CN116581733A - Control method of direct current conversion circuit, direct current conversion device and energy storage equipment - Google Patents

Control method of direct current conversion circuit, direct current conversion device and energy storage equipment Download PDF

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Publication number
CN116581733A
CN116581733A CN202310553036.1A CN202310553036A CN116581733A CN 116581733 A CN116581733 A CN 116581733A CN 202310553036 A CN202310553036 A CN 202310553036A CN 116581733 A CN116581733 A CN 116581733A
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China
Prior art keywords
pulse width
width modulation
value
conversion circuit
feedforward
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CN202310553036.1A
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Chinese (zh)
Inventor
郑锐畅
陈熙
王雷
杜正
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Ecoflow Technology Ltd
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Ecoflow Technology Ltd
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Priority to CN202310553036.1A priority Critical patent/CN116581733A/en
Publication of CN116581733A publication Critical patent/CN116581733A/en
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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
    • H02J1/00—Circuit arrangements for dc mains or dc distribution networks
    • H02J1/10—Parallel operation of dc sources
    • H02J1/102—Parallel operation of dc sources being switching converters
    • 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
    • H02J7/0063—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with circuits adapted for supplying loads from the battery
    • 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
    • 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
    • H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
    • 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
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The application provides a control method of a direct current conversion circuit, a direct current conversion device and energy storage equipment. Because the output end load change of the direct current conversion circuit can influence the output current, the feedforward compensation is carried out on the first pulse width modulation value through the feedforward pulse width modulation value determined by the actual output current, the second pulse width modulation value is determined, and the driving signal is output according to the second pulse width modulation value, so that the output voltage of the direct current conversion circuit can be quickly regulated, and the dynamic performance of the output voltage of the direct current conversion circuit is improved.

Description

Control method of direct current conversion circuit, direct current conversion device and energy storage equipment
Technical Field
The application relates to the technical field of voltage conversion, in particular to a control method of a direct current conversion circuit, a direct current conversion device and energy storage equipment.
Background
In the energy storage product, the output voltage control of the direct current conversion circuit of the energy storage product adopts a competing mode of three loops of a voltage loop, a current loop and a current feedforward, namely, adopts a loop with the minimum duty cycle value in the three loops to adjust the duty cycle of the direct current conversion circuit. In the running process of the direct current conversion circuit, when the output end of the direct current conversion circuit is suddenly connected into heavy load, the output voltage of the output end can drop sharply to generate larger fluctuation, and at the moment, the duty ratio of the direct current conversion circuit needs to be adjusted in time to stabilize the output voltage. However, the control mode of three-loop competition cannot timely adjust the duty ratio of the direct current conversion circuit, so that the output voltage is difficult to quickly stabilize, and the dynamic performance of the output voltage of the direct current conversion circuit is poor.
Disclosure of Invention
In view of the above, the present application provides a control method of a dc conversion circuit, a dc conversion device and an energy storage device, so as to solve the problem that the output voltage of the dc conversion circuit cannot be stabilized rapidly.
The first aspect of the present application provides a control method of a dc conversion circuit, including: acquiring actual output voltage and actual output current of the direct current conversion circuit; determining a first pulse width modulation value according to the actual output voltage, the actual output current and a preset reference output voltage; determining a feedforward pulse width modulation value according to the actual output current; determining a second pulse width modulation value from the first pulse width modulation value and the feedforward pulse width modulation value; and outputting a driving signal to a switching tube of the direct current conversion circuit according to the second pulse width modulation value so as to control the on-off of the switching tube.
In the above embodiment, the control method of the dc conversion circuit determines the first pulse width modulation value according to the actual output voltage, the actual output current and the preset reference output voltage of the dc conversion circuit, determines the feedforward pulse width modulation value according to the actual output current, determines the second pulse width modulation value according to the first pulse width modulation value and the feedforward pulse width modulation value, and outputs the driving signal to the switching tube of the dc conversion circuit according to the second pulse width modulation value, thereby adjusting the output voltage of the dc conversion circuit. Because the output end load change of the direct current conversion circuit can influence the output current, the feedforward compensation is carried out on the first pulse width modulation value through the feedforward pulse width modulation value determined by the actual output current, the second pulse width modulation value is determined, and the driving signal is output according to the second pulse width modulation value, so that the output voltage of the direct current conversion circuit can be quickly regulated, the output voltage is quickly stabilized, and the dynamic performance of the output voltage of the direct current conversion circuit is improved.
