CN111082646A - Current ripple eliminating circuit and power converter using same - Google Patents

Current ripple eliminating circuit and power converter using same Download PDF

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Publication number
CN111082646A
CN111082646A CN201911352351.8A CN201911352351A CN111082646A CN 111082646 A CN111082646 A CN 111082646A CN 201911352351 A CN201911352351 A CN 201911352351A CN 111082646 A CN111082646 A CN 111082646A
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transformer
current
power converter
current ripple
cancellation circuit
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李鹏
王志燊
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Mornsun Guangzhou Science and Technology Ltd
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Mornsun Guangzhou Science and Technology Ltd
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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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/14—Arrangements for reducing ripples from dc input or output
    • 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
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
    • H02M3/33523—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters with galvanic isolation between input and output of both the power stage and the feedback loop
    • 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
    • H02M1/0048—Circuits or arrangements for reducing losses
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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

Abstract

The invention discloses a current ripple eliminating circuit and a power converter using the same, wherein the current ripple eliminating circuit comprises an energy storage inductor, an auxiliary inductor, a transformer, a capacitor, a current input end and a current output end; the current input end is connected with one end of the primary winding of the transformer, and the other end of the primary winding of the transformer is connected with the current output end; the current input end is also connected with one end of an auxiliary inductor, the other end of the auxiliary inductor is connected with one end of a secondary winding of the transformer, the other end of the secondary winding of the transformer is connected with one end of a capacitor, and the other end of the capacitor is grounded; the energy storage inductor is connected with the primary winding of the transformer in parallel. The current ripple eliminating circuit can transfer current ripples generated by the converter, so that the current ripples in the power line are zero, and meanwhile, the auxiliary inductor can be integrated in the magnetic piece of the transformer, so that the power density of the power module is further improved.

Description

Current ripple eliminating circuit and power converter using same
Technical Field
The invention relates to the field of power converters, in particular to improvement of power converter ripples.
Background
With the progress of science and technology, the switching power supply develops towards the directions of high frequency, high efficiency and high power density, replaces the traditional low-efficiency and huge linear power supply, and has increasingly wide application in the aspects of medical institutions, aerospace, scientific research and the like. The switching power supply generally controls the on and off of electronic switching devices (such as transistors, field effect transistors, thyristor, etc.) through Pulse Width Modulation (PWM), and further performs Pulse Modulation on the input dc voltage to realize voltage conversion.
When the DC-DC power converter works, because the internal switching device is continuously turned on and off, the current in the inductor fluctuates up and down at the input and output effective values to form ripple current, and the generation of the ripple current causes difficulties in input and output filtering, control problems, electromagnetic compatibility problems, and other problems. Low ripple power supplies are needed in signal processing, high performance imaging, instrumentation, and other ripple sensitive applications. In order to reduce the ripple current or voltage, the conventional idea is to use multiple stages or large-volume LC filters on the input and output sides of the circuit to reduce the ripple current or voltage to an acceptable level, which has the disadvantages: increasing circuit cost and reducing power density limits power supply applications.
Disclosure of Invention
Accordingly, the present invention is directed to a current ripple cancellation circuit, which is applied to a power converter to increase the power density of the power converter, and a power converter using the current ripple cancellation circuit.
The power supply module is characterized in that the auxiliary inductor, the transformer and the blocking capacitor are additionally arranged, current ripples generated by the converter are transferred, the current ripples in the power line are theoretically zero, and therefore voltage ripples generated by the power converter are ultra-low, and meanwhile the auxiliary inductor can be integrated in the magnetic piece of the transformer, and the power density of the power supply module is further improved.
