Each topology has its own characteristics and applicable occasions. Some topologies are suitable for off-line AC /DC converters. Some of them are suitable for low power output (~ 200 V) or multi-group (more than 4 ~ 5 groups) output occasions.
Some use fewer devices at the same output power, or achieve a good compromise between the number of devices and reliability. Small input/output ripple and noise are also factors often considered when choosing topology.
Question 2: What is the circuit topology 1? Definition of circuit topology:
Circuit topology refers to the connection relationship of circuits or the connection relationship between electronic components that make up a circuit.
Second, for example:
The circuit topologies of AC/DC and DC/DC are the same, and the AC after rectification and filtering is DC270V V. The main topologies are flyback, single-tube forward, double-tube forward, half-bridge, full-bridge and LLC resonant.
Question 3: What does it mean that two circuits have the same topology? Is a connection method. Route mode.
Question 4: What does topological circuit mean? It refers to the structure of the circuit. For example, the sound restoration of AM broadcast signals can be achieved by direct reception, amplification and detection filtering, or by superheterodyne reception, amplification and detection filtering. These are two kinds of topological circuits.
Question 5: What is the circuit topology? Circuit topology refers to the connection relationship of circuits or the connection relationship between electronic components that make up a circuit.
As far as the structure is concerned, the switching power supply circuit has several typical structures, such as buck, boost, flyback, forward, half bridge, full bridge and so on. And the actual circuit is also based on these structures and then materialized.
Question 6: Topology of switching power supply With the continuous development and improvement of PWM technology, switching power supply has been widely used for its high cost performance. There are many circuit topologies of switching power supply, including push-pull, full-bridge, half-bridge, single-ended forward and single-ended flyback. Among them, in the half-bridge circuit, the primary current of the transformer flows in full cycle, the magnetic core is fully utilized, and there is no magnetic bias problem. The required voltage of the power switch tube is low, the saturation voltage drop of the switch tube is the smallest, and the voltage requirement of the input filter capacitor is also low. Based on the above reasons, half-bridge converter is widely used in the design of high-frequency switching power supply. There are about 14 basic topologies commonly used in switching power supply, and each topology has its own characteristics and applicable occasions. Some topologies are suitable for off-line AC /DC converters. Some of them are suitable for low power output (~ 200 V) or multi-group (more than 4 ~ 5 groups) output occasions. Some use fewer devices at the same output power, or achieve a good compromise between the number of devices and reliability. Small input/output ripple and noise are also factors often considered when choosing topology. Some topologies are more suitable for DC/DC converters. When selecting, it depends on whether it is high power or low power, high voltage output or low voltage output, and whether the fewer devices are required, the better. In addition, some topologies have their own defects, which require additional complex and difficult quantitative analysis circuits to work. Therefore, it is very important to choose a suitable topology and be familiar with the advantages, disadvantages and application scope of various topologies. The wrong choice will make the power supply design doomed to failure from the beginning. Common topologies of switching power supply: buck switching topology, boost switching topology, reverse polarity switching topology, push-pull topology, forward converter topology, double-ended forward converter topology, staggered forward converter topology, half-bridge converter topology, full-bridge converter topology, flyback converter, current mode topology and current zeta topology, SCR harmonic topology and CUK converter topology. Firstly, six basic DC/DC converter topologies are given, followed by buck. Disadvantages of tree topology: each node is too dependent on the root.
Question 7: What is topological structure? Geometric topology is a branch of mathematics formed in19th century, which belongs to geometric category. Some contents about topology appeared as early as the eighteenth century. Some isolated problems were discovered at that time, which later played an important role in the formation of topology.
Mathematically, the problem of the Seven Bridges in Konigsberg, the polyhedral euler theorem and the four-color problem are all important problems in the development history of topology.
Konigsberg (now Kaliningrad, Russia) is the capital of East Prussia, and the Pledgel River runs through it. /kloc-in the 0/8th century, seven bridges were built on this river, connecting the two islands in the middle of the river with the riverbank. People often walk on it in their spare time. One day, someone asked: can we just walk on each bridge once and finally return to the original position? This question looks very simple and interesting, attracting everyone. Many people are trying various methods, but no one can do it. It seems that it is not so easy to get a clear and ideal answer.
