CN206422696U - The quasi- source of resistance AC AC converters of New Cascading - Google Patents

Abstract

The utility model discloses a novel cascaded quasi-impedance source AC-AC converter, and specifically relates to the technical field of AC converters. The novel cascaded quasi-impedance source AC-AC converter includes an AC converter circuit, the AC converter circuit includes a large boost ratio impedance network, and the large boost ratio impedance network is connected to the input end and the output end of the AC converter circuit. The step-up ratio impedance network includes a cascaded first-stage quasi-impedance source 1 and a multi-stage improved quasi-impedance source 2, the improved quasi-impedance source is more than one level, and the first-stage quasi-impedance source includes the first energy storage inductance L1, the second Two energy storage inductors L2, a first energy storage capacitor C1, a second energy storage capacitor C2 and a first switch S1, each stage of improved quasi-impedance source includes a switch S2, an energy storage inductor L3 and two energy storage capacitors C3, C4, The output terminal of the last improved quasi-impedance source is connected to the third switch S3.

Description

A Novel Cascaded Quasi-Impedance Source AC-AC Converter

technical field

The utility model belongs to the technical field of AC converters, in particular to a novel cascaded quasi-impedance source AC-AC converter.

Background technique

At present, the topological structures of AC voltage conversion circuits that are widely used include Boost type, Buck type, and Buck-Boost type. On the basis of their DC-DC converter topology, bidirectional power switches are used instead of unidirectional switches. The sinusoidal AC power supply replaces the DC power supply. The Buck and Boost circuit topologies are the earliest researched topologies of the two power electronic circuits. The Buck circuit can only realize the step-down function of the AC input voltage, and the Boost circuit can only realize For the step-up function of the AC input voltage, the single implementation of step-down and step-up functions limits the application occasions of the two topological circuits. Although the Buck-Boost AC topology circuit can realize the step-down adjustment of the input voltage, as a second-order system, the circuit topology has a zero point on the right half plane of its Nyquist curve, so there will be a zero point in the system. The existence of unstable response restricts its application and promotion in AC step-up and step-down occasions. The traditional quasi-impedance source AC voltage regulator has only one quasi-impedance source network, limited by the current industrial manufacturing level, the electronic devices in the circuit cannot fully match the theoretical parameters, so when a higher voltage transformation capability is required, Its output waveform will be distorted, and even cannot be the same as the theoretical result at all, which will deteriorate the quality of output power and pollute the entire power grid.

Utility model content

The purpose of this utility model is to address the above-mentioned shortcomings, and propose a new type of cascaded quasi-impedance source AC-AC converter with stable electric energy output, infinite cascading, and improved voltage transformation capability.

The utility model specifically adopts the following technical solutions:

The novel cascaded quasi-impedance source AC-AC converter includes an AC converter circuit, the AC converter circuit includes a large step-up ratio impedance network, and the large step-up ratio impedance network is connected to the input end and the output end of the AC converter circuit, The large step-up ratio impedance network includes a cascaded first-stage quasi-impedance source and a multi-stage improved quasi-impedance source. The first-stage quasi-impedance source includes a first energy storage inductor, a second energy storage inductor, a first energy storage capacitor, The second energy storage capacitor and the first switch, each stage of the improved quasi-impedance source includes a switch, an energy storage inductance and two energy storage capacitors, and the output end of the last stage of the improved quasi-impedance source is connected to the third switch.

Preferably, the first switch and the switches in the improved quasi-impedance source form a switch group, and the switches in the switch group are complementary to the third switch.

Preferably, the output end of the last stage improved quasi-impedance source is connected to a filter circuit, and the filter circuit is an LC filter circuit.

Preferably, the inductance values of the first energy storage inductance, the second energy storage inductance and the energy storage inductance in the improved quasi-impedance source are equal.

Preferably, the capacitances of the first energy storage capacitor, the second energy storage capacitor and the energy storage capacitor in the improved quasi-impedance source are equal.

Preferably, the improved quasi-impedance source has more than one level.

