TW202143613A - Resonant switching power converter - Google Patents

Abstract

The present invention provides a resonant switching power converter including: a plurality of capacitors; a plurality of switches; at least one charging inductor; and at least one discharging inductor. In a charging process, the plural capacitors are electrically connected to the charging inductor in series between an input voltage and an output voltage by switching the corresponding switches to form a charging path, and a turn-on time point and a turn-off time point of the corresponding switches are synchronous with a start time point and an end time point of a positive half wave of a charging resonant current of the charging process. In a discharging process, each of the capacitors is electrically connected to the corresponding discharging inductor in series between the output voltage and a ground level by switching the corresponding switches to form a plurality of discharging paths, and the turn-on time point and the turn-off time point of the corresponding switches are synchronous with a start time point and an end time point of a positive half wave of a discharging resonant current of the discharging process.

Description

Resonant switching power converter

The present invention relates to a resonant switching power converter, and in particular to a resonant switching power converter in which the charging or discharging duration is related to the resonant frequency of the charging or discharging.

Figure 1 shows a conventional power converter. During the charging operation, the switches Q1, Q3, Q5, Q8, and Q9 are turned on, and the switches Q2, Q4, Q6, Q7, and Q10 are not turned on, so that the capacitor C1 is connected in series with the inductor L1 between the input voltage VIN and the output voltage VOUT, and The capacitor C2 is connected in series with the capacitor C3 and the inductor L2 between the ground potential and the output voltage VOUT. In the discharging operation, the switches Q2, Q4, Q6, Q7, Q10 are turned on, and the switches Q1, Q3, Q5, Q8, Q9 are not turned on, so that the inductor L1 is connected in series with the capacitor C1 and the capacitor C2 between the ground potential and the output voltage VOUT , And the inductor L2 is connected in series with the capacitor C3 between the ground potential and the output voltage VOUT. The capacitor of this conventional power converter needs to withstand a higher rated voltage. For example, the DC bias of capacitor C1 is 3 times the output voltage Vc1=3VOUT, and the DC bias of capacitor C2 is twice the output voltage Vc2=2VOUT, The DC bias voltage of the capacitor C3 is equivalent to the output voltage Vc3=VOUT. Because the DC bias voltage of the capacitor is relatively high, the conventional power converter needs to use a capacitor with a larger volume. In addition, the capacitance of the capacitor usually decreases with the increase of the DC bias voltage. When the input voltage range is between 36V and 76V, the DC bias voltage range of the capacitor C1 will be between 27V and 57V. The bias voltage has a wide variation range, so the capacitance value of the conventional power converter varies greatly, and its resonant frequency also changes with the variation of the capacitance. This will cause a large switching power loss and require complex control to change the power conversion efficiency. Furthermore, the voltage conversion ratio between the input voltage VIN and the output voltage VOUT of the conventional power converter can only be 4:1 or 2:1, and the voltage conversion ratio of 3:1 cannot be performed.

In view of this, the present invention aims at the above-mentioned shortcomings of the prior art, and proposes an innovative power converter.

In one aspect, the present invention provides a resonant switching power converter for converting an input voltage into an output voltage. The resonant switching power converter includes: a complex capacitor; a complex switch correspondingly coupled to the complex capacitor , Respectively according to a corresponding operation signal to switch the electrical connection relationship of the corresponding capacitor; at least one charging inductor connected in series with at least one of the plurality of capacitors; and at least one discharge inductor connected with the plurality of capacitors At least one of them is connected in series; wherein, in a charging process, by switching the plurality of switches, the plurality of capacitors and the at least one charging inductor are connected in series with each other between the input voltage and the output voltage to form a The charging path, and the corresponding turn-on and non-turn-on timings of the plurality of switches are synchronized with the start and end of the positive half-wave of one of the charging resonant currents in the charging process; wherein, in a discharging process, the The switching of a plurality of switches makes each of the capacitors and the corresponding discharge inductance connect in series between the output voltage and a ground potential to form a plurality of discharge paths, and the conduction and non-conduction times of the corresponding plurality of switches are synchronized with the The start time and end time of the positive half-wave of the discharge resonance current, one of the discharge procedures; wherein the charging procedure and the discharging procedure are alternately sequenced repeatedly to convert the input voltage into the output voltage.

In one embodiment, the at least one charging inductance is a single charging inductance, and the at least one discharging inductance is a single discharging inductance. In the discharging process, by switching the plurality of switches, the plurality of capacitors are connected in parallel with each other and then connected in series. The single discharge inductor.

