A broadband harmonic disturbance device and control method

Abstract

The present invention discloses a broadband harmonic disturbance device and a control method. The device includes: a harmonic power injection unit, a voltage disturbance injection branch, and a current disturbance injection branch; the power-taking end of the harmonic power injection unit is connected to a single-phase power network, and its voltage and current injection ends are respectively connected to the single-phase power network through the voltage disturbance injection branch and the current disturbance injection branch; the present invention controls the broadband harmonic disturbance device through the control method to enable the device to simultaneously have a current disturbance mode and a voltage disturbance mode.

Description

Technical Field

[0001] The present invention relates to the technical field of impedance measurement of single-phase power networks and VSC type converters, and particularly relates to a broadband harmonic disturbance device and a control method. Background Art

[0002] With the rapid development of new energy power generation, flexible DC power transmission, and high-speed railways, the major industrial systems represented by these three all rely on high-power power electronic conversion technology. The voltage source converter (VSC) is widely used due to its strong controllability, fast dynamic response, high energy conversion efficiency, etc. However, problems such as its diverse control methods, non-linear changes, and strong asymmetric coupling characteristics have brought a series of oscillation and instability problems covering the entire frequency domain. Currently, most of the research on oscillation and instability problems is based on the method of impedance matching analysis. However, due to the non-linear time-varying characteristics of the converter equipment, the dynamic changes of power network parameters, and the black-boxing of equipment parameters, it is extremely difficult to establish an accurate mathematical model for the impedance characteristics of the converter equipment. By means of impedance measurement, the above problems can be avoided. Therefore, it is of great significance to study the impedance measurement technology of high-power converter equipment.

[0003] Among the current impedance measurement methods, the perturbation injection method has high measurement accuracy. This method can be divided into the voltage perturbation injection method and the current perturbation injection method according to the perturbation injection method. By serially injecting a perturbation voltage or parallel injecting a perturbation current into the system respectively, the response of the measured system is obtained, and then the frequency-domain impedance characteristics of the measured system are obtained through impedance calculation. When performing impedance measurement, due to the large difference in impedance between the power network and the VSC type converter equipment, according to the principle of series voltage division and parallel current division, only using one perturbation injection method when measuring different measured systems cannot meet the requirements of measurement accuracy. The traditional "sweeping frequency method" has a long measurement time and cannot reflect the real-time frequency-domain impedance characteristics of the system. Summary of the Invention

[0004] Aiming at the above deficiencies in the prior art, a broadband harmonic disturbance device and a control method provided by the present invention solve the following problems:

[0005] 1. When measuring the VSC type converter equipment and the single-phase power network, using one perturbation injection method results in low measurement accuracy.

[0006] 2. The traditional "sweeping frequency method" has a long measurement time and cannot reflect the real-time frequency-domain impedance characteristics of the VSC type converter equipment.

[0007] To achieve the above invention purpose, the technical solution adopted by the present invention is: a broadband harmonic disturbance device, including: a harmonic power injection unit, a voltage perturbation injection branch, and a current perturbation injection branch;

[0008] The power-taking end of the harmonic power injection unit is connected to the single-phase power network, and its voltage and current injection ends are respectively connected to the single-phase power network through a voltage disturbance injection branch and a current disturbance injection branch.

[0009] Further, the harmonic power injection unit includes: a single-phase multi-winding step-down transformer T1, a plurality of harmonic power sub-modules, a mode selector, and a broadband coupling transformer T2;

