A multi-topology DC voltage converter for DC microgrid

Abstract

A novel multi-topology DC voltage converter for a DC microgrid includes a power layer, a transmission layer, a conditioning layer and a control layer, wherein the power layer is connected to the conditioning layer through the transmission layer; the power layer includes seven terminals, a three-phase two-level IGBT half-bridge power module, a first capacitor and a second capacitor, the pins of the third terminal are respectively connected to one end of the first capacitor and the AC side of the three-phase two-level IGBT half-bridge power module, the pins of the fourth terminal are respectively connected to the three-phase two-level IGBT half-bridge power module and the sixth terminal, the pins of the sixth terminal are connected to the second capacitor, and the pins of the fifth terminal are respectively connected to the three-phase two-level IGBT half-bridge power module and the second capacitor. The present invention overcomes the shortcomings of the prior art and realizes a function conversion that can not only perform boost control, buck control, boost bidirectional conversion, buck bidirectional conversion, and parallel expansion structure, but also can perform fast and safe DC voltage conversion.

Description

Technical Field

[0001] The present invention relates to the technical field of open source scientific research and testing of direct current voltage converters, and in particular to a multi-topology direct current voltage converter for a direct current microgrid. Background Art

[0002] DC microgrids, with their advantages of simple control structure and fewer conversion times, can more efficiently and reliably accommodate distributed renewable energy generation systems such as wind and light, energy storage units, electric vehicles and other DC power loads. As a key component of DC microgrids, DC voltage converters are widely used in research fields such as DC photovoltaic grid-connected systems, DC boost control systems, DC buck control systems, DC energy storage systems, and high-power DC transmission, with their advantages of DC voltage conversion, bidirectional current control, and simple buck-boost control logic. In these research occasions, researchers not only require the underlying open source, but more importantly, they hope that the converter can perform unidirectional and bidirectional energy flow of boost and buck. In addition, they are increasingly favoring the study of a structure in which power devices are connected in parallel to expand capacity.

[0003] Among the existing low-level open source converters, first of all, most of them are separately divided into single-function devices such as DC boost converters, DC step-down converters, buck / boost converters, etc. This is inconvenient for researchers to conduct research on multiple topologies, and it also takes up a lot of space in the laboratory. In terms of safety and convenience, a few open source devices with two sets of functions have problems such as difficulty in replacement and messy wiring harnesses; in addition, in some devices with bidirectional power flow, since the PWM signal opens the upper and lower bridge signals at the same time, users need to set the dead zone themselves. If the setting is improper, it will cause the power tube to blow up. At the same time, these problems constitute application barriers for beginners and are extremely unfavorable for the iteration of scientific research results. Summary of the invention

[0004] In view of the deficiencies of the prior art, the present invention provides a multi-topology DC voltage converter for a DC microgrid, which overcomes the deficiencies of the prior art and has a reasonable design. A voltage sensor, a current sensor, PWM signal processing and configuration instructions are introduced to perform control optimization, thereby realizing a function conversion that can not only perform boost control, buck control, boost bidirectional conversion, buck bidirectional conversion, and parallel expansion structure, but also perform fast and safe DC voltage conversion.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0006] A multi-topology DC voltage converter for a DC microgrid comprises a power layer, a transmission layer, a conditioning layer and a control layer, wherein the power layer is connected to the conditioning layer via the transmission layer, and an output end of the conditioning layer is connected to the control layer;

