TWI433440B - High boost converter - Google Patents

Description

High boost converter

The present invention relates to a boost converter, and more particularly to a high boost converter capable of converting a low voltage to a high voltage.

In many applications, it is often necessary to boost the existing low voltage to a higher voltage to provide equipment requirements, such as power electronics for automobiles, active burner loads with energy recovery, and boost converters ( Boost Converters and Buck-Boost Converters are commonly used in the market, but there is a disadvantage that neither a boost converter nor a buck-boost converter can achieve a high boost ratio.

Boost converter in continuous conduction mode (CCM), its boost ratio , D is the duty cycle; in theory, although the boost ratio There is no upper limit, but it is actually limited by the parasitic effects of the components and the ability of the controller, and the boost ratio is lowered by 4 to 5 times, so it is impossible to increase the boost ratio without limitation.

According to the prior art, the voltage conversion ratio of the output voltage V _o of the boost converter device and the input voltage V _in proposed by the applicant in the patent application No. 97294233 is Compared to the general boost ratio There has been better performance.

In order to achieve better performance and a better boost ratio of the boost converter, the present invention can provide a high boost converter having a higher boost ratio.

Therefore, the high boost converter of the present invention includes a first charge pump, a second charge pump, a coupled inductor, a voltage clamp buffer, and an output circuit.

The first charge pump is configured to receive an input voltage and boost the input voltage, and has a first switching element, a second switching element connected in series with the first switching element, and a terminal connected to the first switching element a diode and a first boosting capacitor bridging the first switching element and the diode; the second charge pump is electrically connected to the first charge pump, and has a third switching element and a string a fourth switching element connected to the third switching element, a diode connected to one end of the third switching element, and a second boosting capacitor bridging the third switching element and the diode.

The coupled inductor is electrically connected to the second boosting capacitor and the fifth switching component, and has a primary side inductance, a secondary side inductance, and a leakage inductance; the voltage clamping buffer is electrically connected to the coupled inductor and the a second charge pump having a fifth switching element and clamping a voltage across the fifth switching element; and the output circuit has an output diode and an output capacitor coupled to the output diode A voltage clamp buffer is used to store the energy released by the leakage inductance of the coupled inductor.

In the first embodiment, the switching elements are turned on or off by a wave width adjustment control signal, and the duty cycle intervals of the wave width adjustment control signals are D and 1-D, respectively, wherein the interval D is the first a switching element, the third switching element is electrically connected to the fifth switching element, and the second switching element is not conductive to the fourth switching element, and the interval 1-D is that the second switching element is electrically connected to the fourth switching element and the The first switching element, the third switching element, and the fifth switching element are not conductive.

In the second embodiment, the switching elements are turned on or off by a wave width adjustment control signal, and the duty cycle intervals of the wave width adjustment control signals are D and 1-D, respectively, wherein the interval D is the first A switching element, the fourth switching element is electrically connected to the fifth switching element, and the interval 1-D is that the second switching element is electrically connected to the third switching element.

Preferably, the voltage clamping buffer further has a clamping capacitor, at least one clamping diode and a clamping inductor. When the fifth switching component is non-conductive, the leakage energy is passed through the clamping diode. The clamp capacitor is charged and the energy stored by the clamp capacitor is output via the clamp inductor. When the high boost converter is N-phase interleaved to increase the output power, N-1 clamp diodes are added to the voltage clamp buffer.

The high boost converter of the present invention combines components including two sets of charge pumps, coupled inductors, voltage clamp buffers, and output capacitors, and the circuit is simplified, and energy transfer can be achieved at a high load range.

The foregoing and other objects, features, and advantages of the invention are set forth in the <RTIgt;

Referring to FIG. 1, a preferred embodiment of the high boost converter 1 of the present invention includes a first charge pump 111, a second charge pump 112, and a coupled inductor 12.