In one embodiment, the determining the feedforward pulse width modulation value according to the actual output current includes: when the actual output current is in a preset current range, obtaining a feedforward pulse width modulation calculated value according to the product of the actual output current and a preset feedforward adjustment coefficient; and if the feedforward pulse width modulation calculated value is in a preset feedforward range, determining the feedforward pulse width modulation calculated value as the feedforward pulse width modulation value.
In one embodiment, the control method further includes: if the feedforward pulse width modulation calculated value is larger than the upper limit value of the preset feedforward range, determining the upper limit value as the feedforward pulse width modulation value; and if the feedforward pulse width modulation calculated value is smaller than the lower limit value of the preset feedforward range, determining the lower limit value as the feedforward pulse width modulation value.
In one embodiment, the control method further includes: acquiring the minimum input voltage of the direct current conversion circuit; taking a pulse width modulation value of the direct current conversion circuit when the minimum input voltage reaches a steady state in a full load state as the upper limit value of the preset feedforward range; obtaining the maximum input voltage of the direct current conversion circuit; and taking a pulse width modulation value of the direct current conversion circuit when the maximum input voltage reaches a steady state in a full load state as the lower limit value of the preset feedforward range.
In one embodiment, the method further comprises: and determining the feedforward regulating coefficient according to the ratio between the actual output current of the direct current conversion circuit in a steady state and the pulse width modulation value.
In one embodiment, the determining the feedforward pulse width modulation value according to the output current further includes: and when the actual output current is smaller than the lower limit value of the preset current range, determining a preset pulse width modulation value as the feedforward pulse width modulation value.
In one embodiment, the determining the second pwm value according to the first pwm value and the feedforward pwm value includes: acquiring a preset modulation factor; and multiplying the sum of the first pulse width modulation value and the feedforward pulse width modulation value by the modulation coefficient to obtain the second pulse width modulation value.
In one embodiment, the determining the first pwm value according to the actual output voltage, the actual output current, and a preset reference output voltage includes: calculating a voltage deviation value according to the actual output voltage and the reference output voltage; performing deviation adjustment on the voltage deviation value to obtain an output current given value of the direct current conversion circuit; calculating a current deviation value according to the output current given value and the actual output current; and performing deviation adjustment on the current deviation value to obtain the first pulse width modulation value.
A second aspect of the present application provides a dc conversion device comprising a dc bus, a dc conversion circuit, and a controller, the input of the dc conversion circuit being connected to the dc bus to receive power from the dc bus, the controller being configured to perform a control method as described above.
A third aspect of the application provides an energy storage device comprising a battery pack and a dc conversion arrangement as described above, the battery pack being connected to the dc bus to power the dc bus.
Drawings
Fig. 1 is a waveform diagram of an output voltage when a heavy load is applied to an output terminal of a dc conversion circuit for adjusting the output voltage by using three loop competing methods.
Fig. 2 is a flowchart of a control method of a dc conversion circuit according to an embodiment of the present application.
Fig. 3 is a detailed flowchart of step S300 in fig. 2.
Fig. 4 is a partial flowchart of a control method of the dc conversion circuit according to an embodiment of the present application.
Fig. 5 is a detailed flowchart of step S400 in fig. 2.
Fig. 6 is a detailed flowchart of step S200 in fig. 2.
Fig. 7 is a specific control block diagram of a control method of the dc conversion circuit according to the embodiment of the present application.
Fig. 8 is a waveform diagram of the output voltage when the output terminal of the dc conversion circuit for regulating the output voltage by the control method of the present application is suddenly loaded.
Fig. 9 is a schematic block diagram of a dc conversion device according to an embodiment of the present application.
Fig. 10 is a schematic block diagram of an energy storage device according to an embodiment of the present application.
Detailed Description
It should be noted that the terms "first" and "second" in the description and claims of the present application and the accompanying drawings are used to distinguish similar objects, and are not used to describe a specific order or sequence.
It should be further noted that, in the method disclosed in the embodiment of the present application or the method shown in the flowchart, one or more steps for implementing the method are included, and the execution order of the steps may be interchanged with each other, where some steps may be deleted without departing from the scope of the claims.
