CN118232703A - Power conversion device and energy storage equipment - Google Patents
Power conversion device and energy storage equipment Download PDFInfo
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- CN118232703A CN118232703A CN202410340094.0A CN202410340094A CN118232703A CN 118232703 A CN118232703 A CN 118232703A CN 202410340094 A CN202410340094 A CN 202410340094A CN 118232703 A CN118232703 A CN 118232703A
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- 238000006243 chemical reaction Methods 0.000 title claims abstract description 67
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Abstract
The invention discloses a power conversion device and energy storage equipment, the power conversion device comprises: at least one DC-DC converter, a DC-AC converter, and a controller; the DC-DC converter is electrically connected with the DC-AC converter; the controller is used for controlling the DC-DC converter and the DC-AC converter; the controller is configured to: the input power of the DC-DC converter is matched by adjusting the output power of the DC-AC converter for a set period of time. According to the technical scheme, the double alternating current power frequency ripple of the input end of the DC-DC converter is smaller, and the voltage of the output end of the DC-DC converter is allowed to have the double alternating current power frequency ripple of the larger voltage, so that the capacity requirements on the DC side capacitor and the middle-stage bus capacitor are reduced, the DC side and the middle-stage bus can use capacitors with small capacity, such as film capacitors, the reliability and the service life of the power conversion device are improved, and meanwhile, the accuracy of direct current side voltage measurement and power calculation is improved.
Description
Technical Field
The present disclosure relates to the field of inverters, and more particularly, to a power conversion device and an energy storage device.
Background
Alternating Current (ALTERNATING CURRENT, AC) -Direct Current (DC) conversion is commonly used for photovoltaic inverters (PV INVERTER), micro-inverters (Micro-inverters), stored energy power conversion units (Power Conversion System, PCS) and bi-directional On-Board chargers (OBCs). Isolation transformers are often used directly between DC and AC to reduce leakage currents, such as micro-inverters, PCS and OBC, etc., based on safety concerns against electric shock.
Currently, as shown in fig. 1, ac-dc conversion is generally implemented by the following architecture: the DC side is electrically connected with the input end of the DC-DC converter, the output end of the DC-DC converter is electrically connected with the input end of the DC-AC converter, the output end of the DC-AC converter is electrically connected with the AC side, the DC-DC converter is used for realizing isolation and voltage rising and falling, and the DC-AC converter is used for realizing AC-DC conversion. In the structure, a large-capacity electrolytic capacitor C1 is required to be placed between the DC side and the DC-DC converter for filtering to obtain a direct-current voltage Vdc1 'with smaller ripple waves, a large-capacity electrolytic capacitor C2 is required to be placed between the DC-DC converter and the DC-AC converter for filtering to obtain a direct-current voltage Vdc2' with smaller ripple waves, and a small-capacity thin-film capacitor C3 is required to be placed between the DC-AC converter and the AC side for alternating-current filtering. In some applications, the DC side voltage needs to have a high detection accuracy, and thus requires a low double ac power frequency ripple interference across C1, thus requiring a large capacitance value for C1 and C2. Because the power density of the electrolytic capacitors is low, a large number of electrolytic capacitors are needed to meet the requirements, so that the AC-DC converter has large occupied space and high cost; in addition, the electrolytic capacitor has weaker ripple current resistance and high temperature resistance, so that the AC-DC converter has the problems of low reliability and short service life, and the application prospect of the AC-DC converter is greatly limited.
Disclosure of Invention
The invention provides a power conversion device and energy storage equipment, which are used for solving the problems in the prior art, reducing the capacity requirements on a DC side capacitor and a middle-stage bus capacitor, enabling the DC side and middle-stage bus to use a small capacity capacitor, such as a thin film capacitor, and being beneficial to improving the reliability and the service life of the power conversion device and improving the accuracy of DC side voltage measurement and power calculation.
In a first aspect, the present invention provides a power conversion apparatus comprising: at least one DC-DC converter, a DC-AC converter, and a controller;
The DC-DC converter is electrically connected with the DC-AC converter;
the controller is used for controlling the DC-DC converter and the DC-AC converter; the controller is configured to:
The input power of the DC-DC converter is matched by adjusting the output power of the DC-AC converter within a set period of time.
Optionally, the input end of the DC-DC converter is connected in parallel with a first filter capacitor; a second filter capacitor is connected in parallel between the DC-DC converter and the DC-AC converter;
The controller is configured to:
and controlling the DC-DC converter to output direct current voltage with stable average value to the DC-AC converter, and enabling the direct current voltage to be smaller than or equal to twice the alternating current power frequency ripple voltage of a preset value so as to reduce the twice alternating current power frequency ripple voltage of the voltages at the two ends of the first filter capacitor.
