Switching inductor coupling inductor series connection type direct current boost converter

Abstract

The invention discloses a switch inductor coupling inductor series connection type direct current boost converter, and belongs to the technical field of power electronic inverters. The problem that the boost capability is low due to the fact that the shoot-through time of an existing Boost circuit is limited is solved. The circuit comprises a DC voltage source Vin, diodes D0 to D6, capacitors C0 to C2, inductors L1 to L2, a coupling inductor and a power switch S, the inductors L1 and L2 and the diodes D3 to D5 form a switching inductor; the diode D0, the capacitor C0 and the load resistor R form an output unit of the boost converter, and the output unit can greatly improve the voltage gain. The invention is mainly used for DC boost conversion.

Description

Technical Field

[0001] The invention belongs to the technical field of power electronic inverters, and in particular relates to a switching inductor coupled inductor series type direct current boost converter. Background Art

[0002] Boost converters are widely used in the front-stage converters of distributed power systems to achieve the boost function. The converter can achieve a higher voltage gain with a smaller number of components through the series structure of the switching inductor and the coupled inductor. This structure allows the voltage to be effectively boosted to a higher output level when the input voltage is low, meeting some application scenarios that require high voltage, such as high-voltage direct current transmission and high-voltage battery charging for electric vehicles. In theory, the voltage gain of the boost circuit increases with the increase of the duty cycle. However, considering the parasitic equivalent series impedance in the actual circuit, the actual gain of the boost circuit does not always increase with the increase of the duty cycle. Its through time is limited, resulting in a small boost capability. Therefore, its boost capability is very limited and is not suitable for high voltage gain DC power conversion occasions. Summary of the invention

[0003] The purpose of the present invention is to solve the problem that the current Boost circuit has a limited through time, resulting in a small boost capability. The present invention provides a switching inductor coupled inductor series type DC boost converter.

[0004] A switched inductor coupled inductor series DC boost converter includes a DC voltage source V in , diodes D0 to D6, capacitors C0 to C2, inductors L1 to L2, a coupled inductor and a power switch S; wherein the capacitor C0 serves as an output capacitor and the voltage across it serves as the output voltage V0 of the boost converter;

[0005] Inductors L1 and L2, and diodes D3 to D5 constitute a switching inductor;

[0006] DC voltage source V inThe positive electrode is connected to one end of the capacitor C2 and the same-name end of the primary winding N1 of the coupled inductor at the same time, the anode of the diode D1 is connected to the opposite-name end of the primary winding N1 of the coupled inductor and the same-name end of its secondary winding N2 at the same time, the opposite-name end of the secondary winding N2 of the coupled inductor is connected to the anode of the diode D2, one end of the capacitor C1 is connected to the cathode of the diode D1, the cathode of the diode D2 and the anode of the diode D6 at the same time, the cathode of the diode D6 is connected to the anode of the diode D3, the other end of the capacitor C2 and one end of the inductor L1 at the same time, the anode of the diode D4 is connected to the other end of the inductor L1 and the anode of the diode D5 at the same time, the cathode of the diode D4 is connected to one end of the inductor L2 and the cathode of the diode D3 at the same time, the drain of the power switch S is connected to the cathode of the diode D5, the other end of the inductor L2, the other end of the capacitor C1 and the anode of the diode D0 at the same time, and the cathode of the diode D0 is connected to one end of the capacitor C0 and one end of the load resistor R at the same time;

[0007] DC voltage source V in The cathode of is connected to the source of the power switch S, the other end of the capacitor C0 and the other end of the load resistor R at the same time, and the diode D0, the capacitor C0 and the load resistor R constitute an output unit.

[0008] Preferably, the voltage gain of the boost converter D is the on-duty cycle of the power switch S, and n1 is the turns ratio of the secondary winding N2 to the primary winding N1 of the coupled inductor.

[0009] Preferably, the boost converter has two operating modes in one switching cycle, namely an on state and an off state.

[0010] Preferably, in the on-state working mode, the power switch tube S is turned on, and the DC voltage source V in The capacitor C1 charges the primary winding N1 of the coupled inductor. Due to the principle of magnetic induction, the diode D2 is reverse biased and cut off, and D1 is forward biased and turned on. At the same time, the DC voltage source V in The inductors L1 and L2 are charged by the capacitor C2, and the diodes D4 and D6 are reverse biased and cut off; the diode D0 is reverse biased and cut off, and the capacitor C0 supplies power to the load resistor R independently.