Based on the above inventive concept, the technical solution of the current ripple cancellation circuit proposed in the present invention to solve the above technical problems is as follows:
a current ripple cancellation circuit, characterized by: the device comprises an energy storage inductor, an auxiliary inductor, a transformer, a capacitor, a current input end and a current output end;
the current input end is connected with one end of the primary winding of the transformer, and the other end of the primary winding of the transformer is connected with the current output end;
the current input end is also connected with one end of an auxiliary inductor, the other end of the auxiliary inductor is connected with one end of a secondary winding of the transformer, the other end of the secondary winding of the transformer is connected with one end of a capacitor, and the other end of the capacitor is grounded;
the energy storage inductor is connected with the primary winding of the transformer in parallel.
As one of the alternatives of the above technical solution, the method is characterized in that: the energy storage inductance is multiplexed by the primary winding of the transformer.
As a second alternative of the above technical solution, the method is characterized in that: part or all of the inductance required by the auxiliary inductor is provided by the leakage inductance of the secondary winding of the transformer.
Preferably, the auxiliary inductance is integrated in the transformer magnet.
Preferably, the relation between the inductance L2 of the auxiliary inductor and the inductance L1 of the primary winding of the transformer and the turn ratio N of the primary side and the secondary side of the transformer is
Figure BDA0002334928260000021
Preferably, the primary and secondary turns ratio N of the transformer is greater than 1.
Preferably, the value range of the turn ratio N of the primary side and the secondary side of the transformer is 1< N < 3.
Correspondingly, the power converter applying the current ripple cancellation circuit provided by the invention is characterized in that: the power converter also comprises a main power MOS (metal oxide semiconductor) transistor S1, a freewheeling diode D1 and an output filter capacitor Co;
the anode of an input power supply of the power converter is connected with the current input end of the current ripple eliminating circuit, the current output end of the current ripple eliminating circuit is simultaneously connected with the anode of a fly-wheel diode D1 and the drain of a main power MOS tube S1, and the cathode of a fly-wheel diode D1 is simultaneously connected with the anode of the output voltage of the power converter and one end of an output filter capacitor Co;
the negative electrode of an input power supply of the power converter, the source electrode of the main power MOS tube S1, the other end of the output filter capacitor Co and the negative electrode of the output voltage of the power converter are all grounded;
one end of the primary winding of the transformer and one end of the secondary winding of the transformer are the same-name ends.
Based on the above inventive concept, another technical solution of the current ripple cancellation circuit proposed in the present invention to solve the above technical problems is as follows:
a current ripple cancellation circuit, characterized by: the device comprises an energy storage inductor, an auxiliary inductor, a transformer, a capacitor, a current input end and a current output end;
the current input end is connected with one end of the primary winding of the transformer, and the other end of the primary winding of the transformer is connected with the current output end;
one end of the capacitor is grounded, the other end of the capacitor is connected with one end of the secondary winding of the transformer, the other end of the secondary winding of the transformer is connected with one end of the auxiliary inductor, and the other end of the auxiliary inductor is also connected with the current output end;
the energy storage inductor is connected with the primary winding of the transformer in parallel.
As one of the alternatives of the above technical solution, the method is characterized in that: the energy storage inductance is multiplexed by the primary winding of the transformer.
As a second alternative of the above technical solution, the method is characterized in that: part or all of the inductance required by the auxiliary inductance is provided by the leakage inductance of the secondary winding of the transformer.
Preferably, the auxiliary inductance is integrated in the transformer magnet.
Preferably, the relation between the inductance L2 of the auxiliary inductor and the inductance L1 of the primary winding of the transformer and the primary-secondary turn ratio N of the transformer is
Figure BDA0002334928260000031
Preferably, the primary and secondary turns ratio N of the transformer is greater than 1.
Preferably, the value range of the turn ratio N of the primary side and the secondary side of the transformer is 1< N < 3.
