TWI575860B - Boost converter - Google Patents

Description

Boost converter

The present invention relates to a boost converter, and more particularly to a boost converter for electrically connecting a DC power source.

In many power generation systems, such as wind power, solar power, fuel cells, and hybrid vehicles, boost converters with high voltage conversion ratios (or high boost ratios) are needed to boost the output voltage of the front-end power generation terminals. To a higher voltage to provide power to the downstream load. In addition to the power supply system described above, boost converters with high voltage conversion ratios are also commonly used in other applications such as uninterruptible power systems (UPS), gas discharge headlamps (HID) for vehicles.

In view of this, many scholars have proposed many new high-boost converters, such as using the turns ratio of the coupled inductor to increase the voltage-gain ratio; or using the coupled inductor with a voltage doubler circuit, or with a switched capacitor. Voltage superposition is performed to further increase the voltage conversion ratio. However, the methods for improving the voltage conversion ratio mentioned above have their own shortcomings, including: some technologies use too many circuit components to cause complicated design, resulting in increased circuit cost, and some technologies use floating-type switches and must be isolated and driven; Some technologies require additional switches to implement active clamping circuits, which makes circuit analysis difficult. This inconvenience is often caused by the use of the upper boost converter.

The present invention provides a boost converter device that transmits a fourth coupled inductor in series through a second coupled inductor, thereby improving the usability of the boost converter.

The invention provides a boost converter device electrically connected to a DC power source. The boost converter includes a first coupled inductor, a third coupled inductor, a switch module, and A single pass-through unit. The first coupled inductor is electrically connected to the DC power source for electrically coupling with a second coupled inductor. The third coupled inductor is electrically connected to the DC power source for electrically coupling with a fourth coupled inductor. The switch module is electrically connected to the first coupled inductor and the third coupled inductor. The one-way conduction unit is electrically connected between the first coupled inductor and the second coupled inductor. The second coupled inductor is connected in series with the fourth coupled inductor, and a load is electrically connected to the third coupled inductor and the fourth coupled inductor, and the load is connected in parallel with an energy storage unit.

The specific method of the present invention is to design a circuit of a fourth coupled inductor through a second coupled inductor through a boost converter. When the switch module is turned off, the first and third coupled inductors are electrically coupled to the second and fourth coupled inductors, respectively, and the second and fourth coupled inductors are connected in series to output a high voltage, thereby effectively boosting the boost conversion. The ease of use of the device.

The above summary and the following examples are intended to be illustrative of the invention and the embodiments of the invention.

1‧‧‧Boost converter

10‧‧‧Control Module

L1‧‧‧First coupled inductor

L2‧‧‧Second coupled inductor

L3‧‧‧ Third coupled inductor

L4‧‧‧4th coupled inductor

DS‧‧‧DC power supply

D1‧‧‧One-way unit, diode

SM‧‧‧ switch module

S1‧‧‧ first switch

S2‧‧‧ second switch

Ld‧‧‧ load

Co‧‧‧ energy storage unit, capacitor

Vg1, Vg2, Vds1, Vds2, VD1, Vout‧‧‧ voltage

Ids1, Ids2, IL1, ID1‧‧‧ current

DTs, Ts‧‧

1 is a functional block diagram of a boost converter device according to an embodiment of the present invention.

2 is a circuit diagram of a boost converter device according to another embodiment of the present invention.

FIG. 3 is a schematic diagram of the operation of the switch module of the boost converter according to another embodiment of the present invention in an on state.

4 is a schematic diagram of the operation of the switch module of the boost converter according to another embodiment of the present invention in an off state.

FIG. 5 is a diagram showing voltage and current waveforms of a boost converter according to another embodiment of the present invention. FIG.

FIG. 6 is a graph showing a relationship between an output voltage and a duty cycle of a conventional boost converter circuit according to another embodiment of the present invention.