[0011] Preferably, in the off-state working mode, the power switch tube S remains off, the diodes D2 and D6 are forward biased and turned on, the diode D1 is reverse biased and turned off, the inductors L1 and L2 charge the capacitor C1, the primary winding N1 and the secondary winding N2 of the coupled inductor charge the capacitor C2, and at the same time, the DC voltage source V in The output electric energy passes through the primary winding N1 and the secondary winding N2 of the coupled inductor, as well as the inductor L1, the inductor L2 and the diode D0 in turn to supply power to the load resistor R and the capacitor C0.

[0012] Preferably, the on-duty cycle adjustment range of the power switch tube S is (0, 0.29).

[0013] Preferably, the optimal conduction duty cycle of the power switch tube S is 0.25.

[0014] Advantages of the present invention:

[0015] The switching inductor coupled inductor series DC boost converter proposed by the present invention has a DC voltage source V in Directly connecting the primary winding N1 of the coupled inductor makes the input current continuous and can continuously provide relatively stable energy to the circuit. The coupled inductor increases the amplification factor of the circuit through the effect of the turns ratio. At the same time, due to the principle of magnetic induction, the voltage of the secondary winding N2 increases to charge the capacitor C2. When discharging, the capacitor C1 avoids the instability of the inductor voltage due to the discontinuous current, which in turn causes the DC link voltage to drop and other instabilities, thereby causing the output waveform to be distorted. The voltage of capacitors C1 and C2 is much lower than the output voltage, and the diode component voltage fluctuates over time, which prevents the component from always being in a high voltage state, reduces energy loss, and reduces component voltage stress; at the same time, the charging and discharging characteristics of capacitor C2 further optimize the voltage distribution, reduces the previous requirement to obtain high voltage gain under large duty cycles, and improves the boost capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the switching inductor coupled inductor series type DC boost converter of the present invention;

[0017] Figure 2 is an equivalent circuit diagram of the switch inductor coupled inductor series type DC boost converter of the present invention when the power switch S is turned on and off; wherein,

[0018] Figure 2 a is the equivalent circuit diagram of the boost converter when the power switch S is turned on;

[0019] Figure 2 b is the equivalent circuit diagram of the boost converter when the power switch S is turned off;

[0020] Figure 3 When the switching inductor coupled inductor series type DC boost converter of the present invention is used for boost conversion, when the input voltage V in =50V, the experimental waveform when the output voltage V0 is about 500V; where,

[0021] Figure 3 a is the input voltage of the boost converter V in =50V, output voltage V0 is about 500V waveform comparison chart;

[0022] Figure 3 b is the waveform comparison diagram of the output diode D0 voltage and the power switch S voltage;

[0023] Figure 3 c is a comparison diagram of the voltage waveforms of diode D6 and capacitor C2;

[0024] Figure 3 d is the voltage waveform comparison diagram of capacitor C1 and diode D5. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0027] Specific implementation method 1. Combination Figure 1 As shown, this embodiment provides a switching inductor coupled inductor series type DC boost converter, including a DC voltage source V in , diodes D0 to D6, capacitors C0 to C2, inductors L1 to L2, a coupled inductor and a power switch S; wherein the capacitor C0 serves as an output capacitor and the voltage across it serves as the output voltage V0 of the boost converter;

[0028] Inductors L1 and L2, and diodes D3 to D5 constitute a switching inductor;

[0029] DC voltage source V inThe positive electrode is connected to one end of the capacitor C2 and the same-name end of the primary winding N1 of the coupled inductor at the same time, the anode of the diode D1 is connected to the opposite-name end of the primary winding N1 of the coupled inductor and the same-name end of its secondary winding N2 at the same time, the opposite-name end of the secondary winding N2 of the coupled inductor is connected to the anode of the diode D2, one end of the capacitor C1 is connected to the cathode of the diode D1, the cathode of the diode D2 and the anode of the diode D6 at the same time, the cathode of the diode D6 is connected to the anode of the diode D3, the other end of the capacitor C2 and one end of the inductor L1 at the same time, the anode of the diode D4 is connected to the other end of the inductor L1 and the anode of the diode D5 at the same time, the cathode of the diode D4 is connected to one end of the inductor L2 and the cathode of the diode D3 at the same time, the drain of the power switch S is connected to the cathode of the diode D5, the other end of the inductor L2, the other end of the capacitor C1 and the anode of the diode D0 at the same time, and the cathode of the diode D0 is connected to one end of the capacitor C0 and one end of the load resistor R at the same time;

[0030] DC voltage source V in The cathode of is connected to the source of the power switch S, the other end of the capacitor C0 and the other end of the load resistor R at the same time, and the diode D0, the capacitor C0 and the load resistor R constitute an output unit.