Optionally, the first filter capacitor and the second filter capacitor are thin film capacitors.
Optionally, the controller is configured to: controlling a ripple duty cycle of the DC-DC converter based on an average value of voltages across the second filter capacitor; and controlling the wave-sending duty ratio of the DC-AC converter based on the real-time value of the voltage at two ends of the second filter capacitor.
Optionally, the input end of the DC-DC converter includes two parallel connection terminals for connecting two power sources with the same voltage in parallel, so that the two power sources with the same voltage share the DC-DC converter and the DC-AC converter.
Optionally, the power conversion device includes two DC-DC converters, the input sides of the two DC-DC converters are independent bridge arms, and the output sides of the two DC-DC converters share the bridge arms.
Optionally, the two DC-DC converters are respectively connected to power sources with different voltages.
Optionally, the DC-AC converter is a converter outputting split-phase AC or a converter outputting three-phase AC.
Optionally, the input side and the output side of the DC-DC converter are full-bridge arms, or half-bridge arms, or a combination of the full-bridge arms and the half-bridge arms.
In a second aspect, the present invention also provides an energy storage device comprising: battery management system, energy management system, power conversion system and battery system, power conversion system includes the power conversion device of any one of the above-mentioned.
According to the technical scheme, the controller is configured to match the input power of the DC-DC converter by adjusting the output power of the DC-AC converter in a set time period, so that the power of the DC side is matched with the power of the AC side, the input end of the DC-DC converter can have smaller double alternating current power frequency ripple, the voltage of the output end of the DC-DC converter is allowed to have larger double alternating current power frequency ripple, the capacity requirements on the capacitor of the DC side and the capacitor of the intermediate bus are reduced, the capacitors with small capacity such as film capacitors can be used for the DC side and the intermediate bus, the reliability and the service life of the power conversion device are improved, the size of the power conversion device is reduced, and meanwhile, the accuracy of direct current side voltage measurement and power calculation is improved.
It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the invention or to delineate the scope of the invention. Other features of the present invention will become apparent from the description that follows.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a power conversion device according to the prior art;
Fig. 2 is a schematic structural diagram of a power conversion device according to an embodiment of the present invention;
Fig. 3 is a schematic structural diagram of another power conversion device according to an embodiment of the present invention;
Fig. 4 is a schematic structural diagram of another power conversion device according to an embodiment of the present invention;
Fig. 5 and fig. 6 are schematic structural diagrams of another two power conversion devices according to an embodiment of the present invention;
fig. 7 and fig. 8 are schematic structural diagrams of two power conversion devices according to an embodiment of the present invention;
Fig. 9 to 19 are schematic structural diagrams of another eleven power conversion devices according to an embodiment of the present invention;
Fig. 20 is a block diagram of an energy storage device according to an embodiment of the present invention.
Detailed Description
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein.
The present embodiment provides a power conversion device, fig. 2 is a schematic structural diagram of the power conversion device provided in the embodiment of the present invention, and referring to fig. 1, the power conversion device includes at least one DC-DC converter 1, a DC-AC converter 2, and a controller (not shown in the figure); the DC-DC converter 1 is electrically connected to the DC-AC converter 2; the controller is used for controlling the DC-DC converter 1 and the DC-AC converter 2; the controller is configured to: the input power of the DC-DC converter 1 is matched by adjusting the output power of the DC-AC converter 2 for a set period of time.
The DC-DC converter 1 is used for converting a DC power supply on a DC side into a DC power supply of different voltages, and is capable of realizing accurate conversion and stable output of the DC voltage. The type of DC-DC converter 1 may be chosen according to the voltage requirements, and in an alternative embodiment, the DC-DC converter 1 may comprise a step-up DC-DC converter, a step-down DC-DC converter or a step-up DC-DC converter. It should be noted that the inclusion of at least one DC-DC converter 1 means that only one DC-DC converter 1 is included, or that a plurality of DC-DC converters 1 are included, and fig. 2 shows only the case of including one DC-DC converter by way of example, and does not limit the number of DC-DC converters. In an alternative embodiment, the DC-DC converter may further comprise 2 DC-DC converters. The number of the DC-DC converters 1 may be set according to actual needs, and this is not particularly limited in the present embodiment.
