CN206698111U - It is a kind of using switched inductors and the quasi- boost switching DC DC converters of switching capacity - Google Patents

Abstract

The utility model provides a kind of using switched inductors and the quasi- boost switching DC DC converters of switching capacity, it includes input dc power potential source, switched inductors unit, boost switching unit, switching capacity unit, the second metal-oxide-semiconductor, 6th diode, the 4th electric capacity and load resistance；Wherein switched inductors unit is made up of the first inductance, the second inductance, the first diode, the second diode and the 3rd diode；Boost switching unit is made up of the first electric capacity, the 4th diode, the 5th diode and the first metal-oxide-semiconductor；Switching capacity unit is made up of the second electric capacity, the 3rd electric capacity, the 7th diode and the 8th diode.Whole circuit structure is simple, source current is continuous, input and output common ground, combine switched inductors unit and switching capacity unit charge parallel discharged in series the characteristics of and quasi- boost switching network single-stage buck characteristic, higher output voltage gain is made it have, and inrush current is not present for circuit and switching tube opens the dash current of moment.

Description

A quasi-switching step-up DC-DC converter using switched inductors and switched capacitors

technical field

The utility model relates to the technical field of power electronic converters, in particular to a quasi-switch step-up DC-DC converter using switch inductance and switch capacitor.

Background technique

With the rapid development of modern industrial technology, high-gain DC-DC boost converters have been widely demanded and applied in some industrial fields. For example, in the backup power supply of the uninterruptible DC power supply (UPS), it is necessary to increase the voltage of the 48V battery to 380V or even higher; the high-intensity gas discharge headlights for electric vehicles need to increase the voltage of 12V to a stable value of 100V ; In the field of new energy power generation, the output voltage of solar photovoltaic panels (33-43V), fuel cell stacks (22-48V) and so on are very low, and need to be boosted and paralleled by a high-gain DC-DC converter. The input voltage (380V, 760V) of the grid inverter is matched and then grid-connected for power generation. For this reason, it is becoming more and more important to research and develop high-gain DC-DC converters that can convert low voltage to high voltage. Among them, the traditional Boost converter is the most commonly used, but when the output voltage gain is required to be very high, the duty cycle of the switching tube will be close to 1, which will cause excessive switching loss and reduce the overall power of the system. efficiency. However, the Z-source step-up DC-DC converter proposed in recent years, although the Z-source network is used to realize the boost, but its voltage gain still has a lot of room for improvement. high stress issues.

Utility model content

The purpose of the utility model is to overcome the deficiencies of the above-mentioned prior art, and propose a quasi-switching step-up DC-DC converter using switched inductors and switched capacitors.

The circuit of the utility model specifically includes an input DC voltage source, a switch inductance unit, a switch boost unit, a switch capacitor unit, a second MOS tube, a sixth diode, a fourth capacitor and a load resistor; wherein the switch inductance unit consists of the first The inductor, the second inductor, the first diode, the second diode and the third diode; the switch boost unit is composed of the first capacitor, the fourth diode, the fifth diode and the first MOS tube Composition; the switched capacitor unit is composed of a second capacitor, a third capacitor, a seventh diode and an eighth diode.

The specific connection mode of the utility model circuit is as follows: one end of the input DC voltage source is connected with one end of the first inductance and the anode of the first diode; the other end of the first inductance is respectively connected with the anode of the second diode The anode is connected to the anode of the third diode; the cathode of the first diode is respectively connected to the cathode of the second diode and one end of the second inductance; the other end of the second inductance is respectively connected to the third two The cathode of the pole tube, the drain of the first MOS tube are connected to the anode of the fourth diode; the cathode of the fourth diode is respectively connected to the positive pole of the first capacitor, the negative pole of the second capacitor, and the second MOS tube The drain is connected to the anode of the sixth diode; the negative pole of the first capacitor is respectively connected to the source of the first MOS transistor and the anode of the fifth diode; the cathode of the sixth diode is respectively connected to the first The anode of the seven diodes, the negative pole of the third capacitor and the positive pole of the fourth capacitor are connected; the cathode of the seventh diode is respectively connected with the anode of the eighth diode and the positive pole of the second capacitor; the eighth The cathodes of the diodes are respectively connected to the anode of the third capacitor and one end of the load resistor; the other ends of the load resistor are respectively connected to the cathode of the fourth capacitor, the source of the second MOS transistor, the cathode of the fifth diode and Negative connection for DC input power supply.

