CN109856565B - Power loop test circuit of non-isolated DC/DC converter and control method - Google Patents
Power loop test circuit of non-isolated DC/DC converter and control method Download PDFInfo
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- CN109856565B CN109856565B CN201811612178.6A CN201811612178A CN109856565B CN 109856565 B CN109856565 B CN 109856565B CN 201811612178 A CN201811612178 A CN 201811612178A CN 109856565 B CN109856565 B CN 109856565B
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Abstract
The invention provides a power loop test circuit of a non-isolated DC/DC converter and a control method, belonging to the technical field of power electronic converters. An auxiliary circuit is arranged on a non-isolated DC/DC converter circuit to be tested, and the auxiliary circuit comprises two parts: one part is a lead wire which is used for connecting the output positive electrode and the input positive electrode of the conversion circuit and is called as an auxiliary circuit; the other part is a half-bridge circuit formed by connecting an IGBT (Insulated Gate Bipolar Transistor) switching tube and a diode in series. The auxiliary circuit and the tested DC/DC converter are placed under the same heat dissipation condition to jointly form a test circuit. The invention adopts a bidirectional direct-current power supply or energy storage scheme, greatly saves the cost of an experimental device, avoids energy waste, and can embody great cost advantage in converter test projects with high current level and power level.
Description
Technical Field
The invention belongs to the technical field of power electronic converters, and particularly relates to a full-load power operation test circuit and a control method of three types of non-isolated direct current-direct current (DC/DC) converters.
Background
With the increasing application of distributed new energy, the direct current system is more and more emphasized. DC/DC converters have been developed for use as DC power conversion devices. DC/DC converters are devices that convert one form of DC voltage to another form of DC voltage. Various types of non-isolated DC/DC converters are adopted in equipment such as photovoltaic equipment, energy storage equipment, direct current load equipment and the like according to the requirements of use occasions.
In the development process of the power electronic converters, an important test item is a full-power operation test of the converters, and indexes such as control performance, temperature rise, efficiency and reliability of the converters are examined through the test. In general, in the test, a direct current power supply and a direct current load which accord with the power grade of the DC/DC converter are adopted, and the converter is connected into the direct current power supply and the direct current load to carry out full-load or overload operation. Therefore, the cost of the test device is high, and the electric energy generated in the test process is not reasonably recovered; some test systems adopt a bidirectional direct-current power supply feed network or a direct-current energy storage device, but the cost of the test device is increased.
Disclosure of Invention
The invention provides a power loop test circuit of a non-isolated DC/DC converter and a control method thereof on the basis of three types of non-isolated DC/DC converter topologies, namely a Buck conversion circuit Buck, a Boost conversion circuit Boost and a Buck-Boost amplifier non-inverting Buck-Boost, aiming at the problems of higher device cost and electric energy waste in a full-power operation test system. The invention is based on the topological thought of two degrees of freedom, namely, the degree of freedom of energy control is increased on the basis of the original DC/DC converter by utilizing the connection relation of an auxiliary circuit, thereby forming a power loop test circuit with two degrees of freedom and a control method. The test circuit topology can be applied to direct current circuits of various voltage and power levels, and can also be expanded to other applications with similar circuits.
The invention relates to a power loop test circuit of a non-isolated DC/DC converter, wherein an auxiliary circuit is arranged on the circuit of the non-isolated DC/DC converter to be tested, and the auxiliary circuit comprises two parts: one part is a lead wire which is used for connecting the output positive electrode and the input positive electrode of the conversion circuit and is called as an auxiliary circuit; the other part is a half-bridge circuit formed by connecting an IGBT (Insulated Gate Bipolar Transistor) switching tube and a diode in series. The auxiliary circuit and the tested DC/DC converter are placed under the same heat dissipation condition to jointly form a test circuit.
The specifications of the IGBT switching tube and the diode in the half-bridge circuit are the same as those of the IGBT switching tube and the diode in the DC/DC converter circuit to be tested.
When the tested non-isolated DC/DC converter circuit is a Buck circuit, the half-bridge circuit is arranged in the following mode: the middle point of a bridge arm of the half-bridge circuit is connected with the output end of an inductor of the Buck circuit, and two ends of the bridge arm are respectively connected with the positive electrode and the negative electrode of the output capacitor in parallel. An auxiliary line is arranged in the Buck circuit.