Correspondingly, the present invention provides one of the power converters applying the above another current ripple cancellation circuit technical solution, which is characterized in that: the power converter also comprises a main power MOS (metal oxide semiconductor) transistor S1, a boost inductor Lx, a freewheeling diode D1 and an output filter capacitor Co;
the positive electrode of an input power supply of the power converter is simultaneously connected with the drain electrode of a main power MOS tube S1 and the anode of a fly-wheel diode D1 after passing through a boost inductor Lx, the cathode of the fly-wheel diode D1 is connected with the current input end of a current ripple eliminating circuit, and the current output end of the current ripple eliminating circuit is simultaneously connected with the positive electrode of the output voltage of the power converter and one end of an output filter capacitor Co;
the negative electrode of an input power supply of the power converter, the source electrode of the main power MOS tube S1, the other end of the output filter capacitor Co and the negative electrode of the output voltage of the power converter are all grounded;
one end of the primary winding of the transformer and one end of the secondary winding of the transformer are the same-name ends.
Correspondingly, the second power converter applying the above another technical solution of the current ripple cancellation circuit according to the present invention is characterized in that: the power converter also comprises a main power MOS (metal oxide semiconductor) transistor S1, a freewheeling diode D1 and an output filter capacitor Co;
the positive electrode of an input power supply of the power converter is connected with the drain electrode of a main power MOS tube S1, the source electrode of the main power MOS tube S1 is simultaneously connected with the cathode of a freewheeling diode D1 and the current input end of a current ripple eliminating circuit, and the current output end of the current ripple eliminating circuit is simultaneously connected with the positive electrode of the output voltage of the power converter and one end of an output filter capacitor Co;
the negative electrode of the input power supply of the power converter, the anode of the freewheeling diode D1, the other end of the output filter capacitor Co and the negative electrode of the output voltage of the power converter are all grounded;
one end of the primary winding of the transformer and one end of the secondary winding of the transformer are the same-name ends.
The working principle of the invention is analyzed and explained in the embodiment, which is not described herein, and the invention has the following beneficial effects:
(1) the ripple current eliminating circuit eliminates current ripples generated by a converter through an additional auxiliary inductor, a transformer and a blocking capacitor, so that the current ripples are theoretically zero, and voltage ripples generated by a power converter are ultralow.
(2) Multiple magnetic devices may be integrated into the magnetic member to further increase power module power density.
Drawings
Fig. 1 is a structural diagram of a current ripple cancellation circuit according to a first embodiment of the present invention;
FIG. 2 is a circuit diagram of a power converter employing the embodiment of FIG. 1;
FIG. 3 is a circuit diagram of the magnetic integration of FIG. 2;
FIG. 4 is a key waveform diagram of the current ripple cancellation circuit of FIG. 2;
fig. 5 is a structural diagram of a current ripple cancellation circuit according to a second embodiment of the present invention;
FIG. 6 is a circuit diagram of a power converter employing the embodiment of FIG. 5;
FIG. 7 is a circuit diagram of another power converter to which the embodiment of FIG. 5 is applied;
FIG. 8 is a circuit diagram of the magnetic integration of FIG. 7;
FIG. 9 is a key waveform diagram of the current ripple cancellation circuit of FIG. 5;
in the drawings: vin + is the input voltage anode of the power converter, Vin-is the input voltage cathode of the power converter, L1 is the energy storage inductor, L2 is the auxiliary inductor, T is the transformer, Cb is the capacitor, S1 is the main power MOS tube, D1 is the freewheeling diode, Lx is the boost inductor, Co is the output filter capacitor, Vo + is the output voltage anode of the power converter, Vo-is the output voltage cathode of the power converter, and ". cndot" is the dotted terminal of the transformer T.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
First embodiment
Fig. 1 is a structural diagram of a current ripple cancellation circuit according to a first embodiment of the present invention, including an energy storage inductor L1, an auxiliary inductor L2, a transformer T, a capacitor Cb, a current input terminal a, and a current output terminal B; the current input end A is connected with one end of a primary winding of the transformer T, and the other end of the primary winding of the transformer T is connected with the current output end B; the current input end A is also connected with one end of an auxiliary inductor L2, the other end of the auxiliary inductor L2 is connected with one end of a transformer T secondary winding, the other end of the transformer T secondary winding is connected with one end of a capacitor Cb, and the other end of the capacitor Cb is grounded; the energy storage inductor L1 is connected in parallel with the primary winding of the transformer T.