[0031] In this embodiment, the DC voltage source V in Directly connecting the primary winding N1 of the coupled inductor makes the input current continuous and can continuously provide relatively stable energy to the circuit. The coupled inductor increases the amplification factor of the circuit through the effect of the turns ratio. At the same time, due to the principle of magnetic induction, the voltage of the secondary winding N2 increases to charge the capacitor C2. When discharging, the capacitor C1 avoids the instability of the inductor voltage due to the discontinuous current, which in turn causes the DC link voltage to drop and other instabilities, thereby causing the output waveform to be distorted. The voltage of capacitors C1 and C2 is much lower than the output voltage, and the diode component voltage fluctuates over time, which prevents the component from always being in a high voltage state, reduces energy loss, and reduces component voltage stress; at the same time, the charging and discharging characteristics of capacitor C2 further optimize the voltage distribution, reduces the previous requirement to obtain high voltage gain under large duty cycles, and improves the boost capability.

[0032] The connection relationship of the components of the switching inductor coupled inductor series type DC boost converter greatly reduces the voltage stress at both ends of the diode and increases the service life of the components.

[0033] Furthermore, the voltage gain of the boost converter D is the on-duty cycle of the power switch S, and n1 is the turns ratio of the secondary winding N2 to the primary winding N1 of the coupled inductor. The on-duty cycle adjustment range of the power switch tube S is (0, 0.29). In specific applications, the optimal on-duty cycle of the power switch tube S is 0.25.

[0034] In this preferred embodiment, it can be seen from the voltage gain expression that a very high voltage gain can be obtained under a very small duty cycle, reducing the previous requirement to obtain a high voltage gain under a very large duty cycle. At the same time, the voltage distribution is optimized and the component voltage stress is reduced.

[0035] The boost converter has two operating modes in one switching cycle, namely the on state and the off state. Figure 2 Specifically,

[0036] See also Figure 2 a. In the on-state working mode, the power switch tube S is turned on, and the DC voltage source V in The capacitor C1 charges the primary winding N1 of the coupled inductor. Due to the principle of magnetic induction, the diode D2 is reverse biased and cut off, and D1 is forward biased and turned on. At the same time, the DC voltage source V in The inductors L1 and L2 are charged by the capacitor C2, and the diodes D4 and D6 are reverse biased and cut off; the diode D0 is reverse biased and cut off, and the capacitor C0 supplies power to the load resistor R independently.

[0037] See also Figure 2 b. In the off-state working mode, the power switch tube S remains off, the diodes D2 and D6 are forward biased and turned on, the diode D1 is reverse biased and cut off, the inductors L1 and L2 charge the capacitor C1, and the primary winding N1 and the secondary winding N2 of the coupled inductor charge the capacitor C2. At the same time, the DC voltage source V in The output electric energy passes through the primary winding N1 and the secondary winding N2 of the coupled inductor, as well as the inductor L1, the inductor L2 and the diode D0 in turn to supply power to the load resistor R and the capacitor C0.

[0038] In this preferred embodiment, the two working modes optimize the voltage distribution, avoid the situation where the components are always at high voltage, and improve the energy transfer efficiency.

[0039] Verification test:

[0040] like Figure 3 As shown, the input voltage V in =50V, the output voltage is about V o =500V, D=0.25, n1=2, load resistance R=200Ω.

[0041] Figure 3 a is the input voltage of the boost converter V in =50V, output voltage V0 = 500V waveform comparison chart; from Figure 3 It can be seen from a that when the DC input voltage is 50V, the output voltage is 500V, which is a ten-fold increase in voltage, and has a very high voltage gain.