The DC-AC converter 2 is arranged to convert a supplied DC power supply at the output of the DC-DC converter 1 into an AC power supply, and in an alternative embodiment the DC-AC converter 2 adjusts the frequency and amplitude of the AC voltage it outputs by controlling the frequency and duty cycle of the PWM signal. It should be noted that, depending on the requirements of the actual application scenario of the output AC power, the DC-AC converter 2 may include, but is not limited to, a single-phase DC-AC circuit topology, a split-phase DC-AC circuit topology, or a three-phase AC DC-AC circuit topology. Fig. 2 shows by way of example only a case where the DC-AC converter 2 comprises a single-phase DC-AC circuit topology, without limiting the type of DC-AC converter 2.
The controller is electrically or communicatively connected to the control terminal of the DC-DC converter 1 and the control terminal of the DC-AC converter 2, respectively, so as to control the DC-DC converter 1 and the DC-AC converter 2. The set period of time can be understood as a period of time set according to the magnitude of demand for output power on the AC side and the magnitude of input power on the DC side. In an alternative embodiment, the set time period may include a power up peak time period and a power down peak time period; in the power consumption peak time period, the output power of the DC-AC converter 2 is required to be larger, the input power of the larger DC-DC converter 1 is matched, and if the output power still cannot be met when the input power is maximum, the load is reduced; in the low peak power consumption period, the output power of the DC-AC converter 2 is required to be smaller, matching the input power of the smaller DC-DC converter 1. Since the input power can be matched with the output power, the first filter capacitor C1 is reduced to compensate the output power of the DC-DC converter 1, and the second filter capacitor C2 is reduced to compensate the output power of the DC-AC converter 2, so that the two times of the AC power frequency ripple voltage at the two ends of the first filter capacitor C1 is correspondingly reduced, and the two times of the AC power frequency ripple voltage at the two ends of the second filter capacitor C2 is correspondingly reduced, thereby allowing the first filter capacitor C1 and the second filter capacitor C2 to use small-capacity capacitors, such as film capacitors.
In this embodiment, the controller is configured to adjust the output power of the DC-AC converter to match the input power of the DC-DC converter in a set period of time, so that the power on the DC side is matched with the power on the AC side, the input end of the DC-DC converter can have smaller double AC power frequency ripple, and the voltage on the output end of the DC-DC converter is allowed to have larger double AC power frequency ripple, so that the capacity requirements on the capacitor on the DC side and the bus capacitor on the intermediate stage are reduced, the capacitors with small capacity, such as a film capacitor, can be used by the DC side and the bus on the intermediate stage, the reliability and the service life of the power conversion device are improved, the volume of the power conversion device is reduced, and the accuracy of the voltage measurement on the DC side and the power calculation is improved.
It should be noted that, in the set period, the output power of the DC-AC converter 2 is adjusted to match the input power of the DC-DC converter 1, so that the AC power frequency ripple voltage twice the input voltage of the DC-DC converter 1 can be reduced, when the AC power frequency ripple voltage twice the input voltage of the DC-DC converter 1 meets the voltage precision requirement, the input of the DC-DC converter 1 may not be provided with a filter capacitor, otherwise, if the AC power frequency ripple voltage twice the input voltage of the DC-DC converter 1 does not meet the voltage precision requirement, a filter capacitor may be connected in parallel to the input of the DC-DC converter 1 to further reduce the AC power frequency ripple voltage twice the input voltage of the DC-DC converter 1, so that the AC power frequency ripple voltage twice the input voltage of the DC-DC converter 1 meets the voltage precision requirement.
Optionally, as shown in fig. 2, the input end of the DC-DC converter 1 is connected in parallel with a first filter capacitor C1; a second filter capacitor C2 is connected in parallel between the DC-DC converter 1 and the DC-AC converter 2; the controller is configured to: the DC-DC converter 1 is controlled to output a DC voltage with a stable average value to the DC-AC converter 2, and the DC voltage is made to be less than or equal to twice the AC power frequency ripple voltage of the preset value, so as to reduce twice the AC power frequency ripple voltage of the voltage across the first filter capacitor C1.
