High-voltage battery hybrid inverter topology system

Abstract

The invention provides a high-voltage battery hybrid inverter topology system, and belongs to the technical field of inverter topology. The high-voltage battery hybrid inverter topology system comprises a high-voltage battery, a photovoltaic assembly, an inverter circuit, a buck-boost circuit and a bus assembly. The high-voltage battery is directly connected with the bus assembly, the output power provided by the photovoltaic assembly for the bus assembly is controlled through the buck-boost circuit while a battery charging and discharging circuit is cancelled, the software and hardware cost is greatly reduced, and the system efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of inverter topology, and particularly relates to a high-voltage battery hybrid inverter topology system. BACKGROUND

[0002] Referring to Figure 3 , the existing hybrid inverter topology uses a BOOST circuit to supply power to a bus in photovoltaic, and a battery can be charged and discharged through a BDC. There are many kinds of BDC circuits, including isolated and non-isolated ones. Common ones include a BUCK-BOOST circuit or an LLC circuit, a DAB circuit, etc. When the BUCK-BOOST circuit is used, the battery can provide a wide range of input, and the bus voltage can be raised to be higher than the battery voltage to charge or discharge the battery by adjusting the switch tube. If the PV voltage is lower than the bus voltage, the switch tube of the Boost circuit can be controlled to adjust the power supplied to the bus. When the PV voltage is high, the bus can be boosted or the switch tube of the Boost circuit is turned off to directly supply power to the bus through a diode. When the battery voltage is high enough to meet the minimum voltage requirement of the inverter, the BDC circuit can be saved to save cost, and the battery is directly connected to the bus, and the battery can be charged or discharged through the inverter circuit. When the PV voltage is lower than the bus voltage, the switch tube of the Boost circuit can be adjusted to adjust the power supplied to the bus. However, when the PV voltage is higher than the bus voltage, the PV can only be discharged, and if the discharge power allowed by the inverter circuit is lower than the PV power, the battery can only be charged. At this time, if the battery is fully charged, the PV or the battery must be removed to ensure that the battery is not overcharged. SUMMARY

[0003] The present application aims at the deficiencies of the prior art and provides a high-voltage battery hybrid inverter topology system.

[0004] The present application provides a high-voltage battery hybrid inverter topology system, which comprises a high-voltage battery, a photovoltaic module, an inverter circuit, a boost-buck circuit and a bus assembly. The high-voltage battery is connected to the bus assembly, the inverter circuit is connected to the bus assembly, the input end of the boost-buck circuit is connected to the photovoltaic module, and the output end of the boost-buck circuit is connected to the bus assembly. The boost-buck circuit is used to control the output power provided by the photovoltaic module to the bus assembly.

[0005] Further, the bus assembly comprises a bus capacitor, the positive and negative electrodes of the high-voltage battery are respectively connected to the two ends of the bus capacitor, the inverter circuit is respectively connected to the two ends of the bus capacitor, the photovoltaic module is connected to the input end of the boost-buck circuit, and the output end of the boost-buck circuit is respectively connected to the two ends of the bus capacitor.

[0006] Further, the boost-buck circuit is a BUCK-BOOST circuit.

[0007] Further, the boost-buck circuit comprises a first switch, an inductor and a diode, one end of the first switch is connected to the positive pole of the photovoltaic module, the other end of the first switch is connected to the negative pole of the diode and one end of the inductor respectively, the negative pole of the photovoltaic module is connected to the other end of the inductor and one end of the bus capacitor connected to the positive pole of the high-voltage battery respectively, and the positive pole of the diode is connected to one end of the bus capacitor connected to the negative pole of the high-voltage battery.

[0008] Further, the photovoltaic module charges the inductor when the first switch is closed, and the inductor discharges the bus capacitor when the first switch is opened.

[0009] Further, the first switch is a semiconductor switch.

[0010] Further, when the system meets the first preset condition, the duty cycle of the first switch is equal to the voltage of the high-voltage battery divided by the sum of the voltage of the high-voltage battery and the voltage of the photovoltaic module.