[0042] Figure 3 b is the waveform comparison diagram of the output diode D0 voltage and the power switch S voltage; Figure 3 As can be seen in b, the waveform comparison of the output diode D0 voltage and the power switch S voltage shows that the component voltage fluctuates over time to prevent the component from always being in a high voltage state;

[0043] Figure 3 c is the voltage waveform comparison diagram of diode D6 and capacitor C2; Figure 3 As can be seen in c, the waveform comparison of diode D6 and capacitor C2 shows that the component voltage fluctuates over time, reflecting the process of energy exchange and optimizing voltage distribution;

[0044] Figure 3 d is the voltage waveform comparison diagram of capacitor C1 and diode D5. Figure 3 Comparing the voltage waveforms of capacitor C1 and diode D5 in d, it can be seen that the component voltage stress is not high.

[0045] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A switched inductor coupled inductor series type DC boost converter, characterized in that: Including DC voltage source V in , diodes D0 to D6, capacitors C0 to C2, inductors L1 to L2, coupled inductors and power switch S; Wherein, the capacitor C0 is used as the output capacitor, and the voltage across it is used as the output voltage V0 of the boost converter; Inductors L1 and L2, and diodes D3 to D5 constitute a switching inductor; DC voltage source V in The positive electrode is connected to one end of the capacitor C2 and the same-name end of the primary winding N1 of the coupled inductor at the same time, the anode of the diode D1 is connected to the opposite-name end of the primary winding N1 of the coupled inductor and the same-name end of its secondary winding N2 at the same time, the opposite-name end of the secondary winding N2 of the coupled inductor is connected to the anode of the diode D2, one end of the capacitor C1 is connected to the cathode of the diode D1, the cathode of the diode D2 and the anode of the diode D6 at the same time, the cathode of the diode D6 is connected to the anode of the diode D3, the other end of the capacitor C2 and one end of the inductor L1 at the same time, the anode of the diode D4 is connected to the other end of the inductor L1 and the anode of the diode D5 at the same time, the cathode of the diode D4 is connected to one end of the inductor L2 and the cathode of the diode D3 at the same time, the drain of the power switch S is connected to the cathode of the diode D5, the other end of the inductor L2, the other end of the capacitor C1 and the anode of the diode D0 at the same time, and the cathode of the diode D0 is connected to one end of the capacitor C0 and one end of the load resistor R at the same time; DC voltage source V in The cathode of is connected to the source of the power switch S, the other end of the capacitor C0 and the other end of the load resistor R at the same time, and the diode D0, the capacitor C0 and the load resistor R constitute an output unit.

2. The switched inductor coupled inductor series DC boost converter according to claim 1, characterized in that: Voltage Gain of Boost Converter D is the on-duty cycle of the power switch S, and n1 is the turns ratio of the secondary winding N2 to the primary winding N1 of the coupled inductor.

3. The switched inductor coupled inductor series DC boost converter according to claim 1, characterized in that: The boost converter has two operating modes in one switching cycle, namely the on state and the off state.

4. The switched inductor coupled inductor series DC boost converter according to claim 3, characterized in that: In the on-state operating mode, the power switch tube S is turned on and the DC voltage source V in The capacitor C1 charges the primary winding N1 of the coupled inductor. Due to the principle of magnetic induction, the diode D2 is reverse biased and cut off, and D1 is forward biased and turned on. At the same time, the DC voltage source V in The inductors L1 and L2 are charged by the capacitor C2, and the diodes D4 and D6 are reverse biased and cut off; the diode D0 is reverse biased and cut off, and the capacitor C0 supplies power to the load resistor R independently.

5. The switched inductor coupled inductor series DC boost converter according to claim 3, characterized in that: In the off-state working mode, the power switch tube S remains off, the diodes D2 and D6 are forward-biased, the diode D1 is reverse-biased and cut off, the inductors L1 and L2 charge the capacitor C1, and the primary winding N1 and the secondary winding N2 of the coupled inductor charge the capacitor C2. At the same time, the DC voltage source V in The output electric energy passes through the primary winding N1 and the secondary winding N2 of the coupled inductor, as well as the inductor L1, the inductor L2 and the diode D0 in turn to supply power to the load resistor R and the capacitor C0.

6. The switched inductor coupled inductor series DC boost converter according to claim 1, characterized in that: The on-duty cycle adjustment range of the power switch tube S is (0,0.29).

7. The switched inductor coupled inductor series DC boost converter according to claim 1, characterized in that: The optimal conduction duty cycle of the power switch tube S is 0.25.

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