[0007] The power layer includes a first wiring terminal S1, a second wiring terminal S2, a third wiring terminal S3, a fourth wiring terminal S4, a fifth wiring terminal S5, a sixth wiring terminal S6, a seventh wiring terminal S7, a three-phase two-level IGBT half-bridge power module, a first capacitor C1 and a second capacitor C2, wherein pin 1 and pin 2 of the first wiring terminal S1 are connected, pin 1 and pin 2 of the second wiring terminal S2 are connected, pin 1, pin 2 and pin 3 of the third wiring terminal S3 are all connected to one end of the first capacitor C1, the other end of the first capacitor C1 is connected to pin 1 of the fourth wiring terminal S4, and pin 2 of the fourth wiring terminal S4 is respectively connected to the E pole of the three-phase two-level IGBT half-bridge power module and the sixth wiring terminal The first terminal S1 and the second terminal S2 are connected to the positive pole L+ and the negative pole H- on the high voltage side of the three-phase two-level IGBT half-bridge power module, respectively; the first terminal S1 and the second terminal S2 are connected to the positive pole L+ and the negative pole H- on the high voltage side of the three-phase two-level IGBT half-bridge power module, respectively; the first terminal S1 and the second terminal S2 are connected to the positive pole L+ and the negative pole L- on the low voltage side of the three-phase two-level IGBT half-bridge power module, respectively; the first terminal S1 and the second terminal S2 are connected to the positive pole L+ and the negative pole L- on the low voltage side of the three-phase two-level IGBT half-bridge power module, respectively; the first terminal S2 and the second terminal S3 ... high voltage side of the three-phase two-level IGBT half-bridge power module, respectively; the first terminal S1 and the second terminal S2 are connected to the positive pole L+ and the negative pole L- on the low voltage side of the three-phase two-level IGBT half-bridge power module, respectively; the first terminal S1 and the second terminal S2 are connected to the positive pole L+ and the negative pole L- on the low voltage side of the three-phase two-level IGBT half-bridge power module, respectively; the first terminal S1 and the second terminal S2 are connected to the positive pole L+ and the negative pole L- on the low voltage side of the three-phase two-level IGBT half-bridge power module, respectively; the first terminal S1 and the second terminal S2 are connected to the positive pole L+ and the

[0008] Preferably, the connection circuit between pins 4, 5 and 6 of the connection terminal S3 and the AC side of the three-phase two-level IGBT half-bridge power module is respectively connected to the first inductor L1, the second inductor L2 and the third inductor L3.

[0009] Preferably, current sensors are installed on the connection circuit between pins 4, 5 and 6 of the terminal S3 and the AC side of the three-phase two-level IGBT half-bridge power module and on the connection circuit between pin 1 of the fifth terminal S5 and the positive terminal H+ on the high-voltage side, voltage sensors are installed between the first terminal S1 and the second terminal S2 and between the seventh terminal S7 and the positive terminal H+ on the high-voltage side, a current sampling module and a voltage sampling module are arranged in the conditioning layer, and the output ends of the current sensor and the voltage sensor are connected to the current sampling module and the voltage sampling module respectively.

[0010] Preferably, each phase two-level IGBT half-bridge power module includes two IGBT half-bridge power modules connected in series, the IGBT half-bridge power module includes an upper bridge arm and a lower bridge arm, the bases of the upper bridge arm and the lower bridge arm are connected to a dead zone module, and the dead zone module is arranged in the conditioning layer.

[0011] Preferably, the control layer includes a digital quantity interface and an analog quantity interface.

[0012] The present invention provides a multi-topology DC voltage converter for a DC microgrid. It has the following beneficial effects: the power layer is connected to the conditioning layer through a high-shielded cable, so that the control layer can obtain an analog signal, so that the PWM signal of the control layer drives the power layer, so that not only can boost control, buck control, boost bidirectional conversion, buck bidirectional conversion, parallel expansion structure function conversion be performed, but also fast and safe DC voltage conversion can be performed; compared with traditional DC voltage converters, it provides users with a richer underlying control experimental environment and saves space; by integrating the voltage signal, current signal and PWM signal required by the user for control development into the high-shielded cable, the user is prevented from making flying wires between the sensor and the power drive circuit board, and the clear and concise wiring enables researchers to connect with the theoretical model more quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the present invention or the technical solutions in the prior art, the drawings required for describing the prior art are briefly introduced below.

[0014] Figure 1 A schematic diagram of the structural connection of the present invention;

[0015] Figure 2 A schematic diagram of the BOOST structure connection in Example 1 of the present invention;

[0016] Figure 3 Schematic diagram of BUCK structure connection in Embodiment 2 of the present invention;

[0017] Figure 4 Schematic diagram of BUCK / BOOST structure connection in Example 3 of the present invention;

[0018] Figure 5 Schematic diagram of parallel BOOST structure connection in Example 4 of the present invention;

[0019] Description of the numbers in the figure:

[0020] 1. Power layer; 2. Transmission layer; 3. Conditioning layer; 4. Control layer; 11. Two-level IGBT half-bridge power module; 12. Current sensor; 13. Voltage sensor; 31. Current sampling module; 32. Voltage sampling module; 33. Dead zone module. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention.

