CN114156966A - Multistage power conversion circuit voltage stabilization method and device and power conversion system - Google Patents
Multistage power conversion circuit voltage stabilization method and device and power conversion system Download PDFInfo
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- CN114156966A CN114156966A CN202111276575.2A CN202111276575A CN114156966A CN 114156966 A CN114156966 A CN 114156966A CN 202111276575 A CN202111276575 A CN 202111276575A CN 114156966 A CN114156966 A CN 114156966A
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- 238000006243 chemical reaction Methods 0.000 title claims abstract description 350
- 230000006641 stabilisation Effects 0.000 title claims abstract description 66
- 238000011105 stabilization Methods 0.000 title claims abstract description 66
- 238000000034 method Methods 0.000 title claims abstract description 32
- 230000000087 stabilizing effect Effects 0.000 claims abstract description 95
- 238000004146 energy storage Methods 0.000 claims abstract description 54
- 230000015654 memory Effects 0.000 claims description 12
- 230000033228 biological regulation Effects 0.000 claims description 6
- 238000004590 computer program Methods 0.000 claims description 5
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0068—Battery or charger load switching, e.g. concurrent charging and load supply
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/007—Regulation of charging or discharging current or voltage
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/007—Regulation of charging or discharging current or voltage
- H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/007—Regulation of charging or discharging current or voltage
- H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
- H02J7/007182—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery voltage
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
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Abstract
The invention provides a voltage stabilizing method and device for a multistage power conversion circuit and a power conversion system, wherein the method is applied to the multistage power conversion circuit; the multi-stage power conversion circuit comprises at least two stages of power conversion circuits which are connected in series, one side of each of the at least two stages of power conversion circuits which are connected in series is connected with the energy storage device, the other side of each of the at least two stages of power conversion circuits which are connected in series is connected with an external power supply, and the external power supply is a direct current source or an alternating current source; the method comprises the following steps: acquiring the required voltage of an energy storage device and the current flow direction of a multi-stage power conversion circuit; determining voltage stabilizing points of all levels of power conversion circuits and voltage stabilizing sequences of all levels of power conversion circuits according to the current flow direction; determining a voltage reference value corresponding to each voltage stabilizing point according to the required voltage and the current flow direction; and performing voltage stabilization control on each stage of power conversion circuit based on the voltage reference value corresponding to each voltage stabilization point and the voltage stabilization sequence of each stage of power conversion circuit. The invention can support the voltage stabilization control of the multistage power conversion circuit under a wide voltage range.
Description
Technical Field
The invention belongs to the technical field of circuit control, and particularly relates to a voltage stabilizing method and device for a multi-stage power conversion circuit and a power conversion system.
Background
The voltage stabilization control of the multi-stage power conversion circuit is an important link for ensuring the stable operation of the whole multi-stage power conversion circuit. In the prior art, in order to widen the voltage range of the multi-stage power conversion circuit, the multi-stage power conversion circuit may be adopted in the prior art, and at this time, the voltage stabilizing scheme for the single-stage power conversion circuit in the prior art is no longer applicable.
Disclosure of Invention
The invention aims to provide a voltage stabilizing method and device for a multi-stage power conversion circuit and a power conversion system, so as to realize voltage stabilizing control of the multi-stage power conversion circuit in a wide voltage range.
In order to achieve the above object, the present invention provides a voltage stabilizing method for a multi-stage power conversion circuit, wherein the method is applied to the multi-stage power conversion circuit; the multi-stage power conversion circuit comprises at least two stages of power conversion circuits which are connected in series, wherein one side of each of the at least two stages of power conversion circuits connected in series is used for being connected with the energy storage device, and the other side of each of the at least two stages of power conversion circuits connected in series is used for being connected with an external power supply, wherein the external power supply is a direct current source or an alternating current source; the method comprises the following steps:
acquiring the required voltage of the energy storage device and the current flow direction of the multistage power conversion circuit;
determining a voltage stabilizing point of each stage of power conversion circuit and a voltage stabilizing sequence of each stage of power conversion circuit according to the current flow direction of the multistage power conversion circuit;
determining a voltage reference value corresponding to each voltage stabilizing point according to the required voltage and the current flow direction of the multistage power conversion circuit;
and performing voltage stabilization control on each stage of power conversion circuit based on the voltage reference value corresponding to each voltage stabilization point and the voltage stabilization sequence of each stage of power conversion circuit.