[0011] Further, the controller controls the first switch to be closed or opened at a preset frequency.

[0012] Further, the system further comprises a first connecting line and a second connecting line, the bus assembly further comprises a first bus connected to one end of the bus capacitor and a second bus connected to the other end of the bus capacitor, one end of the first connecting line is connected to the positive pole of the high-voltage battery, and the other end of the first connecting line is connected to the other end of the first bus, one end of the second connecting line is connected to the negative pole of the high-voltage battery, and the other end of the second connecting line is connected to the other end of the second bus.

[0013] Further, the boost-buck circuit further comprises a third connecting line, a fourth connecting line, a fifth connecting line, a sixth connecting line, a seventh connecting line and an eighth connecting line; one end of the third connecting line is connected to the negative pole of the photovoltaic module, and the other end of the third connecting line is connected to the other end of the first bus, one end of the fourth connecting line is connected to the positive pole of the photovoltaic module, and the other end of the fourth connecting line is connected to one end of the first switch, one end of the fifth connecting line is connected to the other end of the first switch, and the other end of the fifth connecting line is connected to the negative pole of the diode, one end of the sixth connecting line is connected to the positive pole of the diode, and the other end of the sixth connecting line is connected to the other end of the second bus, one end of the seventh connecting line is connected to one end of the inductor, and the other end of the seventh connecting line is connected to the third connecting line, one end of the eighth connecting line is connected to the other end of the inductor, and the other end of the eighth connecting line is connected to the fifth connecting line.

[0014] The high-voltage battery hybrid inverter topology system has the following beneficial effects: The high-voltage battery is directly connected to the bus assembly, the battery charging and discharging circuit is cancelled, the output power of the photovoltaic module to the bus assembly is controlled through the boost-buck circuit, the software and hardware costs are greatly reduced, and the system efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0015] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the application and, together with the description, serve to explain the principles of the application. In the drawings, like reference numerals are used to represent like elements. The accompanying drawings are intended to illustrate some, but not all, embodiments of the present application. Other embodiments of the present application will be apparent to those of ordinary skill in the art in view of the following detailed description.

[0016] Figure 1 A high-voltage battery hybrid inverter topology system of an embodiment of the present application; Figure 2 A high-voltage battery hybrid inverter topology system of an embodiment of the present application; Figure 3 A prior art schematic diagram. DETAILED DESCRIPTION

[0017] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other in any manner without conflict.

[0018] Please refer to Figures 1-2 The high-voltage battery hybrid inverter topology system of an embodiment of the present application comprises a high-voltage battery, a photovoltaic module, an inverter circuit, a boost-buck circuit and a bus assembly. The high-voltage battery is connected to the bus assembly, the inverter circuit is connected to the bus assembly, the input end of the boost-buck circuit is connected to the photovoltaic module, and the output end of the boost-buck circuit is connected to the bus assembly. The boost-buck circuit is used to control the output power provided by the photovoltaic module to the bus assembly.

[0019] Here, in the existing high-voltage battery hybrid inverter topology system, the charge and discharge circuit of the high-voltage battery is needed to control the charge and discharge of the high-voltage battery, which needs hardware and algorithm support, increases the cost, reduces the efficiency, and makes the control complex. And some high-voltage battery hybrid inverter topology systems directly remove the charge and discharge circuit and use high-voltage batteries directly to the bus, which makes PV unable to improve the open circuit voltage and cannot meet the economic requirements, which will seriously limit the use value of the high-voltage battery hybrid inverter topology system. The scheme cancels the battery charge and discharge circuit, and innovatively uses the boost-buck circuit to replace the traditional boost circuit to control the PV output, greatly reducing the hardware and software cost and improving the system efficiency.

[0020] Specifically, referring to Figure 2 and Figure 3 , PV represents a photovoltaic module. High-voltage battery: usually refers to a battery pack with a voltage of 48V or more, for example, a new energy vehicle power battery pack with a voltage of 350V-600V, which mainly realizes high-voltage output through cell series connection.

