CN114696616A - Three-port high-gain boost DC/DC converter based on differential connection and control method thereof - Google Patents

Three-port high-gain boost DC/DC converter based on differential connection and control method thereof Download PDF

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CN114696616A
CN114696616A CN202210445365.XA CN202210445365A CN114696616A CN 114696616 A CN114696616 A CN 114696616A CN 202210445365 A CN202210445365 A CN 202210445365A CN 114696616 A CN114696616 A CN 114696616A
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unit
capacitor
diode
power supply
current
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汪诚
华红婷
李磊
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Nanjing University of Science and Technology
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Nanjing University of Science and Technology
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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
    • 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
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H02M3/1584—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load with a plurality of power processing stages connected in parallel
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/14—Arrangements for reducing ripples from dc input or output

Abstract

The invention discloses a three-port high-gain boosting DC/DC converter based on differential connection, which comprises a power supply unit, a first boosting unit, a second boosting unit and a third boosting unit, wherein the first boosting unit is connected with the first boosting unit; the two ends of the first boosting unit are respectively connected with the positive electrode and the negative electrode of the power supply unit, the two ends of the second boosting unit are respectively connected with the positive electrode and the negative electrode of the power supply unit in a reverse mode, the two ends of the third boosting unit are respectively connected with the positive electrode and the negative electrode of the power supply unit in a reverse mode, the negative output end of the first boosting unit is connected with the positive output end of the second boosting unit through a load R1, and the negative output end of the first boosting unit is connected with the positive output end of the third boosting unit through a load R2. The invention effectively improves the step-up ratio from input to output of the DC/DC converter, reduces the current ripple at the end of the storage battery, realizes multi-port output, reduces the use of modules and also improves the power density of the system; meanwhile, the on-off times of the switch are saved, and the switching loss is reduced, so that the system efficiency is improved.

Description

Three-port high-gain boost DC/DC converter based on differential connection and control method thereof
Technical Field
The invention belongs to the field of multi-level power electronic converters and control thereof, and particularly relates to a three-port high-gain boost DC/DC converter based on differential connection and a control method thereof.
Background
A multi-port converter integrates a plurality of input and output ends into a circuit, and the ports of the multi-port converter comprise a power supply, an energy storage element and a load, so that the multi-port converter is applied to large-scale distributed new energy grid-connected occasions such as an electric vehicle charging station, a wind power station, a photovoltaic power station and the like. The multi-port converter can further reduce the number of components, reduce the system cost and improve the power density, and the control method and the unit topology structure of the multi-port converter are similar to those of a single DC/DC converter. The output ends of the DC/DC converter connected in a differential mode can enable the input and the output ends to be directly connected through the capacitor, so that the gain of the converter can be greatly improved, meanwhile, the circulation of power on an active device is reduced, the efficiency of the converter is improved, and a magnetic coupling element or a transformer is not needed to realize the high step-up ratio of the converter. Meanwhile, the converters are connected together in a differential mode, so that the current ripple of the storage battery at the input end can be reduced, the electric energy quality can be improved, and the service life of the battery can be prolonged.
The control of traditional multiport converter can not realize the balance of input current of each port, can cause the ripple of input end battery current to increase, and rely on the parameter and the load of circuit, when load dynamic transformation, output voltage transient response speed is not fast enough, can't realize output voltage's stability even when serious, and this has restricted the performance of converter greatly.
Disclosure of Invention
The invention aims to provide a circuit topology structure of a three-port high-gain boost DC/DC converter based on differential connection and a control method thereof.
The technical solution for realizing the purpose of the invention is as follows: a three-port high-gain boosting DC/DC converter based on differential connection comprises a power supply unit, a first boosting unit, a second boosting unit and a third boosting unit;
the two ends of the first boosting unit are respectively connected with the positive electrode and the negative electrode of the power supply unit, the two ends of the second boosting unit are respectively reversely connected with the positive electrode and the negative electrode of the power supply unit, the two ends of the third boosting unit are respectively reversely connected with the positive electrode and the negative electrode of the power supply unit, and the negative output end of the first boosting unit and the negative output end of the second boosting unitBetween the positive output ends via a load R1The negative output end of the first boosting unit is connected with the positive output end of the third boosting unit through a load R2And the positive output port of the first boosting unit, the negative output port of the second boosting unit and the negative output port of the third boosting unit are connected in a suspended mode.