Fig. 2 is a circuit diagram of a power converter to which the embodiment of fig. 1 is applied, the power converter further includes a main power MOS transistor S1, a freewheeling diode D1, and an output filter capacitor Co; the anode of an input power supply of the power converter is connected with the current input end of the current ripple eliminating circuit, the current output end of the current ripple eliminating circuit is simultaneously connected with the anode of a fly-wheel diode D1 and the drain of a main power MOS tube S1, and the cathode of a fly-wheel diode D1 is simultaneously connected with the anode of the output voltage of the power converter and one end of an output filter capacitor Co; the negative electrode of an input power supply of the power converter, the source electrode of the main power MOS tube S1, the other end of the output filter capacitor Co and the negative electrode of the output voltage of the power converter are all grounded; one end of the primary winding of the transformer and one end of the secondary winding of the transformer are the same-name ends.
Because the primary winding of the transformer has the energy storage function, the energy storage inductor can be reused by the primary winding of the transformer, namely the primary winding of the transformer is also used as the energy storage inductor, and the energy storage inductor L1 does not need to be designed separately in the figure 1; in addition, because the secondary winding of the transformer T has leakage inductance, the inductance of the leakage inductance can be used as part or all of the inductance of the auxiliary inductor, and when the inductance of the leakage inductance can be used as the whole inductance of the auxiliary inductor, the auxiliary inductor L2 does not need to be designed separately in FIG. 1. Therefore, both the energy storage inductor L1 and the auxiliary inductor L2 can be integrated into the magnetic element of the transformer T, and fig. 3 is a circuit diagram of fig. 2 after magnetic integration.
The operation principle of the current ripple cancellation circuit of the present embodiment is described below with reference to the circuit diagram of the power converter of fig. 2:
the current in the power supply line flows through the transformer T and the energy storage inductor L1, the transformer T induces the ripple current to the secondary side of the transformer T, so as to form a compensation current with a current change speed consistent with the ripple current change speed of the primary side of the transformer T but with an opposite phase, and the compensation current is injected to the power supply input side e point through the auxiliary inductor L2, so that the input current Iin is converted into the sum of two branch currents, that is, Iin is IL1+ IL 2. The amplitude of the IL2 current is consistent with the amplitude of the current ripple in IL1, but the phase of the IL2 current is opposite to the phase of the current ripple in IL1, so that the current ripple in Iin is cancelled, and the input side current ripple is zero. Fig. 4 shows the final waveform of the input power supply current Iin and the key waveforms of the related branches IL1 and IL2 in the circuit of the present embodiment.
Specifically, a loop formed by an input power supply, a capacitor Cb, a secondary side of the transformer T, and an auxiliary inductor L2 is obtained according to kirchhoff's voltage law: the voltage across the capacitor Cb is the power converter input voltage, and the voltage across the auxiliary inductor L2 is equal to the transformer T secondary voltage Vsec. The secondary voltage Vsec of the transformer T and the primary voltage Vpri of the transformer T are in a turn ratio relationship, that is, Vsec is equal to Vpri/N. When the ripple current flows through the transformer T, since the primary winding inductance L1 of the transformer T forms a large inductive reactance, most of the ac component in the power line is blocked, and only most of the dc component passes through, so that most of the ac component in the power line flows through the transformer T, i.e., IL1 ═ I4+ I3. Further, the primary and secondary side currents of the transformer T are in turn ratio relation, and the following results are obtained: IL2 ═ N × I3 (defined as the positive direction of current flow with a-B), i.e. the relationship between the line input current and the branch current:
Iin＝IL1+IL2＝I4+I3+IL2＝I4+I3-N*I3＝I4+(1-N)*I3
further, to make the ripple in the input current zero, the following relationship needs to be satisfied, which can be obtained from ampere-second balance of the inductor:
ΔI4＝(N-1)*ΔI3
Figure BDA0002334928260000051
from the above expression, it is possible to obtain a condition that the input side current ripple is zero is satisfied:
Figure BDA0002334928260000061
the expression can analyze that the current ripple cancellation circuit provided by the embodiment is irrelevant to the switching frequency, the input voltage, the duty ratio and the like of the Boost power converter.