Some embodiments will be described below with reference to the accompanying drawings. The following embodiments and features of the embodiments may be combined with each other without conflict.
At present, the control of the output voltage of the direct current conversion circuit in the energy storage device adopts a competing mode of three loops, namely a voltage loop, a current loop and a current feedforward, and the duty ratio of the output voltage is regulated by adopting the loop with the minimum duty ratio value in the three loops. If the direct current conversion circuit suddenly gets over load in the operation process, the output voltage of the direct current conversion circuit drops sharply, and the duty ratio of the direct current conversion circuit needs to be adjusted in time to stabilize the output voltage. Fig. 1 shows a waveform diagram of an output voltage of a dc conversion circuit for adjusting the output voltage in a three-loop competing manner when suddenly switching into a load. According to fig. 1, the duty ratio of the dc conversion circuit is adjusted by adopting the three-loop competing control method, when the output end of the dc conversion circuit is suddenly connected to a heavy load, the output voltage suddenly drops rapidly, and a certain time is required for the output voltage to recover from the drop value to a stable process, so that the duty ratio cannot be adjusted by adopting the three-loop competing control method, and the output voltage dynamic performance of the dc conversion circuit is poor.
Therefore, the application provides a control method of a direct current conversion circuit, a direct current conversion device and energy storage equipment, which can timely adjust the output voltage of the direct current conversion circuit, so that the output voltage is fast and stable, and the dynamic performance of the output voltage of the direct current conversion circuit is improved.
Referring to fig. 2, fig. 2 is a flowchart of a control method of a dc conversion circuit according to an embodiment of the application. It will be appreciated that the control method of the dc conversion circuit may be performed by the controller.
As shown in fig. 2, the control method of the dc conversion circuit includes the following steps S100 to S500.
S100, acquiring actual output voltage and actual output current of the direct current conversion circuit.
It is understood that the dc conversion circuit is a circuit capable of dc converting an input voltage. The present application is not limited to the dc conversion circuit, and the dc conversion circuit may be, for example, a BOOST (BOOST) conversion circuit, a BUCK (BUCK) conversion circuit, or a BUCK-BOOST (BUCK-BOOST) conversion circuit.
The actual output voltage of the direct current conversion circuit can be obtained by detecting the voltage of the output end of the direct current conversion circuit through the voltage detection circuit. The actual output current of the direct current conversion circuit can be obtained by detecting the current of the output end of the direct current conversion circuit through the current detection circuit. The voltage detection circuit and the current detection circuit can be integrated in the controller, and can also be connected with the controller and independently arranged.
S200, determining a first pulse width modulation value according to the actual output voltage, the actual output current and a preset reference output voltage.
Specifically, when the dc conversion circuit starts to operate, the actual output voltage and the actual output current may be zero, so the first pwm value is directly determined according to the preset reference output voltage. The actual output voltage and the actual output current are then adjusted to vary according to the reference output voltage, thereby determining a first pulse width modulation value in combination with the actual output voltage, the actual output current, and the reference output voltage.
The magnitude of the reference output voltage may be preset according to actual needs, which is not limited herein.
S300, determining a feedforward pulse width modulation value according to the actual output current.
In step S300, the actual output current and the feedforward pulse width modulation value may have a corresponding proportional relationship, and thus, the feedforward pulse width modulation value may be determined according to the actual output current and the proportional relationship.
In some specific examples, the feedforward adjustment coefficient may be determined based on a ratio between an actual output current of the DC conversion circuit at steady state and the pulse width modulation value. The feedforward adjustment coefficient is the proportional relation between the actual output current and the feedforward pulse width modulation value, so that the feedforward pulse width modulation value can be determined according to the feedforward adjustment coefficient and the obtained actual output current. Wherein the ratio between the actual output current of the DC conversion circuit at steady state and the pulse width modulation value may be equal to the feedforward adjustment coefficient. The ratio between the actual output current of the DC conversion circuit in steady state and the pulse width modulation value is: when the direct current conversion circuit regulates the output voltage only by the voltage loop and/or the current loop, different loads are applied to the output end of the direct current conversion circuit, the actual output current and the pulse width modulation value which correspond to the output voltage and are in a stable state under different load conditions are recorded, and the ratio between the actual output current and the pulse width modulation value is calculated according to the recorded data. For example, (0.5A, 700), (1A, 1200), (2A, 3400), (3A, 4700) are recorded, and from this data, the ratio between the actual output current and the pulse width modulation value is found to be 1600, that is, the feedforward adjustment coefficient is determined to be 1600.