The utility model has the following beneficial effects:

(1) The new cascaded quasi-impedance source AC-AC converter adopts a new circuit topology. Compared with the traditional quasi-impedance source AC voltage regulator, the output power quality is high, the stability is good, the boost ratio is large, and the capacitance in the circuit The voltage stress and the current stress of the inductor are small;

(2) The large boost ratio impedance network can be cascaded in infinite stages, which greatly improves the voltage transformation capability;

(3) The new cascaded quasi-impedance source AC-AC converter has the advantages of good dynamic performance, simple circuit topology, and high grid-side power factor. And pressure regulating occasions have been more and more widely promoted and applied;

(4) The new cascaded quasi-impedance source AC-AC converter can be used not only in voltage regulation, but also in inverters, which greatly improves the service life of batteries;

(5) The end of the novel cascaded quasi-impedance source AC-AC converter adopts LC filtering, which realizes the bidirectional flow of power flow and has good versatility.

Description of drawings

Figure 1 is a circuit structure diagram of a new type of cascaded quasi-impedance source AC-AC converter;

Fig. 2 is a circuit schematic diagram of a novel cascaded quasi-impedance source AC-AC converter when switches S1 and S2 are turned off at the same time and S3 is turned on;

Fig. 3 is a schematic diagram of the capacitor Cf charging the inductance Lf when the switches S1 and S2 are turned off at the same time and S3 is turned on;

Fig. 4 is a circuit schematic diagram of a novel cascaded quasi-impedance source AC-AC converter when switches S1 and S2 are turned on at the same time and S3 is turned off;

Fig. 5 is a schematic diagram of the circuit state of Vi and L1, L2, L3 supplying power to the load when switches S1 and S2 are turned on at the same time and S3 is turned off;

Figure 6 is a schematic diagram of the state of the circuit where the load is powered by the network capacitor when the switches S1 and S2 are turned on at the same time and S3 is turned off when the inductive current of the network decreases to ILf;

Fig. 7 simulates the circuit topology with Matlab/Simulink, the input and output waveforms of the simulation when D=0.4;

Fig. 8 simulates the circuit topology with Matlab/Simulink, the input and output waveforms of simulation when D=0.6;

Fig. 9 is the circuit boost waveform when D=0.1 measured with an oscilloscope;

Figure 10 is the circuit step-down waveform when D=0.65 measured with an oscilloscope.

Among them, 1 is the first-stage quasi-impedance source, and 2 is the improved quasi-impedance source.

detailed description

Below in conjunction with accompanying drawing and specific embodiment the specific embodiment of the utility model is further described:

As shown in Figure 1, the new cascaded quasi-impedance source AC-AC converter includes an AC converter circuit, the AC converter circuit includes a large boost ratio impedance network, and the large boost ratio impedance network is connected to the input end of the AC converter circuit and the output end, the large step-up ratio impedance network includes a cascaded first-stage quasi-impedance source 1 and a multi-stage improved quasi-impedance source 2, the improved quasi-impedance source is more than one level, and the first-stage quasi-impedance source includes the first Energy storage inductance L1, second energy storage inductance L2, first energy storage capacitor C1, second energy storage capacitor C2 and first switch S1, each stage of improved quasi-impedance source includes switch S2, energy storage inductance L3 and two storage Capacitors C3 and C4, and the output end of the last improved quasi-impedance source is connected to the third switch S3.

The first switch S1 and the switch S2 in the improved quasi-impedance source form a switch group, and the switches in the switch group are complementary to the third switch S3.

The output end of the last improved quasi-impedance source is connected to a filter circuit, and the filter circuit is an LC filter circuit.

The inductance values of the first energy storage inductance L1, the second energy storage inductance L2 and the energy storage inductance L3 in the improved quasi-impedance source are equal, and the first energy storage capacitor C1, the second energy storage capacitor C2 and the energy storage in the improved quasi-impedance source Capacitors C3 and C4 are equal in size.

Because the frequency of the input power is much smaller than the switching frequency fs, the input voltage can be regarded as DC when analyzing the circuit. The new quasi-impedance source AC converter has the following five working states according to different current directions:

Working state 1: As shown in Figure 2, the first switch S1 and switch S2 are turned off at the same time, and the third switch S3 is turned on. There are four voltage circuits in total. The energy storage inductor L1 charges, the first energy storage capacitor C1 and the energy storage capacitor C4 charge the second energy storage inductor L2, the energy storage capacitor C3 charges the energy storage inductor L3, and the inductor Lf supplies power to the load.