The voltage gain G of the converter at steady state output is:

Among them, V _o represents the output voltage on the load side of the converter, V _i is the input voltage of the input DC voltage source, and D is the duty cycle.

Compared with the prior art, the utility model has the following advantages: simple structure and convenient control; Source boost converter (its corresponding output voltage gain is G=(1+D)/(1-3D)), under the same input voltage and duty cycle, it has a higher output voltage gain of G =2(1+D)/(1-3D), and the power supply current is continuous, the input and output share a common ground, and there is no circuit start-up inrush current, etc. Therefore, the circuit of the utility model has a very wide application prospect.

Description of drawings

Fig. 1 is the circuit diagram of a kind of quasi-switch step-up DC-DC converter that adopts switched inductance and switched capacitor described in the utility model example;

Figure 2a and Figure 2b are the main working modes in one switching cycle when the first MOS tube and the second MOS tube are turned on at the same time, and the first MOS tube and the second MOS tube are turned off at the same time respectively in the circuit shown in Figure 1 picture.

Fig. 3a is a comparative graph of the output voltage gain of the converter described in the example of the utility model, the switched inductance Z-source converter and the traditional quasi-Z source converter.

Fig. 3b is a diagram showing the simulation results of relevant variables in the example circuit of the present invention, taking _Vin = 10V and duty cycle D = 0.2 as an example.

detailed description

The utility model will be described in further detail below in conjunction with the embodiments and accompanying drawings, but the implementation of the utility model is not limited thereto. It should be noted that, if there are any processes or parameters that are not specifically described in detail below, those skilled in the art can understand or implement them with reference to the prior art.

The basic topology structure of this embodiment is shown in FIG. 1 . For the convenience of verification, the devices in the circuit structure are regarded as ideal devices unless otherwise specified. A quasi-switching step-up DC-DC converter using switched inductors and switched capacitors, which includes an input DC voltage source V _in , a switched inductor unit, a switched boost unit, a switched capacitor unit, a second MOS transistor S ₂ , and a sixth Diode D ₆ , fourth capacitor C ₄ and load resistor R _L ; wherein the switching inductance unit consists of first inductor L ₁ , second inductor L ₂ , first diode D ₁ , second diode D ₂ and The third diode D ₃ is formed; the switching boost unit is composed of the first capacitor C ₁ , the fourth diode D ₄ , the fifth diode D ₅ and the first MOS transistor S ₁ ; the switched capacitor unit is composed of the second The capacitor C ₂ , the third capacitor C ₃ , the seventh diode D ₇ and the eighth diode D ₈ constitute.

In this embodiment, the driving signals of the first MOS transistor S ₁ and the second MOS transistor S ₂ are set as V _GS1 and V _GS2 . The current of the first inductor L ₁ is i _L1 , the current of the second inductor L ₂ is i _L2 , the voltage of the first capacitor C ₁ is V _C1 , the voltage of the second capacitor C ₂ is V _C2 , the voltage of the third capacitor C ₃ is V _C3 , The voltage of the fourth capacitor C ₄ is V _C4 . And set the duty ratio as D, and set the switching period as T _s .

As shown in Fig. 2a and Fig. 2b, the solid line in the figure indicates the part where the current flows in the converter, and the dotted line indicates the part where the current does not flow in the converter. In this example, the quasi-switching step-up DC-DC converter using switched inductors and switched capacitors has two working modes in different stages within a switching cycle (0, T _s ), which are described as follows:

Working mode 1 (0<t<DT _s ): as shown in Figure 2a, the first MOS transistor S ₁ and the second MOS transistor S ₂ are turned on at the same time, the second diode D ₂ and the fourth diode D ₄ , the fifth diode D ₅ , the sixth diode D ₆ and the eighth diode D ₈ reverse cutoff, the first diode D ₁ , the third diode D ₃ and the seventh diode D ₇ forward conduction. At this time, the input DC voltage source V _in and the first capacitor C ₁ charge the parallel connected first inductor L ₁ and the second inductor L ₂ together, and the fourth capacitor C4 charges the second capacitor through the diode D ₇ and the second MOS transistor S ₂ The capacitor C2 is charged, and at the same time, the _third capacitor C3 and the fourth capacitor _C4 are connected in series to supply power to the load resistor _RL .