It will be appreciated that the data may also be recorded graphically. For example, in some embodiments of the application, the recorded data may be fitted to a curve. Further, the feedforward adjustment coefficient may be determined by determining the ratio between the actual output current and the pulse width modulation value based on the fitted curve.
S400, determining a second pulse width modulation value according to the first pulse width modulation value and the feedforward pulse width modulation value.
Wherein the sum of the first pulse width modulation value and the feedforward pulse width modulation value can be taken as the second pulse width modulation value.
S500, outputting a driving signal to a switching tube of the direct current conversion circuit according to the second pulse width modulation value so as to control the on-off of the switching tube.
It is understood that in the present application, the pulse width modulation (Pulse Width Modulation, PWM) value is proportional to the duty cycle. The second pwm value is proportional to the duty cycle of the driving signal, for example, when the second pwm value is 9500, the duty cycle of the driving signal is 100%, and the duty cycle of the driving signal is obtained by dividing the second pwm value by 9500. Of course, the corresponding second pwm value when the duty ratio of the driving signal is 100% may be set according to the parameters and performance of the dc conversion circuit, which is merely illustrative, and the relationship between the specific second pwm value and the duty ratio is not specifically limited. In this way, the required duty ratio of the driving signal can be calculated according to the second pulse width modulation value corresponding to the duty ratio of the driving signal being 100% and the second pulse width modulation value determined currently, so that the driving signal with the duty ratio is output to the switching tube of the direct current conversion circuit, the on-off of the switching tube is controlled, and the output voltage of the direct current conversion circuit is regulated.
Based on such design, in the embodiment of the application, the first pulse width modulation value is determined according to the actual output voltage, the actual output current and the preset reference output voltage of the direct current conversion circuit, the feedforward pulse width modulation value is determined according to the actual output current, the second pulse width modulation value is determined according to the first pulse width modulation value and the feedforward pulse width modulation value, and the driving signal is output to the switching tube of the direct current conversion circuit according to the second pulse width modulation value, so that the output voltage of the direct current conversion circuit is regulated. Because the output end load change of the direct current conversion circuit can influence the output current, the feedforward pulse width modulation value determined by the actual output current carries out feedforward compensation on the first pulse width modulation value and then determines the second pulse width modulation value, when the output end of the direct current conversion circuit is suddenly connected into heavy load, the feedforward pulse width modulation value can be rapidly determined according to the actual output current, so that the second pulse width modulation value can be timely determined, a driving signal can be output according to the second pulse width modulation value, the output voltage of the direct current conversion circuit can be rapidly regulated, the output voltage is rapidly stabilized, and the dynamic performance of the output voltage of the direct current conversion circuit is improved.
Fig. 3 is a detailed flowchart of step S300 of the control method according to the embodiment of the present application. Referring to fig. 3, step S300 includes:
s310, obtaining a feedforward pulse width modulation calculated value according to the product of the actual output current and a preset feedforward adjustment coefficient when the actual output current is in a preset current range.
There are two cases of the relation between the actual output current and the preset current range, the actual output current being within the preset current range or the actual output current being outside the preset current range. When the actual output current is within the preset current range, the output end of the direct current conversion circuit is connected with a certain load, and a feedforward pulse width modulation calculated value is obtained according to the product of the actual output current and a feedforward adjustment coefficient. For example, the preset current range may be an actual output current greater than 0.3A. Here, the specific preset current range is not specifically limited, and is merely an exemplary illustration.
S320, if the feedforward pulse width modulation calculated value is within the preset feedforward range, determining the feedforward pulse width modulation calculated value as the feedforward pulse width modulation value.
After the feedforward pulse width modulation calculated value is calculated, confirming whether the feedforward pulse width modulation calculated value is in a preset feedforward range, and confirming the feedforward pulse width modulation calculated value in the preset feedforward range as the feedforward pulse width modulation value.
With continued reference to fig. 3, further, the control method of the dc conversion circuit further includes:
s321, if the feedforward pulse width modulation calculated value is larger than the upper limit value of the preset feedforward range, determining the upper limit value as the feedforward pulse width modulation value.