Working state 2: As shown in Figure 3, the first switch S1 and switch S2 are turned off at the same time, and the third switch S3 is turned on. In state 1, when I _Lf decreases to zero, the capacitor Cf will charge the inductor Lf, and the inductor current will reverse Incrementally, at this time it has the same voltage relationship as working state 1.

Working state 3: as shown in Figure 4, the first switch S1 and switch S2 are turned on at the same time, and the third switch S3 is turned off. If I _Lf reverses the current at this time, Lf will feed back energy to the quasi-impedance source network with a large boost ratio. When the power supply voltage Vi and the inductor L1 charge the capacitor C1, the second energy storage inductor L2 charges the second energy storage capacitor C2, the energy storage inductor L3 charges the energy storage capacitor C4, and at the same time Vi, L1, L2, and L3 supply power to the load .

Working state 4: as shown in Figure 5, the third switch S3 is turned off, the first switch S1 and the switch S2 are turned on at the same time, the working state of the quasi-impedance source network with a large boost ratio is similar to state 3, but at this time I _Lf flows forward , Vi and L1, L2, L3 supply power to the load, and the inductor current of the quasi-impedance source network with a large step-up ratio will decrease gradually.

Working state 5: as shown in Figure 6, same as state 4, when the inductive current of the network decreases to I _Lf , the load is powered by the network capacitor, and the voltage relationship remains the same under the condition that the third S3 is turned off, and the first switch S1 and the switch S2 are simultaneously turned on. established.

As shown in Figure 7-8, the circuit topology is simulated and analyzed using MATLAB/Simulink, and the system simulation results are given. The simulation parameters are L1=L2=L3=100μH, C1=C2=C3=C4=25μF , Lf=1mH, Cf=50μF, R=100Ω, fs=20kHz, Vi=24V. The simulated boost and buck waveforms are given respectively when D=0.4 and D=0.6.

The experimental circuit is built according to the simulation results. The control circuit part uses TMS320F2812 to generate complementary PWM signals, the driving part uses Luomuyuan KA962D driver board, and the full-control switch of the main circuit uses SGH80N60UFDU Ultrafast IGBT.

The oscilloscope measured the boost and buck waveforms when D=0.1 and D=0.65 (Ui is the input, Uo is the output), as shown in Figure 9 and Figure 10.

The theoretical analysis and computer simulation results are verified by the experimental results. Through the simulation results and experimental results, it can be known that the new cascaded quasi-impedance source AC-AC converter solves the problems of unstable output voltage and poor power quality of traditional AC converters. From the simulation and experimental results, it can be seen that the output voltage of the new cascaded quasi-impedance source AC-AC converter is very stable, the output power quality is very high, and it has two capabilities of step-up and step-down, which can fully meet the industrial and industrial needs. Requirements for AC voltage regulation in agricultural production.

The new cascaded quasi-impedance source AC-AC converter adopts a new circuit topology. Compared with the traditional quasi-impedance source AC voltage regulator, the output power quality is high, the stability is good, the boost ratio is large, the voltage stress of the capacitor in the circuit and The current stress of the inductor is small;

The large step-up ratio impedance network can be cascaded infinitely, which greatly improves the voltage transformation capability; with the development of society and industry, people's voltage transformation capability of the voltage regulator will inevitably become higher and higher. The new cascade quasi- The impedance source AC-AC converter can meet the demand for improving the transformation capability by cascading more impedance source networks.

The new cascaded quasi-impedance source AC-AC converter has the advantages of good dynamic performance, simple circuit topology, and high grid-side power factor. The occasion has been widely promoted and applied; in some remote areas where the voltage fluctuation is relatively large and the power supply quality is relatively poor, the use of a new type of cascaded quasi-impedance source AC-AC converter can eliminate filtering of the input voltage and purify the voltage quality , The function of stabilizing voltage. In many civil electrical equipment and electrical production equipment of factories and enterprises, the input power supply needs to match the voltage. This means that the input voltage of the power grid needs to be regulated through AC voltage regulating equipment to adjust the rated voltage required by the electrical equipment. . Therefore, no matter in industrial production or in agricultural applications, the research on new cascaded quasi-impedance source AC-AC converters is very necessary.