In one embodiment, the inductance value of the single charging inductor is equal to the inductance value of the single discharging inductor.

In one embodiment, the at least one charging inductance and the at least one discharging inductance are a single same inductance. In the discharging process, by switching the plurality of switches, the plurality of capacitors are connected in parallel with each other and then the single same inductance is connected in series. .

In one embodiment, the resonant switching power converter maintains conduction at least one of the plurality of switches during the charging process and the discharge process, and keeps at least two specific ones of the plurality of switches turned off , And change the voltage conversion ratio of the input voltage to the output voltage.

In one embodiment, the resonant switching power converter further includes a front-end converter, wherein the front-end converter has a front-end inductor to assist the charging inductor.

In one embodiment, the front-end converter includes a buck converter, a boost converter, a buck-boost converter, a back-voltage converter, or a boost-back converter.

In one embodiment, the charging process has a charging resonance frequency, and the discharging process has a discharging resonance frequency, and the charging resonance frequency is the same as the discharging resonance frequency.

In one embodiment, the charging process has a charging resonance frequency, and the discharging process has a discharging resonance frequency, and the charging resonance frequency is different from the discharging resonance frequency.

In one embodiment, the resonant switching power converter adjusts the duration of the charging process to achieve soft switching (zero voltage switching).

In one embodiment, the resonant switching power converter adjusts the duration of the discharge process to achieve soft switching (zero voltage switching).

In one embodiment, the resonant switching power converter is a bidirectional resonant switching power converter.

In one embodiment, the voltage conversion ratio of the input voltage to the output voltage of the resonant switching power converter is 4:1, 3:1, or 2:1.

In one embodiment, the power converter may further include a controller coupled to the plurality of switches for generating the operation signal.

One of the advantages of the present invention is that the present invention can reduce the number of inductances so that only one inductance is used as the charging inductance and the discharging inductance in different periods of time.

Another advantage of the present invention is that the present invention can reduce the voltage stress, can make all the resonant capacitors have the same rated current and rated voltage while using a smaller volume capacitor and can resonate to achieve zero current switching (ZCS) or zero voltage. Flexible switching of switching (ZVS).

Another advantage of the present invention is that the present invention can adjust the voltage conversion ratio more flexibly, can be combined with a resonant inductor and a front-end converter, and can be operated bidirectionally.

The following detailed descriptions are given through specific embodiments, so that it will be easier to understand the purpose, technical content, features, and effects of the present invention.

The drawings in the present invention are all schematic, and are mainly intended to show the coupling relationship between the circuits and the relationship between the signal waveforms. As for the circuits, signal waveforms, and frequencies, they are not drawn to scale.

2A is a schematic diagram showing a circuit of a resonant switching power converter according to an embodiment of the present invention; FIG. 2B is a schematic diagram showing signal waveforms of related signals in the resonant switching power converter shown in FIG. 2A. In this embodiment, multiple capacitors share one charging inductance or one discharging inductance, so that no matter how many capacitors there are, only one charging inductance and one discharging inductance are needed, which can further reduce the number of inductances. As shown in FIG. 2A, the resonant switching power converter 20 of the present invention includes capacitors C1, C2, C3, switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, Q10, charging inductor L1, discharge Inductance L2. The switches Q1-Q3 are respectively connected in series with the corresponding capacitors C1-C3, and the switch Q4 is connected in series with the charging inductor L1. It should be noted that the number of capacitors in the resonant switching power converter of the present invention is not limited to three in this embodiment, and can also be two or more than four. The number of components shown in this embodiment is only for illustration. The present invention does not limit the present invention.

As shown in FIG. 2A, one end of the switch Q5 is coupled to the node between the switch Q1 and the capacitor C1, one end of the switch Q6 is coupled to the node between the switch Q2 and the capacitor C2, and one end of the switch Q7 is coupled to the switch Q3 The node between and capacitor C3. One end of the switch Q8 is coupled to the node between the capacitor C1 and the switch Q2, one end of the switch Q9 is coupled to the node between the capacitor C2 and the switch Q3, and one end of the switch Q10 is coupled to the node between the capacitor C3 and the switch Q4 node. As shown in FIG. 2A, after the other ends of the switches Q5-Q7 are electrically connected to a node, they are connected in series to the discharge inductor L2. The other ends of the switches Q8-Q10 are commonly coupled to the ground potential. The other ends of the charging inductor L1 and the discharging inductor L2 are commonly coupled to the output voltage Vout, and the other end of the switch Q1 is coupled to the input voltage Vin.