In a possible implementation manner, the determining, according to the required voltage and a current flow direction of the multi-stage power conversion circuit, a voltage reference value corresponding to each regulated voltage point includes:
if the current flow direction of the multistage power conversion circuit is in a first direction, determining a voltage reference value corresponding to a voltage stabilizing point of a primary power conversion circuit and a voltage reference value corresponding to a voltage stabilizing point of a final power conversion circuit according to the required voltage, and determining a voltage reference value corresponding to a voltage stabilizing point of a middle stage power conversion circuit according to a voltage reference value corresponding to a voltage stabilizing point of a primary power conversion circuit and a preset pressure difference between adjacent stages of power conversion circuits;
the current flow direction is a first direction, which means that current flows from the energy storage device to an external power supply, the primary power conversion circuit is a first-stage power conversion circuit from the energy storage device as a starting point, the final-stage power conversion circuit is a last-stage power conversion circuit from the energy storage device as the starting point, and the middle-stage power conversion circuit is other power conversion circuits except the primary power conversion circuit and the final-stage power conversion circuit.
In a possible implementation manner, the determining, according to the required voltage, a voltage reference value corresponding to a regulated point of a primary power conversion circuit and a voltage reference value corresponding to a regulated point of a final power conversion circuit includes:
determining a range to which the required voltage belongs;
and determining a voltage reference value corresponding to a voltage stabilizing point of the primary power conversion circuit and a voltage reference value corresponding to a voltage stabilizing point of the final power conversion circuit according to the range to which the required voltage belongs and various preset reference values corresponding to the range.
In a possible implementation manner, the method for determining the preset voltage difference between adjacent power conversion circuits in each stage is as follows:
acquiring a boosting ratio of the multi-stage power conversion circuit;
and determining a preset pressure difference between adjacent power conversion circuits of each stage according to the voltage boosting ratio.
In a possible implementation manner, the determining, according to the required voltage and a current flow direction of the multi-stage power conversion circuit, a voltage reference value corresponding to each regulated voltage point includes:
if the current flow direction of the multistage power conversion circuit is in a second direction, acquiring a preset charging voltage of the energy storage device, determining a voltage reference value corresponding to a voltage stabilizing point of a primary power conversion circuit according to the preset charging voltage, and determining a voltage reference value corresponding to the voltage stabilizing point of a final power conversion circuit and a middle power conversion circuit according to the required voltage;
the current flowing direction is the second direction, which means that the current flows from an external power supply to the energy storage device, the primary power conversion circuit is a first-stage power conversion circuit from the energy storage device as a starting point, the final-stage power conversion circuit is a last-stage power conversion circuit from the energy storage device as the starting point, and the middle-stage power conversion circuit is other power conversion circuits except the primary power conversion circuit and the final-stage power conversion circuit.
In a possible implementation manner, the determining, according to the required voltage, voltage reference values corresponding to voltage stabilization points of the final stage power conversion circuit and the intermediate stage power conversion circuit includes:
determining a range to which the required voltage belongs;
and determining voltage reference values corresponding to the voltage stabilizing points of the final power conversion circuit and the middle power conversion circuits according to the range to which the required voltage belongs and various preset reference values corresponding to the range.
In a possible implementation manner, determining a voltage stabilizing sequence of each stage of power conversion circuit according to a current flow direction of the multi-stage power conversion circuit includes:
if the current flow direction of the multistage power conversion circuit is in a first direction, setting the power conversion circuit farthest away from the battery to start voltage stabilization firstly, and then starting the voltage stabilization of each power conversion circuit in sequence by taking the energy storage device as a starting point;
if the current flow direction of the multistage power conversion circuit is in a second direction, setting the power conversion circuit farthest from the battery to start voltage stabilization firstly, and then starting the voltage stabilization of each power conversion circuit in sequence by taking the power conversion circuit farthest from the battery as a start;
the current flowing in the first direction refers to the current flowing from the energy storage device to the external power supply, and the current flowing in the second direction refers to the current flowing from the external power supply to the energy storage device.
In a possible implementation manner, determining a voltage regulation point of each stage of power conversion circuit according to a current flow direction of the multi-stage power conversion circuit includes:
if the current flow direction of the multistage power conversion circuit is in a first direction, setting a voltage stabilizing point of a primary power conversion circuit as the output voltage of the primary power conversion circuit, and setting voltage stabilizing points of other stages of power conversion circuits as the input voltage of the primary power conversion circuit;
if the current flow direction of the multistage power conversion circuit is in a second direction, setting the voltage stabilizing points of the multistage power conversion circuits to be output voltages of the multistage power conversion circuits;
the current flowing direction is the first direction, namely the current flows from the energy storage device to an external power supply, and the current flowing direction is the second direction, namely the current flows from the external power supply to the energy storage device; the primary power conversion circuit is a first-stage power conversion circuit from the energy storage device as a starting point, and the other power conversion circuits at each stage are other power conversion circuits except the primary power conversion circuit.