[0010] The primary winding of the single-phase multi-winding step-down transformer T1 serves as the power-taking end of the harmonic power injection unit; each secondary winding of the single-phase multi-winding step-down transformer T1 is connected to the input end of a harmonic power sub-module; the plurality of harmonic power sub-modules are: harmonic power sub-module 1, harmonic power sub-module 2,..., harmonic power sub-module j,..., harmonic power sub-module N, where j and N are positive integers; each harmonic power sub-module includes: a first output end and a second output end; the second output end of the harmonic power sub-module j is connected to the first output end of the harmonic power sub-module j + 1, where 1 ≤ j ≤ N - 1; the second output end of the harmonic power sub-module N is connected to the common end of the mode selector; the first output end of the harmonic power sub-module 1 is connected to the input end of the mode selector; one end of the primary side of the broadband coupling transformer T2 is connected to the output end of the mode selector, and the other end of its primary side is connected to the common end of the mode selector; the secondary side of the broadband coupling transformer T2 serves as the voltage and current injection end of the harmonic power injection unit.

[0011] Further, the mode selector includes: a single-pole single-throw switch S2, a single-pole single-throw switch S2', a single-pole single-throw switch S3, a single-pole single-throw switch S4, a single-pole single-throw switch S5, a single-pole single-throw switch S6, a current-limiting resistor R1, a current-limiting resistor R2, a current-limiting resistor R3, an inductor L1, an inductor L2, a capacitor C1, and a capacitor C2;

[0012] One end of the single-pole single-throw switch S2 is connected to one end of the single-pole single-throw switch S2', and serves as the input end of the mode selector; the other end of the single-pole single-throw switch S2 is respectively connected to one end of the single-pole single-throw switch S3, one end of the inductor L1, and one end of the capacitor C1; one end of the current-limiting resistor R1 is respectively connected to the other end of the single-pole single-throw switch S3, the other end of the inductor L1, and the other end of the capacitor C1, and its other end is respectively connected to one end of the single-pole single-throw switch S4 and one end of the current-limiting resistor R2; the other end of the current-limiting resistor R2 is respectively connected to the other end of the single-pole single-throw switch S4, one end of the single-pole single-throw switch S5, one end of the current-limiting resistor R3, and one end of the single-pole single-throw switch S6, and serves as the output end of the mode selector; the other end of the current-limiting resistor R3 is respectively connected to the other end of the single-pole single-throw switch S2' and the other end of the single-pole single-throw switch S5; one end of the inductor L2 is connected to the other end of the single-pole single-throw switch S6, and its other end is connected to one end of the capacitor C2; the other end of the capacitor C2 serves as the common end of the mode selector.

[0013] Further, the harmonic power sub-module includes: an inductor L3, switching transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, and a capacitor C3;

[0014] One end of the inductor L3 serves as the first input end of the harmonic power sub-module, and its other end is respectively connected to the emitter of the switching transistor Q2 and the collector of the switching transistor Q1; the collector of the switching transistor Q2 is respectively connected to the collectors of the switching transistors Q3, one end of the capacitor C3, the collectors of the switching transistors Q5, and the collectors of the switching transistors Q6; the emitter of the switching transistor Q1 is respectively connected to the emitters of the switching transistors Q4, the other end of the capacitor C3, the emitters of the switching transistors Q8, and the emitters of the switching transistors Q7; the emitter of the switching transistor Q3 is connected to the collector of the switching transistor Q4, and serves as the second input end of the harmonic power sub-module; the emitter of the switching transistor Q5 is connected to the collector of the switching transistor Q8, and serves as the first output end of the harmonic power sub-module; the emitter of the switching transistor Q6 is connected to the collector of the switching transistor Q7, and serves as the second output end of the harmonic power sub-module.

[0015] Further, the voltage disturbance injection branch includes: a double-pole double-throw switch S7 and a single-pole single-throw switch S8;

[0016] The first end of the double-pole double-throw switch S7 is connected to one end of the secondary side of the broadband coupling transformer T2, its second end is connected to the other end of the secondary side of the broadband coupling transformer T2, and its third end and fourth end are connected to the live wire of the single-phase power network; the single-pole single-throw switch S8 is connected to the live wire and is located between the third end and the fourth end of the double-pole double-throw switch S7.