1 is a functional block diagram of a boost converter device according to an embodiment of the present invention. Please refer to Figure 1. A boost converter device 1 is electrically connected to a DC power source DS. The boost converter device 1 includes a first coupled inductor L1, a second coupled inductor L2, a third coupled inductor L3, a fourth coupled inductor L4, a switch module SM, a single-conducting unit D1, and a control module. Group 10. In practice, the boost converter 1 is, for example, a boost circuit for converting a low voltage to a high voltage output. This embodiment does not limit the aspect of the boost converter device 1.

The DC power source DS is, for example, a low-voltage DC power source, such as a photovoltaic power source through solar panels, wind power, water or natural energy power generation, a battery or other power source DC power source DS. This embodiment does not limit the aspect of the DC power source DS. In addition, the first coupled inductor L1 and the second coupled inductor L2 are, for example, a first group of transformers. The third coupled inductor L3 and the fourth coupled inductor L4 are, for example, a second set of transformers. The first coupled inductor L1 and the second coupled inductor L2 are respectively disposed, for example, in the primary side winding and the secondary side winding of the first group of transformers. The third coupled inductor L3 and the fourth coupled inductor L4 are respectively disposed, for example, in the primary side winding and the secondary side winding of the second group of transformers. This embodiment does not limit the aspects of the first, second, third, and fourth coupled inductors L1, L2, L3, and L4.

In detail, the first coupled inductor L1 is electrically connected to the DC power source DS for electrically coupling with a second coupled inductor L2. The third coupled inductor L3 is electrically connected to the DC power source DS for electrically coupling with a fourth coupled inductor L4. The inductance of the first coupled inductor L1 is the same as the inductance of the third coupled inductor L3. That is to say, the first and second coupled inductors L1, L2 are a group, and the third and fourth coupled inductors L3, L4 are a group, and the two groups are respectively wound on two iron cores.

Next, the turns ratio of the first coupled inductor L1 to the second coupled inductor L2 is 1 to N, and the turns ratio of the third coupled inductor L3 to the fourth coupled inductor L4 is 1 to N, and N is a value greater than zero. That is to say, the turns ratio of the two sets of transformers is such that the number of turns of the primary side winding is equal to or smaller than the number of turns of the secondary side winding, for example, 1:1, 1:2, 1:3 or 1:N. For example, N is for example 2. Wherein the first and second coupled inductors L1, L2 The turns ratio is the same as the turns ratio of the third and fourth coupled inductors L3, L4, and the turns ratio is 1:2.

In practice, the transformer has a primary side winding and a secondary side winding corresponding to magnetic coupling. The primary side winding is, for example, the first or third coupled inductor L1, L3. The secondary side winding is, for example, a second or fourth coupled inductor L2, L4. The transformer transmits or converts energy through the magnetically coupled primary side winding and the secondary side winding, for example, the number of turns of the secondary side winding is greater than the number of turns of the primary side winding, whereby the transformer raises the voltage, for example, 15 volts. The voltage is regulated to a voltage of 400V volts. Of course, the number of turns of the primary side winding can be equal to the number of turns of the secondary winding, whereby the transformer transfers energy.

In other embodiments, the turns ratio of the first coupled inductor L1 to the second coupled inductor L2 is M ratio 1, and the turns ratio of the third coupled inductor L3 to the fourth coupled inductor L4 is M ratio 1, and M is greater than zero. The value. That is to say, the number of turns of the primary side winding is larger than the number of turns of the secondary side winding, whereby the transformer reduces the voltage, for example, by a voltage of 240 volts to 110 volts. This embodiment does not limit the aspects of the first, second, third, and fourth coupled inductors L1, L2, L3, and L4.

The switch module SM is electrically connected to the first coupled inductor L1 and the third coupled inductor L3. In practice, the switch module SM is implemented, for example, by a plurality of power transistors, gate transistors, or field effect transistors. The switch module SM is controlled by the control signal, the pulse width modulation signal or the synchronization signal output by the control module 10. This embodiment does not limit the aspect of the switch module SM.