In this working mode, the relevant electrical parameter relational formula is:

V _{L1_on} ＝V _{L2_on} ＝V _in +V _C1 (1)

V _C2 = V _C4 (2)

V _o =V _C3 +V _C4 (3)

Among them, V _L1-on and V _{L2_on} represent the voltage across the first inductance L ₁ and the second inductance L ₂ during the simultaneous conduction period of the first MOS transistor S ₁ and the second MOS transistor S ₂ , V _o represents the voltage on the load side of the converter The output voltage.

Working mode 2 (DT _s <t<T _s ): As shown in Figure 2b, the first MOS transistor S ₁ and the second MOS transistor S ₂ are turned off at the same time, then the second diode D ₂ and the fourth diode The tube D ₄ , the fifth diode D ₅ , the sixth diode D ₆ and the eighth diode D ₈ conduct, and the first diode D ₁ , the third diode D ₃ and the seventh diode Tube _D7 is turned off. At this time, the input DC voltage source V _in is connected in series with the first inductor L ₁ and the second inductor L ₂ to charge the first capacitor C ₁ and the fourth capacitor C ₄ , and the second capacitor C ₂ charges the third capacitor C ₃ . At the same time, the input DC voltage source V _in is connected in series with the first inductor L ₁ , the second inductor L ₂ and the second capacitor C ₂ to supply power to the load resistor _RL . In this working mode, the relevant electrical parameter relational formula is:

V _{L1_off} +V _{L2_off} =V _in -V _C1 (4)

V _C1 = V _C4 (5)

V _C2 =V _C3 (6)

V _o =V _C2 +V _C1 (7)

Wherein, V _L1-off and V _L2-off represent voltages across the first inductor L ₁ and the second inductor L ₂ when the first MOS transistor S ₁ and the second MOS transistor S ₂ are turned off simultaneously.

According to the above analysis, apply the volt-second balance principle to the first inductance L ₁ and the second inductance L ₂ , that is, the average value of the inductance voltage in one switching cycle is zero, and the simultaneous equations (1) and (4) can be obtained

Then the simultaneous formulas (2), (3), (5), (6), (7) and (8) can obtain the expressions of capacitor voltage and output voltage in steady state respectively as follows:

Then the voltage gain G of a quasi-switch step-up DC-DC converter steady-state output using switched inductance and switched capacitor described in the utility model example is:

As shown in Fig. 3a, the output voltage gain curve of the example circuit of the utility model is compared with the voltage gain curves of the switch inductor Z-source converter and the traditional quasi-Z source converter. It can be seen from the figure that the output voltage gain G of the example circuit of the utility model can reach a large value when the duty ratio D does not exceed 0.33, which is obviously higher than the voltage gain of the other two converters, and the example circuit of the utility model has a The duty cycle D will not exceed 0.33.

Fig. 3b is a diagram of the simulation results of relevant variables in the example circuit of the utility model given as an example of _Vin = 10V and duty cycle D = 0.2. When D=0.2, the corresponding output voltage gain is G=6, the first, second, third and fourth capacitor voltages (V _C1 , V _C2 , V _C3 , V _C4 )=30V, and the output voltage V _o =60V. In addition, Figure 3b also shows the waveforms of the first and second inductor currents (i _L1 , i _L2 ) and the driving signals (V _GS , V _GS2 ) of the first MOS transistor S ₁ and the second MOS transistor S ₂ waveform.

In summary, a quasi-switching step-up DC-DC converter using switched inductors and switched capacitors proposed by the utility model example has simple structure and convenient control; compared with traditional quasi-Z source converters and switched inductors Z The source converter has a higher output voltage gain under the same input voltage and duty cycle, and the power supply current is continuous, and the input and output share a common ground. There is no start-up surge current at the moment the circuit starts, so this The utility model circuit has a very wide application prospect.