Preferably, said power supply unit comprises a battery Vin。
Preferably, the first boosting unit includes an inductor L1Active switch S1Two capacitors C1、C2And two diodes D1、D2Said inductance L1Negative pole and the switch tube S1The drain of the inductor L is connected with1Is connected with the positive pole of the power supply unit, the switch tube S1Is connected with the negative pole of the power supply unit, and the capacitor C1Positive electrode and inductor L1And a switching tube S1Is connected to the connection point of the diode D1Anode and capacitor C1Diode D1Cathode and switching tube S1Of the diode D, the diode D2Cathode and diode D1Anode connection of (2), diode D2And the capacitor C2Is connected to the negative pole of the capacitor C2Anode and diode D1Is connected to the cathode.
Preferably, the second boosting unit comprises an inductor L2An active switch S2Two capacitors C3、C4And two diodes D3、D4Said inductance L2Positive pole and the switch tube S2The source of the inductor L2Is connected with the negative pole of the power supply unit, and a switching tube S2Is connected with the positive pole of the power supply unit, and the capacitor C3Negative electrode of (1) and inductor L2And a switching tube S2Is connected to the connection point of the diode D3Cathode and capacitor C3The anode of the diode D3And a switch tube S2Is connected to the drain of the diodeD4Anode of (2) and diode D3Cathode connection of (2), diode D4And the capacitor C4The positive pole of the capacitor C is connected4Cathode and diode D3Is connected to the cathode.
Preferably, the third boosting unit has the same structure as the second boosting unit.
The invention also provides a control method of the three-port high-gain boost DC/DC converter based on differential connection, which is used for controlling the three-port high-gain boost DC/DC converter based on differential connection and comprises the following steps: dividing a switching mode, establishing a prediction model, and selecting an optimal switching state on line;
the divided switching modes are specifically: the switch modes comprise 8 types, namely A0：S1Off, S2Off, S3Turning off; a. the1：S1Off, S2Off, S3Conducting; a. the2：S1Off, S2Conduction, S3Turning off; a. the3：S1Off, S2Conduction, S3Conducting; a. the4：S1Conduction, S2Off, S3Turning off; a. the5：S1Conduction, S2Off, S3Conducting; a. the6：S1Conduction, S2Conduction, S3Turning off; a. the7：S1Conduction, S2Conduction, S3Conducting;
the process of establishing the prediction model specifically comprises the following steps: calculating the voltage at two ends of the inductor in different switching states, obtaining an equation of the inductor current according to the relation between the current and the voltage at the two ends of the inductor, and discretizing the equation to obtain the predicted value of the inductor current in 8 switching states;
the specific process of selecting the optimal switch state on line comprises the following steps: and obtaining a predicted value of the inductive current according to the prediction model, calculating an objective function value corresponding to each switching mode, and selecting the switching mode corresponding to the lowest objective function value as the switching state at the next moment.
Compared with the prior art, the invention has the following remarkable advantages: the boosting units are connected after being subjected to mirror symmetry in a differential connection mode, and as long as the voltage of any one output port is controlled to tend to a reference value, the voltage of the other output port automatically tends to the reference value; because the circuit topology has a loop in which the input and the output are directly connected through the capacitor, the circuit can realize the direct transmission of partial power without an active device, the efficiency of the system can be improved, the boost ratio of the converter is improved, the current ripple of the input storage battery is reduced, and only the voltage of any one output port needs to be controlled, thereby reducing the use of a voltage sensor and saving the cost.
The present invention is described in further detail below with reference to the attached drawing figures.
Drawings
Fig. 1 is a schematic of the topology of the present invention.
FIG. 2 is a schematic diagram of a power supply unit according to the present invention
Fig. 3 is a schematic diagram of the first boosting unit according to the present invention.
Fig. 4 is a schematic diagram of a second boosting unit according to the present invention.
Fig. 5 is a schematic diagram of a third boosting unit according to the present invention.
FIG. 6 shows a load R according to the invention1Schematic representation.
FIG. 7 shows a load R according to the invention2Schematic representation.
Fig. 8 is a schematic diagram of 8 switching modes of the differential connection based three-port boost DC/DC converter of the present invention.
FIG. 9 is a control block diagram of a three-port boost DC/DC converter topology based on differential connection according to the present invention.