When the tested non-isolated DC/DC converter circuit is a Boost circuit, the half-bridge circuit is arranged in the following mode: the middle point of a bridge arm of the half-bridge circuit is connected with the input end of an inductor in the Boost circuit, and two ends of the bridge arm of the half-bridge circuit are respectively connected with the positive electrode and the negative electrode of the input capacitor in parallel. And an auxiliary line is arranged in the Boost circuit.
When the tested non-isolated DC/DC converter circuit is a non-inverting buck-boost circuit, a half-bridge circuit is not arranged in the circuit, and only an auxiliary circuit is arranged.
Correspondingly, the control method of the power loop test circuit of the non-isolated DC/DC converter provided by the invention comprises the following steps: the tested non-isolated DC/DC converter circuit comprises two switching tubes T after an auxiliary circuit is arranged1And T2Wherein the switch tube T1An input end of an inductor L connected in the circuit, a switching tube T1An output terminal of an inductor L connected in the circuit, a switching tube T1Switching tube T according to a set fixed duty cycle2Performing closed-loop control on the current in the inductor L; during closed-loop regulation, the switching tube T2The driving pulse firstly adjusts the current value of the inductor L to a set instruction value, and after the current value of the inductor L enters a stable state, the switch tube T is switched on and off2Driving pulse and switching tube T1Are in a complementary relationship.
Compared with the prior art, the invention has the following obvious advantages:
the auxiliary circuit added in the invention is a power electronic device and a connecting wire which have the same specification as the converter to be tested, compared with the existing scheme of adopting a bidirectional direct-current power supply or storing energy, the cost of an experimental device is greatly saved, and meanwhile, the energy waste is avoided.
Drawings
FIG. 1 is a schematic diagram of a power loop test circuit formed by adding an auxiliary circuit to a Buck circuit of the present invention;
FIG. 2 is a schematic diagram of a power loop test circuit formed by adding an auxiliary circuit to the Boost circuit of the present invention;
FIG. 3 is a schematic diagram of a power loop test circuit formed by adding an auxiliary circuit to the non-inverting buck-boost circuit of the present invention;
FIG. 4 is a diagram showing the control results of the Buck circuit, the Boost circuit and the boosting Buck-Boost circuit according to the present invention.
Detailed Description
To facilitate understanding and practice of the invention by those of ordinary skill in the art, the invention is described in further detail below with reference to the accompanying drawings.
The invention relates to a test circuit and a control method which can enable a DC/DC converter to operate according to the designed power under the condition of only needing a unidirectional direct current source with smaller power, thereby examining the performance of the converter under the power. An auxiliary circuit is added (or not added) on the basis of three types of non-isolated DC/DC converter topologies, and then the auxiliary circuit and a direct current source form a power loop togetherAnd (6) testing the circuit. In addition to the converter device to be tested, an auxiliary circuit (T) consisting of an active switching tube and a diode is added to the circuit1、D1Or T2、D2) And an auxiliary line, wherein the line on which the current Io is positioned is the auxiliary line. The invention merges the consumed power which is originally output to the direct current load into the input end again according to the voltage requirement of the input side, namely, the current Io feeds back the input power to the input side, thus the set power is operated in the converter body and the auxiliary circuit, and the output power of the direct current source of the input side is only the loss power.
The invention relates to a power loop test circuit of a non-isolated DC/DC converter, which aims at three types of non-isolated DC/DC converters, namely a Buck conversion circuit Buck circuit, a Boost conversion circuit Boost circuit and a non-inverting Buck-Boost circuit of a same-phase Boost/Buck conversion circuit. The auxiliary circuit implementation comprises two parts, namely, a lead for connecting the output anode and the input anode of the conversion circuit is added, namely an auxiliary circuit; and the other is to arrange a half-bridge circuit formed by connecting an IGBT switching tube and a diode in series. The auxiliary circuit and the tested DC/DC converter are placed under the same heat dissipation condition to jointly form a test circuit.
Three types of non-isolated DC/DC converters are described below with reference to the drawings and the embodiments.