[0021] The bus assembly can include a bus capacitor; the positive and negative electrodes of the high-voltage battery are connected to the two ends of the bus capacitor, and the inverter circuit is connected to the two ends of the bus capacitor; the photovoltaic module is connected to the input end of the boost-buck circuit, and the output end of the boost-buck circuit is connected to the two ends of the bus capacitor.

[0022] Specifically, the inverter circuit includes a first input end and a second input end, and the first input end and the second input end of the inverter circuit are connected to the two ends of the bus capacitor.

[0023] The boost-buck circuit can be a BUCK-BOOST circuit.

[0024] Specifically, the present application is different from the prior art in that the output power of the photovoltaic module is controlled by a boost circuit, and the present application controls the output power of the photovoltaic module by a boost-buck circuit while removing the battery charge and discharge circuit. Among them, the BUCK-BOOST circuit is only a typical form of the boost-buck circuit, and other boost-buck circuits can also replace the BUCK-BOOST circuit mentioned in the present application to achieve the effect of the present scheme.

[0025] Specifically, the present application can realize that the high-voltage battery is directly connected to the bus assembly, while allowing the photovoltaic module to be configured with a higher open circuit voltage to improve the economy of the system. Unlike the prior art, the photovoltaic module is discharged by a boost circuit, and the present application uses a BUCK-BOOST circuit to discharge the photovoltaic module. When the voltage of the photovoltaic module is higher or lower than the bus voltage, the output power to the bus assembly can be controlled.

[0026] Specifically, the BUCK-BOOST circuit belongs to a boost-buck circuit, and its core function is to realize voltage regulation through a single circuit. The BUCK-BOOST circuit realizes voltage conversion through switch tube switching. When the input voltage is higher or lower than the output voltage, it runs in buck or boost mode respectively, and only 6 components are needed to complete the buck-boost function. The circuit adjusts the output voltage by controlling the switching frequency and duty cycle, and is suitable for scenarios that require flexible voltage adjustment. The efficiency of the BUCK-BOOST circuit and the mode: buck mode: when the input voltage is higher than the output voltage, the inductor stores energy to achieve voltage reduction; boost mode: when the input voltage is lower than the output voltage, the inductor stores energy to achieve voltage increase; buck-boost mode: through dynamic adjustment of switching frequency and inductor current continuity to achieve bidirectional regulation.

[0027] The boost-buck circuit can include a first switch, an inductor, and a diode. One end of the first switch is connected to the positive pole of the photovoltaic module. The other end of the first switch is connected to the negative pole of the diode and one end of the inductor, respectively. The negative pole of the photovoltaic module is connected to the other end of the inductor and one end of the bus capacitor connected to the positive pole of the high-voltage battery, respectively. The positive pole of the diode is connected to one end of the bus capacitor connected to the negative pole of the high-voltage battery.

[0028] The photovoltaic module can charge the inductor when the first switch is closed. The inductor discharges the bus capacitor when the first switch is open.

[0029] The first switch can be a semiconductor switch.

[0030] Specifically, the semiconductor switch is a sensor made of semiconductor materials, mainly used in switch mode converters.

[0031] When the system meets the first preset condition, the duty cycle of the first switch can be equal to the high-voltage battery voltage divided by the sum of the high-voltage battery voltage and the photovoltaic module voltage.

[0032] Specifically, the system meeting the first preset condition can be system stability. Therefore, when the system is stable, the duty cycle of the semiconductor switch is D=Vbat / (Vbat+Vpv), where Vbat represents the high-voltage battery voltage and Vpv represents the photovoltaic module voltage.

[0033] As one of the high-voltage battery hybrid inverter topologies in this embodiment, the system can also include a controller that controls the first switch to be closed or opened at a preset frequency.

[0034] Specifically, the controller controls the first switch in a fixed frequency manner. When the first switch is turned on, the photovoltaic module charges the inductor. After the first switch is turned off, the inductor continues to flow to discharge the bus capacitor. The controller can be a PLC controller.

