A switching converter topology and control method

Abstract

The present invention discloses a switching converter topology and control method. The device comprises two ports, Port1 and Port2. Switch tubes S1 to S4 form an H bridge. The midpoint of the H bridge is connected to the inductor L. S0 is connected to the positive electrode of Port1 and the midpoint of the H bridge. The device combines the switching states of power electronic switch devices to realize a boost circuit, a buck circuit, and a buck-boost circuit. The power electronic devices include but are not limited to IGBT, MOSFET, GTO, diode, and solid-state relay. The converter can realize multiple voltage conversion functions through one device.

Description

Technical Field

[0001] The present invention belongs to the technical field of power electronic converters, and in particular relates to a switching converter topology and a control method. Background Art

[0002] With the rapid development of modern industry, the demand for electric energy continues to expand, and the requirements for the efficiency and flexibility of electric energy transmission and conversion are becoming higher and higher. As the core equipment to solve this problem, power electronic converters are widely used in various electric energy usage scenarios. Corresponding to the demand for electric energy conversion between different DC voltages, a large number of DC-DC converters have been proposed, which are mainly divided into three categories: boost converter, buck converter and buck-boost converter.

[0003] However, in new power consumption occasions such as data center power supply, DC microgrid system and electric vehicle charging, DC-DC often requires multi-stage conversion, wide voltage range input and output, and multi-port voltage up and down free conversion. Traditional single-function boost, buck or buck-boost DC-DC converters are difficult to meet such application occasions. If multi-stage series connection is adopted, the cost is high and the efficiency is low, which is difficult to meet the needs of new power consumption occasions. Summary of the invention

[0004] The present invention provides a switching converter topology and control method, realizing three functions of voltage boost, voltage reduction and voltage boost / reduction, and simplifying existing multi-port power electronic equipment and multi-stage conversion circuits.

[0005] To achieve the above-mentioned purpose, a switching converter topology described in the present invention includes a switch tube S1, a switch tube S2, a switch tube S3 and a switch tube S4; the first end of the switch tube S1 is connected to the first end of the switch tube S2, the first end of the switch tube S3 is connected to the first end of the switch tube S4, the second end of the switch tube S1 is connected to the second end of the switch tube S3, the second end of the switch tube S2 is connected to the second end of the switch tube S4, the connection point between the first end of the switch tube S1 and the first end of the switch tube S2 is the first midpoint, the connection point between the first end of the switch tube S3 and the first end of the switch tube S4 is the second midpoint, the first end of the inductor L is connected to the first midpoint, the second end is connected to the second midpoint, the first end of the switch tube S0 is connected to the first midpoint, the second end of the switch tube S0 and the second end of the switch tube S2 form a port Port1, and the first end of the switch tube S3 and the second end of the switch tube S4 form a port Port2.

[0006] Furthermore, the switch tube S0 , the switch tube S1 , the switch tube S2 , the switch tube S3 and the switch tube S4 are the same.

[0007] Furthermore, the switch tube S0 , the switch tube S1 , the switch tube S2 , the switch tube S3 and the switch tube S4 are the same, and all use two IGBTs connected in reverse series.

[0008] Furthermore, a capacitor C is connected in parallel to the port Port2.

[0009] In the above-mentioned control method of a switching converter topology, the port Port1 is used as an input terminal and connected to a DC power supply E, and the port Port2 is used as an output terminal and connected to a load R; the switch tubes S1 and S4 are normally open, the switch tube S3 is normally closed, and the switch tubes S0 and S2 are controlled to be on and off, thereby realizing the function of a buck converter.

[0010] In the above-mentioned control method of a switching converter topology, the port Port1 is used as an input terminal and connected to a DC power supply E, and the port Port2 is used as an output terminal and connected to a load R; the switch tubes S1 and S2 are normally open, the switch tube S0 is normally closed, and the switch tubes S3 and S4 are controlled to be on and off, thereby realizing the function of a boost converter.

[0011] In the above-mentioned control method of a switching converter topology, the port Port1 is used as an input end and connected to a DC power supply E, and the port Port2 is used as an output end and connected to a load R; the switch tubes S2 and S3 are normally open, the switch tube S4 is normally closed, and the on and off of the switch tubes S0 and S1 are controlled to realize the function of a buck-boost converter.

[0012] In the control method of the switching converter topology described above, the port Port1 is used as an input terminal and connected to a DC power source E, and the port Port2 is used as an output terminal and connected to a load R, and time-sharing switching is achieved by the following method;

[0013] At time t0-t3, the switch tubes S1 and S4 are normally open, the switch tube S3 is normally closed, and the switch tubes S0 and S2 are controlled to be on and off, thereby realizing the function of a buck converter;

[0014] At time t3-t6, the switch tubes S1 and S2 are normally open, the switch tube S0 is normally closed, and the switch tubes S3 and S4 are controlled to be on and off, thereby realizing the function of the boost converter;

[0015] At time t6 to t8, the switch tubes S2 and S3 are normally open, the switch tube S4 is normally closed, and the switch tubes S0 and S1 are controlled to be on and off, thereby realizing the function of a buck-boost converter.