In another aspect of the present invention, there is also provided a multi-stage power conversion circuit voltage stabilizing apparatus, including a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor implements the steps of the multi-stage power conversion circuit voltage stabilizing method described above when executing the computer program.
In still another aspect of the present invention, there is provided a power conversion system including: the multi-stage power conversion circuit and the multi-stage power conversion circuit voltage stabilizing device are applied, and the multi-stage power conversion circuit is connected with the multi-stage power conversion circuit voltage stabilizing device.
The voltage stabilizing method and device of the multistage power conversion circuit and the power conversion system have the advantages that:
the invention is different from the prior art, provides a voltage stabilization scheme applicable to a multi-stage power conversion circuit under a wide voltage range scene, and particularly determines the starting and voltage stabilization sequence of each stage of power conversion circuit and the voltage stabilization point of each stage of power conversion circuit according to the current flow direction in the multi-stage power conversion circuit, judges the voltage reference value corresponding to each voltage stabilization point according to the required voltage and the current flow direction in the multi-stage power conversion circuit, and finally performs voltage stabilization based on the voltage reference value corresponding to each voltage stabilization point and the current flow direction in the multi-stage power conversion circuit. The invention considers the difference of the voltage stabilization reference values of each stage of power conversion circuit under the conditions of the required voltages of different energy storage devices and different battery charging and discharging states, and can self-adaptively adjust the voltage stabilization parameters according to the required voltages and the battery charging and discharging states, thereby realizing the effective voltage stabilization of the multi-stage power conversion circuit under the wide voltage range.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed for the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic flowchart of a voltage stabilizing method for a multi-stage power conversion circuit according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a multi-stage power conversion circuit according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a voltage regulator of a multi-stage power conversion circuit according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a power conversion system according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a multi-stage power conversion circuit according to another embodiment of the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
Referring to fig. 1, fig. 1 is a schematic flow chart of a voltage stabilizing method for a multi-stage power conversion circuit according to an embodiment of the present invention, where the method is applied to a multi-stage power conversion circuit 200 shown in fig. 2, the multi-stage power conversion circuit 200 includes at least two stages of power conversion circuits connected in series, one side of the at least two stages of power conversion circuits connected in series is used for being connected to an energy storage device, and the other side of the at least two stages of power conversion circuits connected in series is used for being connected to an external power source, and the external power source may be a dc source or an ac source. The power conversion circuit may be a DC/DC circuit or a DC/AC circuit.
The voltage stabilizing method of the multistage power conversion circuit comprises the following steps:
s101: and acquiring the required voltage of the energy storage device and the current flow direction of the multi-stage power conversion circuit.
In this embodiment, the current flowing direction of the multi-stage power conversion circuit is a second direction or a first direction, where the current flowing direction is the first direction and the current flows from the energy storage device to the external power source, and the current flowing direction is the second direction and the current flows from the external power source to the energy storage device.
In this embodiment, the required voltage of the energy storage device may be determined according to the rated capacity of the energy storage device, or may be determined according to the number of minimum energy storage units (for example, may be determined according to the number of battery sections) in the case that the required voltage is variable.
S102: and determining a voltage stabilizing point of each stage of power conversion circuit and a voltage stabilizing sequence of each stage of power conversion circuit according to the current flow direction of the multi-stage power conversion circuit.
In this embodiment, the voltage stabilizing sequence of each stage of power conversion circuit refers to the sequence of starting and stabilizing voltage of each stage of power conversion circuit, and the voltage stabilizing point of each stage of power conversion circuit refers to a specific voltage stabilizing position of each stage of power conversion circuit (for example, the output voltage of each stage of power conversion circuit may be stabilized, and the voltage may also be stabilized according to the input voltage of each stage of conversion circuit).
S103: and determining a voltage reference value corresponding to each voltage stabilizing point according to the required voltage and the current flow direction of the multi-stage power conversion circuit.
In this embodiment, the voltage reference value corresponding to each voltage stabilization point may be an input voltage reference value corresponding to each stage of power conversion circuit, or may be an output voltage reference value corresponding to each stage of power conversion circuit.