[0022] like Figure 1 As shown, a multi-topology DC voltage converter for a DC microgrid includes a power layer 1, a transmission layer 2, a conditioning layer 3 and a control layer 4, wherein the power layer 1 is connected to the conditioning layer 3 through the transmission layer 2, and the output end of the conditioning layer 3 is connected to the control layer 4;

[0023] The power layer 1 includes a first terminal S1, a second terminal S2, a third terminal S3, a fourth terminal S4, a fifth terminal S5, a sixth terminal S6, a seventh terminal S7, a three-phase two-level IGBT half-bridge power module 11, a first capacitor C1 and a second capacitor C2, pin 1 and pin 2 of the first terminal S1 are connected, pin 1 and pin 2 of the second terminal S2 are connected, pin 1, pin 2 and pin 3 of the third terminal S3 are all connected to one end of the first capacitor C1, the other end of the first capacitor C1 is connected to pin 1 of the fourth terminal S4, and pin 2 of the fourth terminal S4 is respectively connected to the E pole and the sixth terminal of the three-phase two-level IGBT half-bridge power module 11. The first terminal S1 and the second terminal S2 are connected to the positive pole L+ and the negative pole H- on the high voltage side of the three-phase two-level IGBT half-bridge power module 11, respectively; the first terminal S1 and the second terminal S2 are connected to the positive pole L+ and the negative pole L- on the low ... Among them, the low-voltage side supports a DC voltage range of 0-300V, the high-voltage side supports 0-650V, the overvoltage protection value of the high-voltage side is 720V, and its rated power (current) is 15KW (50A). The PWM signal switching frequency of the unit is 20KHz, and its overload capacity currently supports a maximum of 2.5 times overload (overload time 1 second). The circuit board uses 6 layers to improve anti-interference ability. A variable topology structure is provided through power layer 1.

[0024] In the present application, the transmission layer 2 uses a high-shielded cable to enhance the stability and anti-interference of high-precision PWM digital signals and high-resolution sensor signals, while also avoiding the clutter of the wiring harness.

[0025] In the present application, the connection circuit between pins 4, 5 and 6 of the connection terminal S3 and the AC side of the three-phase two-level IGBT half-bridge power module 11 is respectively connected to the first inductor L1, the second inductor L2 and the third inductor L3.

[0026] In the present application, current sensors 12 are installed on the connection circuit between pins 4, 5 and 6 of terminal S3 and the AC side of the three-phase two-level IGBT half-bridge power module 11, and on the connection circuit between pin 1 of the fifth terminal S5 and the positive terminal H+ on the high-voltage side. Voltage sensors 13 are installed between the first terminal S1 and the second terminal S2 and between the seventh terminal S7 and the positive terminal H+ on the high-voltage side. A current sampling module 31 and a voltage sampling module 32 are arranged in the conditioning layer 3, and the output ends of the current sensor 12 and the voltage sensor 13 are respectively connected to the current sampling module 31 and the voltage sampling module 32. The current sampling module 31 includes 1 DC side current and 1 AC side current, with a sampling accuracy of 0.5%, a response time of less than 1us, and a frequency of 100KHz. The voltage sampling module 32 includes 1 DC side voltage, 1 AC outlet voltage, and 1 filtered voltage, with a voltage sampling accuracy of 0.3%, a response time of less than 40us, and a frequency of 100Hz. The voltage signals output by the voltage and current sensors are conditioned by the conditioning layer 3.

[0027] Among them, the current signals on the connection circuit between the No. 4 pin, the No. 5 pin and the No. 6 pin of the connection terminal S3 and the AC side of the three-phase two-level IGBT half-bridge power module 11 are I L1 ,I L2 ,I L3 The current signal on the connection circuit between pin 1 of the fifth terminal S5 and the positive terminal H+ on the high-voltage side is I H , the voltage signal between the first terminal S1 and the second terminal S2 is U L The voltage signal between the seventh terminal S7 and the positive terminal H+ on the high voltage side is U H .

[0028] In the present application, each phase two-level IGBT half-bridge power module 11 includes two IGBT half-bridge power modules connected in series, and the IGBT half-bridge power module includes an upper bridge arm and a lower bridge arm, and the base of the upper bridge arm and the lower bridge arm is connected to the dead zone module 33, and the dead zone module 33 is arranged in the conditioning layer 3. The dead zone module 33 is added to protect the power module of the driving layer from explosion. The dead zone modules 33 corresponding to the three-phase two-level IGBT half-bridge power module are respectively output as PWM1 signals, PWM2 signals and PWM3 signals, and are adjusted by the control layer 4.