The above-mentioned embodiment is a preferred implementation mode of the present utility model, but the implementation mode of the present utility model is not limited by the described embodiment, and any other changes, modifications, modifications, Substitution, combination, and simplification should all be equivalent replacement methods, and are all included in the protection scope of the present utility model.

Claims (2)

1. A quasi-switching step-up DC-DC converter using switched inductors and switched capacitors, characterized in that it includes an input DC voltage source ( V _in ), a switched inductor unit, a switched boost unit, a switched capacitor unit, and a second MOS tube (S ₂ ), the sixth diode (D ₆ ), the fourth capacitor (C ₄ ) and the load resistor ( R _L ); where the switching inductance unit consists of the first inductor (L ₁ ), the second inductor (L ₂ ), the first diode (D ₁ ), the second diode (D ₂ ) and the third diode (D ₃ ); the switch boost unit consists of the first capacitor (C ₁ ), the fourth diode tube (D ₄ ), the fifth diode (D ₅ ) and the first MOS tube (S ₁ ); the switched capacitor unit consists of the second capacitor (C ₂ ), the third capacitor (C ₃ ), the seventh diode tube (D ₇ ) and the eighth diode (D ₈ ); one end of the input DC voltage source ( V _in ) is connected to one end of the first inductor (L ₁ ) and the first diode (D ₁ ) connected to the anode; the other end of the first inductor (L ₁ ) is respectively connected to the anode of the second diode (D ₂ ) and the anode of the third diode (D ₃ ); the first diode ( The cathode of D ₁ ) is respectively connected to the cathode of the second diode (D ₂ ) and one end of the second inductance (L ₂ ); the other end of the second inductance (L ₂ ) is respectively connected to the third diode ( The cathode of D ₃ ), the drain of the first MOS transistor (S ₁ ) and the anode of the fourth diode (D ₄ ); the cathode of the fourth diode (D ₄ ) is connected to the first capacitor ( The positive pole of C ₁ ), the negative pole of the second capacitor (C ₂ ), the drain of the second MOS transistor (S ₂ ) and the anode of the sixth diode (D ₆ ); the first capacitor (C ₁ ) The cathode of the first MOS transistor (S ₁ ) and the anode of the fifth diode (D ₅ ) are respectively connected; the cathode of the sixth diode (D ₆ ) is respectively connected to the seventh diode ( The anode of D ₇ ), the negative pole of the third capacitor (C ₃ ) and the positive pole of the fourth capacitor (C ₄ ) are connected; the cathode of the seventh diode (D ₇ ) is respectively connected to the eighth diode (D ₈ ) is connected to the anode of the second capacitor (C ₂ ); the cathode of the eighth diode (D ₈ ) is respectively connected to the anode of the third capacitor (C ₃ ) and one end of the load resistor ( _RL ); The other end of the load resistor ( _RL ) is respectively connected to the cathode of the fourth capacitor (C ₄ ), the source of the second MOS tube (S ₂ ), the cathode of the fifth diode (D ₅ ) and the input DC voltage Negative connection for source (V _in ). 2. A quasi-switching step-up DC-DC converter using switched inductors and switched capacitors according to claim 1, characterized in that when the first MOS tube and the second MOS tube are turned on simultaneously, the second diode, The fourth diode, the fifth diode, the sixth diode and the eighth diode are reverse-blocked, and the first diode, the third diode and the seventh diode are forward-conducted; then this When the input DC voltage source and the first capacitor charge the parallel first inductor and the second inductor together, the fourth capacitor charges the second capacitor through the diode and the second MOS tube, and at the same time, the third capacitor and the fourth capacitor are connected in series to the load Resistor power supply; when the first MOS tube and the second MOS tube are turned off at the same time, the second diode, the fourth diode, the fifth diode, the sixth diode and the eighth diode are turned on, The first diode, the third diode and the seventh diode are turned off; then the input DC voltage source is connected in series with the first inductance and the second inductance to charge the first capacitor and the fourth capacitor together, and the second capacitor Charging the third capacitor; at the same time, the input DC voltage source is connected in series with the first inductor, the second inductor and the second capacitor to supply power to the load resistor.