For the Buck circuit, a half-bridge circuit formed by connecting an IGBT (insulated gate bipolar transistor) and a diode in series is added at the output end of the Buck circuit, the specifications of the added IGBT and the added diode are respectively the same as those of the IGBT and the diode in the Buck circuit, the middle point of a bridge arm of the half-bridge circuit is connected with the output end of an inductor of the Buck circuit, two ends of the bridge arm are respectively connected with the positive electrode and the negative electrode of an output capacitor in parallel, and in addition, the positive electrode of the output capacitor is connected with the positive electrode of an input capacitor through a lead wire to form a circuit where. The added auxiliary circuit and the tested Buck converter are in the same heat dissipation condition. The line on which the current Io is located is the auxiliary line.
As shown in FIG. 1, a power loop test circuit formed by adding an auxiliary circuit to a Buck circuit is provided. Wherein, Bat is a direct current power supply required by the test, and can also be obtained by rectifying an alternating current power supply, and the output voltage value of the direct current power supply is adjusted to be equal to the voltage value of a direct current bus. Buck circuit is composed of DC capacitor C1Switch tube T1Diode D1A DC inductor L and a DC capacitor C2And (4) forming. On the basis, a switching tube T is connected2And a diode D2A half-bridge circuit formed by series connection and an output capacitor C2The anode passes through the lead and the input capacitor C1The positive electrodes are connected by a lead to form a circuit where the current Io is located, and the circuit together form a power loop circuit required by testing. In FIG. 1, a switch tube T2And a diode D2One end of the switch tube is connected with the output end of the inductor L, and the switch tube T2The other end of the capacitor C is connected with a capacitor C2Negative electrode of (2), diode D2The other end of the capacitor C is connected with a capacitor C2The positive electrode of (1).
The line on which the current Io is located is a capacitor C1Positive electrode and output capacitor C2The positive connecting wire is the connecting wire of the output positive electrode and the input positive electrode of the conversion circuit. DC capacitor C1Is an input capacitor, a DC capacitor C2Is the output capacitance.
Switch tube T1And T2There is a difference in the drawing that the added switch tube is actually the same as the switch tube already present in the circuit or T2The switch tube is an anti-parallel diode with the same specification.
For the Boost circuit, a half-bridge circuit with an IGBT switching tube and a diode connected in series is added at the input end of the Boost circuit, the middle point of a bridge arm of the half-bridge circuit is connected with the input end of an inductor of the Boost circuit, and two ends of the bridge arm of the half-bridge circuit are respectively connected with an input capacitor C1The positive and negative electrodes of the anode and the cathode are connected in parallel. Will output the capacitance C2Positive electrode of and input capacitor C1The positive electrodes of the two electrodes are connected by a lead wire to form a circuit where the current Io is located. The added auxiliary circuit and the tested Boost converter are in the same heat dissipation condition. The specifications of the added IGBT switch tube and the added diode are respectively the same as those of the IGBT switch tube and the added diode in the Boost circuit.
Fig. 2 shows a power loop test circuit formed by adding an auxiliary circuit to a certain Boost circuit. Bat is testAnd (6) testing the required direct current power supply. Unlike Buck circuit, Boost circuit is composed of DC capacitor C1Switch tube T2Diode D2A DC inductor L and a DC capacitor C2And (4) forming. On the basis, a switching tube T is connected1And a diode D1Forming a half-bridge circuit while providing an output capacitor C2The anode passes through the lead and the input capacitor C1The positive electrodes are connected to form a power loop circuit required by the test. In FIG. 2, the switch tube T1And diode D1One end of the switch tube is connected with the input end of the inductor L, and the switch tube T1The other end of the first capacitor is connected with an input capacitor C1Anode of (2), diode D1The other end of the first capacitor is connected with an input capacitor C1The negative electrode of (1).
For the non-inverting buck-boost circuit, the auxiliary circuit is to output the capacitor C2Positive electrode of and input capacitor C1The positive electrodes of the two electrodes are connected by a lead wire to form a circuit where the current Io is located.
As shown in fig. 3, the power loop test circuit is formed by adding an auxiliary circuit to a certain non-inverting buck-boost circuit. The output of the boosting Buck-Boost circuit is a form obtained by combining a Buck circuit and a Boost circuit, and in fig. 3, Bat is a direct current power supply required by the test. The chopping-boost circuit comprises a DC capacitor C1Switch tube T1Diode D1Switch tube T2Diode D2A DC inductor L and a DC capacitor C2. The power loop experiment circuit only needs to input a capacitor C1Positive electrode and output capacitor C2The positive electrode is connected through a lead. The non-inverting buck-boost circuit does not require an additional half-bridge circuit.