S104: and performing voltage stabilization control on each stage of power conversion circuit based on the voltage reference value corresponding to each voltage stabilization point and the voltage stabilization sequence of each stage of power conversion circuit.
In this embodiment, the voltage stabilization of each stage of power conversion circuit may be sequentially started according to the voltage stabilization sequence of each stage of power conversion circuit, and the power conversion circuit at each stage performs voltage stabilization control based on the voltage reference value corresponding to the voltage stabilization point after voltage stabilization is started.
As can be seen from the above description, different from the prior art, an embodiment of the present invention provides a voltage stabilization scheme applicable to a multi-stage power conversion circuit in a wide voltage range scene, and specifically, a voltage stabilization starting sequence and a voltage stabilization point of each stage of the power conversion circuit are determined according to a current flow direction in the multi-stage power conversion circuit, a voltage reference value corresponding to each voltage stabilization point is determined according to a required voltage and a current flow direction in the multi-stage power conversion circuit, and finally, voltage stabilization is performed based on the voltage reference value corresponding to each voltage stabilization point and the current flow direction in the multi-stage power conversion circuit. According to the embodiment of the invention, the voltage stabilization parameters can be adaptively adjusted according to the required voltage and the battery charge and discharge state in consideration of the required voltages of different energy storage devices and the difference of the voltage stabilization reference values of each stage of power conversion circuit in different battery charge and discharge states, so that the effective voltage stabilization of the multi-stage power conversion circuit in a wide voltage range is realized.
In a possible implementation manner, determining a voltage reference value corresponding to each regulated voltage point according to a required voltage and a current flow direction of the multi-stage power conversion circuit includes:
if the current flow direction of the multi-stage power conversion circuit is in the first direction, determining a voltage reference value corresponding to a voltage stabilizing point of the primary power conversion circuit and a voltage reference value corresponding to a voltage stabilizing point of the final power conversion circuit according to the required voltage, and determining a voltage reference value corresponding to a voltage stabilizing point of the middle power conversion circuit according to a voltage reference value corresponding to a voltage stabilizing point of the primary power conversion circuit and a preset voltage difference between adjacent power conversion circuits.
The primary power conversion circuit is a first-stage power conversion circuit from the energy storage device as the starting point, the final-stage power conversion circuit is a last-stage power conversion circuit from the energy storage device as the starting point, and the middle-stage power conversion circuit is other power conversion circuits except the primary power conversion circuit and the final-stage power conversion circuit. That is, the closest to the energy storage device is the primary power conversion circuit, the closest to the external power supply is the final power conversion circuit, and the counting direction is from the energy storage device side to the external power supply side.
In one possible implementation manner, determining a voltage reference value corresponding to a regulated point of a primary power conversion circuit and a voltage reference value corresponding to a regulated point of a final power conversion circuit according to a required voltage includes:
the range to which the required voltage belongs is determined.
And determining a voltage reference value corresponding to the voltage stabilizing point of the primary power conversion circuit and a voltage reference value corresponding to the voltage stabilizing point of the final power conversion circuit according to the range to which the required voltage belongs and various preset reference values corresponding to the range.
In this embodiment, the correspondence relationship between the above-mentioned range and the voltage reference value corresponding to the voltage stabilizing point of the primary power conversion circuit and the voltage reference value corresponding to the voltage stabilizing point of the final power conversion circuit may be preset, and after the range to which the required voltage belongs is determined, the voltage reference value corresponding to the voltage stabilizing point of the primary power conversion circuit and the voltage reference value corresponding to the voltage stabilizing point of the final power conversion circuit are determined according to the required voltage and the correspondence relationship.
In this embodiment, after determining the voltage reference value corresponding to the voltage stabilizing point of the primary power converting circuit, the reference value corresponding to the voltage stabilizing point of the next power converting circuit (the next power converting circuit is denoted as the second power converting circuit) may be determined according to a preset voltage difference between the primary power converting circuit and the next power converting circuit. After the voltage reference value corresponding to the voltage stabilizing point of the second-stage power conversion circuit is determined, the voltage reference value corresponding to the voltage stabilizing point of the next-stage power conversion circuit can be determined according to the preset voltage difference between the second-stage power conversion circuit and the next-stage power conversion circuit, and the like until the voltage reference values corresponding to the voltage stabilizing points of all the power conversion circuits are obtained. The preset voltage difference between every two adjacent power conversion circuits may be the same or different, and is not limited herein.