The first filter capacitor C1 is configured to filter the voltage at the input end of the DC-DC converter 1 to reduce the ripple of the voltage at the input end of the DC-DC converter 1, and the second filter capacitor C2 is configured to filter the voltage at the input end of the DC-AC converter 2 to reduce the ripple of the voltage at the input end of the DC-DC converter 1. The first filter capacitor C1 and the second filter capacitor C2 may include, but are not limited to, electrolytic capacitors or thin film capacitors, etc.; in an alternative embodiment, the first filter capacitor C1 and the second filter capacitor C2 are thin film capacitors, and the thin film capacitors have the advantages of small volume, low cost, insensitivity to temperature change, and the like, so that the first filter capacitor C1 and the second filter capacitor C2 are thin film capacitors, which are beneficial to reducing the volume and the cost of the power conversion device, improving the reliability and the service life of the power conversion device.
It is understood that the dc voltage with stable average value is that the actual average value of the dc voltage is within a set range in each period, and the absolute value of the difference between the upper limit value and the lower limit value of the set range and the preset dc voltage is smaller than or equal to a first set value, where the first set value is smaller than the fluctuation amount of the average value of the acceptable dc voltage. The preset direct voltage may be an output voltage preset by the DC-DC converter 1, and in an exemplary embodiment, the preset direct voltage may be 3V.
The preset value may be a value of an AC voltage to be output at the output terminal of the DC-AC converter 2, for example, 220V when the AC voltage to be output at the output terminal of the DC-AC converter 2 is 220V. The controller is used for controlling the DC-DC converter 1 to output the DC voltage with stable average value to the DC-AC converter 2, wherein the output DC voltage is required to be smaller than or equal to twice the AC power frequency ripple voltage of a preset value, so that the input power and the output power can be matched, the twice AC power frequency ripple voltage of the voltages at the two ends of the first filter capacitor C1 can be reduced, the first filter capacitor C1 can meet the requirement of DC side voltage detection precision without selecting a large capacity capacitor, and in addition, the second filter capacitor C2 can meet the filtering requirement without selecting a large capacity capacitor because the output DC voltage is required to be smaller than or equal to twice the AC power frequency ripple voltage of the preset value, thereby being beneficial to reducing the volume of the power conversion device.
Optionally, controlling the DC-DC converter 1 to output a DC voltage with a stable average value to the DC-AC converter 2 and making the DC voltage less than or equal to twice the AC power frequency ripple voltage of the preset value may specifically include: controlling a ripple duty ratio of the DC-DC converter 1 based on an average value of voltages across the second filter capacitor C2; the ripple duty cycle of the DC-AC converter 2 is controlled based on the real-time value of the voltage across the second filter capacitor C2.
The duty cycle of the wave of the DC-DC converter 1 means that the ratio of the on time of the switch in the DC-DC converter 1 to the whole period time is in a complete period, and the output voltage and current of the DC-DC converter 1 can be controlled by adjusting the duty cycle of the wave of the DC-DC converter 1, when the output voltage needs to be increased, the duty cycle of the wave can be increased to make the on time of the switch longer, otherwise, in order to reduce the output voltage, the duty cycle of the wave needs to be reduced to make the on time of the switch shorter. The ripple duty ratio of the DC-DC converter 1 is controlled based on the average value of the voltages at the two ends of the second filter capacitor C2, so that the average value of the DC voltage output by the DC-DC converter 1 is stable, and the output DC voltage is less than or equal to twice the ac power frequency ripple voltage of the preset value.
The ripple duty ratio of the DC-AC converter 2 refers to the duty ratio of the pulse width modulated signal of the DC-AC converter 2, thereby controlling the modulated signal for driving the switching element of the DC-AC converter 2. By adjusting the ripple duty cycle of the DC-AC converter 2, the amplitude and waveform of the alternating voltage output by the DC-AC converter 2 can be controlled. The ripple duty ratio of the DC-AC converter 2 is controlled based on the real-time value of the voltage across the second filter capacitor C2, so that the DC-AC converter 2 can output an alternating voltage or current meeting the target accuracy requirement.
Optionally, fig. 3 is a schematic structural diagram of another power conversion device according to an embodiment of the present invention, and referring to fig. 3, an input end of a DC-DC converter 1 includes two parallel connection terminals for connecting two power DC1 sides and DC2 sides with the same voltage in parallel, so that the two power DC1 sides and the DC2 sides with the same voltage share the DC-DC converter 1 and the DC-AC converter 2, and thus, the two power DC1 sides and the DC2 sides with the same voltage together provide a direct current voltage for the input end of the DC-DC converter 1, which improves the input power of the DC-DC converter 1, thereby being capable of meeting the requirement of higher output power of the DC-AC converter 2.