The first charge pump 111 is configured to receive an input voltage V _i and boost the input voltage V _i , and has a first switching element S ₁ (with a diode D ₁ connected in parallel) and a series connected first switching element the second switching element S ₁ S ₂ (connected in parallel a diode D _2), a first diode D is connected one end of a first switching element S _{1 b 1,} a crossover and a first switching _{element. 1} S and a first diode D _{b 1} of the first boost capacitor C _{b 1;} a second charge pump 112 is electrically connected to the first charge pump 111, having a third switching element S ₃ (a diode connected in parallel D ₃ ), a fourth switching element S ₄ connected in series with the third switching element S ₃ (with a diode D ₄ connected in parallel), and a second diode D _{b 2} connected to one end of the third switching element S ₃ and a third switching element connected across the second S ₃ and diode D _{b 2} of the second boost capacitor C _{b 2.}

Referring to FIG. 2, the coupled inductor 12 of the high boost converter 1 is electrically connected to one end of the second boost capacitor C _{b 2} and has a primary side inductance L _p , a secondary side inductance L _{s ,} and a leakage inductance L _LK ; the primary side inductance L _p and the secondary side inductance L _s are the primary side self-inductance and the secondary side self-inductance of the coupled inductor 12, respectively, and the coupled inductor 12 has a leakage inductance L _LK .

Referring to FIG. 3, since the energy of the leakage inductance L _LK of the high boost converter 1 is accumulated on the parasitic capacitance of the fifth switching element S ₅ , if the voltage is too high, the fifth switching element S ₅ is broken. The high boost converter device 1 of the present invention further includes a voltage clamping buffer (Snubber) 13 to overcome the leakage inductance L _LK problem; the voltage clamping buffer 13 is electrically connected to the coupling inductor 12 and the second charge pump 112, and has a a fifth switching element S ₅ coupled to the fourth switching element S ₄ (with a diode D ₅ connected in parallel), a clamping capacitor C _sn , a clamping diode D _sn and a clamping inductor L _sn ; voltage clamping buffer The device 13 is configured to clamp the fifth switching element S ₅ across the voltage to avoid the voltage being too high to break through the fifth switching element S ₅ .

The circuit of the output circuit of the high boost converter device 1 further has an output diode D _o , an output capacitor C _o and an output resistor R _o , and the output capacitor C _o is coupled to the voltage clamp via the output diode D _{o .} The buffer 13 is configured to store the energy released by the leakage inductance of the coupled inductor 12 and then loaded to the output resistor R _o . It should be noted that when the high boost converter 1 adopts multi-phase interleaving control to increase the output power, for example, the N phase, only N-1 clamp diodes D _{sn need} to be added, and the circuit is very concise.

In the preferred embodiment, the component specifications of the high boost converter 1 are: (i) the input voltage V _{i is} set to 5 volts; (ii) the output voltage Vo is set to 60 volts; (iii) the DC output power is 30 watts. (iv) The switching frequency fs is selected to be 120 kHz; (v) the turns ratio of the coupled inductor is Ns/Np is 5; (vi) the capacitance of the output capacitor C _o is 100-μF; (vii) The model of a diode D _{b 1} is STPS20L25LT, the model of the second diode D _{b 2} is STPS20-L25LT, the model of the clamp diode D _sn is RGP10G, and the model of D _o is BYQ28X; (viii) first The switching element S ₁ , the second switching element S ₂ , the third switching element S ₃ , the fourth switching element S ₄ and the fifth switching element S _{5 are} selected as IRF 1404, IRF 1404, IRF 1404, IRF 1404 and IRFB 3206; (ix) FPGA control The chip (not shown) is model EP1C3T100.

Referring to FIG. 4 to FIG. 7, assuming that the switching element is in the continuous conduction mode, according to two embodiments in which the gate driving signal is different, the first embodiment assumes the voltages of the first capacitor C _{b 1} and the second capacitor C _{b 2} . For the input voltage V _i , and in the second embodiment, the voltages at the first capacitor C _{b 1} and the second capacitor C _{b 2} are the input voltages V _i and 2 V _i .

For convenience of explanation, the voltage clamping buffer 13 of FIG. 3 only shows the fifth switching element S ₅ and the diode D ₅ in FIGS. 4 to 7 , and the remaining components and leakage inductance of the voltage clamping buffer 13 are omitted. L _LK .

The working principle of the first preferred embodiment is described below with reference to FIG. 4 and FIG. 5, wherein the duty cycle interval of the bandwidth adjustment control signal is (D, 1- D ), wherein the interval D is the first switching element S ₁ , The third switching element S ₃ and the fifth switching element S _{5 are} turned on, and the interval 1- D is that the second switching element S ₂ and the fourth switching element S _{4 are} turned on, according to which the voltage conversion ratio is V _o / V _i = [ (3 n -1) D +1]/(1- D ).