S322, if the feedforward pulse width modulation calculated value is smaller than the lower limit value of the preset feedforward range, determining the lower limit value as the feedforward pulse width modulation value.
And when the feedforward pulse width modulation calculated value is larger than the upper limit value of the preset feedforward range, determining the upper limit value as the feedforward pulse width modulation value. And when the feedforward pulse width modulation calculated value is smaller than the lower limit value of the preset feedforward range, determining the lower limit value as the feedforward pulse width modulation value. Therefore, the feedforward pulse width modulation value can be limited in a preset feedforward range, and the phenomenon that the output voltage of the direct current conversion circuit is excessively regulated or cannot be timely regulated due to the fact that the feedforward pulse width modulation value is excessively large or excessively small is prevented.
In some embodiments, step S300 further comprises:
and when the actual output current is smaller than the lower limit value of the preset current range, determining the preset pulse width modulation value as a feedforward pulse width modulation value.
When the actual output current is smaller than the lower limit value of the preset current range, the output end of the direct current conversion circuit is in a light load or no-load state, and the output current requirement of the direct current conversion circuit is small. Therefore, the duty ratio required for the driving signal of the dc conversion circuit is relatively small at this time. Thus, the second pulse width modulation value required is smaller, so a smaller feedforward pulse width modulation value may not be set or set. For example, the preset pulse width modulation values may be set to 0, 20, 30, etc.
Referring to fig. 4, in some embodiments, the control method of the dc conversion circuit further includes:
s301, acquiring the minimum input voltage of the direct current conversion circuit.
The minimum input voltage is the minimum value of the input voltage allowed when the dc conversion circuit works normally, and if the input voltage of the dc conversion circuit is smaller than the minimum input voltage, the dc conversion circuit cannot work normally, for example, the minimum voltage protection value of the dc conversion circuit or the voltage value when the power supply of the dc conversion circuit is insufficient.
S302, taking a pulse width modulation value of the direct current conversion circuit when the direct current conversion circuit reaches a steady state in a full load state at the minimum input voltage as an upper limit value of a preset feedforward range.
It will be appreciated that the pulse width modulation value of the dc conversion circuit at the minimum input voltage and reaching a steady state in the full load state means: when the output voltage of the direct current conversion circuit is regulated by the voltage loop and/or the current loop and the input voltage is the minimum input voltage, the load connected to the output end of the direct current conversion circuit is fully loaded, and the pulse width modulation value is obtained after the output voltage of the direct current conversion circuit is stabilized.
S303, acquiring the maximum input voltage of the direct current conversion circuit.
The maximum input voltage is the maximum value of the input voltage allowed when the dc conversion circuit operates normally, and may be the maximum voltage that the power supply can supply to the input terminal of the dc conversion circuit, for example, the voltage when the power supply is full.
S304, taking a pulse width modulation value of the direct current conversion circuit at the maximum input voltage and reaching a steady state in a full load state as a lower limit value of a preset feedforward range.
It will be appreciated that the pulse width modulation value of the dc conversion circuit at maximum input voltage and reaching steady state in full load state refers to: when the output voltage of the direct current conversion circuit is regulated by the voltage loop and/or the current loop only, and the input voltage is the maximum input voltage, the load connected to the output end of the direct current conversion circuit is fully loaded, and the pulse width modulation value is obtained after the output voltage of the direct current conversion circuit is stabilized.
The output end of the direct current conversion circuit is provided with the same load, and the larger the input voltage is, the smaller the pulse width modulation value of the required driving signal is. And taking the pulse width modulation value of the direct current conversion circuit when the direct current conversion circuit reaches a steady state under the minimum input voltage and full load state as the upper limit value of the preset feedforward range. And taking the pulse width modulation value of the direct current conversion circuit when the direct current conversion circuit reaches a steady state under the maximum input voltage and full load state as the lower limit value of the preset feedforward range. When the output end of the direct current conversion circuit suddenly loads, the feedforward pulse width modulation value is limited in the preset feedforward range, so that the second pulse width modulation value determined by the first pulse width modulation value and the feedforward pulse width modulation value approaches to the pulse width modulation value in a steady state in the full load state, the drop value of the output voltage when the output end of the direct current conversion circuit suddenly loads is smaller, the pulse width modulation value of the driving signal of the direct current conversion circuit can be quickly regulated to the required pulse width modulation value, and the output voltage can quickly reach the steady state.