It should be noted that, the topology of the DC-DC converter 1 and the topology of the DC-AC converter 2 may be selected according to practical needs, for example, the topology of the DC-DC converter 1 may include, but not limited to, a Double Active Full Bridge (DAFB), a Double Active Half Bridge (DAHB), a double active full bridge+half bridge (DAFB + DAHB), an LLC, a CLLC, a phase-shifting full bridge, a hard switching full bridge, etc., and the topology of the DC-AC converter 2 may include, but not limited to, a two-level DC-AC (H4, H5, H6, HERIC, etc.), a three-level DC-AC (T-type three-level, I-type three-level), a four-level DC-AC, etc. The topology of the DC-DC converter 1 and the topology of the DC-AC converter 2 are not particularly limited in this embodiment, and the core point of the present embodiment may be realized.
In an alternative embodiment, the input side and the output side of the DC-DC converter 1 are full bridge legs, or half bridge legs, or a combination of full bridge legs and half bridge legs.
Optionally, fig. 4 is a schematic structural diagram of another power conversion device provided by the embodiment of the present invention, referring to fig. 4, the power conversion device includes two DC-DC converters 1, the input sides of the two DC-DC converters 1 are independent bridge arms, the output sides of the two DC-DC converters 1 share the bridge arms, at this time, the input power of the two DC-DC converters 1 can be matched by adjusting the output power of the DC-AC converter 2, so that the first DC-DC converter 11 and the second DC-DC converter 12 are respectively responsible for controlling the DC1 side and the DC2 side to output a DC voltage with stable average value, and the DC voltage is smaller than or equal to twice the AC power frequency ripple voltage of a preset value, so that the input power is matched with the output power, and thus the two times of the AC power frequency ripple voltage of the voltage at two ends of the two first filter capacitors C1 can be reduced, and the two first filter capacitors C1-1 and C1-C2 can meet the requirement of DC side voltage detection without using a large-capacity capacitor, and the DC voltage requirement of the second filter capacitor can meet the output voltage requirement of the two times the AC power frequency ripple voltage requirement of the preset value, and the AC power requirement can be reduced without the requirement of the large-capacity voltage requirement of the filter device.
The two DC-DC converters 1 adopt independent bridge arms, and the input side of each DC-DC converter 1 can be connected to a DC power supply, and the voltages of the connected DC power supplies may be the same or different. In an alternative embodiment, the two DC-DC converters 1 are respectively connected to power sources with different voltages, so that the voltage range of the input voltage of the DC-DC converters can be enlarged, so that the output power of the DC-AC converters matches the input power of the same DC-DC converter as much as possible, which is beneficial to further improving the accuracy of the DC-side voltage measurement and power calculation of the power conversion device.
It should be noted that, the two DC-DC converters 1 may be discrete devices or may be integrated into one magnetic element, which is not particularly limited in this embodiment. When two DC-DC converters use the separating device, when one DC-DC converter fails, the failed DC-DC converter can be replaced to enable the power conversion device to be continuously used, and the cost is saved. When two DC-DC converters are integrated in one magnetic element, the size of the power conversion device is further reduced, and the miniaturization of the power conversion device is realized.
Alternatively, fig. 5 and fig. 6 are schematic structural diagrams of another two power conversion devices according to the embodiments of the present invention, and referring to fig. 5 and fig. 6, the DC-AC converter 2 is a split phase AC output converter or a three phase AC output converter, so that the power conversion device can be suitable for application scenarios with split phase AC output and three phase AC output, thereby further increasing the application range of the power conversion device.
It should be noted that, according to actual requirements, different bridge arms may be selected on the input side and/or the output side of the DC-DC converter 1, which is not limited in this embodiment. In an alternative embodiment, the input side and the output side of the DC-DC converter 1 are full bridge legs, or half bridge legs, or a combination of full bridge legs and half bridge legs.
Fig. 7 and 8 are schematic structural diagrams of two further power conversion devices according to the embodiments of the present invention, and fig. 7 and 8 show a case where an input side and an output side of the DC-DC converter 1 are half bridge arms when the power conversion device includes one DC-DC converter 1, so that resources and costs can be saved.
Fig. 9 to 19 show the case where when the power conversion apparatus includes two DC-DC converters 1, the input side and the output side of the DC-DC converters 1 are half-bridge legs, and part of the bridge legs are full-bridge legs, and the control and operation principles thereof are the same as those of the embodiment shown in fig. 4, so that the beneficial effects of the embodiment shown in fig. 4 can be achieved, and the same points can be described with reference to the above.