FIG. 10 shows the output port voltage V when the load rating of the output port is switched from 400W to 800W and back to 400W when the three-port boost DC/DC converter topology system based on differential connection operateso1、Vo2Input battery current IbAn inductor current iL1、iL2、iL3Schematic representation.
Detailed Description
In order to more clearly describe the idea, technical solution and advantages of the present invention, the detailed description is shown by the examples and the attached drawings. It is to be understood that the embodiments described are only some of the embodiments of the invention, and not all of them. All other embodiments, which can be obtained by a person skilled in the art without any inventive work based on the embodiments of the present invention, are within the scope of protection of the present invention.
2. As shown in fig. 1, a circuit topology structure of a three-port boost DC/DC converter based on differential connection includes a power supply unit (1), a first boost unit (2), a second boost unit (3), and a third boost unit (4);
the two ends of the first boosting unit (2) are respectively connected with the positive electrode and the negative electrode of the power supply unit (1), the two ends of the second boosting unit are respectively reversely connected with the positive electrode and the negative electrode of the power supply unit (1), the two ends of the third boosting unit are respectively reversely connected with the positive electrode and the negative electrode of the power supply unit (1), and the negative output end of the first boosting unit and the positive output end of the second boosting unit are connected through a load R1The negative output end of the first boosting unit is connected with the positive output end of the third boosting unit through a load R2And the positive output port of the first boosting unit, the negative output port of the second boosting unit and the negative output port of the third boosting unit are connected in a suspended mode.
In a further embodiment, as shown in fig. 2, the power supply unit 1 comprises a battery Vin。
In a further embodiment, as shown in fig. 3, the first booster unit 2 comprises an inductor L1An active switch S1Two capacitors C1、C2And two diodes D1、D2. The inductance L1Negative pole and the switch tube S1Is connected in series with the power supply unit 1 after being connected, and has an inductance L1Is connected with the positive pole of the power supply unit 1, and a switching tube S1Is connected to the negative pole of the power supply unit 1, the capacitor C1Positive electrode and inductor L1And a switching tube S1Is connected to the connection point of the diode D1Anode and capacitor C1Diode D1Cathode and switching tube S1The source of the diode D is connected2Cathode and diode D1Anode connection of (2), diode D2And the capacitor C2Is connected to the negative pole of the capacitor C2Anode and diode D1Is connected to the cathode.
In a further embodiment, as shown in fig. 4, the second booster unit 3 comprises an inductor L2An active switch S2Two capacitors C3、C4And two diodes D3、D4. The inductance L2Positive pole and the switch tube S2Is connected with the power supply unit 1 in series after being connected with the source electrode, and has an inductor L2Is connected to the negative pole of the power supply unit 1, and a switching tube S2Is connected to the positive pole of the power supply unit 1, the capacitor C3Negative electrode of (1) and inductor L2And a switching tube S2Is connected to the connection point of the diode D3Cathode and capacitor C3Anode connection of diode D3Anode and switch tube S2Is connected to the drain of the diode D4Anode of (2) and diode D3Cathode connection of (2), diode D4And the capacitor C4The positive pole of the capacitor C is connected4Cathode of and diode D3Is connected to the cathode.
In a further embodiment, as shown in fig. 5, the third boost unit 4 comprises an inductor L3An active switch S3Two capacitors C5、C6And two diodes D5、D6And the structure of the third boosting unit is the same as that of the second boosting unit. The inductance L3Positive pole and the switch tube S3Is connected with the power supply unit 1 in series after being connected with the source electrode, and has an inductor L3Is connected to the negative pole of the power supply unit 1, and a switching tube S3Is connected to the positive pole of the power supply unit 1, the capacitor C5Negative electrode of (2) and inductor L3And a switching tube S3Is connected to the connection point of the diode D5Of a cathodeAnd a capacitor C5Anode connection of diode D5Anode and switch tube S3Of the diode D, the diode D6Anode of (2) and diode D5Cathode connection of (2), diode D6And the capacitor C6The positive pole of the capacitor C is connected6Cathode and diode D5Is connected to the cathode.
In a further embodiment, as shown in fig. 6, the load R1One end is set to be A, the other end is set to be B, wherein the A end and a capacitor C in the first boosting unit 22Is connected with the negative pole of the second booster unit 3, and the end B is connected with the capacitor C in the second booster unit 34Is connected to the positive electrode.