The unidirectional conduction unit D1 is electrically connected between the first coupling inductor L1 and the second coupling inductor L2. In practice, the one-way conduction unit D1 is realized, for example, by a diode. The unidirectional conduction unit D1 is, for example, a unidirectional conduction component in the boost converter circuit, whereby current can flow from the first coupling inductor L1 to the second coupling inductor L2. This embodiment does not limit the aspect of the one-way conduction unit D1.

The control module 10 is electrically connected to the switch module SM. In practice, the control module 10 is, for example, a central processing unit (CPU), a micro processing unit (MCU), or a digital signal processor. (Digital Signal Processor) for performing signal calculation, processing, and control switch switching operations in the boost converter 1. This embodiment does not limit the aspect of the control module 10.

Further, the control module 10 transmits the synchronization signal to control the synchronous conduction or the synchronous cutoff of the plurality of switches in the switch module SM. The synchronization signal includes, for example, a plurality of identical pulse width modulation signals. That is to say, the switches in the switch module SM will be turned on or off simultaneously according to the synchronization signal.

Next, the second coupled inductor L2 is connected in series with the fourth coupled inductor L4, and a load Ld is electrically connected to the third coupled inductor L3 and the fourth coupled inductor L4, and the load Ld is connected in parallel with an energy storage unit Co. In practice, the present embodiment connects the fourth coupled inductor L4 through the second coupled inductor L2 to increase the output voltage after the series connection. The second and fourth coupled inductors L2 and L4 are connected in series and the voltage polarity is additive. That is, the present embodiment can provide a higher output voltage to the load Ld. The other energy storage unit Co is realized, for example, by a capacitor or an electrolytic capacitor. This embodiment does not limit the aspect of the energy storage unit Co.

For example, when the switch module SM is in an on state, the first coupled inductor L1 and the third coupled inductor L3 are respectively in a charged state. In other words, when the switch module SM is in the on state, the DC power source DS will charge the first coupled inductor L1 and the third coupled inductor L3. And the one-way conduction unit D1 is in an off state. Therefore, the energy storage unit Co is in a discharged state to discharge to the load Ld.

Conversely, when the switch module SM is in the off state, the first coupled inductor L1 will convert electrical energy to the second coupled inductor L2, and the third coupled inductor L3 will convert electrical energy to the fourth coupled inductor L4. In other words, when the switch module SM is in the off state, the first coupled inductor L1 will convert electrical energy to the second coupled inductor L2, and the third coupled inductor L3 will convert electrical energy to the fourth coupled inductor L4. The second coupled inductor L2 is connected in series with the fourth coupled inductor L4, thereby increasing the output voltage after the series connection. In addition, the switch module SM is in a circuit in an off state, and the energy storage unit Co is in a charging state.

Based on the above, this embodiment uses low voltage direct current to convert to high voltage direct current, an output voltage of about 200 to 400 volts. Wherein, the second and fourth coupled inductors L2, L4 The first and third coupled inductors L1 and L3 are electrically coupled to each other, and are connected in series via the second and fourth coupled inductors L2 and L4 to output a high voltage. Wherein, when the ratio of the turns of the first and second coupled inductors L1 and L2 is larger, or when the ratio of the turns of the third and fourth coupled inductors L4 is larger, N is a larger value. In the boost ratio conversion device 1 of the turns ratio, the control module 10 can cause the boost converter device 1 to reach the same high-voltage DC output through a small duty cycle.

2 is a circuit diagram of a boost converter device according to another embodiment of the present invention. Please refer to Figure 2. For convenience of description, the switch module SM of the present embodiment includes two switches S1 and S2 for explanation. The switch module SM includes a first switch S1 and a second switch S2. For convenience of explanation, the first ends of the coupled inductors L1, L2, L3, and L4 are current input terminals, and the second ends of the coupled inductors L1, L2, L3, and L4 are current output terminals.