1736, someone found the great mathematician Euler with this question. After some thinking, Euler quickly gave the answer in a unique way. Euler simplified this problem first, and then used points and lines to represent the road and bridge schematic diagram in the seven-bridge problem. He regarded two small islands and the river bank as four points respectively, and seven bridges as connecting lines between these four points. Then the question is simplified to, can you draw this figure with one stroke? After further analysis, Euler came to the conclusion that it is impossible to walk every bridge and finally return to its original position. And gives the conditions that all the drawings can be drawn. This is the pioneer of topology.
In the history of topology, there is also a famous and important theorem about polyhedron, which is also related to Euler. The content of this theorem is: if the number of vertices, edges and faces of a convex polyhedron is V, then they always have such a relationship: f+v-e=2. Only five regular polyhedrons
According to the euler theorem of polyhedron, we can get an interesting fact: there are only five regular polyhedrons. They are regular tetrahedron, regular hexahedron, regular octahedron, regular dodecahedron and regular icosahedron.
The famous "four-color problem" is also related to the development of topology. The four-color problem, also known as the four-color conjecture, is one of the three major mathematical problems in the modern world.
The four-color conjecture was put forward by Britain. 1852, when Francis guthrie, who graduated from London University, came to a scientific research unit to do map coloring, he found an interesting phenomenon: "It seems that every map can be colored with four colors, so countries with the same border will be colored with different colors."
1872, Kelly, the most famous mathematician in Britain at that time, formally put forward this question to the London Mathematical Society, so the four-color conjecture became a concern of the world mathematical community. Many first-class mathematicians in the world have participated in the great battle of four-color conjecture. During the two years from 1878 to 1880, Kemp and Taylor, two famous lawyers and mathematicians, respectively submitted papers to prove the four-color conjecture and announced that they had proved the four-color theorem. But later mathematician Hurwood pointed out that Kemp's proof and his own accurate calculation were wrong. Soon, Taylor's proof was also denied. As a result, people began to realize that this seemingly simple topic is actually a difficult problem comparable to Fermat's conjecture.
Since the 20th century, scientists have basically proved the four-color conjecture according to Kemp's idea. After the emergence of electronic computers, the process of proving the four-color conjecture has been greatly accelerated due to the rapid improvement of calculation speed and the emergence of man-machine dialogue. 1976, American mathematicians Appel and Harken spent 1200 hours on two different computers at the University of Illinois in the United States, made 1000 billion judgments, and finally completed the proof of the four-color theorem. However, many mathematicians are not satisfied with the achievements made by computers. They think there should be a simple and clear written proof method.
The above examples are all related to geometric figures, but these problems are different from traditional geometry, but some new geometric concepts. These are pioneers of "topology".
= = = = = = = What is a topology? ===============
The English name of Topology is topology, and the literal translation is geography, which is similar to topography and geomorphology. In the early days of China, it was translated into "situational geometry", "continuous geometry" and "geometry under one-to-one continuous transformation group", but this >:>
Question 8: What is the topology of the inverter? Current inverter topologies include: full-bridge inverter topology, half-bridge inverter topology, multilevel inverter topology, push-pull inverter topology, forward inverter topology, flyback inverter topology and so on. Among them, high-voltage and high-power photovoltaic grid-connected inverters can adopt multilevel inverter topology, medium-power photovoltaic grid-connected inverters mostly adopt full-bridge and half-bridge inverter topology, and low-power photovoltaic grid-connected inverters adopt forward and flyback inverter topology.
The choice of topology is related to the rated output power of inverter. For photovoltaic inverters below 4kw, the topology with DC bus less than 500V and single-phase output is usually selected.
The boost circuit realizes maximum power point tracking by adjusting the input voltage. H-bridge inverter converts direct current into sinusoidal alternating current and injects it into power grid. As a polarity controller, the IGBT of the upper half bridge works at 50HZ, thus reducing the total loss and output electromagnetic interference of the inverter. The IGBT or MOSFET in the lower half bridge performs PWM high frequency switching. In order to minimize the size of the boost inductor and the output filter, the switching frequency is required to be as high as possible, such as 16KHz.
Question 9: What does the topology of the circuit mean? Topology is the composition structure in my personal understanding. Switching power supply circuit has several typical structures, such as buck, boost, flyback, forward, half bridge, full bridge and so on. The actual circuit is also embodied based on these structures.