[0029] In the present application, the control layer 4 includes a digital interface and an analog interface, wherein the analog interface is a 5V, 20mA differential signal, and the digital interface is a 5V / 20mA PWM interface input. Example

[0030] Regarding unidirectional and bidirectional control of BOOST, by connecting pin 2 of the first terminal S1 and pin 4 of the third terminal S3, pin 2 of the second terminal S2 and pin 2 of the fourth terminal S4, and pins 1 and 2 of the fifth terminal S5, a circuit is formed as follows: Figure 2 As shown in the BOOST structure connection diagram, the user connects the positive and negative ends of the low-voltage unidirectional or bidirectional power supply to the No. 1 pin of the first wiring terminal S1 and the No. 1 pin of the second wiring terminal S2 at the power layer 1, and connects the positive and negative ends of the load or power supply at the high-voltage side to H+ and H- respectively; at the control layer 4, the user collects I L1 and U H The signal can be adjusted through PWM1, and the user can perform closed-loop control of the output side voltage when the input voltage changes suddenly; by connecting pins 1 and 4 of the third terminal S3 and pins 1 and 2 of the fourth terminal S4, the first capacitor C1 can be connected on the input side to filter the input voltage; at the same time, MPPT control of DC photovoltaic grid connection can be performed. Example

[0031] Regarding the unidirectional and bidirectional control of the BUCK, by connecting the No. 2 pin of the first terminal S1 and the No. 4 pin of the third terminal S3, the No. 1 pin and the No. 4 pin of the third terminal S3, the No. 2 pin of the second terminal S2 and the No. 1 pin of the fourth terminal S4, and the No. 1 pin and the No. 2 pin of the sixth terminal S6, the following can be formed: Figure 3 As shown in the BUCK structure connection diagram, the user connects the positive and negative ends of the load or power supply on the low voltage side to the No. 1 pin of the first wiring terminal S1 and the No. 1 pin of the second wiring terminal S2 at the power layer 1, and connects the positive and negative ends of the unidirectional or bidirectional power supply on the high voltage side to H+ and H- respectively; at the control layer 4, the user collects I H and U L The signal can be adjusted through PWM1, and the user can perform closed-loop control of the output voltage when the input voltage suddenly changes; by connecting to pins 1 and 2 of the fifth terminal S5, a capacitor can be connected on the input side to filter the input voltage. Example

[0032] Regarding unidirectional and bidirectional control of BUCK / BOOST, by connecting pin 2 of the first terminal S1 and pin 1 of the third terminal S3, pin 1 and pin 4 of the third terminal S3, pin 4 of the third terminal S3 and pin 1 of the seventh terminal S7, the following can be constructed: Figure 4 As shown in the BUCK structure connection diagram, the user connects the positive and negative ends of the load or power supply on the low voltage side to the No. 1 pin of the first wiring terminal S1 and the No. 1 pin of the second wiring terminal S2 at the power layer 1, and connects the positive and negative ends of the unidirectional or bidirectional power supply on the high voltage side to H+ and H- respectively; at the control layer 4, the user collects I H and U L The signal can be adjusted through PWM1, and the user can perform closed-loop control of the output side voltage when the input voltage changes suddenly; by connecting pins 1 and 2 of the fifth terminal S5, pin 1 of the sixth terminal S6, and pin 1 of the seventh terminal S7, a capacitor can be connected on the input side to filter the input voltage. Example

[0033] Regarding the unidirectional and bidirectional control of parallel BOOST, by connecting pin 2 of the first terminal S1 and pin 4 of the third terminal S3, pin 4 and pin 5 of the third terminal S3, pin 5 and pin 6 of the third terminal S3, pin 1 and pin 2 of the fifth terminal S5, pin 1 and pin 2 of the sixth terminal S6, pin 2 of the sixth terminal S6 and pin 1 of the seventh terminal S7, the following can be constructed: Figure 5 As shown in the parallel BOOST structure connection diagram, the user connects the positive and negative ends of the unidirectional or bidirectional power supply on the low voltage side to the No. 1 pin of the first wiring terminal S1 and the No. 1 pin of the second wiring terminal S2 at the power layer 1, and connects the positive and negative ends of the load or power supply on the high voltage side to H+ and H- respectively; at the control layer 4, the user collects I L1 ,I L2 ,I L3 and U H The signal can be adjusted through PWM1, PWM2 and PWM3, and the user can perform closed-loop control of the output voltage when the input voltage suddenly changes; by connecting the No. 1 and No. 2 pins of the fourth wiring terminal S4, the No. 1 and No. 4 pins of the third wiring terminal S3 (or the No. 2 and No. 5 pins of the third wiring terminal S3 or the No. 3 and No. 6 pins of the third wiring terminal S3), a capacitor can be connected on the input side to filter the input voltage.