It is understood that the preset feedforward range may be obtained by performing experiments on the dc conversion circuit in advance. For example, in some specific examples, the minimum input voltage of the dc conversion circuit is 42V and the maximum input voltage is 55V. The direct current conversion circuit is set to be only used for regulating output voltage by a voltage loop and/or a current loop, 42V voltage is provided for the input end of the direct current conversion circuit, so that a load connected to the output end of the direct current conversion circuit is fully loaded, and after the output voltage of the direct current conversion circuit is stable, the pulse width modulation value of the direct current conversion circuit at the moment is recorded as the upper limit value of a preset feedforward range. And providing 55V voltage to the input end of the direct current conversion circuit, fully loading a load connected to the output end of the direct current conversion circuit, and recording the pulse width modulation value of the direct current conversion circuit at the moment as the lower limit value of the preset feedforward range after the output voltage of the direct current conversion circuit is stable.
In addition, the input voltage of the direct current conversion circuit can be regulated from 42V to 55V, the pulse width modulation value of each regulated voltage in the range when the output voltage is stable under the full load state is recorded, and the relationship between the pulse width modulation value of each regulated voltage in the full load state when the output voltage is stable and the input voltage is obtained according to the recorded data, so that the pulse width modulation value of each voltage in the range when the output voltage is stable under the full load state can be obtained. Of course, the specific minimum input voltage and maximum input voltage are not specifically limited herein for illustrative purposes only.
Fig. 5 is a detailed flowchart of step S400 of the control method according to the embodiment of the present application. Referring to fig. 7, step S400 includes:
s410, acquiring a preset modulation factor.
The modulation factor K may be set according to practical situations, for example, K may be 1.
S420, multiplying the sum of the first pulse width modulation value and the feedforward pulse width modulation value by the modulation coefficient to obtain a second pulse width modulation value.
When the dc conversion circuit is over-current or over-voltage, the duty ratio of the driving signal needs to be adjusted to restore the output voltage of the dc conversion circuit. In order to make the duty ratio of the output driving signal change smoothly to prevent the output voltage of the direct current conversion circuit from fluctuating excessively, the modulation factor K may be set to 0.2 at the initial moment when the direct current conversion circuit triggers overcurrent or overvoltage, and the modulation factor K is increased by 0.05 every one control period for controlling the on-off of the switching tube until the modulation factor K returns to 1, so that the second pulse width modulation value increases smoothly, and the duty ratio of the driving signal changes smoothly. Therefore, in the application, the modulation factor K is required to be set, and the sum of the first pulse width modulation value and the feedforward pulse width modulation value is multiplied by the modulation factor to obtain the second pulse width modulation value, so that the output voltage fluctuation can be prevented from being too large when the direct current conversion circuit has overcurrent or overvoltage.
It can be understood that the setting value of the modulation factor K at the initial moment of triggering the over-current or over-voltage by the dc conversion circuit is not limited to 0.2, and the increasing value of each control period is not limited to 0.05, which can be set according to the actual circuit requirement.
Fig. 6 is a detailed flowchart of step S200 of the control method according to the embodiment of the present application. Referring to fig. 8, step S200 includes:
s210, calculating a voltage deviation value according to the actual output voltage and the reference output voltage.
It is understood that the voltage deviation value is the difference between the actual output voltage and the reference output voltage.
S220, performing deviation adjustment on the voltage deviation value to obtain an output current given value of the direct current conversion circuit.
Deviation adjustment of the voltage deviation value may be performed by proportional integral adjustment or proportional adjustment, i.e. deviation adjustment may refer to proportional integral adjustment or proportional adjustment. Specifically, the voltage deviation value is input into a proportional integral regulator to output the given value of the output current of the direct current conversion circuit. Of course, the deviation adjustment in the embodiment of the present application may also be performed by a proportional adjuster, and may specifically be set according to actual requirements. Steps S210 and S220 may be implemented by a voltage loop with a proportional integral regulator or a proportional regulator.
S230, calculating a current deviation value according to the given value of the output current and the actual output current.
The current deviation value is the difference between the given value of the output current and the actual output current.
S240, performing deviation adjustment on the current deviation value to obtain a first pulse width modulation value.
