does not increase, the computational effort is higher, requiring more computing power and time, which can have a certain impact on the system. Therefore, it is necessary to design a method that is both applicable to SVPWM technology and effectively reduces the computational complexity associated with sinusoidal signal input. For SVPWM (vector pulse width modulation technology), the use of horn wave signal input can effectively avoid excessive calculation. Therefore, when controlling three-phase SPWM inverter, if the sine wave signal can be converted into a horn wave signal first and then input into SVPWM (vector pulse width modulation technology) for signal modulation, it can effectively reduce the calculation amount and avoid excessive cost. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a system and method for generating a three-phase horn modulation wave from a three-phase sinusoidal modulation wave. The three-phase horn modulation wave generated by the present invention is convenient for SVPWM modulation and can effectively reduce costs.

[0004] The technical solution adopted by the present invention is a system for generating a three-phase ram-horn modulated wave from a three-phase sinusoidal modulated wave, the system comprising: a three-way multiplier for receiving a proportional coefficient Coe and original sinusoidal wave signals UA, UB, UC inputs to ensure the quality of the output waveform; Amplitude conversion module for performing equal amplitude conversion on original sinusoidal wave signals UA, UB, UC; a first summing module configured to sum the signal output by the multiplier and the signal output by the amplitude conversion module; a channel selection module for selecting different input channels according to whether the original sinusoidal wave signal is located on the positive half axis or the negative half axis, wherein one channel output by the multiplier is one channel and one channel output by the first summing module is another channel; a second summing module for obtaining the content Ucom of the injected original signal, wherein the output amplitude of the amplitude conversion module and the amplitude output of the channel selection module are both input into the second summing module; and A third summing module is used to superimpose the original sinusoidal wave signals UA, UB, UC and the content Ucom of the injected original signal output by the second summing module, and the third summing module outputs a ram's horn modulated wave signal.

[0005] A method for performing ram-horn wave modulation using the above-mentioned system for generating a three-phase ram-horn modulation wave from a three-phase sinusoidal modulation wave comprises the following steps: a. Use the sinusoidal modulation wave generation system to generate the original sinusoidal wave signal. Assume that the three-phase original sinusoidal wave signal is as follows: UA = M*Sin(wt) UB = M*Sin(wt+2*π / 3) ……Formula (Ⅰ), UC = M*Sin(wt+4*π / 3) Where UA, UB, and UC represent the instantaneous values ​​of the three-phase voltages, M represents the peak value of the voltage, w represents the angular frequency, and t represents time. b. Use the amplitude conversion module to perform equal amplitude conversion on the three-phase original sine wave signal to obtain the composite amplitude Uamp of the three-phase original signal. The conversion formula is as follows: Uamp=(UA*Cos(θ)+UB*Cos(θ+2*π / 3)+UC*Cos(θ+4*π / 3))*2 / 3…Formula (II), Wherein, θ represents the synchronous angular frequency in the coordinate system; c. Set the proportional coefficient Coe and use the multiplier to rectify the original sinusoidal wave signals UA, UB, and UC, wherein the value range of the proportional coefficient Coe is 0<Coe<1. When the original sine wave signal is located on the positive half axis, then Ua=UA*Coe Ub=UB*Coe ...Formula (III); Uc=UB*Coe When the original sine wave signal is located at the negative half axis, through the first summing module, we have Ua=UA*Coe+Uamp Ub=UB*Coe+Uamp...Formula (IV); Uc=UB*Coe+Uamp d. The maximum value Max and the minimum value Min among Ua, Ub, and Uc are selected at the same time by the channel selection module and input into the second summing module. The second summing module sums the selected maximum value Max, the minimum value Min, and the composite amplitude Uamp output by the amplitude conversion module, and performs a 1 / 2 multiplication to obtain the content Ucom of the injected original signal. The calculation formula is as follows: Ucom=(Uamp-Max(Ua, Ub, Uc)-Min(Ua, Ub, Uc)) / 2...Formula (V); e. Superimpose the original sinusoidal wave signals UA, UB, UC with the content Ucom of the injected original signal obtained in step d to obtain the ram horn modulated wave signal.

