A high-gain modular multi-level DC-DC converter system

Abstract

The utility model discloses a high-gain modular multi-level DC-DC converter system, which includes a sensor sampling module, a signal conditioning circuit, an analog-to-digital conversion circuit, a controller, a driving module and an MMC; the input end of the sensor sampling module is connected to a load, the output end of the sensor sampling module is connected to the input end of the signal conditioning circuit, the output end of the signal conditioning circuit is connected to the input end of the analog-to-digital conversion circuit, the output end of the analog-to-digital conversion circuit is connected to the input end of the controller, the output end of the controller is connected to the input end of the driving module, the output end of the driving module is connected to the input end of the MMC, and the output end of the MMC is connected to the load. The utility model provides a high-gain modular multi-level DC-DC converter system, which builds a set of practical specific hardware circuits for traditional MMCs to meet applications that require higher voltage gain.

Description

Technical Field

[0001] The utility model relates to a high-gain modular multi-level DC-DC converter system. Background Art

[0002] At present, the traditional half-bridge boost converter has a simple structure, high reliability, easy to design drive module, and is widely used in ordinary boost occasions. Theoretically, a very high voltage gain can be obtained by using the extreme duty cycle method. However, in practical applications, due to the influence of the equivalent series resistance of the inductor and capacitor and the parasitic parameters of the switching device, the conversion efficiency will drop sharply after the duty cycle reaches a certain value, and even when the duty cycle is close to the limit value of 1, it is difficult for the traditional boost converter to achieve a higher voltage gain. Since the transmission of DC power requires a higher voltage, the traditional MMC (modular multi-level converter) cannot be widely used in practice. Utility Model Content

[0003] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide a high-gain modular multi-level DC-DC converter system, which builds a set of practical specific hardware circuits for traditional MMC to meet the application occasions requiring higher voltage gain.

[0004] In order to solve the above technical problems, the technical solution of the utility model is:

[0005] A high-gain modular multi-level DC-DC converter system includes a sensor sampling module, a signal conditioning circuit, an analog-to-digital conversion circuit, a controller, a driving module and an MMC;

[0006] The input end of the sensor sampling module is connected to the load, the output end of the sensor sampling module is connected to the input end of the signal conditioning circuit, the output end of the signal conditioning circuit is connected to the input end of the analog-to-digital conversion circuit, the output end of the analog-to-digital conversion circuit is connected to the input end of the controller, the output end of the controller is connected to the input end of the driving module, the output end of the driving module is connected to the input end of the MMC, and the output end of the MMC is connected to the load.

[0007] Furthermore, it also includes an overcurrent protection circuit, one end of which is connected to the signal conditioning circuit, and the other end of which is connected to the driving module.

[0008] Furthermore, the sensor sampling module includes a voltage sampling circuit and a current sampling circuit, the output end of the voltage sampling circuit is connected to the input end of the signal conditioning circuit, and the output end of the current sampling circuit is connected to the input end of the signal conditioning circuit.

[0009] Furthermore, the voltage sampling circuit includes a Hall sensor U4, and the model of the Hall sensor U4 is TBV5 / 25A.

[0010] Furthermore, the current sampling circuit includes a current transformer U5, and the model of the current transformer U5 is LA55-P.

[0011] Furthermore, the driving module includes an optocoupler power supply circuit, an IGBT driving circuit and an IGBT module, the optocoupler power supply circuit is used to supply power to the IGBT driving circuit, the IGBT driving circuit is used to drive the IGBT module to work, and the IGBT module is used to control the start and stop of the MMC.

[0012] Furthermore, the optocoupler power supply circuit includes an optocoupler power supply chip U1, and the model of the optocoupler power supply chip U1 is QA01.

[0013] Furthermore, the IGBT driving circuit includes an optocoupler chip U2, and the model of the optocoupler chip U2 is TLP5754.

[0014] Furthermore, the controller includes an MCU chip U3, and the model of the MCU chip U3 is STM32F429IGT6.

[0015] Furthermore, the analog-to-digital conversion circuit includes an ADC chip, and the model of the ADC chip is ADC7938.