The invention relates to a power loop experiment control method of a test circuit for three types of non-isolated DC/DC converters, which combines open-loop control and closed-loop control to realize different power levels transmitted in the converter. And under the output voltage level set by the direct current source, the control of the set power of the DC/DC converter is realized by the open-loop control of one IGBT switching tube and the closed-loop control of the inductive current in the DC/DC converter. The power loop test control method is the same for the three types of non-isolated DC/DC converters.
The control method for realizing the power loop test of the non-isolated DC/DC converter comprises the following steps: switch tube T1Switching tube T according to a fixed duty cycle2The current in the inductor L is closed-loop controlled, and the switching tube T is closed-loop regulated2The driving pulse firstly adjusts the inductance current value to a set instruction value, and then is connected with the switching tube T after entering a steady state1Are in complementary relationship, as are the first and second channels of fig. 4. The third channel shown in fig. 4 is the output voltage of the converter, which is the set value of the input voltage since the output is connected in parallel with the input in the test circuit. The fourth channel shown in fig. 4 is the output current whose magnitude reaches the command value. The fifth channel shown in fig. 4 is the actual value of the inductor current, the average of which is the command value. The sixth and seventh channels shown in FIG. 4 are switching tubes T1And a switching tube T2The voltage and the current of the transformer can be seen to reach the power level required by the test. It can be seen that the power loop test circuit provided by the invention meets the power level requirements of a Buck circuit, a Boost circuit and a boosting Buck-Boost circuit.
In addition, in the power loop test circuit designed by the invention, the added auxiliary circuit can also use the tested converter with the same specification, and only needs to be connected with the tested converter according to the corresponding connection relation, and the two are mutually test objects and simultaneously carry out test examination, thereby further reducing the test cost of the test and improving the test efficiency.
The above description is only for the preferred embodiment of the present invention and not intended to limit the present invention, and any changes or substitutions that can be easily conceived by one skilled in the art within the technical scope of the present invention are included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (6)
1. A power loop test circuit of a non-isolated DC/DC converter is characterized in that an auxiliary circuit is arranged on the tested non-isolated DC/DC converter circuit, and the auxiliary circuit comprises two parts:
one part is a lead wire connecting the output positive electrode and the input positive electrode of the converter circuit, and the lead wire is called an auxiliary line;
the other part is a half-bridge circuit formed by connecting an IGBT switching tube and a diode in series;
the auxiliary circuit and the DC/DC converter to be tested are placed under the same heat dissipation condition to jointly form a test circuit;
wherein DC/DC represents DC-DC, and IGBT represents insulated gate bipolar transistor;
the tested non-isolated DC/DC converter circuit comprises two switching tubes T after an auxiliary circuit is arranged1And T2Wherein the switch tube T1An input end of an inductor L connected in the circuit, a switching tube T2An output terminal of an inductor L connected in the circuit, a switching tube T1Switching tube T according to a set fixed duty cycle2Performing closed-loop control on the current in the inductor L; during closed-loop regulation, the switching tube T2The driving pulse firstly adjusts the current value of the inductor L to a set instruction value, and after the current value of the inductor L enters a stable state, the switch tube T is switched on and off2Driving pulse and switching tube T1Are in a complementary relationship.
2. The circuit of claim 1 wherein the IGBT switches and diodes in the half bridge circuit are of the same size as the IGBT switches and diodes in the DC/DC converter circuit being tested.
3. The circuit of claim 1 or 2, wherein when the non-isolated DC/DC converter circuit under test is a Buck circuit, the half-bridge circuit is arranged in a manner that: the middle point of a bridge arm of the half-bridge circuit is connected with the output end of an inductor of the Buck circuit, and two ends of the bridge arm are respectively connected with the positive electrode and the negative electrode of the output capacitor in parallel.
4. The circuit according to claim 1 or 2, wherein when the non-isolated DC/DC converter circuit to be tested is a Boost circuit, the half-bridge circuit is arranged in a manner that: the middle point of a bridge arm of the half-bridge circuit is connected with the input end of an inductor in the Boost circuit, and two ends of the bridge arm of the half-bridge circuit are respectively connected with the positive electrode and the negative electrode of the input capacitor in parallel.