[0006] The beneficial effects of the present invention are as follows: 1. Significantly reduce harmonic content and optimize grid quality: By converting the sinusoidal modulation wave into a horn wave, the generation of 3rd, 5th, and 7th order low-order harmonics in traditional SPWM modulation is effectively suppressed. Experimental data shows that the total harmonic distortion rate of the grid current is significantly reduced under the horn wave input, reducing the complexity and cost of subsequent filter design.

[0007] 2. Avoid complex vector calculations and significantly reduce computing power requirements: Compared with SVPWM, which requires real-time calculation of vector action time and spatial position, horn wave modulation can complete modulation through simple multiplication, superposition and channel selection. This solution avoids the complex coordinate transformation and sector judgment process in SVPWM, significantly reducing the computing power consumption and real-time calculation delay of the control chip.

[0008] 3. Dynamically adjust the modulation ratio to prevent over-modulation distortion: through the proportional coefficient Coe (0 <Coe<1)对正弦波进行限幅(公式III、IV),结合幅值变换模块(公式II)的实时反馈,动态调整注入信号含量Ucom(公式V);该机制能保证输出羊角波的幅值与相位精度,提升系统稳定性。

[0009] 4. Simplified hardware implementation reduces costs: The horn wave generation requires only three multipliers, an adder, and a channel selection module, eliminating the complex sector determination logic and storage units required in SVPWM. This simplified hardware structure reduces the inverter control board's bill of materials (BOM) cost and PCB layout area, meeting the industry's demand for cost reduction and efficiency improvement.

[0010] 5. Strong compatibility, adaptable to various topologies and scenarios: This solution can be directly applied to three-phase NPC inverters and can also be extended to other power electronic conversion scenarios (such as SVG, UPS, etc.); by adjusting the Coe coefficient, it can flexibly adapt to different grid voltage levels and load requirements, expanding the scope of application of the technology.

[0011] 6. Experimental verification of high efficiency, balancing THD and efficiency: Test results show that the THD of horn wave modulation is only 1.05% when Coe=0.8, which improves the filtering performance by about 17% compared with traditional solutions. At the same time, due to the reduced calculation amount, the inverter switching loss is reduced by about 12%, and the overall efficiency is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a simplified structural block diagram of the system for generating a three-phase ram horn modulation wave from a three-phase sinusoidal modulation wave; Figure 2 This is a simplified connection structure diagram of the system of the present invention applied to a three-phase power system; Figure 3 is a principle block diagram of the amplitude conversion module; Figure 4 It is the waveform diagram of the original three-phase sinusoidal modulation wave; Figure 5 1 is a waveform diagram of a ram horn modulation wave with a coefficient Coe of 0.8 in an embodiment of the present invention; Figure 6 1 is a waveform diagram of a ram horn modulation wave with a coefficient Coe of 0.3 in an embodiment of the present invention; Figure 7 This is a test result diagram of the current harmonic signal after the ram horn wave output by the system of the present invention is input into the three-phase power system; Figure 8 This is the test result diagram of the current harmonic signal after the traditional sine wave is input into the three-phase power system and processed. DETAILED DESCRIPTION

[0013] like Figures 1-8 As shown, in the present invention, a system for generating a three-phase ram horn modulation wave from a three-phase sinusoidal modulation wave includes A three-way multiplier 1 for receiving the proportional coefficient Coe and the original sine wave signals UA, UB, and UC to ensure the quality of the output waveform; Amplitude conversion module 2 for performing equal amplitude conversion on the original sinusoidal wave signals UA, UB, UC; a first summing module 3 for summing the signal output by the multiplier 1 and the signal output by the amplitude conversion module 2; a channel selection module 4 for selecting different input channels according to whether the original sinusoidal wave signal is located on the positive half-axis or the negative half-axis, wherein one of the outputs of the multiplier 1 is one channel and one of the outputs of the first summation module 3 is another channel; a second summation module 5 for calculating the content Ucom of the injected original signal, wherein the output amplitude of the amplitude transformation module 2 and the output amplitude of the channel selection module 4 are both input into the second summation module 5; and a third summation module 6 for superimposing the original sinusoidal wave signals UA, UB, UC and the content Ucom of the injected original signal output by the second summation module 5, wherein the third summation module 6 outputs a goat horn modulation wave signal.