In a further embodiment, as shown in fig. 7, the load R2One end is set to be A, the other end is set to be C, the A end and the capacitor C in the first boosting unit 22Is connected to the negative terminal of the second booster unit 3, and the terminal C is connected to the capacitor C in the second booster unit 36The A, B, C ports are three ports of a three-port high-gain boost DC/DC converter based on differential connection.
In the invention, the working principle of the three-port high-gain boost DC/DC converter based on differential connection is as follows:
when the controllable switch S1When in on-state, the power supply VinTo the inductance L1Power supply, inductance L1Storing energy while a capacitor C1Capacitor C2Charging; when the controllable switch S1In the off state, the power supply VinAnd an inductance L1To the capacitor C1Discharging while the capacitor C2Maintaining a substantially constant output voltage and powering the load.
For the same reason, for the controllable switch S2When the controllable switch S2When in on state, the power supply VinTo the inductance L2Power supply, inductance L2Storing energy while a capacitor C3Capacitor C4Charging; when the controllable switch S2In the off state, the power supply VinAnd an inductance L2To the capacitor C3Discharging while the capacitor C4Maintaining a substantially constant output voltage and powering the load.
For the controllable switch S3When the controllable switch S3When in on-state, the power supply VinTo the inductance L3Power supply, inductance L3Storing energy while a capacitor C5Capacitor C6Charging; when the controllable switch S3In the off state, the power supply VinAnd an inductance L3To the capacitor C5Discharging while the capacitor C6Maintaining a substantially constant output voltage and powering the load.
In the working process, the first boosting unit can realize the input to the output capacitor C2The second boosting unit can realize the input to the output capacitor C4The third boosting unit can realize the input to the output capacitor C6And boosting the voltage at the two ends. According to kirchhoff's voltage law, load R1The voltage at both ends is a capacitor C2Capacitor C4And a power supply VinSo that the first boosting unit and the second boosting unit are connected together in a differential manner to realize a high boosting ratio of the converter. Similarly, load R2The voltage at both ends is a capacitor C2Capacitor C6And a power supply VinThe first boosting unit and the third boosting unit are connected together in a differential mode to realize the high boosting ratio of the converter.
A control method of a three-port high-gain boost DC/DC converter based on differential connection is disclosed, as shown in FIG. 9, the electrolytic capacitor C of a first boost unit 2 is detected by a voltage sampling circuit1Voltage V ofC1Voltage V of electrolytic capacitor of second booster unit 3C3Voltage V of electrolytic capacitor of third booster unit 4C5Load R1Voltage V ofo1Detecting the load R by a current sampling circuit1Current i ofo1Load R2Current i ofo2 First boost unit 2 inductor L1Current i ofL1And the second booster unit 3 inductor L2Current i ofL2And a third boost unit 4 inductor L3Current i ofL3；
And controlling according to the acquired data as follows: dividing a switching mode, establishing a prediction model, and selecting an optimal switching state on line;
the switch mode is divided into: as shown in FIG. 1, the positive directions of the voltage and the current at two ends of the circuit topological structure load R1 of the high-gain DC/DC converter based on the differential connection are taken as the B end relative to the A end, and the positive directions of the voltage and the current at two ends of the circuit topological structure load R2 of the high-gain DC/DC converter based on the differential connection are taken as the C end relative to the A end, the switching modes comprise 8 types, which are respectively A end0：S1Off, S2Off, S3Turning off; a. the1：S1Off, S2Off, S3Conducting; a. the2：S1Off, S2Conduction, S3Turning off; a. the3：S1Off, S2Conduction, S3Conducting; a. the4：S1Conduction, S2Off, S3Turning off; a. the5：S1Conduction, S2Off, S3Conducting; a. the6：S1Conduction, S2Conduction, S3Turning off; a. the7：S1Conduction, S2Conduction, S3Conducting;
the establishing process of the prediction model specifically comprises the following steps: the voltage of two ends of the inductor is calculated under different switch states, an equation of the inductor current can be obtained according to the relation between the current and the voltage of the two ends of the inductor, and the equation is discretized to obtain the predicted value of the inductor current under 8 switch states, as shown in formulas (1) to (8):
A0the predicted value of the inductive current in the mode is as follows:
Figure BDA0003616552080000061
A1the predicted value of the inductive current in the mode is as follows:
Figure BDA0003616552080000062
A2the predicted value of the inductive current in the mode is as follows:
Figure BDA0003616552080000071
A3the predicted value of the inductive current in the mode is as follows:
Figure BDA0003616552080000072
A4the predicted value of the inductive current in the mode is as follows:
Figure BDA0003616552080000073
A5the predicted value of the inductive current in the mode is as follows:
Figure BDA0003616552080000074
A6the predicted value of the inductive current in the mode is as follows:
Figure BDA0003616552080000075
A7the predicted value of the inductive current in the mode is as follows:
Figure BDA0003616552080000081
wherein, Vin(k)、VC1(k)、VC3(k)、VC5(k) A storage battery and a capacitor C at the time of k1Capacitor C3Capacitor C5Magnitude of voltage across, iL1(k)、iL2(k)、iL3(k) Respectively, the inductance L at the time k1、L2、L3Instantaneous value of the upper current, TsIs the sampling period of the system.