[0035] Specifically, the core mechanism of the BUCK-BOOST circuit for regulating the output voltage by controlling the switching frequency and the duty cycle is as follows: 1. Duty cycle regulates the output voltage: the output voltage is determined by the duty cycle of the switching signal. The specific relationship is: Vout=Vin*(D / 1-D), where D is the duty cycle. When the duty cycle D>50%, the voltage is boosted, and when D<50%, the voltage is reduced. For example, when the input voltage range is wide (such as 8V~16V) and the output voltage needs to be constant at 12V, the target voltage can be maintained by adjusting the DD value in real time, which is not affected by input fluctuations; 2. Switching frequency affects ripple and efficiency: the switching frequency determines the inductance current charging and discharging speed: high-frequency switching reduces the size of the inductance and the value of the output capacitor, but increases the switching loss; low-frequency switching reduces the loss, but requires a larger inductance to suppress current ripple; the frequency itself does not change the average output voltage, but only optimizes the circuit dynamic response and efficiency; 3. Closed-loop control for voltage stabilization: the PWM controller continuously monitors the output voltage and dynamically adjusts the duty cycle to compensate for load changes. At the same time, combined with frequency tuning (such as fixed frequency / variable frequency mode), the efficiency and noise are balanced.

[0036] As one of the high-voltage battery hybrid inverter topologies in the embodiment, the bus assembly further includes a first bus connected to one end of the bus capacitor and a second bus connected to the other end of the bus capacitor, the first connecting line is connected to the positive electrode of the high-voltage battery at one end and to the other end of the first bus at the other end, and the second connecting line is connected to the negative electrode of the high-voltage battery at one end and to the other end of the second bus at the other end.

[0037] The boost-buck circuit can further include a third connecting line, a fourth connecting line, a fifth connecting line, a sixth connecting line, a seventh connecting line, and an eighth connecting line; the third connecting line is connected to the negative electrode of the photovoltaic assembly at one end and to the other end of the first bus at the other end, the fourth connecting line is connected to the positive electrode of the photovoltaic assembly at one end and to one end of the first switch at the other end, the fifth connecting line is connected to the other end of the first switch at one end and to the negative electrode of the diode at the other end, the sixth connecting line is connected to the positive electrode of the diode at one end and to the other end of the second bus at the other end, the seventh connecting line is connected to one end of the inductor at one end and to the third connecting line at the other end, and the eighth connecting line is connected to the other end of the inductor at one end and to the fifth connecting line at the other end.

[0038] Specifically, the output end of the inverter circuit is connected to the power grid or the load. The ninth connecting line and the tenth connecting line are further included, the inverter circuit includes the first input end and the second input end, one end of the ninth connecting line is connected to the first input end, the other end of the ninth connecting line is connected to the other end of the first bus, one end of the tenth connecting line is connected to the second input end, and the other end of the tenth connecting line is connected to the other end of the second bus. The other end of the first connecting line, the other end of the third connecting line and the one end of the seventh connecting line can be connected to one end of the first bus connected to the positive electrode of the high-voltage battery, and the other end of the second connecting line and the other end of the sixth connecting line can be connected to one end of the second bus connected to the negative electrode of the high-voltage battery.

[0039] Specifically, referring to Figure 2 The high-voltage battery is directly connected to the bus, and the minimum voltage is required to ensure the operation of the inverter circuit. The photovoltaic module is connected to the bus capacitor through the BUCK-BOOST circuit. The first switch is controlled in a fixed frequency mode, and the first switch is a semiconductor switch. When the first switch is turned on, the PV charges the inductor to store energy, and after the first switch is turned off, the inductor continues to flow to discharge the bus capacitor. When the system is stable, the duty cycle of the semiconductor switch is: D=Vbat / (Vbat+Vpv), wherein Vbat represents the voltage of the high-voltage battery, and Vpv represents the voltage of the photovoltaic module.

[0040] The above-described content can be implemented individually or in various combinations, and these variants are within the protection scope of the present application.

[0041] It should be noted that in the description of the present application, the terms "upper end", "lower end", "bottom end" indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is used, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment containing a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the element defined by the statement "including one" does not exclude the presence of another identical element in the process, method, article or equipment including the element.