In a possible implementation manner, the method for determining the preset voltage difference between adjacent power conversion circuits in each stage is as follows:
the step-up ratio of the multi-stage power conversion circuit is obtained.
And determining a preset pressure difference between adjacent power conversion circuits of each stage according to the boost ratio.
In this embodiment, to ensure that energy flows from the battery side to the external circuit side, it is necessary to set a certain difference between voltage reference values corresponding to power conversion circuits of each stage, and on this basis, to ensure the step-up ratio of the multi-stage power conversion circuits, a certain limitation needs to be made on this difference, so this embodiment may consider determining the preset difference between adjacent power conversion circuits of each stage according to the step-up ratio of the multi-stage power conversion circuits.
In a possible implementation manner, determining a voltage reference value corresponding to each regulated voltage point according to a required voltage and a current flow direction of the multi-stage power conversion circuit includes:
if the current flow direction of the multi-stage power conversion circuit is in the second direction, acquiring a preset charging voltage of the energy storage device, determining a voltage reference value corresponding to a voltage stabilizing point of the primary power conversion circuit according to the preset charging voltage, and determining a voltage reference value corresponding to the voltage stabilizing point of the final power conversion circuit and the middle power conversion circuit according to the required voltage.
The primary power conversion circuit is a first-stage power conversion circuit from the energy storage device as the starting point, the final-stage power conversion circuit is a last-stage power conversion circuit from the energy storage device as the starting point, and the middle-stage power conversion circuit is other power conversion circuits except the primary power conversion circuit and the final-stage power conversion circuit. That is, the closest to the energy storage device is the primary power conversion circuit, the closest to the external power supply is the final power conversion circuit, and the counting direction is from the energy storage device side to the external power supply side.
In this embodiment, when the energy storage device is charged, the voltage reference value corresponding to the voltage stabilizing point of the primary power conversion circuit can be directly set according to the preset charging voltage. If the energy storage device is a battery, the voltage reference value corresponding to the voltage stabilizing point of the primary power conversion circuit can be set according to the average float voltage of the battery, wherein the average float voltage of the battery can be calculated by multiplying the average float voltage of a single battery by the number of battery sections.
In one possible implementation manner, determining voltage reference values corresponding to voltage stabilization points of the final-stage power conversion circuit and the middle-stage power conversion circuit according to the required voltage includes:
the range to which the required voltage belongs is determined.
And determining voltage reference values corresponding to the voltage stabilizing points of the final power conversion circuit and the middle power conversion circuits according to the range to which the required voltage belongs and various preset reference values corresponding to the range.
In this embodiment, the correspondence relationship between the above-mentioned range and the voltage reference value corresponding to the voltage stabilization point of the final power conversion circuit and the voltage reference value corresponding to the voltage stabilization point of the middle power conversion circuit may be preset, and after the range to which the required voltage belongs is determined, the voltage reference value corresponding to the voltage stabilization point of the final power conversion circuit and the voltage reference value corresponding to the voltage stabilization point of the middle power conversion circuit may be determined according to the required voltage and the correspondence relationship.
In a possible implementation manner, determining a voltage stabilizing sequence of each stage of power conversion circuit according to a current flow direction of each stage of power conversion circuit includes:
if the current flow direction of the multistage power conversion circuit is in the first direction, the power conversion circuit which is farthest away from the battery is set to start voltage stabilization firstly, and then the voltage stabilization of each power conversion circuit is started in sequence by taking the energy storage device as a starting point.
If the current flow direction of the multistage power conversion circuit is in the second direction, the power conversion circuit farthest from the battery is set to start voltage stabilization firstly, and then the power conversion circuit farthest from the battery is used as the start to start voltage stabilization of each power conversion circuit in sequence.
In a possible implementation manner, determining a voltage regulation point of each stage of power conversion circuit according to a current flow direction of each stage of power conversion circuit includes:
if the current flow direction of the multi-stage power conversion circuit is in the first direction, the voltage stabilizing point of the primary power conversion circuit is set as the output voltage of the multi-stage power conversion circuit, and the voltage stabilizing points of the other stages of power conversion circuits are set as the input voltages of the multi-stage power conversion circuits.