According to the formula, the denominator (N-1) should be greater than 0, so the primary-secondary turn ratio of the transformer T should be greater than 1. Wherein, the smaller the primary and secondary turn ratio N of the transformer T is, the smaller the induced AC current IL2 will be, and the loss of ripple current eliminating circuit can be reduced (I)2R can know), also can reduce condenser Cb both ends voltage ripple simultaneously, can make ripple current cancelling circuit's performance more stable, the most suitable turn ratio value range: 1<N<3。
In addition, the capacitor Cb is mainly a blocking capacitor, the capacitance value of the capacitor Cb is critical to eliminating ripple current, and a large AC voltage is formed at two ends of the capacitor Cb when the capacitance value of the capacitor Cb is too small, so that the efficiency of the ripple current eliminating circuit is reduced; too large a value of capacitor Cb creates a pair of low frequency poles making control difficult and therefore a correct choice of capacitor Cb is required.
Second embodiment
Fig. 5 is a structural diagram of a current ripple cancellation circuit according to a second embodiment of the present invention, which includes an energy storage inductor L1, an auxiliary inductor L2, a transformer T, a capacitor Cb, a current input terminal C, and a current output terminal D; the current input end C is connected with one end of a primary winding of the transformer T, and the other end of the primary winding of the transformer T is connected with the current output end D; one end of the capacitor Cb is grounded, the other end of the capacitor Cb is connected with one end of a secondary winding of the transformer T, the other end of the secondary winding of the transformer T is connected with one end of an auxiliary inductor L2, and the other end of the auxiliary inductor L2 is also connected with a current output end D; the energy storage inductor L1 is connected in parallel with the primary winding of the transformer T.
Fig. 6 is a circuit diagram of a power converter to which the embodiment of fig. 5 is applied, the power converter further includes a main power MOS transistor S1, a boost inductor Lx, a freewheeling diode D1, and an output filter capacitor Co; the positive electrode of an input power supply of the power converter is simultaneously connected with the drain electrode of a main power MOS tube S1 and the anode of a fly-wheel diode D1 after passing through a boost inductor Lx, the cathode of the fly-wheel diode D1 is connected with the current input end of a current ripple eliminating circuit, and the current output end of the current ripple eliminating circuit is simultaneously connected with the positive electrode of the output voltage of the power converter and one end of an output filter capacitor Co; the negative electrode of an input power supply of the power converter, the source electrode of the main power MOS tube S1, the other end of the output filter capacitor Co and the negative electrode of the output voltage of the power converter are all grounded; one end of the primary winding of the transformer and one end of the secondary winding of the transformer are the same-name ends.
Fig. 7 is a circuit diagram of another power converter to which the embodiment of fig. 5 is applied, the power converter further including a main power MOS transistor S1, a freewheeling diode D1, and an output filter capacitor Co; the positive electrode of an input power supply of the power converter is connected with the drain electrode of a main power MOS tube S1, the source electrode of the main power MOS tube S1 is simultaneously connected with the cathode of a freewheeling diode D1 and the current input end of a current ripple eliminating circuit, and the current output end of the current ripple eliminating circuit is simultaneously connected with the positive electrode of the output voltage of the power converter and one end of an output filter capacitor Co; the negative electrode of the input power supply of the power converter, the anode of the freewheeling diode D1, the other end of the output filter capacitor Co and the negative electrode of the output voltage of the power converter are all grounded; one end of the primary winding of the transformer and one end of the secondary winding of the transformer are the same-name ends.