Referring to FIG. 4, when the high boost converter 1 operates in the continuous conduction mode, the first switching element S ₁ , the third switching element S ₃ and the fifth switching element S _{5 are} turned on, and the second switching element S ₂ and the When the four switching elements S _{4 are} not turned on, the boosting capacitor C _{b 1} across the voltage V _{cb 1} = V _i , the primary side inductance L _p generates an exciting voltage higher than the input voltage V _i , and the output is generated by the output capacitor C _o Voltage V _o .

Referring to FIG. 5, when the second switching element S ₂ and the fourth switching element S _{4 of the} high-boost converter device 1 are turned on, the first switching element S ₁ , the third switching element S _{3 ,} and the fifth switching element S _{5 are} not turned on. The output diodes D _{b 1} and D _{b 2} are turned on by the forward bias, and the first boosting capacitor C _{b 1} and the second boosting capacitor C _{b 2 are} charged as the input voltage V _i , so that the primary side inductor is previously stored. The energy of L _p is transferred to the secondary side inductance L _s , and the released energy charges the output capacitance C _{o to} produce an output voltage V _o .

The working principle of the second preferred embodiment is described below with reference to FIG. 6 and FIG. 7. The duty cycle interval of the bandwidth adjustment control signal is (D, 1- D ), wherein the interval D is the first switching element S ₁ , The fourth switching element S ₄ and the fifth switching element S _{5 are} turned on, and the interval 1- D is that the second switching element S ₂ and the third switching element S _{3 are} turned on, and the voltage conversion ratio thereof is V _o / V _i = [( 2 n -3) D +3] / (1- D ).

Referring to FIG. 6, the first switching element S ₁ , the fourth switching element S ₄ and the fifth switching element S _{5 of the} high boost converter 1 are turned on, and the second switching element S ₂ and the third switching element S _{3 are} not turned on. The second diode D _{b 2} is turned on by the forward bias, and the second boosting capacitor C _{b 2 is} charged as the input voltage V _i , and the primary side inductor L _p generates an excitation voltage higher than the input voltage V _i , and The output capacitor C _o produces an output voltage V _o .

Referring to FIG. 7, when the second switching element S ₂ and the third switching element S _{3 of the} high-boost converter device 1 are turned on, and the first switching element S ₁ , the fourth switching element S _{4 ,} and the fifth switching element S _{5 are} not turned on The first diode D _{b 1} and the second diode D _{b 2} are turned on by the forward bias, and the first boost capacitor C _{b 1 is} charged as the input voltage V _i , so that the primary side inductor L _{p is} previously stored. The energy is transferred to the secondary side inductance L _s and the released energy charges the output capacitance C _{o to} produce an output voltage V _o .

Referring to Figures 8 and 9, the voltage clamping buffer 13 of Figure 3 is a passive clamping voltage having two modes.

1) First mode: see FIG. 8, when the fifth switching element S _{non-conductive. 5,} the leakage inductance L _LK energy is clamped via a diode D _sn charging of the clamp capacitor C _sn, thereby protecting the fifth switching element S ₅ .

2) Second mode: Referring to FIG. 9, when the third switching element S _{3 is} turned on, the energy stored in the clamp capacitor C _sn is pumped into the output circuit via the clamp inductor L _sn and the clamp diode D _sn .

Referring to FIG. 10, using the simulation result of the IsSpice simulation software, it can be seen that when the input voltage V _i of the high boost converter device 1 of the present invention is 5 volts, the output voltage Vo can be stably reached 60 volts.

The verification results of the high boost converter 1 of the present invention are as shown in Figs. 11 to 18 and will be described below.

For the high boost converter 1 operating in the light load case, (1) is to measure the driving signal of the fifth switching element S ₅ ; (2) is to measure the driving signal of the second switching element S ₂ ; (3) is The current flowing through the primary side inductor L _p is measured; and (4) is the voltage flowing through the output capacitor C _o .

Referring to FIG. 11 , in the case of the half-load operation of the high-boost converter device 1 in the first mode, (1) is to measure the driving signal of the fifth switching element S ₅ ; (2) to measure the second switching element S ₂ Driving the signal; (3) measuring the current flowing through the primary side inductor L _p ; and (4) measuring the voltage flowing through the output capacitor C _o .

Referring to FIG. 11 , in the case of the half-load operation of the high-boost converter 1 in the second mode, (1) is to measure the driving signal of the fifth switching element S ₅ ; (2) to measure the second switching element S ₂ driving signal; (3) to measure the current flowing through the primary side inductor L _p; and (4) measuring the voltage through the output capacitor C _o of.