[0017] Further, the current disturbance injection branch includes: a single-pole single-throw switch S9;

[0018] One end of the single-pole single-throw switch S9 is connected to the live wire of the single-phase power network, and the other end is connected to one end of the secondary side of the broadband coupling transformer T2. The other end of the secondary side of the broadband coupling transformer T2 is connected to the neutral wire of the single-phase power network.

[0019] A control method for a broadband harmonic disturbance device includes the following steps:

[0020] S1. Turn off the single-pole single-throw switch S2, the single-pole single-throw switch S8, and the single-pole single-throw switch S9, disconnect the single-pole single-throw switch S2' and the double-pole double-throw switch S7, or turn off the single-pole single-throw switch S2' and the double-pole double-throw switch S7, and disconnect the single-pole single-throw switch S2, the single-pole single-throw switch S8, and the single-pole single-throw switch S9;

[0021] S2. Perform real-time sampling on the input terminal voltage u j , current i j , and DC voltage u dcj of N harmonic power sub-modules, where j is the jth harmonic power sub-module;

[0022] S3. Based on the double closed-loop decoupling control in the dq coordinate system, control the single-phase voltage rectifier according to the real-time sampled input terminal voltage u j , current i j , and DC voltage u dcj ;

[0023] S4. Calculate the modulation wave of the single-phase H-bridge converter;

[0024] S5. Perform unipolar frequency-doubled carrier phase-shifted modulation on the modulation wave to obtain the switching control signal of each switching tube of each single-phase H-bridge converter;

[0025] S6. Apply the switching control signal to each switching tube of each single-phase H-bridge converter in each harmonic power sub-module, and cooperate with the control of the single-phase voltage rectifier in step S3 to obtain a voltage disturbance or current disturbance signal.

[0026] Further, the formula for the modulation wave of the single-phase H-bridge converter in step S4 is:

[0027]

[0028] where D is the modulation wave of the single-phase H-bridge converter, k is the modulation ratio of the modulation wave, f0 is the starting frequency, Δf is the frequency resolution, N0 is the number of harmonics, N is the number of harmonic power sub-modules, and j is the jth harmonic power sub-module.

[0029] In summary, the beneficial effects of the present invention are:

[0030] 1. When the single-pole single-throw switch S2, the single-pole single-throw switch S8, and the single-pole single-throw switch S9 are closed, and the single-pole single-throw switch S2' and the double-pole double-throw switch S7 are opened, the device operates in the current perturbation mode. When the single-pole single-throw switch S2' and the double-pole double-throw switch S7 are closed, and the single-pole single-throw switch S2, the single-pole single-throw switch S8, and the single-pole single-throw switch S9 are opened, the device operates in the voltage perturbation mode. In the voltage perturbation mode, the harmonic power injection unit is connected in series between the single-phase power network and the VSC type converter device under test. Most of the perturbation voltages are distributed on the side of the VSC type converter device under test with a larger impedance; in the current perturbation mode, the harmonic power injection unit is connected in parallel with the single-phase power network and the VSC type converter device under test. Most of the perturbation currents are distributed on the side of the single-phase power network under test with a smaller impedance. By using different perturbation modes, high-precision impedance measurement of the single-phase power network under test and the VSC type converter device can be achieved.

[0031] 2. Through the voltage perturbation or current perturbation signals generated by the one-time injection device, whose amplitude and frequency band range can be flexibly adjusted, the broadband frequency-domain impedance characteristics of the VSC type converter device under test or the single-phase power network can be obtained at one time. Compared with the traditional "frequency sweep method" impedance measurement method, the impedance measurement speed is greatly improved, and the real-time frequency-domain impedance characteristics of the single-phase power network and the VSC type converter device under test can be reflected.

[0032] 3. The voltage and current dual-mode perturbations adopt the same switch control signal, which can reduce the complexity of the device. In different perturbation modes, the double closed-loop decoupling control method is adopted to adjust the single-phase voltage rectifier to achieve flexible adjustment of the magnitude of the perturbation output voltage or current in the dual mode.