In this embodiment, both the energy storage inductor L1 and the auxiliary inductor L2 can be integrated into the magnetic element of the transformer T, and fig. 8 is a circuit diagram of fig. 7 after magnetic integration.
The operation principle of the current ripple cancellation circuit of the present embodiment is described below with reference to the circuit diagram of the power converter of fig. 6:
the current in the power supply line flows through the transformer T and the primary winding inductor L1, the transformer T induces the ripple current to the secondary side of the transformer T to form a compensation current with a current change speed consistent with the change speed of the primary ripple current of the transformer T but with an opposite phase, and the compensation current is injected to the power supply input side e point through the auxiliary inductor L2, so that the output current Iout is converted into the sum of the two branch currents, that is, Iout is IL1+ IL 2. Different from the first embodiment, the present embodiment eliminates the current ripple at the output terminal of the converter, and the detailed working principle is not described herein again because the implementation principle and the parameter relationship of the current ripple eliminating circuit are consistent.
The embodiment also requires that the turn ratio of the primary side and the secondary side of the transformer T should be greater than 1, and the most suitable turn ratio value range is as follows: 1< N <3, and the reason for the values is not described in detail.
The capacitor Cb of this embodiment is also mainly a dc blocking capacitor, and as in the first embodiment, the capacitance of the capacitor Cb needs to be selected correctly.
The above embodiments are only for the understanding of the inventive concept of the present application and are not intended to limit the present invention, and any modification, equivalent replacement, improvement, etc. made by those skilled in the art without departing from the principle of the present invention should be included in the protection scope of the present invention.

Claims (17)

1. A current ripple cancellation circuit, characterized by: the device comprises an energy storage inductor, an auxiliary inductor, a transformer, a capacitor, a current input end and a current output end;
the current input end is connected with one end of the primary winding of the transformer, and the other end of the primary winding of the transformer is connected with the current output end;
the current input end is also connected with one end of an auxiliary inductor, the other end of the auxiliary inductor is connected with one end of a secondary winding of the transformer, the other end of the secondary winding of the transformer is connected with one end of a capacitor, and the other end of the capacitor is grounded;
the energy storage inductor is connected with the primary winding of the transformer in parallel.
2. The current ripple cancellation circuit of claim 1, wherein: the energy storage inductance is multiplexed by the primary winding of the transformer.
3. The current ripple cancellation circuit of claim 1, wherein: part or all of the inductance required by the auxiliary inductor is provided by the leakage inductance of the secondary winding of the transformer.
4. The current ripple cancellation circuit of claim 1, wherein: the auxiliary inductor is integrated in the transformer magnet.
5. The current ripple cancellation circuit of claim 1, wherein: inductance L2 of auxiliary inductorThe relation between the inductance L1 of the primary winding of the transformer and the turn ratio N of the primary side and the secondary side of the transformer is
Figure FDA0002334928250000011
6. The current ripple cancellation circuit of claim 1, further characterized by: the turn ratio N of the primary side and the secondary side of the transformer is more than 1.
7. The current ripple cancellation circuit of claim 1, further characterized by: the value range of the turn ratio N of the primary side and the secondary side of the transformer is 1< N < 3.
8. A power converter using the current ripple cancellation circuit of any one of claims 1 to 7, wherein: the power converter also comprises a main power MOS (metal oxide semiconductor) transistor S1, a freewheeling diode D1 and an output filter capacitor Co;
the anode of an input power supply of the power converter is connected with the current input end of the current ripple eliminating circuit, the current output end of the current ripple eliminating circuit is simultaneously connected with the anode of a fly-wheel diode D1 and the drain of a main power MOS tube S1, and the cathode of a fly-wheel diode D1 is simultaneously connected with the anode of the output voltage of the power converter and one end of an output filter capacitor Co;
the negative electrode of an input power supply of the power converter, the source electrode of the main power MOS tube S1, the other end of the output filter capacitor Co and the negative electrode of the output voltage of the power converter are all grounded;
one end of the primary winding of the transformer and one end of the secondary winding of the transformer are the same-name ends.