And if the current flow direction of the multistage power conversion circuit is in the second direction, setting the voltage stabilizing points of the multistage power conversion circuits to be output voltages of the multistage power conversion circuits. In a possible implementation manner, the present invention will describe the above scheme in detail by taking an example that the multi-stage power conversion circuit includes three stages of power conversion circuits connected in series, the energy storage device is a battery, and the external power source is a power grid. As shown in fig. 5, the three-stage power conversion circuit includes a first stage DC/DC circuit (counted from the battery end), a second stage DC/DC circuit, and a DC/AC circuit, which are connected in series in sequence, wherein the first stage DC/DC circuit is further connected with the battery, the DC/AC circuit is further connected with the power grid, and the input voltage reference value of each stage of power conversion circuit is used as the voltage reference value corresponding to each regulated point. The method comprises the steps of recording an input voltage reference value corresponding to a first-stage DC/DC circuit as Uref1, recording an input voltage reference value corresponding to a second-stage DC/DC circuit as Uref2, recording an input voltage reference value corresponding to a DC/AC circuit as Uref3, setting the number of battery sections to be 6-75, setting the range of required voltage of a corresponding battery to be 9-180V, and setting the preset voltage difference between the first-stage DC/DC circuit and the second-stage DC/DC circuit to be 20V. According to the scheme:
if the current flow direction of the multi-stage power conversion circuit is the battery discharge direction (i.e. the first direction), the voltage stabilizing point at which the multi-stage power conversion circuit starts voltage stabilization is as follows: the output voltage (marked as Uref1) of the first stage DC/DC circuit, the input voltage (marked as Uref2) of the second stage DC/DC circuit and the input voltage (marked as Uref3) of the DC/AC circuit, and the sequence of starting and stabilizing the voltage of the multi-stage power conversion circuit sequentially comprises the following steps: the DC/AC circuit is regulated to Uref3 first, then the first stage DC/DC circuit is regulated to Uref1, and finally the second stage DC/DC circuit is regulated to Uref 2.
If the current flow direction of the multi-stage power conversion circuit is the battery charging direction (i.e. the second direction), the voltage stabilizing point at which the multi-stage power conversion circuit starts voltage stabilization is as follows: the output voltage (marked as Uref4) of the first stage DC/DC circuit, the output voltage (marked as Uref5) of the second stage DC/DC circuit and the output voltage (marked as Uref6) of the DC/AC circuit, and the sequence of starting and stabilizing the voltage of the multi-stage power conversion circuit sequentially comprises the following steps: the DC/AC circuit is regulated to Uref6 first, then the second stage DC/DC circuit is regulated to Uref5, and finally the first stage DC/DC circuit is regulated to Uref 4.
When the current flow direction of the multi-stage power conversion circuit is the battery discharge direction:
if the battery node number is not more than 15, Uref1 is set to be 70V, Uref3 to 180V, and Uref2 is set to be Uref1-20V to 50V.
If the number of battery nodes is greater than 15 and not greater than 35, Uref1 is set to 120V, Uref3 to 200V, where Uref2 is set to Uref1-20V to 100V.
If the number of battery nodes is greater than 36 and not greater than 55, Uref1 is set to 180, 180V, Uref3, 220V, where Uref2 is set to Uref1-20V, 160V.
If the number of battery nodes is greater than 55 and not greater than 75, Uref1 ═ 240V, Uref3 ═ 260V, where Uref2 ═ Uref1-20V ═ 220V.
In this embodiment, the main voltage regulation object is Uref3, and the boost ratio is controlled within 5 times (the lower the boost ratio, the higher the circuit efficiency), the efficiency of the whole circuit is higher, and during discharging, Uref2< Uref1 is ensured to ensure that energy moves to the grid side, and in consideration of sampling errors, the difference between Uref2 and Uref1 is ensured to be greater than a certain value, but the low voltage is too low, which may result in no guarantee of 5 times voltage ratio, so the preset voltage difference between the first stage DC/DC circuit and the second stage DC/DC circuit is set to be 10-20V (the preset voltage difference adopted in this embodiment is 20V).
When the current flow direction of the multi-stage power conversion circuit is the battery charging direction:
uref4 is determined from the battery's average float voltage.
If the number of battery nodes is not more than 15, set Uref 5-50V, Uref 6-180V.
If the number of battery cells is greater than 15 and not greater than 35, Uref5 is set to 100V, Uref6 to 200V.
If the number of battery nodes is greater than 36 and not greater than 55, Uref5 is set to 160V, Uref6 to 220V.
If the number of battery nodes is greater than 55 and not greater than 75, Uref5 is set to 220V, Uref 6V to 260V.