The one-way conduction unit shown in FIG. 2 is a diode D1. The energy storage unit is a capacitor Co. The first switch S1 and the second switch S2 are respectively a gate transistor. The drain of the first switch S1 is electrically connected to the first end of the first coupled inductor L1. The source of the first switch S1 is electrically connected to the first end of the third coupled inductor L3. The drain of the second switch S2 is electrically connected to the second end of the first coupled inductor L1. The source of the second switch S2 is electrically connected to the second end of the third coupled inductor L3.

Further, the first end of the first coupled inductor L1 is electrically connected to the anode of the DC power source DS and the first switch S1 of the switch module SM. The second end of the first coupled inductor L1 is electrically connected to the first pole of the one-way conduction unit D1 and the second switch S2 of the switch module SM. The second pole of the single-conducting unit D1 is electrically connected to the first end of the second coupled inductor L2. The second end of the second coupled inductor L2 is electrically connected to the first end of the fourth coupled inductor L4. The second end of the fourth coupled inductor L4 is electrically connected to the capacitor Co and the load Ld. The first end of the third coupled inductor L3 is electrically connected to the first switch S1, the capacitor Co and the load Ld of the switch module SM. The second end of the third coupled inductor L3 is electrically connected to the cathode of the DC power source DS and the second switch S2 of the switch module SM.

The control module 10 outputs a synchronization signal to a first switch S1 and a second switch S2 of the switch module SM to control the synchronous conduction or synchronous cutoff of the switch module SM. That is, the control module 10 controls the on/off pulse width modulation signal of the first switch S1 to be synchronized with the pulse width modulation signal that controls the on or off of the second switch S2.

In detail, a general boost converter circuit usually performs a boosting operation by controlling the on or off of a switch. Therefore, this switch often has a large cross-over pressure. In this embodiment, two switches are used to share the operation of the switch on the general boost converter circuit. Therefore, compared with the general boost converter circuit, the first switch S1 and the second switch S2 of the embodiment respectively have a small crossover voltage. Furthermore, in this embodiment, the fourth coupled inductor L4 is connected in series through the second coupled inductor L2 to increase the output voltage after the series connection.

It is worth mentioning that the output voltage maintenance time is taken as the design of the energy storage unit. The voltage maintenance time is defined as: When the input power supply stops supplying energy to the load Ld at the output end, the output voltage must remain above the preset minimum output voltage for a certain period of time. In the actual circuit of the embodiment, the electrolytic capacitor Co is selected as the energy storage unit.

Next, the charging and discharging operation of the boost converter device 1 will be further described.

FIG. 3 is a schematic diagram of the operation of the switch module of the boost converter according to another embodiment of the present invention in an on state. Please refer to Figure 3. FIG. 3 illustrates a switch module SM in an on state. That is, the first and second switches S1, S2 are in a circuit state when they are in conduction.

The DC power source DS charges the first and third coupled inductors L1 and L3. A current flows from the anode of the DC power source DS through the first coupled inductor L1 and the second switch S2 to the cathode of the DC power source DS. Another current flows from the anode of the DC power source DS through the first switch S1 and the third coupled inductor L3 to the cathode of the DC power source DS. The other diode D1 is in an off state, and the capacitor Co is discharged to the load Ld. Among them, "on the first And the charging loop of the third coupled inductor L1, L3 charging" and the "discharge loop of the capacitor Co discharge to the load Ld" operate independently, as shown in FIG.

4 is a schematic diagram of the operation of the switch module of the boost converter according to another embodiment of the present invention in an off state. Please refer to Figure 4. FIG. 4 illustrates a switch module SM in an off state. That is, the first and second switches S1, S2 are synchronized in the circuit state at the time of the cutoff. Wherein, a current flows from the anode of the DC power source DS through the first coupled inductor L1, the diode D1, the second and fourth coupled inductors L2, L4, the load Ld and the third coupled inductor L3 to the cathode of the DC power source DS. The other current flows from the anode of the DC power source DS through the first coupled inductor L1, the diode D1, the second and fourth coupled inductors L2, L4, the load Ld and the third coupled inductor L3 to the cathode of the DC power source DS.