The novel cascaded quasi-impedance source AC-AC converter can be used not only in voltage regulation, but also in inverters, which greatly improves the service life of batteries. At present, in industrial production, voltage regulation is a very popular research direction, but in actual production, it is also necessary to convert AC power into DC power, such as charging mobile phones and laptops, charging mobile power supplies, etc., which requires inverter Inverter, and not only simply invert the input power, but first adjust the voltage of the input power and then get the required DC power through the inverter bridge. The most widely used is the mobile phone and laptop charger, because the mobile phone and laptop The internal components of the notebook computer are all weak current devices, so the 220V voltage cannot be directly input into the battery to charge the mobile phone and the notebook computer. At present, in the application of industry and daily life, the most popular method is to step up or step down the input voltage first, which requires a voltage regulator that can stabilize the output in front of the inverter. At present, mobile phones and notebook computers are relatively sophisticated and high-end electrical equipment, so the input voltage needs to have high accuracy, stability and controllability. Traditional voltage regulators, because they mainly use diodes as control devices, diodes are uncontrollable devices, and their on and off are only limited by the forward or reverse direction of the current, and they cannot be freely controlled according to people's needs. , and very unstable, poor anti-interference ability, which leads to poor controllability and stability of traditional voltage regulators, traditional voltage regulators are often theoretically established in the laboratory, but after the experimental circuit is built There are many reasons for not getting the desired results, but diode instability is a very common one. The new cascaded quasi-impedance source AC-AC converter uses MOSFET/IGBT as a switch control device. MOSFET/IGBT is a very stable power electronic device, and its biggest feature is controllability compared to diodes. A controllable device, which can be turned on and off completely according to people's needs. At present, due to the overwhelming advantages of MOSFET/IGBT switching tubes compared with diodes, it is widely used, its development and use are very mature, and its price is also low. No matter its stability, controllability or economy are unique. choose. The new cascaded quasi-impedance source AC-AC converter uses MOSFET/IGBT as a switch, which greatly improves the stability and controllability of the entire circuit topology. Therefore, if the new cascaded quasi-impedance source is required The impedance source AC-AC converter will greatly improve the reliability of electrical equipment. It can be predicted that if the new cascaded quasi-impedance source AC-AC converter is placed before the inverter bridge and applied to mobile phone and notebook computer chargers, the service life of the battery will be greatly improved.

The terminal of the novel cascaded quasi-impedance source AC-AC converter adopts LC filtering, which realizes the bidirectional flow of power flow and has good versatility.

Of course, the above description is not a limitation of the present utility model, and the present utility model is not limited to the above-mentioned examples, and changes, modifications, additions or replacements made by those skilled in the art within the essential scope of the present utility model are also acceptable. Should belong to the protection scope of the present utility model.

Claims (6)

1. the quasi- source of resistance AC-AC converters of New Cascading, including AC converter circuit, the AC converter circuit include big Step-up ratio impedance network, the input and output end of big step-up ratio impedance network connection AC converter circuit, it is characterised in that Big step-up ratio impedance network includes the quasi- source of resistance of the first order mutually cascaded and the multistage quasi- source of resistance of improvement, the quasi- source of resistance bag of the first order The first energy storage inductor, the second energy storage inductor, the first storage capacitor, the second storage capacitor and first switch are included, improves accurate per one-level Source of resistance includes switch, energy storage inductor and two storage capacitors, and the output end connection the 3rd that afterbody improves quasi- source of resistance is opened Close.

2. the quasi- source of resistance AC-AC converters of New Cascading as claimed in claim 1, it is characterised in that the first switch with The switch and the 3rd switch complementary improved in switch one switches set of formation in quasi- source of resistance, switches set is turned on.

3. the quasi- source of resistance AC-AC converters of New Cascading as claimed in claim 1, it is characterised in that the afterbody changes Enter the output end connection filter circuit of quasi- source of resistance, filter circuit is LC filter circuits.

4. the quasi- source of resistance AC-AC converters of New Cascading as claimed in claim 1, it is characterised in that the first energy storage electricity Sense, the second energy storage inductor are equal with the inductance value for improving the energy storage inductor in quasi- source of resistance.

5. the quasi- source of resistance AC-AC converters of New Cascading as claimed in claim 1, it is characterised in that the first energy storage electricity Appearance, the second storage capacitor are equal with the capacitance size for improving the storage capacitor in quasi- source of resistance.

6. the quasi- source of resistance AC-AC converters of New Cascading as claimed in claim 1, it is characterised in that the quasi- impedance of improvement Source is more than one-level.