[0016] By adopting the above technical scheme, the utility model expands the specific practical hardware circuit design of the sensor sampling module, signal conditioning circuit, analog-to-digital conversion circuit, controller, and drive module on the basis of MMC, and can apply the traditional MMC to occasions with high transmission voltage requirements. The modular system design makes the overall architecture more concise and the working efficiency higher. The MMC has a large number of output levels and there is no dynamic voltage balancing problem caused by the series connection of multiple switching devices. It shows great application value in the field related to flexible direct current transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a principle block diagram of a high-gain modular multi-level DC-DC converter system of the utility model;

[0018] Figure 2 This is a circuit schematic diagram of the sensor sampling module of the utility model;

[0019] Figure 3 It is a circuit schematic diagram of the signal conditioning circuit of the utility model;

[0020] Figure 4 This is a circuit diagram of the controller of the utility model;

[0021] Figure 5 This is a circuit schematic diagram of the drive module of the utility model;

[0022] Figure 6 The utility model is a circuit diagram of the overcurrent protection circuit. DETAILED DESCRIPTION

[0023] In order to make the content of the utility model more clearly understood, the utility model is further described in detail below based on specific embodiments and in conjunction with the accompanying drawings.

[0024] like Figure 1 As shown, this embodiment provides a high-gain modular multi-level DC-DC converter system, which includes a sensor sampling module, a signal conditioning circuit, an analog-to-digital conversion circuit, a controller, a driving module, an MMC and an overcurrent protection circuit.

[0025] The input end of the sensor sampling module is connected to the load, the output end of the sensor sampling module is connected to the input end of the signal conditioning circuit, the output end of the signal conditioning circuit is connected to the input end of the analog-to-digital conversion circuit, the output end of the analog-to-digital conversion circuit is connected to the input end of the controller, the output end of the controller is connected to the input end of the driving module, the output end of the driving module is connected to the input end of the MMC, and the output end of the MMC is connected to the load.

[0026] like Figure 2 As shown, the sensor sampling module of this embodiment includes a voltage sampling circuit and a current sampling circuit, the input end and the output end of the voltage sampling circuit are connected to the input end of the signal conditioning circuit, and the input end and the output end of the current sampling circuit are connected to the input end of the signal conditioning circuit. Figure 1 As shown, the voltage sampling circuit includes a Hall sensor U4, the model of which is TBV5 / 25A. The Hall sensor U4 detects the interruption voltage when the entire converter system loop is disconnected. Figure 1 As shown, the current sampling circuit includes a current transformer U5, the model of which is LA55-P, and the current transformer U5 detects the working current of the entire converter system loop. The working mechanism of the sensor sampling module is to convert the voltage signal and current signal in the circuit into a small voltage signal that can be detected by the chip and then input into the next level signal conditioning circuit.

[0027] like Figure 3As shown, the signal conditioning circuit of this embodiment works at the next level of the sensor sampling module in the entire converter system loop. Because the input signal sampled by the ADC must be a positive level, a circuit is required to perform level processing on the sampled signal so that the signal can be received and processed. Therefore, this embodiment adds a signal conditioning circuit, and the signal conditioning circuit can be divided into DC signal conditioning and AC signal conditioning. The analog-to-digital conversion circuit of this embodiment can convert analog signals into digital signals and input them into the controller. The analog-to-digital conversion circuit includes an ADC chip, and the model of the ADC chip is ADC7938.

[0028] like Figure 4 As shown, the controller of this embodiment includes an MCU chip U3, and the model of the MCU chip U3 is STM32F429IGT6.

[0029] like Figure 5 As shown, the drive module of this embodiment includes an optocoupler power supply circuit, an IGBT drive circuit and an IGBT module. The optocoupler power supply circuit is used to power the IGBT drive circuit, the IGBT drive circuit is used to drive the IGBT module to work, and the IGBT module is used to control the start and stop of the MMC. The optocoupler power supply circuit includes an optocoupler power supply chip U1, and the model of the optocoupler power supply chip U1 is QA01. The IGBT drive circuit includes an optocoupler chip U2, and the model of the optocoupler chip U2 is TLP5754.