[0016] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0017] The present invention provides a switching converter topology, the topology includes two ports, the switch tubes S1 to S4 form an H bridge, the midpoint of the H bridge is connected to the inductor L, and the switch tube S0 is connected to the positive pole of Port1 and the midpoint of the H bridge. The switching converter topology combines the switching states of the power electronic switching devices to realize a boost circuit, a buck circuit, and a buck-boost circuit. The power electronic devices include but are not limited to IGBT, MOSFET, GTO, diode, and solid-state relay. The converter can realize multiple voltage conversion functions through one device.

[0018] Furthermore, by using reverse-series IGBTs, as long as a drive signal is given, the switch is either turned off or closed, no follow-current is generated, the switch state is clear, and control is convenient.

[0019] A switching converter control method provided by the present invention controls the on-off states of switch tubes S0, S1, S2, S3 and S4, so that the switching converter operates in three working states: boost, buck and buck-boost. This method can meet the requirements of DC-DC for multi-stage conversion, wide voltage range input and output, and free conversion of multi-port voltage up and down, and meet the needs of new power usage occasions.

[0020] Furthermore, different control modes are adopted at different times to realize a time-sharing switching function, that is, at different times, the converter is made to work in a step-up, step-down or step-up / step-down working state respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of a switching converter topology;

[0022] Figure 2 It is an application example of a switching converter topology;

[0023] Figure 3 This is a working waveform diagram of a switching converter. DETAILED DESCRIPTION

[0024] In order to make the purpose and technical solution of the present invention clearer and easier to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] Reference Figure 1 A switching converter topology includes two ports, Port1 and Port2. Switch tubes S1, S2, S3, S4 and an inductor L form an H bridge, wherein the switch tubes S1 and S2 form one bridge arm, the switch tubes S3 and S4 form another bridge arm, the two ends of the inductor L are respectively connected to the two midpoints of the H bridge, the first end of the switch tube S0 is connected to the positive electrode of Port1, and the second end is connected to the H bridge.

[0027] Specifically, the first end of the switch tube S1 is connected to the first end of the switch tube S2, the first end of the switch tube S3 is connected to the first end of the switch tube S4, the second end of the switch tube S1 is connected to the second end of the switch tube S3, the second end of the switch tube S2 is connected to the second end of the switch tube S4, the connection point between the first end of the switch tube S1 and the first end of the switch tube S2 is the first midpoint, the connection point between the first end of the switch tube S3 and the first end of the switch tube S4 is the second midpoint, the first end of the inductor L is connected to the first midpoint, and the second end is connected to the second midpoint, the first end of the switch tube S0 is connected to the first midpoint, the second end of the switch tube S0 and the second end of the switch tube S2 form a port Port1, and the first end of the switch tube S3 and the second end of the switch tube S4 form a port Port2.

[0028] The switch tubes S1 to S4 include but are not limited to IGBT, MOSFET, GTO, diode, and solid-state relay.

[0029] Port1 is used as the input end, and Port2 is used as the output end to realize the functions of boost, buck, and buck-boost.

[0030] Port1 is used as the input end, Port2 is used as the output end, the switch tubes S1 and S4 are normally open, S3 is normally closed, and the on and off of S0 and S2 are controlled to realize the function of a buck converter.

[0031] Port1 is used as the input terminal, Port2 is used as the output terminal, the switches S1 and S2 are normally open, S0 is normally closed, and S3 and S4 are controlled to be on and off, thereby realizing the function of a boost converter.

[0032] Port1 is used as the input end, Port2 is used as the output end, the switch tubes S2 and S3 are normally closed, S4 is normally closed, and S0 and S1 are controlled to realize the function of the buck-boost converter.

[0033] The switching converter can also be realized by using Port2 as the input terminal and Port1 as the output terminal.

[0034] The control method of a switching converter topology of the present invention realizes the function of a buck converter, referring to Figure 2 Port 1 is used as the input terminal and connected to the DC power supply E, and port 2 is used as the output terminal and connected to the load R. The switch tube adopts a bidirectional switch, and the switch tubes S1 and S4 are normally open, and the switch tube S3 is normally closed. The on and off of the switch tubes S0 and S2 can be controlled to realize the function of the buck converter. Among them, the switch tubes S0, S1, S2, S3 and S4 are the same, and all use two IGBTs connected in reverse series.

[0035] refer to Figure 3 , when t=t0, the switch tube S0 is controlled to be turned on and the switch tube S2 is turned off, the power supply E supplies power to the load R, the load voltage Vo=E, and the inductor current IL rises according to the exponential curve; when t=t1, the switch tube S0 is controlled to be turned off and the switch tube S2 is turned on, the inductor current continues to flow through the switch tube S2 until a cycle T ends, and the process of the previous cycle is repeated. When the circuit works in a steady state, the initial value and final value of the load current in a cycle are equal, and the average value of the load voltage V o for

[0036]

[0037] Where, t on is the time that the switch tube S0 is in the on state; t off is the time that Vo is in the off state, T is the switching period, and α is the duty cycle. The maximum average voltage Vo output to the load is E. By reducing the duty cycle, Vo will decrease accordingly, and voltage reduction can be achieved.