In the present embodiment, the main voltage regulation object is Uref4, Uref4 can be determined directly from the average float voltage of the battery (obtained by multiplying the average float voltage of a single battery by the required voltage), and Uref5 and Uref6 can be determined from the number of battery cells.
In the above embodiments, the number of stages of the power conversion circuit employed may be determined according to the required voltage.
In the above embodiments, each power conversion circuit may also be a DC/DC circuit, which can be set according to actual requirements.
In another aspect of the present invention, there is provided a voltage stabilizer 300 for a multi-stage power conversion circuit, including: one or more processors 301, one or more input devices 302, one or more output devices 303, and one or more memories 304. The processor 301, the input device 302, the output device 303, and the memory 304 are in communication with each other via a communication bus 305. The memory 304 is used to store a computer program comprising program instructions. Processor 301 is operative to execute program instructions stored in memory 304. Wherein the processor 301 is configured to invoke program instructions to perform the steps of the above-described method embodiments. It should be understood that, in the embodiment of the present invention, the processor 301 may be a Central Processing Unit (CPU). The processor may also be other general purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The input device 302 may include a touch pad, a fingerprint sensor (for collecting fingerprint information of a user and direction information of the fingerprint), a microphone, etc., and the output device 303 may include a display (LCD, etc.), a speaker, etc. The memory 304 may include a read-only memory and a random access memory, and provides instructions and data to the processor 301. A portion of the memory 304 may also include non-volatile random access memory. For example, the memory 304 may also store device type information. In a specific implementation manner, the processor 301, the input device 302, and the output device 303 described in the embodiment of the present invention may execute the implementation manners described in the first embodiment and the second embodiment of the voltage stabilizing method for a multi-stage power conversion circuit provided in the embodiment of the present invention.
Referring to fig. 4, in yet another aspect of the present invention, a power conversion system 40 is further provided, including: the above applied multi-stage power conversion circuit 200 and the above described multi-stage power conversion circuit voltage stabilization apparatus 300, the multi-stage power conversion circuit 200 is connected to the multi-stage power conversion circuit voltage stabilization apparatus 300.
While the invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A voltage stabilizing method for a multi-stage power conversion circuit is characterized in that the method is applied to the multi-stage power conversion circuit; the multi-stage power conversion circuit comprises at least two stages of power conversion circuits which are connected in series, wherein one side of each of the at least two stages of power conversion circuits connected in series is used for being connected with the energy storage device, and the other side of each of the at least two stages of power conversion circuits connected in series is used for being connected with an external power supply, wherein the external power supply is a direct current source or an alternating current source; the method comprises the following steps:
acquiring the required voltage of the energy storage device and the current flow direction of the multistage power conversion circuit;
determining a voltage stabilizing point of each stage of power conversion circuit and a voltage stabilizing sequence of each stage of power conversion circuit according to the current flow direction of the multistage power conversion circuit;
determining a voltage reference value corresponding to each voltage stabilizing point according to the required voltage and the current flow direction of the multistage power conversion circuit;
and performing voltage stabilization control on each stage of power conversion circuit based on the voltage reference value corresponding to each voltage stabilization point and the voltage stabilization sequence of each stage of power conversion circuit.
2. The method for stabilizing the voltage of the multi-stage power conversion circuit according to claim 1, wherein the determining the voltage reference value corresponding to each stabilizing point according to the required voltage and the current flowing direction of the multi-stage power conversion circuit comprises:
if the current flow direction of the multistage power conversion circuit is in a first direction, determining a voltage reference value corresponding to a voltage stabilizing point of a primary power conversion circuit and a voltage reference value corresponding to a voltage stabilizing point of a final power conversion circuit according to the required voltage, and determining a voltage reference value corresponding to a voltage stabilizing point of a middle stage power conversion circuit according to a voltage reference value corresponding to a voltage stabilizing point of a primary power conversion circuit and a preset pressure difference between adjacent stages of power conversion circuits;
the current flow direction is a first direction, which means that current flows from the energy storage device to an external power supply, the primary power conversion circuit is a first-stage power conversion circuit from the energy storage device as a starting point, the final-stage power conversion circuit is a last-stage power conversion circuit from the energy storage device as the starting point, and the middle-stage power conversion circuit is other power conversion circuits except the primary power conversion circuit and the final-stage power conversion circuit.