[0014] The method for generating a goat horn modulation wave by using the system for generating a three-phase sinusoidal modulation wave as described above, characterized in that the method comprises the following steps: a. generating original sinusoidal wave signals by using a sinusoidal modulation wave generation system, wherein the three-phase original sinusoidal wave signals are as follows: UA = M*Sin(wt) UB = M*Sin(wt+2*π / 3) ……Equation (I), UC = M*Sin(wt+4*π / 3) wherein UA, UB and UC represent the instantaneous values of three-phase voltage, M represents the peak value of voltage, w represents the angular frequency, and t represents time; b. performing equal amplitude transformation on the three-phase original sinusoidal wave signals by using the amplitude transformation module 2 to obtain the resultant amplitude Uamp of the three-phase original signals, wherein the transformation formula is as follows: Uamp=(UA*Cos(θ)+UB*Cos(θ+2*π / 3)+UC*Cos(θ+4*π / 3))*2 / 3 ……Equation (II), wherein θ represents the synchronous angular frequency in the coordinate system; c. setting a proportional coefficient Coe and rectifying the original sinusoidal wave signals UA, UB and UC by using the multiplier 1, wherein the value range of the proportional coefficient Coe is 0

[0015] When the original sinusoidal wave signal is located on the positive half-axis, then Ua=UA*Coe Ub=UB*Coe ……Equation (III); Uc=UB*Coe When the original sine wave signal is located at the negative half axis, through the first summing module 3, we have Ua=UA*Coe+Uamp Ub=UB*Coe+Uamp...Formula (IV); Uc=UB*Coe+Uamp d. The maximum value Max and the minimum value Min among Ua, Ub, and Uc are selected at the same time by the channel selection module 4 and input into the second summing module 5. The second summing module 5 sums the selected maximum value Max, the minimum value Min, and the composite amplitude Uamp output by the amplitude conversion module 2, and performs a 1 / 2 multiplication. This can limit the amplitude and further obtain the content Ucom of the injected original signal. The calculation formula is as follows: Ucom=(Uamp-Max(Ua, Ub, Uc)-Min(Ua, Ub, Uc)) / 2...Formula (V); e. Superimpose the original sinusoidal wave signals UA, UB, UC with the content Ucom of the injected original signal obtained in step d to obtain the ram horn modulated wave signal.

[0016] like Figure 2 As shown, the three-phase signal of the three-phase source is collected through CT2 / PT1, filtered by L2, C1, and L1, and then collected by CT1 and input to NPC. On the other side, the voltage value is set according to the demand (such as Figure 2 The 800V in the circuit is then generated by the sinusoidal modulation wave generation system to generate a sinusoidal wave signal. This signal is then input into the three-phase sinusoidal modulation wave generation system to generate a three-phase horn modulation wave. This horn modulation wave is then modulated by PWM and input into the NPC to modulate the signal input by CT1. This signal is then output to the load R.

[0017] like Figure 3 The figure shows the amplitude conversion principle of the amplitude conversion module 2. Cos1, cos2, and cos3 correspond to three-phase sine waves (commonly referred to as phases A, B, and C), with a phase difference of 120°. "1, 2, and 3" correspond to the three-phase labels (a, b, and c), and "x" may indicate signal preprocessing. The adder symbol "⊕" indicates signal superposition. The coefficient "2 / 3" is used for amplitude compensation to ensure that the amplitude remains unchanged before and after the transformation. The process is as follows: each phase signal is directly input into "x" and multiplied by "1, 2, and 3" respectively to perform amplitude conversion, or phase weighting is performed according to the coordinate transformation requirements. The adder performs a superposition operation on the transformed signals. To restore equal amplitude, the superposition result is multiplied by 2 / 3 to offset the amplitude attenuation during the transformation process. Ultimately, the output amplitude is equal to the amplitude of the input phase signal.

[0018] likeFigure 5 and Figure 6 The waveform diagrams of the goat-horn wave generated by the system of the application are shown in Figs. Figure 5 The coefficient Coe set in the formula is 0.8, Figure 6 The coefficient Coe set in the formula is 0.3.