[0033] 4. In the current perturbation mode, by using the parallel resonance circuit of the inductor L1 and capacitor C1 of the mode selector, which presents a large impedance to the fundamental frequency signal, the fundamental voltage borne by the harmonic power sub-module can be reduced; in the voltage perturbation mode, by using the series resonance circuit of the inductor L2 and capacitor C2 of the mode selector, which presents a low impedance to the fundamental frequency signal, the fundamental current borne by the harmonic power module can be reduced, enabling the device to output broadband voltage or current perturbations with uniform amplitude.

[0034] 5. The broadband coupling transformer T2 is a step-up transformer, which connects the harmonic power sub-module to the high voltage output by the single-phase power network, can reduce the system voltage borne by the harmonic power sub-module, and ensures the safety of the device. Description of the Drawings

[0035] Figure 1 It is an overall schematic diagram of a broadband harmonic perturbation device;

[0036] Figure 2It is the circuit diagram of the harmonic power sub-module. Detailed implementation manners

[0037] The following describes the detailed implementation manners of the present invention to facilitate those skilled in the art of the present technology to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the detailed implementation manners. For those of ordinary skill in the art of the present technology, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are within the scope of protection.

[0038] As Figure 1 shown, a broadband harmonic disturbance device includes: a harmonic power injection unit, a voltage disturbance injection branch, and a current disturbance injection branch;

[0039] The power-taking end of the harmonic power injection unit is connected to the single-phase power network, and its voltage and current injection ends are respectively connected to the single-phase power network through the voltage disturbance injection branch and the current disturbance injection branch.

[0040] The harmonic power injection unit includes: a single-phase multi-winding step-down transformer T1, a plurality of harmonic power sub-modules, a mode selector, and a broadband coupling transformer T2;

[0041] The primary winding of the single-phase multi-winding step-down transformer T1 serves as the power-taking end of the harmonic power injection unit; each secondary winding of the single-phase multi-winding step-down transformer T1 is connected to the input end of a harmonic power sub-module; the plurality of harmonic power sub-modules are: harmonic power sub-module 1, harmonic power sub-module 2,..., harmonic power sub-module j,..., harmonic power sub-module N, where j and N are positive integers; each of the harmonic power sub-modules includes: a first output end and a second output end; the second output end of the harmonic power sub-module j is connected to the first output end of the harmonic power sub-module j + 1, where 1 ≤ j ≤ N - 1; the second output end of the harmonic power sub-module N is connected to the common end of the mode selector; the first output end of the harmonic power sub-module 1 is connected to the input end of the mode selector; one end of the primary side of the broadband coupling transformer T2 is connected to the output end of the mode selector, and the other end of its primary side is connected to the common end of the mode selector; the secondary side of the broadband coupling transformer T2 serves as the voltage and current injection end of the harmonic power injection unit.

[0042] In this embodiment, the broadband coupling transformer T2 is a step-up transformer, which isolates the single-phase power network from the broadband harmonic disturbance device and reduces the voltage level borne by the device.

[0043] The single-phase multi-winding step-down transformer T1 is connected to the single-phase power network through the double-pole double-throw switch S1. There are two sets of turns ratios (realized through the center tap) in the primary side of the single-phase multi-winding step-down transformer T1. When the device is working, the double-pole double-throw switch S1 is closed.

[0044] One secondary winding of the single-phase multi-winding step-down transformer T1 is used as the auxiliary power supply of the device.