3. The method for stabilizing voltage of multi-stage power conversion circuit according to claim 2, wherein said determining the voltage reference value corresponding to the voltage stabilizing point of the primary power conversion circuit and the voltage reference value corresponding to the voltage stabilizing point of the final power conversion circuit according to the required voltage comprises:
determining a range to which the required voltage belongs;
and determining a voltage reference value corresponding to a voltage stabilizing point of the primary power conversion circuit and a voltage reference value corresponding to a voltage stabilizing point of the final power conversion circuit according to the range to which the required voltage belongs and various preset reference values corresponding to the range.
4. The method for stabilizing the voltage of the multi-stage power conversion circuit according to claim 2, wherein the predetermined voltage difference between the adjacent stages of the power conversion circuit is determined by:
acquiring a boosting ratio of the multi-stage power conversion circuit;
and determining a preset pressure difference between adjacent power conversion circuits of each stage according to the voltage boosting ratio.
5. The method for stabilizing the voltage of the multi-stage power conversion circuit according to claim 1, wherein the determining the voltage reference value corresponding to each stabilizing point according to the required voltage and the current flowing direction of the multi-stage power conversion circuit comprises:
if the current flow direction of the multistage power conversion circuit is in a second direction, acquiring a preset charging voltage of the energy storage device, determining a voltage reference value corresponding to a voltage stabilizing point of a primary power conversion circuit according to the preset charging voltage, and determining a voltage reference value corresponding to the voltage stabilizing point of a final power conversion circuit and a middle power conversion circuit according to the required voltage;
the current flowing direction is the second direction, which means that the current flows from an external power supply to the energy storage device, the primary power conversion circuit is a first-stage power conversion circuit from the energy storage device as a starting point, the final-stage power conversion circuit is a last-stage power conversion circuit from the energy storage device as the starting point, and the middle-stage power conversion circuit is other power conversion circuits except the primary power conversion circuit and the final-stage power conversion circuit.
6. The method for stabilizing voltage of multi-stage power conversion circuit according to claim 5, wherein said determining voltage reference values corresponding to the voltage stabilization points of the final stage power conversion circuit and the middle stage power conversion circuit according to said required voltage comprises:
determining a range to which the required voltage belongs;
and determining voltage reference values corresponding to the voltage stabilizing points of the final power conversion circuit and the middle power conversion circuits according to the range to which the required voltage belongs and various preset reference values corresponding to the range.
7. The method according to any one of claims 1 to 6, wherein determining the voltage stabilization sequence of each stage of power conversion circuit according to the current flow direction of the power conversion circuit comprises:
if the current flow direction of the multistage power conversion circuit is in a first direction, setting the power conversion circuit farthest away from the battery to start voltage stabilization firstly, and then starting the voltage stabilization of each power conversion circuit in sequence by taking the energy storage device as a starting point;
if the current flow direction of the multistage power conversion circuit is in a second direction, setting the power conversion circuit farthest from the battery to start voltage stabilization firstly, and then starting the voltage stabilization of each power conversion circuit in sequence by taking the power conversion circuit farthest from the battery as a start;
the current flowing in the first direction refers to the current flowing from the energy storage device to the external power supply, and the current flowing in the second direction refers to the current flowing from the external power supply to the energy storage device.
8. The method for stabilizing the voltage of the multi-stage power conversion circuit according to any one of claims 1 to 6, wherein determining the voltage stabilization point of each stage of the power conversion circuit according to the current flowing direction of the multi-stage power conversion circuit comprises:
if the current flow direction of the multistage power conversion circuit is in a first direction, setting a voltage stabilizing point of a primary power conversion circuit as the output voltage of the primary power conversion circuit, and setting voltage stabilizing points of other stages of power conversion circuits as the input voltage of the primary power conversion circuit;
if the current flow direction of the multistage power conversion circuit is in a second direction, setting the voltage stabilizing points of the multistage power conversion circuits to be output voltages of the multistage power conversion circuits;
the current flowing direction is the first direction, namely the current flows from the energy storage device to an external power supply, and the current flowing direction is the second direction, namely the current flows from the external power supply to the energy storage device; the primary power conversion circuit is a first-stage power conversion circuit from the energy storage device as a starting point, and the other power conversion circuits at each stage are other power conversion circuits except the primary power conversion circuit.
9. A multi-stage power conversion circuit voltage stabilization apparatus comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method according to any one of claims 1 to 8 when executing the computer program.
10. A power conversion system, comprising: a multi-stage power conversion circuit as claimed in claim 1 and a multi-stage power conversion circuit regulation device as claimed in claim 9, the multi-stage power conversion circuit being connected to the multi-stage power conversion circuit regulation device.
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