9. A current ripple cancellation circuit, characterized by: the device comprises an energy storage inductor, an auxiliary inductor, a transformer, a capacitor, a current input end and a current output end;
the current input end is connected with one end of the primary winding of the transformer, and the other end of the primary winding of the transformer is connected with the current output end;
one end of the capacitor is grounded, the other end of the capacitor is connected with one end of the secondary winding of the transformer, the other end of the secondary winding of the transformer is connected with one end of the auxiliary inductor, and the other end of the auxiliary inductor is also connected with the current output end;
the energy storage inductor is connected with the primary winding of the transformer in parallel.
10. The current ripple cancellation circuit of claim 9, wherein: the energy storage inductance is multiplexed by the primary winding of the transformer.
11. The current ripple cancellation circuit of claim 9, wherein: part or all of the inductance required by the auxiliary inductance is provided by the leakage inductance of the secondary winding of the transformer.
12. The current ripple cancellation circuit of claim 9, wherein: the auxiliary inductor is integrated in the transformer magnet.
13. The current ripple cancellation circuit of claim 9, wherein: the relation between the inductance L2 of the auxiliary inductor, the inductance L1 of the primary winding of the transformer and the primary-secondary turn ratio N of the transformer is
Figure FDA0002334928250000021
14. The current ripple cancellation circuit of claim 9, further characterized by: the turn ratio N of the primary side and the secondary side of the transformer is more than 1.
15. The current ripple cancellation circuit of claim 9, further characterized by: the value range of the turn ratio N of the primary side and the secondary side of the transformer is 1< N < 3.
16. A power converter using the current ripple cancellation circuit of any one of claims 9 to 15, wherein: the power converter also comprises a main power MOS (metal oxide semiconductor) transistor S1, a boost inductor Lx, a freewheeling diode D1 and an output filter capacitor Co;
the positive electrode of an input power supply of the power converter is simultaneously connected with the drain electrode of a main power MOS tube S1 and the anode of a fly-wheel diode D1 after passing through a boost inductor Lx, the cathode of the fly-wheel diode D1 is connected with the current input end of a current ripple eliminating circuit, and the current output end of the current ripple eliminating circuit is simultaneously connected with the positive electrode of the output voltage of the power converter and one end of an output filter capacitor Co;
the negative electrode of an input power supply of the power converter, the source electrode of the main power MOS tube S1, the other end of the output filter capacitor Co and the negative electrode of the output voltage of the power converter are all grounded;
one end of the primary winding of the transformer and one end of the secondary winding of the transformer are the same-name ends.
17. A power converter using the current ripple cancellation circuit of any one of claims 9 to 15, wherein: the power converter also comprises a main power MOS (metal oxide semiconductor) transistor S1, a freewheeling diode D1 and an output filter capacitor Co;
the positive electrode of an input power supply of the power converter is connected with the drain electrode of a main power MOS tube S1, the source electrode of the main power MOS tube S1 is simultaneously connected with the cathode of a freewheeling diode D1 and the current input end of a current ripple eliminating circuit, and the current output end of the current ripple eliminating circuit is simultaneously connected with the positive electrode of the output voltage of the power converter and one end of an output filter capacitor Co;
the negative electrode of the input power supply of the power converter, the anode of the freewheeling diode D1, the other end of the output filter capacitor Co and the negative electrode of the output voltage of the power converter are all grounded;
one end of the primary winding of the transformer and one end of the secondary winding of the transformer are the same-name ends.
CN201911352351.8A 2019-12-25 2019-12-25 Current ripple eliminating circuit and power converter using same Pending CN111082646A (en)

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CN115276503B (en) * 2022-07-25 2024-05-14 南京华士电子科技有限公司 Output ripple eliminating system of small-capacitance frequency converter with permanent magnet synchronous motor load and control method

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