The switches Q1-Q10 can switch the electrical connection relationship between the corresponding capacitors C1-C3 and the charging inductor L1 and the discharging inductor L2 according to the corresponding operation signal. In a charging procedure, the switches Q1-Q4 are turned on and the switches Q5-Q10 are not turned on, so that the capacitors C1-C3 are connected in series with the charging inductor L1 in series between the input voltage Vin and the output voltage Vout to form a Charging path. In a discharge process, the switches Q5-Q10 are turned on, and the switches Q1-Q4 are not turned on. The capacitor C1, the capacitor C2, and the capacitor C3 are connected in parallel to each other and the inductor L2 is discharged in series to form a plurality of discharge paths. It should be noted that the above-mentioned charging process and the above-mentioned discharging process are repeatedly and staggered at different time periods, rather than being performed at the same time. In a preferred embodiment, the duration of the charging process and the duration of the discharging process do not overlap with each other. Wherein, the charging process and the discharging process are alternately sequenced repeatedly to convert the input voltage Vin into the output voltage Vout. In this embodiment, the DC bias voltage of each of the first capacitors C1, C2, C3 is Vo. Therefore, the first capacitors C1, C2, C3 in this embodiment have the same input voltage and output voltage compared to the prior art. In voltage applications, only a lower rated voltage is required, so a smaller volume capacitor can be used.

In one embodiment, the resonant frequency of charging in the charging process is the same as the resonant frequency of discharging in the discharging process. In one embodiment, the resonant frequency of charging in the charging process is different from the resonant frequency of discharging in the discharging process. In one embodiment, the above-mentioned resonant switching power converter 20 may be a bidirectional resonant switching power converter. The so-called two-way resonant switching power converter means that the roles of the input terminal (providing the input voltage Vin) and the output terminal (providing the output voltage Vout) are reversed, which means that in the embodiment shown in FIG. 2A, the resonant switching power converter The device 20 can convert the output voltage Vout into an input voltage Vin. In one embodiment, the voltage conversion ratio between the input voltage Vin and the output voltage Vout of the resonant switching power converter 20 may be 4:1, 3:1, or 2:1.

In one embodiment, the duration of the charging process (Ton1) is related to the resonant frequency (fr1) of the charging process. In a preferred embodiment, the duration of the charging process (Ton1) is related to the positive half-wave of the charging resonant current of the charging process. For example, the conduction time and non-conduction time of the switches Q1-Q4 are substantially synchronized with the charging process One of the starting and ending points of the positive half-wave of the resonant charging current. In one embodiment, the duration (Ton2) of the above-mentioned discharge process is related to the discharge resonance frequency (fr2) of the above-mentioned discharge process. In a preferred embodiment, the duration of the discharge process (Ton2) is related to the positive half-wave of the discharge resonant current of the discharge process. For example, the conduction time and non-conduction time point of the switches Q5-Q10 are roughly synchronized with the discharge process. One is the starting point and ending point of the positive half wave of the discharge resonant current.

In the embodiment in which the charging resonance frequency (fr1) of the charging process is equal to the discharging resonance frequency (fr2) of the discharging process, when the duration of the charging process (Ton1) is equal to the duration of the discharging process (Ton2), for example When the duty cycle is roughly equal to 50%, the current flowing through the switch can be switched at a relatively low level of the positive half-wave, so as to achieve flexible switching. In a preferred embodiment, zero current switch (ZCS) can be achieved.

In addition, it should be noted that the parasitic effects of the circuit components or the matching between the components are not necessarily ideal. Therefore, although it is desired to make the duration of the charging procedure equal to the duration of the discharging procedure (that is, in this embodiment) The duration of the charging process is 50% of the duty cycle) to achieve zero current switching of soft switching. However, in reality, it may not be exactly 50% of the duty cycle, but only close to the 50% duty cycle. That is, according to the present invention, the charging process can be accepted due to the imperfectness of the circuit. There is a certain degree of error between the duration and 50% of the work cycle. This means that the aforementioned discharge to "approximately" means 50% of the work cycle. Other references to "approximately" in this article Same place.