The deviation adjustment of the current deviation value can also be performed by proportional integral adjustment or proportional adjustment, and the current deviation value is input into another proportional integral adjuster or proportional adjuster, so that the first pulse width modulation value can be calculated. Steps S230 and S240 may be implemented by a current loop with a proportional integral regulator or a proportional regulator.
As shown in fig. 7, the control method of the dc conversion circuit can be commonly performed by employing a first proportional integral regulator 130, a second proportional integral regulator 131, a feed forward regulator 132, a coefficient regulator 133, a PWM (Sinusoidal Pulse Width Modulation ) modulator 134.
The following describes a specific workflow of the control method provided by the embodiment of the present application according to a specific control block diagram shown in fig. 7.
Firstly, the actual output voltage Vout and the actual output current Iout of the direct-current conversion circuit are obtained. The actual output voltage Vout and the reference output voltage Vref are differenced to obtain a voltage deviation value. The voltage deviation value is input to the first proportional integral regulator 130 to obtain an output current given value Iref. And then, the output current set value Iref and the actual output current Iout are subjected to difference to obtain a current deviation value. The current deviation value is input to the second proportional-integral regulator 131 to obtain a first pulse width modulation value.
The actual output current Iout is input to the feedforward regulator 132, and a feedforward pulse width modulation value is obtained. The first pwm value and the feedforward pwm value are summed and then input to the coefficient adjuster 133, and the coefficient adjuster 133 multiplies the sum of the first pwm value and the feedforward pwm value by the modulation coefficient K to obtain a second pwm value. The second pulse width modulation value is input into the PWM modulator 134, and the PWM modulator 134 outputs a driving signal to the switching tube of the dc conversion circuit according to the second pulse width modulation value to control the switching tube to be turned on or off, so that the output voltage of the dc conversion circuit is stabilized to the reference output voltage.
As shown in fig. 8, fig. 8 shows waveforms of the output voltage when the output terminal of the dc conversion circuit for regulating the output voltage using the control method of the present application is suddenly overloaded. Comparing fig. 1 and fig. 8, it can be known that, by adopting the control method of the present application to adjust the output voltage of the dc conversion circuit, compared with adopting the competing mode of the voltage loop, the current loop and the current feedforward to adjust the output voltage of the dc conversion circuit, the output voltage will not drop too much, and the output voltage of the dc conversion circuit can be adjusted to a stable state more quickly, thereby improving the dynamic performance of the output voltage of the dc conversion circuit.
Referring to fig. 9, the embodiment of the application further provides a dc conversion device 10. As shown in fig. 9, the dc conversion device 10 includes a dc BUS (bus+, BUS-), a dc conversion circuit 12, and a controller 13.
Wherein the input of the dc conversion circuit 12 is connected to a dc BUS (bus+, BUS-) for receiving power on the dc BUS (bus+, BUS-).
The dc conversion circuit 12 may be referred to the corresponding description in the foregoing control method embodiments, and will not be described herein.
The controller 13 is configured to execute the control method as described above, thereby enabling the output voltage of the dc conversion circuit 12 to be regulated to a steady state more quickly and improving the dynamic performance of the output voltage of the dc conversion circuit 12. It is understood that the first proportional integral regulator 130, the second proportional integral regulator 131, the feedforward regulator 132, the coefficient regulator 133, and the PWM modulator 134 in the control block diagram shown in fig. 7 may be integrated in the controller 13.
Referring to fig. 10, the present application further provides an energy storage device 100, where the energy storage device 100 includes a dc conversion device 10 and a battery pack 20.
The battery pack 20 is connected with a direct current BUS (BUS+, BUS-) in the direct current conversion device 10 to supply power to the direct current BUS (BUS+, BUS-).
The battery pack 20 is connected with a direct current BUS (bus+, BUS-) so that the direct current conversion circuit 12 in the direct current conversion device 10 provides an input voltage by the battery pack 20, and can perform direct current conversion on the voltage of the battery pack 20 and then supply power to a load. Of course, in the embodiment of the present application, the battery pack 20 may also be directly connected to the load through the dc BUS (bus+, BUS-) that is, directly power the load.
The dc conversion means 10 in the energy storage device 100 may be referred to as correspondingly described in the embodiment shown in fig. 9. Therefore, the output voltage of the dc conversion device 10 in the energy storage device 100 of the present application has better dynamic performance.