[0042] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit it. Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A high voltage battery hybrid inverter topology system, characterized by: The application relates to a high-voltage battery, a photovoltaic assembly, an inverter circuit, a boost-buck circuit and a busbar assembly, wherein the high-voltage battery is connected to the busbar assembly, the inverter circuit is connected to the busbar assembly, the input end of the boost-buck circuit is connected to the photovoltaic assembly, and the output end of the boost-buck circuit is connected to the busbar assembly; the boost-buck circuit is used to control the output power provided by the photovoltaic assembly to the busbar assembly.

2. A high voltage battery hybrid inverter topology system as claimed in claim 1, wherein: The busbar assembly comprises a busbar capacitor; the positive and negative poles of the high-voltage battery are respectively connected to the two ends of the busbar capacitor, and the inverter circuit is respectively connected to the two ends of the busbar capacitor; the photovoltaic assembly is connected to the input end of the boost-buck circuit, and the output end of the boost-buck circuit is respectively connected to the two ends of the busbar capacitor.

3. A high voltage battery hybrid inverter topology system as claimed in claim 2, wherein: The boost-buck circuit is a BUCK-BOOST circuit.

4. A high voltage battery hybrid inverter topology system as claimed in claim 2 or 3, characterized in that: The boost-buck circuit comprises a first switch, an inductor and a diode; one end of the first switch is connected to the positive pole of the photovoltaic assembly, the other end of the first switch is respectively connected to the negative pole of the diode and one end of the inductor, the negative pole of the photovoltaic assembly is respectively connected to the other end of the inductor and one end of the busbar capacitor connected to the positive pole of the high-voltage battery, and the positive pole of the diode is connected to one end of the busbar capacitor connected to the negative pole of the high-voltage battery.

5. A high voltage battery hybrid inverter topology system as claimed in claim 4, wherein: The photovoltaic assembly charges the inductor when the first switch is closed, and the inductor discharges the busbar capacitor when the first switch is opened.

6. A high voltage battery hybrid inverter topology system as claimed in claim 4, wherein: The first switch is a semiconductor switch.

7. A high voltage battery hybrid inverter topology system as claimed in claim 5, wherein: When the system meets the first preset condition, the duty cycle of the first switch is equal to the voltage of the high-voltage battery divided by the sum of the voltage of the high-voltage battery and the voltage of the photovoltaic assembly.

8. A high voltage battery hybrid inverter topology system as claimed in claim 5, wherein: The application further comprises a controller which controls the first switch to be closed or opened at a preset frequency.

9. A high voltage battery hybrid inverter topology system as claimed in claim 4, wherein: The application further comprises a first connecting line and a second connecting line; the busbar assembly further comprises a first busbar connected to one end of the busbar capacitor and a second busbar connected to the other end of the busbar capacitor; one end of the first connecting line is connected to the positive pole of the high-voltage battery, and the other end of the first connecting line is connected to the other end of the first busbar; one end of the second connecting line is connected to the negative pole of the high-voltage battery, and the other end of the second connecting line is connected to the other end of the second busbar.

10. A high voltage battery hybrid inverter topology system as claimed in claim 9, wherein: The boost-buck circuit further comprises a third connecting line, a fourth connecting line, a fifth connecting line, a sixth connecting line, a seventh connecting line and an eighth connecting line; one end of the third connecting line is connected to the negative pole of the photovoltaic assembly, and the other end of the third connecting line is connected to the other end of the first busbar; one end of the fourth connecting line is connected to the positive pole of the photovoltaic assembly, and the other end of the fourth connecting line is connected to one end of the first switch; one end of the fifth connecting line is connected to the other end of the first switch, and the other end of the fifth connecting line is connected to the negative pole of the diode; one end of the sixth connecting line is connected to the positive pole of the diode, and the other end of the sixth connecting line is connected to the other end of the second busbar; one end of the seventh connecting line is connected to one end of the inductor, and the other end of the seventh connecting line is connected to the third connecting line; one end of the eighth connecting line is connected to the other end of the inductor, and the other end of the eighth connecting line is connected to the fifth connecting line.

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