[0045] The mode selector includes: single-pole single-throw switch S2, single-pole single-throw switch S2', single-pole single-throw switch S3, single-pole single-throw switch S4, single-pole single-throw switch S5, single-pole single-throw switch S6, current-limiting resistor R1, current-limiting resistor R2, current-limiting resistor R3, inductor L1, inductor L2, capacitor C1 and capacitor C2;

[0046] One end of the single-pole single-throw switch S2 is connected to one end of the single-pole single-throw switch S2' and serves as the input end of the mode selector; the other end of the single-pole single-throw switch S2 is respectively connected to one end of the single-pole single-throw switch S3, one end of the inductor L1 and one end of the capacitor C1; one end of the current-limiting resistor R1 is respectively connected to the other end of the single-pole single-throw switch S3, the other end of the inductor L1 and the other end of the capacitor C1, and its other end is respectively connected to one end of the single-pole single-throw switch S4 and one end of the current-limiting resistor R2; the other end of the current-limiting resistor R2 is respectively connected to the other end of the single-pole single-throw switch S4, one end of the single-pole single-throw switch S5, one end of the current-limiting resistor R3 and one end of the single-pole single-throw switch S6 and serves as the output end of the mode selector; the other end of the current-limiting resistor R3 is respectively connected to the other end of the single-pole single-throw switch S2' and the other end of the single-pole single-throw switch S5; one end of the inductor L2 is connected to the other end of the single-pole single-throw switch S6, and its other end is connected to one end of the capacitor C2; the other end of the capacitor C2 serves as the common end of the mode selector.

[0047] The inductor L1 and the capacitor C1 form a parallel resonance circuit. The inductor L2 and the capacitor C2 form a series resonance circuit.

[0048] The single-pole single-throw switch S2, the single-pole single-throw switch S2', the single-pole single-throw switch S3, the single-pole single-throw switch S4, the single-pole single-throw switch S5 and the single-pole single-throw switch S6 are used to control the on-off of the branch where they are located.

[0049] The single-pole single-throw switch S3 is connected in parallel across the parallel resonance circuit of the inductor L1 and the capacitor C1, determining whether the parallel resonance circuit is put into operation. When it is in the off state, the parallel resonance circuit is put into operation, and the parallel resonance bears the fundamental voltage, reducing the withstand voltage level of the harmonic power injection unit; when it is in the closed state, the parallel resonance circuit is cut off from operation.

[0050] The single-pole single-throw switch S4 and the single-pole single-throw switch S5 are respectively connected in parallel across the current-limiting resistors R2 and R3, and are used to limit the current when the device is put into operation.

[0051] The single-pole single-throw switch S6 is connected in series in the series resonance circuit of the inductor L2 and the capacitor C2, and determines whether the series resonance circuit is put into operation. When it is in the closed state, the series resonance circuit is put into operation, and the series resonance passes the fundamental wave current, reducing the current-carrying rating of the harmonic power injection unit; when it is in the open state, the series resonance circuit is cut off from operation.

[0052] When the single-pole single-throw switch S2, the single-pole single-throw switch S8 and the single-pole single-throw switch S9 are closed, and the single-pole single-throw switch S2' and the double-pole double-throw switch S7 are opened, the device operates in the current disturbance mode.

[0053] When the single-pole single-throw switch S2' and the double-pole double-throw switch S7 are closed, and the single-pole single-throw switch S2, the single-pole single-throw switch S8 and the single-pole single-throw switch S9 are opened, the device operates in the voltage disturbance mode.

[0054] As Figure 2 shown, the harmonic power sub-module includes: an inductor L3, switching transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8 and a capacitor C3;

[0055] One end of the inductor L3 serves as the first input terminal of the harmonic power sub-module, and the other end is respectively connected to the emitter of the switching transistor Q2 and the collector of the switching transistor Q1; the collector of the switching transistor Q2 is respectively connected to the collectors of the switching transistors Q3, one end of the capacitor C3, the collectors of the switching transistors Q5 and Q6; the emitter of the switching transistor Q1 is respectively connected to the emitters of the switching transistors Q4, the other end of the capacitor C3, the emitters of the switching transistors Q8 and Q7; the emitter of the switching transistor Q3 is connected to the collector of the switching transistor Q4 and serves as the second input terminal of the harmonic power sub-module; the emitter of the switching transistor Q5 is connected to the collector of the switching transistor Q8 and serves as the first output terminal of the harmonic power sub-module; the emitter of the switching transistor Q6 is connected to the collector of the switching transistor Q7 and serves as the second output terminal of the harmonic power sub-module.