Based on the above, the transfer function of this embodiment is different from the conventional boost converter and the switched inductor boost converter. This embodiment achieves a high boost ratio by operating the coupled inductors of the two sets of transformers. That is to say, in the present embodiment, when the conventional boost converter is operated at a high boost ratio, due to the parasitic components of the circuit, when the duty cycle is too large, a large conduction loss will be caused, so that the duty cycle of the switch is limited. The conventional boost converter cannot achieve the problem of higher boost ratio.

Another difference from the conventional boost converter is that the conventional boost converter has a higher voltage stress but a higher on-resistance switch because the voltage stress on the switch is equal to the output voltage on the output load Ld. Increase the loss of conduction on the switch, so it is not suitable for high boost applications. Briefly, this embodiment may use switches S1, S2 of lower voltage stress. Among them, the two switches S1, S2 share the high voltage stress of one switch, thereby reducing the cross voltage of each of the switches S1, S2.

FIG. 5 is a diagram showing voltage and current waveforms of a boost converter according to another embodiment of the present invention. FIG. Please refer to Figure 5. 5 shows the waveforms of the gate voltages Vg1 and Vg2 of a switch S1 and S2, the voltages Vds1 and Vds2 between the drain and the source of a switch S1 and S2, and the drain and source of a switch S1 and S2. Current between Ids1, Ids2 The waveform, the waveform of the voltage VD1 of the diode D1, the waveform of the current IL1 of a first coupled inductor L1, the waveform of the current ID1 of a diode D1, and the waveform of the output voltage Vout of a load Ld.

In practice, this embodiment operates in continuous conduction mode (CCM) with the circuit of FIG. Among them, the current flowing through its coupled inductor L1 does not fall to zero.

Further, in the interval of 0<t<DTS, the first switch S1 and the second switch S2 respectively conduct current paths. In this interval, the first and third coupled inductors L1, L3 are in a parallel energy storage state, and the currents of the first and third coupled inductors L1, L3 rise linearly. The diode D1 is off, and the output capacitor Co supplies power to the load Ld. According to the volt-second balance theorem, the relationship between the input voltage and the output voltage and duty cycle of the continuous conduction mode of the circuit can be derived. Those skilled in the art should be aware of the relationship between input voltage and output voltage, duty cycle.

In the DTS<t<TS interval, the first and second switches S1, S2 respectively cut off the current path. When the first and second switches S1, S2 are simultaneously in an off state. Due to the continuity of the currents of the first, second, third, and fourth coupled inductors L1, L2, L3, and L4, the diode D1 is turned on, and the second coupled inductor L2 is connected in series with the fourth coupled inductor L4. The second coupled inductor L2 and the fourth coupled inductor L4 simultaneously discharge electricity to the output capacitor Co and the load Ld. This embodiment does not limit the state of the voltage and current waveforms of the boost converter device 1.

6 is a graph showing a relationship between an output voltage and a duty cycle of a conventional boost converter according to another embodiment of the present invention. Please refer to Figure 6. 6 shows an output voltage-responsibility cycle curve BC1, a conventional boost converter output voltage-responsibility cycle curve BC2, and a conventional switched inductor boost converter output voltage-responsibility. Cycle curve BC3.

As can be seen from FIG. 6, this embodiment can achieve the purpose of boosting in a small duty cycle. For example, in the case of boosting to 200 volts, this embodiment can achieve boosting to 200 volts with a duty cycle of about 0.6. Conventional boost converters and conventional switched inductor boost converters must each have a duty cycle of about 0.8 to 0.9 to achieve boost to 200 volts. special. In brief, this embodiment improves the problem that other boost converters have to achieve a high boost ratio, resulting in an excessively large duty cycle resulting in inefficient efficiency.