In one embodiment, the duration of the charging process is less than a specific ratio of the duty cycle for a predetermined period, for example, a duty cycle of less than 50% for a predetermined period; thereby, the switch Q1-Q4 is not turned on in advance. There is a tiny current flowing through the charging inductor L1. Therefore, the accumulated charge of the parasitic capacitance stored in the switch Q10 can be taken away through the parasitic diode of the switch Q4, and the cross voltage of the switch Q10 can be reduced to achieve Flexible switching. In a preferred embodiment, the preset period is adjusted to achieve zero voltage switch (ZVS). In one embodiment, relatively, the duration of the above-mentioned discharge process is greater than a predetermined ratio of the duty cycle for a predetermined period, for example, a duty cycle greater than 50% for a predetermined period; thereby, the non-conduction switch Q5 is delayed. -After Q10, the negative current of the discharge inductor L2 will charge the parasitic capacitance of the switch Q1 through the parasitic diode of the switch Q5, and reduce the cross voltage of the switch Q1 to achieve flexible switching. In a preferred embodiment, the preset period is adjusted to achieve zero voltage switching.

(1)

(2) 假設C 1=C 2=C 3=C r，且如上所述欲使fr 1=fr 2，則結合式(1)與(2)可得下式

進而可導出L2與L1的電感值需符合下式

(3) 亦即欲使fr 1=fr 2時，L2與L1的電感值需設置符合式(3)的關係。The charging resonance frequency (fr1) of the above charging process and the discharging resonance frequency (fr2) of the above discharging process are shown in the following equations.

(1)

(2) Assuming that C 1 = C 2 = C 3 = C r, and we want to make fr 1 = fr 2, as described above, the following equation can be obtained by combining equations (1) and (2)

Then it can be derived that the inductance values of L2 and L1 must conform to the following formula

(3) That is, when fr 1 = fr 2, the inductance values of L2 and L1 need to be set in accordance with the relationship of formula (3).

FIG. 2B shows a schematic diagram of signal waveforms of related signals in the resonant switching power converter shown in FIG. 2A. The output voltage Vout, output current Io, charging resonance current IL1, discharging resonance current IL2, capacitor C1 DC bias voltage Vc1, capacitor C1 current Ic1, switch Q7 current IS7, and switch Q9 current IS9 are shown in FIG. 2B. In this embodiment, the resonant frequency of charging is equal to the resonant frequency of discharging, and the duration of the charging process and the duration of the discharging process are approximately 50% of the duty cycle.

由上式中可理解到，當L1的電感值等於L2的電感值時，充電諧振頻率與放電諧振頻率是不相等的，在此條件下，若欲達成零電流切換，則持續時間(Ton1)及持續時間(Ton2)需各自對應設置為充電諧振頻率(fr1)及充電諧振頻率(fr2)的半週期，如下式所示:

若欲達成零電流切換，綜合以上公式可知，持續時間(Ton1)及持續時間(Ton2)需符合下式的關係:

(4)In another embodiment, when the inductance value of L1 is equal to the inductance value of L2, and assuming that C 1 = C 2 = C 3 = C r, equations (1) and (2) can be rewritten as follows:

It can be understood from the above formula that when the inductance value of L1 is equal to the inductance value of L2, the charging resonance frequency and the discharging resonance frequency are not equal. Under this condition, if you want to achieve zero current switching, the duration (Ton1) And the duration (Ton2) should be set to the half cycle of the charging resonance frequency (fr1) and the charging resonance frequency (fr2) respectively, as shown in the following formula:

If you want to achieve zero-current switching, based on the above formula, it can be known that the duration (Ton1) and the duration (Ton2) must conform to the relationship of the following formula:

(4)

That is, when the inductance value of L1 is equal to the inductance value of L2, the duration of the discharging process (Ton2) needs to be set to 3 times the duration of the charging process (Ton1), that is, the duration of the charging process (Ton1) is roughly Equal to 25% of the duty cycle, the duration of the discharge process (Ton2) is roughly equal to 75% of the duty cycle, and the aforementioned zero current switching can still be achieved.

It is worth noting that a special case in which the inductance value of L1 is equal to the inductance value of L2 is that the charging inductance L1 and the discharging inductance L2 can share the same inductance and act as the charging inductance and the discharging inductance at different times.

Therefore, please refer to FIG. 3, which is a circuit diagram showing a resonant switching power converter according to another embodiment of the present invention. In this embodiment, the charging inductance and the discharging inductance can be the same inductance L1, and this configuration can further reduce the number of inductances. As shown in FIG. 3, the resonant switching power converter 30 of the present invention includes capacitors C1, C2, C3, switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, Q10, and inductor L1. The switches Q1-Q3 are respectively connected in series with the corresponding capacitors C1-C3, and the switch Q4 is connected in series with the inductor L1. It should be noted that the number of capacitors in the resonant switching power converter of the present invention is not limited to three in this embodiment, and can also be two or more than four. The number of components shown in this embodiment is only for illustration. The present invention does not limit the present invention.