The online selection of the optimal switch state specifically comprises the following steps: and obtaining a predicted value of the inductive current according to the prediction model, calculating an objective function value corresponding to each switching mode, and selecting the switching mode corresponding to the lowest objective function value as the switching state at the next moment.
The inductance current is selected as a control variable, and a design objective function is shown as a formula (9).
Figure BDA0003616552080000082
Wherein i*The command value of the inductor current is shown.
As shown in FIG. 1, a circuit topological structure load R of a high-gain DC/DC converter based on differential connection is taken as a terminal B relative to a terminal A1Circuit topological structure load R of high-gain DC/DC converter based on differential connection for positive voltage and current directions at two ends and taking C end relative to A end2Positive direction of voltage and current at both ends, load R to be detected1Voltage V acrosso1Average value of and voltage command VrefComparing, obtaining the command value of the current of the storage battery by the obtained difference value through a PI algorithm, and subtracting the load R1Current of (i)o1And an upper load R2Current i ofo2Then, obtaining the instruction value i of the inductive current*。
The three DC/DC converter boosting units in the invention adopt a differential connection structure, multi-port output can be realized, and under the condition of only controlling the voltage of any one output end, the voltage of the other output end can approach to a reference voltage value at the same time, so that the use of a voltage sensor can be reduced. Meanwhile, the differentially connected three-port high-gain DC/DC converter and the control method thereof can realize the output of larger voltage and smaller input current ripple, and can realize high boost ratio without a magnetic coupling element or an isolating device. Moreover, the switching tube has only one state in each switching period, switching is not needed, the turn-on and turn-off times of the switching device are greatly reduced, the switching loss is reduced, meanwhile, partial power can be directly transmitted to the output port, active devices are not needed, and the efficiency of the system can be improved.
Example 1
A circuit topology structure of a three-port boosting DC/DC converter based on differential connection comprises a power supply unit 1, a first boosting unit 2, a second boosting unit 3 and a third boosting unit 4;
the power supply unit 1 includes a battery Vin。
The first booster unit 2 comprises an inductor L1An active switch S1Two capacitors C1、C2And two diodes D1、D2. The inductance L1Negative pole and the switch tube S1Is connected in series with the power supply unit 1 after being connected, and has an inductance L1Is connected with the positive pole of the power supply unit 1, and a switching tube S1Is connected to the negative pole of the power supply unit 1, the capacitor C1Positive electrode and inductor L1And a switching tube S1Is connected to the connection point of the diode D1Anode and capacitor C1Diode D1Cathode and switching tube S1The source of the diode D is connected2Cathode and diode D1Anode connection of (2), diode D2And the capacitor C2Is connected to the negative pole of the capacitor C2Anode and diode D1Is connected to the cathode.
The second booster unit 3 comprises an inductor L2An active switch S2Two capacitors C3、C4And two diodes D3、D4. The inductance L2Positive pole and the switch tube S2Is connected with the power supply unit 1 in series after being connected with the source electrode, and has an inductor L2Is connected to the negative pole of the power supply unit 1, and a switching tube S2Is connected to the positive pole of the power supply unit 1, the capacitor C3Negative electrode of (1) and inductor L2And a switching tube S2Is connected to the connection point of the diode D3Cathode and capacitor C3Anode connection of (2), diode D3Anode and switch tube S2Of the diode D, the diode D4Anode of (2) and diode D3Cathode connection of (2), diode D4And the capacitor C4The positive pole of the capacitor C is connected4Cathode and diode D3Is connected to the cathode.