In summary, the present invention is a boost converter device that is electrically connected between the first and third coupled inductors through two switches. When the two switches are turned off, the first and third coupled inductors are electrically coupled to the second and fourth coupled inductors, respectively, and are connected in series via the second and fourth coupled inductors to output a high voltage. The turns ratio of the first and second coupled inductors is the same as the turns ratio of the third and fourth coupled inductors. When the N value of the turns ratio 1:N is larger, the control module can cause the boost converter to achieve the same high-voltage DC output through a small duty cycle. Furthermore, the present invention utilizes these two switches to share the operation of a switch on a general boost converter circuit. Therefore, compared with the general boost converter circuit, the first and second switches of the present invention will respectively have a small cross-over voltage, whereby the present invention can select a switch with a lower voltage stress but a smaller on-resistance, thus reducing the switch. The loss of the conduction. As such, the present embodiment is indeed suitable for application in high boost applications and improves the usability of the boost converter.

The above description is only an embodiment of the present invention, and is not intended to limit the scope of the invention.

1‧‧‧Boost converter

10‧‧‧Control Module

L1‧‧‧First coupled inductor

L2‧‧‧Second coupled inductor

L3‧‧‧ Third coupled inductor

L4‧‧‧4th coupled inductor

DS‧‧‧DC power supply

D1‧‧‧One-way unit

SM‧‧‧ switch module

Ld‧‧‧ load

Co‧‧‧ Energy Storage Unit

Claims (10)

A boost converter device is electrically connected to a DC power supply. The boost converter includes: a first coupled inductor electrically connected to the DC power source for electrically coupling with a second coupled inductor; and a third coupled inductor Electrically connecting the DC power source for electrically coupling with a fourth coupled inductor; a switch module electrically connecting the first coupled inductor and the third coupled inductor; and a single conducting unit, electrically connected Between the first coupled inductor and the second coupled inductor; wherein the second coupled inductor is connected in series with the fourth coupled inductor, and a load is electrically connected to the third coupled inductor and the fourth coupled inductor, and the load is coupled An energy storage unit is connected in parallel. The boost converter device of claim 1, further comprising a control module, wherein the control module outputs a synchronization signal to a first switch and a second switch of the switch module to control the first switch and The second switch is turned on or off synchronously. The boost converter device of claim 2, wherein the first end of the first coupled inductor is electrically connected to the anode of the DC power source and the first switch of the switch module, and the second end of the first coupled inductor The first pole of the one-way conduction unit and the second switch of the switch module are electrically connected. The boost converter device of claim 2, wherein the second pole of the unidirectional conduction unit is electrically connected to the first end of the second coupled inductor, and the second end of the second coupled inductor is electrically connected to the fourth The first end of the coupled inductor is electrically connected to the energy storage unit and the load. The boost converter device of claim 2, wherein the first end of the third coupled inductor is electrically connected to the first switch, the energy storage unit and the load of the switch module, and the third coupled inductor The two ends are electrically connected to the cathode of the DC power source and The second switch of the switch module. The boost converter device of any one of claims 1 to 5, wherein when the switch module is in an on state, the DC power source is charged to the first coupled inductor and the third coupled inductor, and the switch module is In the off state, the first coupled inductor will convert electrical energy to the second coupled inductor, and the third coupled inductor will convert electrical energy to the fourth coupled inductor. The boost converter according to any one of claims 3 to 5, wherein the first end is a current input end of each of the coupled inductors, and the second end is a current output end of each of the coupled inductors. The boost converter of claim 1, wherein a ratio of turns of the first coupled inductor to the second coupled inductor is 1 to N, and a ratio of turns of the third coupled inductor to the fourth coupled inductor is 1. The ratio N, N is a value greater than zero. The boost converter device of claim 1, wherein the inductance of the first coupled inductor is the same as the inductance of the third coupled inductor, and the first coupling inductor and the second coupled inductor have the same turns ratio. The turns ratio of the third coupled inductor to the fourth coupled inductor. The boost converter device of claim 2, wherein the unidirectional conduction unit is a diode, the energy storage unit is a capacitor, and the first switch and the second switch are respectively a gate transistor.