[0030] The drive module is the core module of the entire converter system loop, and plays an important role in ensuring the safety of the entire system. In this embodiment, the optocoupler chip U2 is used as an optocoupler driver, and the optocoupler power supply chip U1 is used to power the optocoupler chip U2. Its working principle is: when Figure 5 When MMC_DRV is at a high level and the MMC_S signal is at a low level, the drive signal is exported through pin 5 of the optocoupler chip U2, driving the IGBT module to turn on, and the MMC is in working state.

[0031] like Figure 6 As shown, one end of the overcurrent protection circuit of this embodiment is connected to the signal conditioning circuit, and the other end of the overcurrent protection circuit is connected to the drive module. Its working principle is to detect the current of a pair of bridge arms of the IGBT module and Figure 6 The half-wave rectification in the circuit determines the direction of the current, and then the current signal is followed by a voltage. If the current direction is negative, reverse following is performed. The voltage signal is amplified by the amplifier circuit and compared with the previously set comparison value. The OC signal and the LOCK signal are output according to the comparison result. If an overcurrent fault occurs, the OC signal and the LOCK signal are both low-level and output to the IGBT drive circuit, so that the IGBT module is turned off. Otherwise, the OC signal and the LOCK signal are both high-level, and the IGBT module continues to conduct.

[0032] The specific embodiments described above further illustrate the technical problems, technical solutions and beneficial effects solved by the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-gain modular multi-level DC-DC converter system, characterized in that: It includes a sensor sampling module, a signal conditioning circuit, an analog-to-digital conversion circuit, a controller, a driving module and an MMC; The input end of the sensor sampling module is connected to the load, the output end of the sensor sampling module is connected to the input end of the signal conditioning circuit, the output end of the signal conditioning circuit is connected to the input end of the analog-to-digital conversion circuit, the output end of the analog-to-digital conversion circuit is connected to the input end of the controller, the output end of the controller is connected to the input end of the driving module, the output end of the driving module is connected to the input end of the MMC, and the output end of the MMC is connected to the load.

2. The high-gain modular multi-level DC-DC converter system according to claim 1, characterized in that: It also includes an overcurrent protection circuit, one end of which is connected to the signal conditioning circuit, and the other end of which is connected to the driving module.

3. The high-gain modular multi-level DC-DC converter system according to claim 1, characterized in that: The sensor sampling module comprises a voltage sampling circuit and a current sampling circuit. The output end of the voltage sampling circuit is connected to the input end of the signal conditioning circuit, and the output end of the current sampling circuit is connected to the input end of the signal conditioning circuit.

4. The high-gain modular multi-level DC-DC converter system according to claim 3, characterized in that: The voltage sampling circuit includes a Hall sensor U4, and the model of the Hall sensor U4 is TBV5 / 25A.

5. The high-gain modular multi-level DC-DC converter system according to claim 3, characterized in that: The current sampling circuit includes a current transformer U5, and the model of the current transformer U5 is LA55-P.

6. The high-gain modular multi-level DC-DC converter system according to claim 1, characterized in that: The driving module includes an optocoupler power supply circuit, an IGBT driving circuit and an IGBT module. The optocoupler power supply circuit is used to supply power to the IGBT driving circuit, the IGBT driving circuit is used to drive the IGBT module to work, and the IGBT module is used to control the start and stop of the MMC.

7. The high-gain modular multi-level DC-DC converter system according to claim 6, characterized in that: The optocoupler power supply circuit includes an optocoupler power supply chip U1, and the model of the optocoupler power supply chip U1 is QA01.

8. The high-gain modular multi-level DC-DC converter system according to claim 6, characterized in that: The IGBT driving circuit includes an optocoupler chip U2, and the model of the optocoupler chip U2 is TLP5754.

9. The high-gain modular multi-level DC-DC converter system according to claim 6, characterized in that: The controller includes an MCU chip U3, and the model of the MCU chip U3 is STM32F429IGT6.

10. The high-gain modular multi-level DC-DC converter system according to claim 1, characterized in that: The analog-to-digital conversion circuit includes an ADC chip, and the model of the ADC chip is ADC7938.

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