[0038] (2) The control method of a switching converter topology according to the present invention realizes the function of a boost converter, referring to Figure 2 Port Port1 is used as the input terminal and connected to the DC power supply E, and port Port2 is used as the output terminal and connected to the load R. The switch tube adopts a bidirectional switch, and the switch tubes S1 and S2 are normally open, and S0 is normally closed. The switch tubes S3 and S4 are controlled to be on and off, so as to realize the function of a boost converter.

[0039] refer to Figure 3 At t=t3, the switch tube S4 is turned on and the switch tube S3 is turned off. The time when the switch tube S4 is in the on state is t on , the energy accumulated on the inductor L at this stage is E*I 1 *t on ; When t=t4, S4 is in the off state, E and L charge the capacitor C together and provide energy to the load R. Suppose the time S4 ​​is in the off state is t off , then the energy released by the inductor L at this stage is (Vo-E)*I 1 *t off , when the circuit works in steady state, the energy stored in the inductor in one cycle T is equal to the energy released.

[0040] EI 1 t on =(V o -E)I 1 t off

[0041] Simplified

[0042]

[0043] T / t off Indicates the boost ratio. By adjusting its value, the output voltage can be changed. off ≥1, boost can be achieved.

[0044] (3) The control method of a switching converter topology according to the present invention realizes the function of a buck-boost converter, referring to Figure 2 Port 1 is used as the input terminal and connected to the DC power supply E, and port 2 is used as the output terminal and connected to the load R. The switch tube adopts a bidirectional switch, and the switch tubes S2 and S3 are normally open, and the switch tube S4 is normally closed. By controlling the on and off of the switch tubes S0 and S1, the function of the buck-boost converter can be realized.

[0045] refer to Figure 3, control switch tube S4 to be always on, at t=t6, control switch tube S0 to be on, switch tube S1 to be off, power source E supplies power to inductor L, inductor L stores energy, suppose the time that switch tube S0 is on is t on At t=t7, the switch tube S0 is turned off and the switch tube S1 is turned on. The energy stored in the inductor L is released to the load R through the switch tube S1. When the switch tube S0 is in the on state, U L =E; and when S0 is in the off state, U L = -Vo, so

[0046] E on =V o t off

[0047]

[0048] By changing the duty cycle α, the output voltage can be higher or lower than the power supply voltage. When 0<α<0.5, it is step-down, and when 0.5<α<1, it is step-up.

[0049] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A switching converter topology, characterized in that: It includes a switch tube S1, a switch tube S2, a switch tube S3 and a switch tube S4; the first end of the switch tube S1 is connected to the first end of the switch tube S2, the first end of the switch tube S3 is connected to the first end of the switch tube S4, the second end of the switch tube S1 is connected to the second end of the switch tube S3, the second end of the switch tube S2 is connected to the second end of the switch tube S4, the connection point between the first end of the switch tube S1 and the first end of the switch tube S2 is the first midpoint, the connection point between the first end of the switch tube S3 and the first end of the switch tube S4 is the second midpoint, the first end of the inductor L is connected to the first midpoint, the second end is connected to the second midpoint, the first end of the switch tube S0 is connected to the first midpoint, the second end of the switch tube S0 and the second end of the switch tube S2 form a port Port1, and the first end of the switch tube S3 and the second end of the switch tube S4 form a port Port2; Make the switch tubes S1 and S4 normally open, and the switch tube S3 normally closed, and control the on and off of the switch tubes S0 and S2 to realize the function of the buck converter; The switch tubes S1 and S2 are normally open, the switch tube S0 is normally closed, and the switch tubes S3 and S4 are controlled to be on and off, so as to realize the function of the boost converter; The switch tubes S2 and S3 are normally open, the switch tube S4 is normally closed, and the on and off of the switch tubes S0 and S1 are controlled to realize the function of the buck-boost converter.

2. A switching converter topology according to claim 1, characterized in that: The switch tubes S0, S1, S2, S3 and S4 are the same.

3. A switching converter topology according to claim 1, characterized in that: The switch tube S0, the switch tube S1, the switch tube S2, the switch tube S3 and the switch tube S4 are the same, and all use two IGBTs connected in reverse series.

4. A switching converter topology according to claim 1, characterized in that: The port Port2 is connected in parallel with a capacitor C.

5. The control method of a switching converter topology according to claim 1, characterized in that: The port Port1 is used as an input terminal and connected to a DC power source E, and the port Port2 is used as an output terminal and connected to a load R, and time-sharing switching is achieved by the following method; At t0-t3, the switch tubes S1 and S4 are normally open, the switch tube S3 is normally closed, and the switch tubes S0 and S2 are controlled to be on and off, thus realizing the function of a buck converter; At time t3-t6, the switch tubes S1 and S2 are normally open, the switch tube S0 is normally closed, and the switch tubes S3 and S4 are controlled to be on and off, thereby realizing the function of a boost converter; At time t6 to t8, the switch tubes S2 and S3 are normally open, the switch tube S4 is normally closed, and the switch tubes S0 and S1 are controlled to be on and off, thereby realizing the function of a buck-boost converter.

Images