The embodiments of the present application have been described in detail with reference to the accompanying drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge of one of ordinary skill in the art without departing from the spirit of the present application.

Claims (10)

1. A control method of a direct current conversion circuit, the control method comprising:
acquiring actual output voltage and actual output current of the direct current conversion circuit;
determining a first pulse width modulation value according to the actual output voltage, the actual output current and a preset reference output voltage;
determining a feedforward pulse width modulation value according to the actual output current;
determining a second pulse width modulation value from the first pulse width modulation value and the feedforward pulse width modulation value;
and outputting a driving signal to a switching tube of the direct current conversion circuit according to the second pulse width modulation value so as to control the on-off of the switching tube.
2. The control method of claim 1, wherein said determining a feed forward pulse width modulation value based on said actual output current comprises:
when the actual output current is in a preset current range, obtaining a feedforward pulse width modulation calculated value according to the product of the actual output current and a preset feedforward adjustment coefficient;
and if the feedforward pulse width modulation calculated value is in a preset feedforward range, determining the feedforward pulse width modulation calculated value as the feedforward pulse width modulation value.
3. The control method according to claim 2, characterized in that the control method further comprises:
if the feedforward pulse width modulation calculated value is larger than the upper limit value of the preset feedforward range, determining the upper limit value as the feedforward pulse width modulation value;
and if the feedforward pulse width modulation calculated value is smaller than the lower limit value of the preset feedforward range, determining the lower limit value as the feedforward pulse width modulation value.
4. A control method according to claim 3, characterized in that the control method further comprises:
acquiring the minimum input voltage of the direct current conversion circuit;
taking a pulse width modulation value of the direct current conversion circuit when the minimum input voltage reaches a steady state in a full load state as the upper limit value of the preset feedforward range;
obtaining the maximum input voltage of the direct current conversion circuit;
and taking a pulse width modulation value of the direct current conversion circuit when the maximum input voltage reaches a steady state in a full load state as the lower limit value of the preset feedforward range.
5. The control method according to claim 2, characterized in that the method further comprises:
and determining the feedforward regulating coefficient according to the ratio between the actual output current of the direct current conversion circuit in a steady state and the pulse width modulation value.
6. The control method of claim 2, wherein said determining a feed forward pulse width modulation value from said output current further comprises:
and when the actual output current is smaller than the lower limit value of the preset current range, determining a preset pulse width modulation value as the feedforward pulse width modulation value.
7. The control method of claim 1, wherein the determining a second pulse width modulation value from the first pulse width modulation value and the feed forward pulse width modulation value comprises:
acquiring a preset modulation factor;
and multiplying the sum of the first pulse width modulation value and the feedforward pulse width modulation value by the modulation coefficient to obtain the second pulse width modulation value.
8. The control method according to claim 1, wherein the determining a first pulse width modulation value from the actual output voltage, the actual output current, and a preset reference output voltage includes:
calculating a voltage deviation value according to the actual output voltage and the reference output voltage;
performing deviation adjustment on the voltage deviation value to obtain an output current given value of the direct current conversion circuit;
calculating a current deviation value according to the output current given value and the actual output current;
and performing deviation adjustment on the current deviation value to obtain the first pulse width modulation value.
9. A dc conversion device, characterized in that the dc conversion device comprises a dc bus, a dc conversion circuit, and a controller, the input of the dc conversion circuit being connected to the dc bus for receiving power on the dc bus, the controller being adapted to perform the control method according to any one of claims 1-8.
10. An energy storage device comprising a battery pack and the dc conversion device of claim 9, the battery pack being connected to the dc bus to power the dc bus.
CN202310553036.1A 2023-05-16 2023-05-16 Control method of direct current conversion circuit, direct current conversion device and energy storage equipment Pending CN116581733A (en)

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CN202310553036.1A CN116581733A (en) 2023-05-16 2023-05-16 Control method of direct current conversion circuit, direct current conversion device and energy storage equipment

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Application Number Priority Date Filing Date Title
CN202310553036.1A CN116581733A (en) 2023-05-16 2023-05-16 Control method of direct current conversion circuit, direct current conversion device and energy storage equipment

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CN116581733A true CN116581733A (en) 2023-08-11

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