[0056] The voltage disturbance injection branch includes: a double-pole double-throw switch S7 and a single-pole single-throw switch S8;

[0057] The first end of the double-pole double-throw switch S7 is connected to one end of the secondary side of the broadband coupling transformer T2, its second end is connected to the other end of the secondary side of the broadband coupling transformer T2, and its third end and fourth end are connected to the live wire of the single-phase power network; the single-pole single-throw switch S8 is connected to the live wire and is located between the third end and the fourth end of the double-pole double-throw switch S7.

[0058] The current disturbance injection branch includes: a single-pole single-throw switch S9;

[0059] One end of the single-pole single-throw switch S9 is connected to the live wire of the single-phase power network, and the other end is connected to one end of the secondary side of the broadband coupling transformer T2. The other end of the secondary side of the broadband coupling transformer T2 is connected to the neutral wire of the single-phase power network.

[0060] A control method for a broadband harmonic disturbance device includes the following steps:

[0061] S1. Close the single-pole single-throw switch S2, the single-pole single-throw switch S8, and the single-pole single-throw switch S9, disconnect the single-pole single-throw switch S2' and the double-pole double-throw switch S7, or close the single-pole single-throw switch S2' and the double-pole double-throw switch S7, and disconnect the single-pole single-throw switch S2, the single-pole single-throw switch S8, and the single-pole single-throw switch S9;

[0062] S2. Real-time sample the input voltage u j , current i j and DC voltage u dcj of the N harmonic power sub-modules, where j is the jth harmonic power sub-module;

[0063] S3. Based on the double closed-loop decoupling control in the dq coordinate system, control the single-phase voltage rectifier according to the real-time sampled input voltage u j , current i j and DC voltage u dcj ;

[0064] At the starting point of each sampling period, real-time sample the input voltage u j , current i j and DC voltage u dcj of the N harmonic power sub-modules, j = 1, 2, … N, N ≥ 1; Control the single-phase voltage rectifier of the N harmonic power sub-modules to stably output DC voltage according to the real-time sampled input voltage u j , current i j and DC voltage u dcj , and use the double closed-loop decoupling control in the dq coordinate system to achieve the control of the single-phase voltage rectifier.

[0065] S4. Calculate the modulation wave of the single-phase H-bridge converter;

[0066] S5. Perform unipolar frequency-doubled carrier phase-shifted modulation on the modulation wave to obtain the switching control signals of each switching tube of each single-phase H-bridge converter;

[0067] S6. Apply switching control signals to each switching device of each single-phase H-bridge converter in each harmonic power sub-module, and cooperate with the control of the single-phase voltage-type rectifier in step S3 to obtain voltage disturbance or current disturbance signals.

[0068] Before implementing the control method of the present invention, the rated voltage, rated current level of the VSC type converter device and the system background harmonics can be considered first. Combining the requirements of the capacity size and signal-to-noise ratio of this device, determine the number N of harmonic power sub-modules of the disturbance, the effective value U of the voltage disturbance out , the effective value I of the current disturbance out , the number N0 of harmonics, the modulation ratio k of the modulation wave, and the frequency resolution Δf, so as to obtain the modulation wave, and realize the control of the single-phase H-bridge converter through the modulation wave.

[0069] The formula for the modulation wave of the single-phase H-bridge converter in step S4 is:

[0070]

[0071] where S is the modulation wave of the single-phase H-bridge converter, k is the modulation ratio of the modulation wave, f0 is the starting frequency, Δf is the frequency resolution, N0 is the number of harmonics, N is the number of harmonic power sub-modules, and j is the jth harmonic power sub-module.