Referring to FIG. 12, the high boost converter 1 operates at full load, (1) is a driving signal for measuring the fifth switching element S ₅ ; (2) is a driving signal for measuring the second switching element S ₂ ; ) to measure the current flowing through the primary side inductor L _p ; and (4) to measure the voltage flowing through the output capacitor C _o .

Referring to FIG. 13 and FIG. 14 , the first mode and the second mode are respectively full load (1) is a driving signal for measuring the fifth switching element S ₅ ; (2) is a driving signal for measuring the second switching element S ₂ (3) is to measure the current flowing through the primary side inductor L _p ; and (4) is to measure the voltage flowing through the output capacitor C _o .

Referring to FIG. 15 and FIG. 16, the first mode and the second mode are respectively half-loaded. (1) is a driving signal for measuring the fifth switching element S ₅ ; and (2) is for measuring a voltage of the fifth switching element S ₅ (3) is to measure the voltage of the diode D _{b 1} ; and (4) is to measure the voltage of the diode D _{b 2} .

Referring to FIG. 17 and FIG. 18, (1) is a driving signal for measuring the fifth switching element S ₅ ; and (2) is for measuring a voltage of the fifth switching element S ₅ ; (3) measuring the voltage of the first diode D _{b 1} ; and (4) measuring the voltage of the second diode D _{b 2} .

In summary, the high boost converter 1 of the present invention uses two sets of charge pump 11 in combination with the coupled inductor 12, taking the input voltage 5V as an example, and the available output voltage V _o is 60 volts, with a boost ratio of 12 times. Therefore, the object of the present invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

111‧‧‧First charge pump

112‧‧‧Second charge pump

12‧‧‧coupled inductor

13‧‧‧Voltage clamp buffer

Figure 1 is a schematic view showing a preferred embodiment of the high boost converter of the present invention;

2 is a circuit diagram showing a preferred embodiment of the high boost converter of the present invention having a leakage inductance;

3 is a circuit diagram showing a preferred embodiment of the high boost converter of the present invention having a voltage clamp buffer that overcomes leakage inductance;

4 and 5 are schematic circuit diagrams illustrating the operation of the first preferred embodiment of the high boost converter;

6 and 7 are schematic circuit diagrams illustrating the operation of the second preferred embodiment of the high boost converter;

FIG. 8 and FIG. 9 are respectively a circuit diagram illustrating the working principle of voltage clamping buffer clamping voltage;

Figure 10 is a graph illustrating the simulation results of the preferred embodiment using the simulation software;

11 to 18 are waveform diagrams respectively showing the measurement results of the relevant elements in the case where the high boost converters operate in the first mode and the second mode, respectively, under half load and full load.

111. . . First charge pump

112. . . Second charge pump

12. . . Coupled inductor

13. . . Voltage clamp buffer

Claims (3)

A high boost converter includes a first charge pump for receiving an input voltage and boosting the input voltage, and having a first switching element and a second switching element connected in series with the first switching element a first diode connected to one end of the first switching element and a first boosting capacitor bridging the first switching element and the first diode; a second charge pump electrically connected to the first diode a first charge pump having a third switching element, a fourth switching element connected in series with the third switching element, a second diode connected to one end of the third switching element, and a third switching element a second boosting capacitor of the second diode; a voltage clamping buffer electrically connected to the coupled inductor and the second charge pump, having a fifth switching component and clamping the cross of the fifth switching component a coupled inductor electrically connected to the second boosting capacitor and the fifth switching component, and having a primary side inductance, a secondary side inductance and a leakage inductance; and an output circuit having an output diode Body and an output capacitor through which the output capacitor The diode is coupled to the voltage clamping buffer for storing energy released by the leakage inductance of the coupled inductor; wherein the switching elements are driven to be turned on or off by a wave width adjustment control signal, and the width adjustment is performed. The duty cycle interval of the control signal is D and 1-D, respectively, wherein the interval D is the first switching element, the fourth switching element is electrically connected to the fifth switching element, and the interval 1-D is the second switching element It is electrically connected to the third switching element. The high-boost converter device of claim 1, wherein the voltage-clamping buffer further has a clamp capacitor, at least one clamp diode and a clamp inductor, and when the fifth switch component is non-conductive, The energy of the leakage inductance charges the clamp capacitor via the clamp diode, and the energy stored by the clamp capacitor is output through the clamp inductor. The high-boost switching device according to claim 2, wherein when the high-boost switching device adopts N-phase interleaving control to increase output power, N-1 clamps are added to the voltage clamp buffer. Polar body.