The third boosting unit 4 comprises an inductor L3An active switch S3Two capacitors C5、C6And two diodes D5、D6And the structure of the third boosting unit is the same as that of the second boosting unit. The inductance L3Positive pole and the switch tube S3Connected with the power supply unit 1 in series, and an inductor L3Is connected to the negative pole of the power supply unit 1, and a switching tube S3Is connected to the positive pole of the power supply unit 1, the capacitor C5Negative electrode of (2) and inductor L3And a switching tube S3Is connected to the connection point of the diode D5Cathode and capacitor C5Anode connection of diode D5Anode and switch tube S3Of the diode D, the diode D6Anode of (2) and diode D5Cathode connection of (2), diode D6And the capacitor C6The positive pole of the capacitor C is connected6Cathode and diode D5Is connected to the cathode.
The load R1Negative pole and capacitor C in first booster unit 22Negative pole connection of (1), load R1Capacitor C in the anode and the second booster unit 34Is connected to the positive electrode.
The load R2Negative electrode and capacitor C in second booster unit 32Negative pole connection of (1), load R2Capacitor C in the anode and third booster unit 56Is connected to the positive electrode.
Taking the voltage V of the accumulatorin40V, inductance L1＝L2＝L35mH, electrolytic capacitor C1＝C2＝C3＝C4＝C5＝C6980uF, voltage reference Vref200V, sampling frequency fs40kHZ, load R1＝R2200 Ω, the load rated power is 400W until t is 0.4s, and the load R is 0.4s1、R2All become 100 Ω, the rated power is switched to 800W, and when t is 0.7s, the load R becomes1、R2Becomes 200 Ω and its rated power is switched to 400W. As shown in FIG. 10, before and after switching the load, the load R1Voltage V ono1And a load R2Voltage V ono2Waveform all can converge to the reference voltage VrefThe purpose of controlling the voltages of the two output ports can be realized only by a single voltage sensor, and meanwhile, the current ripple of the input storage battery is 1A, and the inductance L of the first boosting unit is shown1Current i ofL1And an inductor L of the second boosting unit2Current i ofL2And the inductance L of the third boosting unit3Current i ofL3The waveforms are almost identical.

Claims (9)

1. A three-port high-gain boost DC/DC converter based on differential connection is characterized by comprising a power supply unit (1), a first boost unit (2), a second boost unit (3) and a third boost unit (4);
the two ends of the first boosting unit (2) are respectively connected with the positive electrode and the negative electrode of the power supply unit (1), the two ends of the second boosting unit are respectively reversely connected with the positive electrode and the negative electrode of the power supply unit (1), the two ends of the third boosting unit are respectively reversely connected with the positive electrode and the negative electrode of the power supply unit (1), and the negative output end of the first boosting unit and the positive output end of the second boosting unit are connected through a load R1The negative output end of the first boosting unit is connected with the positive output end of the third boosting unit through a load R2And the positive output port of the first boosting unit, the negative output port of the second boosting unit and the negative output port of the third boosting unit are connected in a suspended mode.
2. The differential connection-based three-port high-gain of claim 1Step-up DC/DC converter, characterized in that the power supply unit (1) comprises a battery Vin。
3. Three-port high-gain boost DC/DC converter based on differential connection according to claim 1, characterized in that the first boost unit (2) comprises an inductance L1Active switch S1Two capacitors C1、C2And two diodes D1、D2Said inductance L1Negative pole and the switch tube S1The drain of the inductor L is connected with1Is connected with the positive pole of the power supply unit (1), the switch tube S1Is connected to the negative pole of the power supply unit (1), the capacitor C1Positive electrode and inductor L1And a switching tube S1Is connected to the connection point of the diode D1Anode and capacitor C1Diode D1Cathode and switching tube S1The source of the diode D is connected2Cathode and diode D1Anode connection of (2), diode D2And the capacitor C2Is connected to the negative pole of the capacitor C2Anode and diode D1Is connected to the cathode.