Fig. 9 to 12 show the case where the input side and the output side of the two DC-DC converters 1 are half bridge arms. As shown in fig. 9 and 11, the input sides of the two DC-DC converters 1 are independent half-bridge legs, and the output sides of the two DC-DC converters 1 share the half-bridge legs; as shown in fig. 10 and 12, the input sides of the two DC-DC converters 1 are independent half-bridge legs, and the output sides of the two DC-DC converters 1 are also independent half-bridge legs.
Fig. 13 to 19 show the case where the input side of the two DC-DC converters 1 is a half-bridge arm and the output side of the two DC-DC converters 1 is a full-bridge arm. As shown in fig. 13 to 15, the input sides of the two DC-DC converters 1 are independent half-bridge legs, and the output sides of the DC-DC converters 1 share a full-bridge leg; as shown in fig. 16 to 19, the input sides of the two DC-DC converters 1 are independent full-bridge legs, and the output sides of the two DC-DC converters 1 share a half-bridge leg.
Based on the same inventive concept, an embodiment of the present invention further provides an energy storage device, and fig. 20 is a block diagram of a structure of the energy storage device provided by the embodiment of the present invention, as shown in fig. 20, where the energy storage device includes a battery management system, an energy management system, a power conversion system, and a battery system, where the power conversion system includes the power conversion apparatus provided by any embodiment of the present invention.
Because the energy storage device provided by the embodiment of the invention comprises the power conversion device provided by the embodiment, the energy storage device has the corresponding structure and characteristics of the power conversion device, and can achieve the beneficial effects of the power conversion device provided by any embodiment of the invention, and the same points can be described with reference to the above.
The above embodiments do not limit the scope of the present invention. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.
Claims (10)
1. A power conversion apparatus, comprising: at least one DC-DC converter, a DC-AC converter, and a controller;
The DC-DC converter is electrically connected with the DC-AC converter;
the controller is used for controlling the DC-DC converter and the DC-AC converter; the controller is configured to:
The input power of the DC-DC converter is matched by adjusting the output power of the DC-AC converter within a set period of time.
2. The power conversion device according to claim 1, wherein the input end of the DC-DC converter is connected in parallel with a first filter capacitor; a second filter capacitor is connected in parallel between the DC-DC converter and the DC-AC converter;
The controller is configured to:
and controlling the DC-DC converter to output direct current voltage with stable average value to the DC-AC converter, and enabling the direct current voltage to be smaller than or equal to twice the alternating current power frequency ripple voltage of a preset value so as to reduce the twice alternating current power frequency ripple voltage of the voltages at the two ends of the first filter capacitor.
3. The power conversion device of claim 2, wherein the first filter capacitor and the second filter capacitor are thin film capacitors.
4. A power conversion device according to claim 2 or 3, wherein the controller is configured to: controlling a ripple duty cycle of the DC-DC converter based on an average value of voltages across the second filter capacitor; and controlling the wave-sending duty ratio of the DC-AC converter based on the real-time value of the voltage at two ends of the second filter capacitor.
5. The power conversion device according to claim 1, wherein the input of the DC-DC converter comprises two parallel connection terminals for connecting two power sources of the same voltage in parallel such that the two power sources of the same voltage share the DC-DC converter and the DC-AC converter.
6. The power conversion device of claim 1, comprising two DC-DC converters, the input sides of the two DC-DC converters being separate legs, the output sides of the two DC-DC converters sharing a leg.
7. The power conversion apparatus according to claim 6, wherein the two DC-DC converters are connected to power sources having different voltages, respectively.
8. The power conversion device of claim 1, wherein the DC-AC converter is either a split-phase AC output converter or a three-phase AC output converter.
9. The power conversion device of claim 1, wherein the input side and the output side of the DC-DC converter are full bridge legs, or half bridge legs, or a combination of full bridge legs and half bridge legs.
10. An energy storage device, comprising: battery management system, energy management system, power conversion system and battery system, characterized in that the power conversion system comprises a power conversion device according to any of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202410340094.0A CN118232703A (en) | 2024-03-25 | 2024-03-25 | Power conversion device and energy storage equipment |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202410340094.0A CN118232703A (en) | 2024-03-25 | 2024-03-25 | Power conversion device and energy storage equipment |
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| CN118232703A true CN118232703A (en) | 2024-06-21 |
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| CN202410340094.0A Pending CN118232703A (en) | 2024-03-25 | 2024-03-25 | Power conversion device and energy storage equipment |
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- 2024-03-25 CN CN202410340094.0A patent/CN118232703A/en active Pending
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