5. The circuit of claim 1, wherein when the non-isolated DC/DC converter circuit to be tested is a non-inverting buck-boost circuit, no half-bridge circuit is provided in the circuit, and only auxiliary lines are provided.
6. A control method based on the circuit of claim 1, characterized in that the tested non-isolated DC/DC converter circuit comprises two switching tubes T after an auxiliary circuit is arranged1And T2Wherein the switch tube T1An input end of an inductor L connected in the circuit, a switching tube T2An output terminal of an inductor L connected in the circuit, a switching tube T1Switching tube T according to a set fixed duty cycle2Performing closed-loop control on the current in the inductor L; during closed-loop regulation, the switching tube T2The driving pulse firstly adjusts the current value of the inductor L to a set instruction value, and after the current value of the inductor L enters a stable state, the switch tube T is switched on and off2Driving pulse and switching tube T1Are in a complementary relationship.
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| CN201811612178.6A CN109856565B (en) | 2018-12-27 | 2018-12-27 | Power loop test circuit of non-isolated DC/DC converter and control method |
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| CN109856565B true CN109856565B (en) | 2021-04-27 |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101753006A (en) * | 2008-12-01 | 2010-06-23 | 香港理工大学 | Phase lead compensation network, power supply converter and closed-loop control system |
| CN103973105A (en) * | 2013-12-10 | 2014-08-06 | 国家电网公司 | Method for controlling high-dynamic properties of high-power bidirectional DC/DC converters |
| WO2015101164A1 (en) * | 2014-01-03 | 2015-07-09 | 国家电网公司 | Single-phase inverter test circuit for modular multi-level convertor and test method therefor |
| CN105480098A (en) * | 2016-01-19 | 2016-04-13 | 重庆邮电大学 | Braking energy recovery system for electric vehicle |
| CN205643659U (en) * | 2016-05-25 | 2016-10-12 | 哈尔滨工业大学 | Multi -functional DC electronic load with current mode plans unit integrated ization |
| CN205753988U (en) * | 2016-06-15 | 2016-11-30 | 晶傲威电气（常州）有限公司 | A kind of power-converting device being applied to High-Speed Flywheel Energy Storage System |
| CN107786099A (en) * | 2017-11-24 | 2018-03-09 | 清华大学 | A kind of highly reliable commutator transformer system of segmentation more and its control method |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7863877B2 (en) * | 2006-12-11 | 2011-01-04 | International Rectifier Corporation | Monolithically integrated III-nitride power converter |
| US9209793B2 (en) * | 2012-02-17 | 2015-12-08 | Infineon Technologies Austria Ag | Bootstrap circuitry for an IGBT |
| US9509261B2 (en) * | 2013-12-02 | 2016-11-29 | Crestron Electronics Inc. | Reduced crosstalk and matched output power audio amplifier |
-
2018
- 2018-12-27 CN CN201811612178.6A patent/CN109856565B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101753006A (en) * | 2008-12-01 | 2010-06-23 | 香港理工大学 | Phase lead compensation network, power supply converter and closed-loop control system |
| CN103973105A (en) * | 2013-12-10 | 2014-08-06 | 国家电网公司 | Method for controlling high-dynamic properties of high-power bidirectional DC/DC converters |
| WO2015101164A1 (en) * | 2014-01-03 | 2015-07-09 | 国家电网公司 | Single-phase inverter test circuit for modular multi-level convertor and test method therefor |
| CN105480098A (en) * | 2016-01-19 | 2016-04-13 | 重庆邮电大学 | Braking energy recovery system for electric vehicle |
| CN205643659U (en) * | 2016-05-25 | 2016-10-12 | 哈尔滨工业大学 | Multi -functional DC electronic load with current mode plans unit integrated ization |
| CN205753988U (en) * | 2016-06-15 | 2016-11-30 | 晶傲威电气（常州）有限公司 | A kind of power-converting device being applied to High-Speed Flywheel Energy Storage System |
| CN107786099A (en) * | 2017-11-24 | 2018-03-09 | 清华大学 | A kind of highly reliable commutator transformer system of segmentation more and its control method |
Non-Patent Citations (1)
| Title |
|---|
| 非隔离升降压式变换器研究;施金菊;《万方学位论文》;20110525;第4,22-24页 * |
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