4. Three-port high-gain boost DC/DC converter based on differential connection according to claim 1, characterized in that said second boost unit (3) comprises an inductor L2An active switch S2Two capacitors C3、C4And two diodes D3、D4Said inductance L2Positive pole and the switch tube S2The source of the inductor L2Is connected with the negative pole of the power supply unit (1), and a switching tube S2Is connected with the positive pole of the power supply unit (1), and the capacitor C3Negative electrode of (1) and inductor L2And a switching tube S2Is connected to the connection point of the diode D3Cathode and capacitor C3The anode of the diode D3Anode and switch tube S2Drain electrode of, the diodePipe D4Anode of (2) and diode D3Cathode connection of (2), diode D4And the capacitor C4The positive pole of the capacitor C is connected4Cathode and diode D3Is connected to the cathode.
5. The three-port high-gain boost DC/DC converter based on differential connection according to claim 1, characterized in that the structure of the third boost unit (4) is identical to the second boost unit (3).
6. A control method of a three-port high-gain boost DC/DC converter based on differential connection, which is used for controlling the three-port high-gain boost DC/DC converter based on differential connection according to any claim 1 to 5, and comprises the following steps: dividing a switching mode, establishing a prediction model, and selecting an optimal switching state on line;
the divided switching modes are specifically: the switch modes comprise 8 types, namely A0：S1Off, S2Off, S3Turning off; a. the1：S1Off, S2Off, S3Conducting; a. the2：S1Off, S2Conduction, S3Turning off; a. the3：S1Off, S2Conduction, S3Conducting; a. the4：S1Conduction, S2Off, S3Turning off; a. the5：S1Conduction, S2Off, S3Conducting; a. the6：S1Conduction, S2Conduction, S3Turning off; a. the7：S1Conduction, S2Conduction, S3Conducting;
the process of establishing the prediction model specifically comprises the following steps: calculating the voltage at two ends of the inductor in different switching states, obtaining an equation of the inductor current according to the relation between the current and the voltage at the two ends of the inductor, and discretizing the equation to obtain the predicted value of the inductor current in 8 switching states;
the specific process of selecting the optimal switch state on line comprises the following steps: and obtaining a predicted value of the inductive current according to the prediction model, calculating an objective function value corresponding to each switching mode, and selecting the switching mode corresponding to the lowest objective function value as the switching state at the next moment.
7. The method of claim 6, wherein the predicted value of the inductor current in each switching mode is as shown in equations (1) to (8):
A0the predicted value of the inductive current in the mode is as follows:
Figure FDA0003616552070000021
A1the predicted value of the inductive current in the mode is as follows:
Figure FDA0003616552070000022
A2the predicted value of the inductive current in the mode is as follows:
Figure FDA0003616552070000031
A3the predicted value of the inductive current in the mode is as follows:
Figure FDA0003616552070000032
A4the predicted value of the inductive current in the mode is as follows:
Figure FDA0003616552070000033
A5the predicted value of the inductive current in the mode is as follows:
Figure FDA0003616552070000034
A6the predicted value of the inductive current in the mode is as follows:
Figure FDA0003616552070000035
A7the predicted value of the inductive current in the mode is as follows:
Figure FDA0003616552070000041
wherein, Vin(k)、VC1(k)、VC3(k)、VC5(k) Respectively a storage battery and a capacitor C at the time of k1Capacitor C3Capacitor C5Magnitude of voltage across, iL1(k)、iL2(k)、iL3(k) Respectively, the inductance L at the time k1、L2、L3Instantaneous value of the upper current, TsIs the sampling period of the system.
8. The method of claim 7, wherein the objective function design rule is: selecting the inductive current as a control variable, wherein the target function formula is as follows:
Figure FDA0003616552070000042
wherein i*The command value of the inductor current is shown.
9. The method of claim 8, wherein the command is based on a control of a three-port high-gain boost DC/DC converterValue i*The determination method comprises the following steps: to load R1Voltage V acrosso1Average value of and voltage command VrefMaking a difference, obtaining the command value of the current of the storage battery by the obtained difference value through a PI algorithm, and subtracting the load R1Current i ofo1And a load R2Current of (i)o2Then obtaining the instruction value i of the inductive current*。
CN202210445365.XA 2022-04-26 2022-04-26 Three-port high-gain boost DC/DC converter based on differential connection and control method thereof Pending CN114696616A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116155102A (en) * 2023-04-20 2023-05-23 深圳市恒运昌真空技术有限公司 High-gain converter

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116155102A (en) * 2023-04-20 2023-05-23 深圳市恒运昌真空技术有限公司 High-gain converter

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