[0019] As shown in Figs. Figure 7 and Figure 8 The detection result diagrams of the total harmonic content of the grid current output after the goat-horn wave and the sine wave are input into the three-phase power system are shown in Figs. After the goat-horn wave is input, the current harmonic THD = 1.05%; after the sine wave is input, the current harmonic THD = 1.27%. It can be seen that the goat-horn wave signal generated by the application has better effect on the suppression of the grid current harmonic after being input into the three-phase power system.

[0020] Finally, it should be emphasized that the above description is only the preferred embodiments of the application and is not used to limit the application. For those skilled in the art, the application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A system for generating a three-phase ram horn modulation wave from a three-phase sinusoidal modulation wave, characterized in that: The system includes A three-way multiplier (1) for receiving the proportional coefficient Coe and the original sine wave signals UA, UB, and UC to ensure the quality of the output waveform; An amplitude conversion module (2) for performing equal amplitude conversion on the original sinusoidal wave signals UA, UB, and UC; a first summing module (3) for summing the signal output by the multiplier (1) and the signal output by the amplitude conversion module (2); A channel selection module (4) for selecting different input channels according to whether the original sinusoidal wave signal is located on the positive half axis or the negative half axis, wherein one channel output by the multiplier (1) is one channel, and one channel output by the first summing module (3) is another channel; A second summing module (5) for obtaining the content Ucom of the injected original signal, wherein the output amplitude of the amplitude conversion module (2) and the amplitude output of the channel selection module (4) are both input into the second summing module (5); as well as A third summing module (6) is used for superimposing the original sinusoidal wave signals UA, UB, UC and the content Ucom of the injected original signal output by the second summing module (5), wherein the third summing module (6) outputs a ram horn modulated wave signal.

2. A method for generating a three-phase spur-horn modulation wave by using the system for generating a three-phase spur-horn modulation wave by using the three-phase sine modulation wave according to claim 1, characterized in that: The method comprises the following steps: a. Use the sinusoidal modulation wave generation system to generate the original sinusoidal wave signal. Assume that the three-phase original sinusoidal wave signal is as follows: UA = M*Sin(wt) UB = M*Sin(wt+2*π / 3) ……Formula (Ⅰ), UC = M*Sin(wt+4*π / 3) Where UA, UB, and UC represent the instantaneous values ​​of the three-phase voltages, M represents the peak value of the voltage, w represents the angular frequency, and t represents time. b. Use the amplitude conversion module (2) to perform equal amplitude conversion on the three-phase original sine wave signal to obtain the composite amplitude Uamp of the three-phase original signal. The conversion formula is as follows: Uamp=(UA*Cos(θ)+UB*Cos(θ+2*π / 3)+UC*Cos(θ+4*π / 3))*2 / 3…Formula (II), Wherein, θ represents the synchronous angular frequency in the coordinate system; c. Set the proportional coefficient Coe and use the multiplier (1) to rectify the original sinusoidal wave signals UA, UB, and UC, wherein the value range of the proportional coefficient Coe is 0<Coe<1. When the original sine wave signal is located on the positive half axis, then Ua=UA*Coe Ub=UB*Coe ...Formula (III); Uc=UB*Coe When the original sine wave signal is located at the negative half axis, through the first summing module (3), we have Ua=UA*Coe+Uamp Ub=UB*Coe+Uamp...Formula (IV); Uc=UB*Coe+Uamp d. The maximum value Max and the minimum value Min among Ua, Ub, and Uc are selected at the same time by the channel selection module (4) and input into the second summing module (5). The second summing module (5) sums the selected maximum value Max, the minimum value Min, and the synthesized amplitude Uamp output by the amplitude conversion module (2), and performs a 1 / 2 multiplication to obtain the content Ucom of the injected original signal. The calculation formula is as follows: Ucom=(Uamp-Max(Ua, Ub, Uc)-Min(Ua, Ub, Uc)) / 2...Formula (V); e. Superimpose the original sinusoidal wave signals UA, UB, UC with the content Ucom of the injected original signal obtained in step d to obtain the ram horn modulated wave signal.

Images