[0034] After completing the configuration of the power layer 1 and the variable selection of the control layer 4 in the above-mentioned embodiments 1 to 4, the power layer 1 is connected to the conditioning layer 3 through the high-shielded cable of the transmission layer 2, so that the control layer 4 can obtain the analog signal, so that the PWM signal of the control layer 4 drives the power layer 1, thereby realizing a functional conversion that can not only perform boost control, buck control, boost bidirectional conversion, buck bidirectional conversion, and parallel expansion structure, but also perform fast and safe DC voltage conversion.

[0035] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-topology DC voltage converter for a DC microgrid, characterized in that: It comprises a power layer (1), a transmission layer (2), a conditioning layer (3) and a control layer (4), wherein the power layer (1) is connected to the conditioning layer (3) via the transmission layer (2), and the output end of the conditioning layer (3) is connected to the control layer (4); The power layer (1) comprises a first wiring terminal S1, a second wiring terminal S2, a third wiring terminal S3, a fourth wiring terminal S4, a fifth wiring terminal S5, a sixth wiring terminal S6, a seventh wiring terminal S7, a three-phase two-level IGBT half-bridge power module (11), a first capacitor C1 and a second capacitor C2, wherein pin No. 1 and pin No. 2 of the first wiring terminal S1 are connected, pin No. 1 and pin No. 2 of the second wiring terminal S2 are connected, pin No. 1, pin No. 2 and pin No. 3 of the third wiring terminal S3 are all connected to one end of the first capacitor C1, the other end of the first capacitor C1 is connected to pin No. 1 of the fourth wiring terminal S4, and pin No. 2 of the fourth wiring terminal S4 is respectively connected to the E pole of the three-phase two-level IGBT half-bridge power module (11) and the sixth wiring terminal S The first terminal S1 is connected to the second terminal S6, the first terminal S2 is connected to one end of the second capacitor C2, the other end of the second capacitor C2 is connected to the second terminal S5, the first terminal S5 is connected to the C pole of the three-phase two-level IGBT half-bridge power module (11) and the positive terminal H+ on the high voltage side, the second terminal S6 is connected to the second terminal S6, the first terminal S6 is connected to one end of the second capacitor C2, the other end of the second capacitor C2 is connected to the second terminal S5, the first terminal S5 is connected to the C pole of the three-phase two-level IGBT half-bridge power module (11) and the positive terminal H+ on the high voltage side, the second terminal S6 is connected to the second terminal S7, the first terminal S1 and the second terminal S2 are connected to the positive terminal L+ and the negative terminal L- on the low voltage side, respectively; The connection circuit between the No. 4 pin, the No. 5 pin and the No. 6 pin of the connection terminal S3 and the AC side of the three-phase two-level IGBT half-bridge power module (11) is respectively connected to a first inductor L1, a second inductor L2 and a third inductor L3; The transmission layer (2) uses a high-shield cable; The control layer (4) includes a digital quantity interface and an analog quantity interface.

2. The multi-topology DC voltage converter for a DC microgrid according to claim 1, characterized in that: Current sensors (12) are installed on the connection circuit between pins 4, 5 and 6 of the connection terminal S3 and the AC side of the three-phase two-level IGBT half-bridge power module (11), and on the connection circuit between pin 1 of the fifth connection terminal S5 and the high-voltage side positive terminal H+; voltage sensors (13) are installed between the first connection terminal S1 and the second connection terminal S2, and between the seventh connection terminal S7 and the high-voltage side positive terminal H+; a current sampling module (31) and a voltage sampling module (32) are arranged in the conditioning layer (3); and the output ends of the current sensor (12) and the voltage sensor (13) are connected to the current sampling module (31) and the voltage sampling module (32), respectively.

3. The multi-topology DC voltage converter for a DC microgrid according to claim 1, characterized in that: Each phase two-level IGBT half-bridge power module (11) comprises two IGBT half-bridge power modules connected in series, the IGBT half-bridge power module comprising an upper bridge arm and a lower bridge arm, the bases of the upper bridge arm and the lower bridge arm are connected to a dead zone module (33), and the dead zone module (33) is arranged in the conditioning layer (3).

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