[0072] Figure 1 The first impedance measurement point in is, in the current disturbance mode, measure the current disturbance on the single-phase power network side and its voltage response signal, which is used to measure the single-phase power network impedance; the second measurement point is, in the voltage disturbance mode, measure the voltage disturbance on the side of the VSC type converter device to be measured and its current response signal, which is used to measure the impedance of the VSC type converter device.

Claims

1. A broadband harmonic disturbance device, characterized in that, Including: A harmonic power injection unit, a voltage disturbance injection branch, and a current disturbance injection branch; The power-taking end of the harmonic power injection unit is connected to the single-phase power network, and its voltage and current injection ends are respectively connected to the single-phase power network through the voltage disturbance injection branch and the current disturbance injection branch; The harmonic power injection unit includes: a single-phase multi-winding step-down transformer T1, a plurality of harmonic power sub-modules, a mode selector, and a broadband coupling transformer T2; The primary winding of the single-phase multi-winding step-down transformer T1 serves as the power-taking end of the harmonic power injection unit; each secondary winding of the single-phase multi-winding step-down transformer T1 is connected to the input end of a harmonic power sub-module; the plurality of harmonic power sub-modules are: harmonic power sub-module 1, harmonic power sub-module 2, …, harmonic power sub-module j, …, harmonic power sub-module N, where j and N are positive integers; each harmonic power sub-module includes: a first output end and a second output end; the second output end of the harmonic power sub-module j is connected to the first output end of the harmonic power sub-module j + 1, where 1 ≤ j ≤ N - 1; the second output end of the harmonic power sub-module N is connected to the common end of the mode selector; the first output end of the harmonic power sub-module 1 is connected to the input end of the mode selector; one end of the primary side of the broadband coupling transformer T2 is connected to the output end of the mode selector, and the other end of its primary side is connected to the common end of the mode selector; the secondary side of the broadband coupling transformer T2 serves as the voltage and current injection end of the harmonic power injection unit; The mode selector includes: a single-pole single-throw switch S2, a single-pole single-throw switch S2', a single-pole single-throw switch S3, a single-pole single-throw switch S4, a single-pole single-throw switch S5, a single-pole single-throw switch S6, a current-limiting resistor R1, a current-limiting resistor R2, a current-limiting resistor R3, an inductor L1, an inductor L2, a capacitor C1, and a capacitor C2; One end of the single-pole single-throw switch S2 is connected to one end of the single-pole single-throw switch S2' and serves as the input end of the mode selector; the other end of the single-pole single-throw switch S2 is respectively connected to one end of the single-pole single-throw switch S3, one end of the inductor L1, and one end of the capacitor C1; one end of the current-limiting resistor R1 is respectively connected to the other end of the single-pole single-throw switch S3, the other end of the inductor L1, and the other end of the capacitor C1, and its other end is respectively connected to one end of the single-pole single-throw switch S4 and one end of the current-limiting resistor R2; the other end of the current-limiting resistor R2 is respectively connected to the other end of the single-pole single-throw switch S4, one end of the single-pole single-throw switch S5, one end of the current-limiting resistor R3, and one end of the single-pole single-throw switch S6 and serves as the output end of the mode selector; the other end of the current-limiting resistor R3 is respectively connected to the other end of the single-pole single-throw switch S2' and the other end of the single-pole single-throw switch S5; one end of the inductor L2 is connected to the other end of the single-pole single-throw switch S6, and its other end is connected to one end of the capacitor C2; the other end of the capacitor C2 serves as the common end of the mode selector.

2. The broadband harmonic disturbance device according to claim 1, characterized in that, The harmonic power sub-module includes: inductor L3, switching transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, and capacitor C3; One end of the inductor L3 serves as the first input terminal of the harmonic power sub-module, and the other end is respectively connected to the emitter of the switching transistor Q2 and the collector of the switching transistor Q1; the collector of the switching transistor Q2 is respectively connected to the collectors of the switching transistors Q3, one end of the capacitor C3, the collectors of the switching transistors Q5 and Q6; the emitter of the switching transistor Q1 is respectively connected to the emitters of the switching transistors Q4, the other end of the capacitor C3, the emitters of the switching transistors Q8 and Q7; the emitter of the switching transistor Q3 is connected to the collector of the switching transistor Q4 and serves as the second input terminal of the harmonic power sub-module; the emitter of the switching transistor Q5 is connected to the collector of the switching transistor Q8 and serves as the first output terminal of the harmonic power sub-module; the emitter of the switching transistor Q6 is connected to the collector of the switching transistor Q7 and serves as the second output terminal of the harmonic power sub-module.

3. The broadband harmonic disturbance device according to claim 1, characterized in that, The voltage disturbance injection branch includes: a double-pole double-throw switch S7 and a single-pole single-throw switch S8; The first end of the double-pole double-throw switch S7 is connected to one end of the secondary side of the broadband coupling transformer T2, the second end is connected to the other end of the secondary side of the broadband coupling transformer T2, and its third end and fourth end are connected to the live wire of the single-phase power network; the single-pole single-throw switch S8 is connected to the live wire and is located between the third end and the fourth end of the double-pole double-throw switch S7.

4. The broadband harmonic disturbance device according to claim 1, characterized in that, The current disturbance injection branch includes: a single-pole single-throw switch S9; One end of the single-pole single-throw switch S9 is connected to the live wire of the single-phase power network, and the other end is connected to one end of the secondary side of the broadband coupling transformer T2. The other end of the secondary side of the broadband coupling transformer T2 is connected to the neutral wire of the single-phase power network.

5. A control method for a broadband harmonic disturbance device, applied to the broadband harmonic disturbance device according to any one of claims 1 to 4, characterized in that, It includes the following steps: S1. In the current disturbance mode, turn off the single-pole single-throw switch S2, the single-pole single-throw switch S8, and the single-pole single-throw switch S9, and disconnect the single-pole single-throw switch S2' and the double-pole double-throw switch S7; in the voltage disturbance mode, turn off the single-pole single-throw switch S2' and the double-pole double-throw switch S7, and disconnect the single-pole single-throw switch S2, the single-pole single-throw switch S8, and the single-pole single-throw switch S9; among them, in the current disturbance mode, the parallel resonance circuit of the inductor L1 and the capacitor C1 of the mode selector is put into operation, and in the voltage disturbance mode, the series resonance circuit of the inductor L2 and the capacitor C2 is put into operation to suppress the fundamental voltage and the fundamental current respectively; S2. Real-time sampling is performed on the input voltage u j , current i j and DC voltage u dcj of N harmonic power sub-modules, where j is the j-th harmonic power sub-module; S3. According to the input terminal voltage u sampled in real time j , current i j and DC voltage u dcj , based on the double closed-loop decoupling control in the dq coordinate system, the single-phase voltage rectifier of N harmonic power sub-modules stably outputs DC voltage, and the single-phase voltage rectifier is controlled; S4. Calculate the modulation wave of the single-phase H-bridge converter; S5. Perform unipolar frequency-doubled carrier phase-shifted modulation on the modulation wave to obtain the switching control signals of each switching transistor of each single-phase H-bridge converter; S6. Apply the switching control signals to each switching transistor of each single-phase H-bridge converter in each harmonic power sub-module, and cooperate with the control of the single-phase voltage rectifier in step S3 to obtain voltage disturbance or current disturbance signals.

6. The control method for a broadband harmonic disturbance device according to claim 5, characterized in that, The formula for the modulation wave of the single-phase H-bridge converter in step S4 is: Among them, S is the modulation wave of the single-phase H-bridge converter, k is the modulation ratio of the modulation wave, f0 is the starting frequency, Δf is the frequency resolution, N0 is the number of harmonics, N is the number of harmonic power sub-modules, and j is the j-th harmonic power sub-module.

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