It should be noted that in this embodiment, the charging inductance and the discharging inductance are the same inductance L1. In the discharging process, the capacitors C1-C3 are connected in parallel and the same in series by switching the switches Q1-Q10. Inductance L1. The so-called charging inductance and discharging inductance are the same inductance L1, which means that in the charging process and the discharging process, the charging resonant current IL1 and the discharging resonant current IL2 only flow through a single inductor L1, and no other inductance components. .

As shown in Figure 3, one end of the switch Q5 is coupled to the node between the switch Q1 and the capacitor C1, one end of the switch Q6 is coupled to the node between the switch Q2 and the capacitor C2, and one end of the switch Q7 is coupled to the switch Q3 The node between and capacitor C3. One end of the switch Q8 is coupled to the node between the capacitor C1 and the switch Q2, one end of the switch Q9 is coupled to the node between the capacitor C2 and the switch Q3, and one end of the switch Q10 is coupled to the node between the capacitor C3 and the switch Q4 node. As shown in FIG. 3, after the other ends of the switches Q5-Q7 are commonly electrically connected to a node, they are coupled to the node between the switch Q4 and the inductor L1, and the other ends of the switches Q8-Q10 are commonly coupled to the ground potential. The other end of the inductor L1 is coupled to the output voltage Vout, and the other end of the switch Q1 is coupled to the input voltage Vin.

The switches Q1-Q10 can switch the electrical connection relationship between the corresponding capacitor C1-C3 and the inductor L1 according to the corresponding operation signal. In a charging process, the switches Q1-Q4 are turned on, and the switches Q5-Q10 are not turned on, so that the capacitors C1-C3 are connected in series with each other and then connected in series with the inductor L1 between the input voltage Vin and the output voltage Vout to form a charge path. In a discharge process, the switches Q5-Q10 are turned on, and the switches Q1-Q4 are not turned on. The capacitor C1, the capacitor C2, and the capacitor C3 are connected in parallel to each other and then the inductor L1 is connected in series to form a complex discharge path. It should be noted that the above-mentioned charging process and the above-mentioned discharging process are repeatedly and staggered at different time periods, rather than being performed at the same time. In this embodiment, the DC bias voltage of each of the first capacitors C1, C2, C3 is Vo. Therefore, the first capacitors C1, C2, C3 in this embodiment need to withstand lower rated voltages, so they can be used. Small size capacitor.

In this embodiment where the charging inductance and the discharging inductance are set to a single and the same inductance L1, the ratio of the duration of the charging procedure (Ton1) and the duration of the discharging procedure (Ton2) can be appropriately configured according to the aforementioned formula to achieve flexibility. Zero current switching of switching. Specifically, in one embodiment, the duration of the charging process is approximately equal to 25 percent of the duty cycle, for example; thereby, the switch can be used when the current flowing through the switch is relatively low in its positive half wave. Switch on time to achieve flexible switching. In a preferred embodiment, zero current switch (ZCS) can be achieved. In one embodiment, the duration of the charging process is less than a specific ratio of the duty cycle for a predetermined period, for example, less than 25% of the duty cycle for a preset period; thereby, the switch Q1-Q4 is not turned on in advance. A small current is maintained and flows through the charging inductor L1. Therefore, the accumulated charge of the parasitic capacitance stored in the switch Q10 can be taken away through the parasitic diode of the switch Q4, and the cross voltage of the switch Q10 can be reduced. Achieve flexible switching. In a preferred embodiment, the preset period is adjusted to achieve zero voltage switch (ZVS). In one embodiment, relatively, the duration of the above-mentioned discharging process is greater than a specific proportion of the duty cycle for a predetermined period, for example, a duty cycle greater than 75% for a predetermined period; thereby, the non-conduction switch is delayed After Q5-Q10, the negative current of the discharge inductor L2 will charge the parasitic capacitance of the switch Q1 through the parasitic diode of the switch Q5, and reduce the cross voltage of the switch Q1 to achieve flexible switching. In a preferred embodiment, the preset period is adjusted to achieve zero voltage switch (ZVS).

In one embodiment, the above-mentioned resonant switching power converter 30 may be a bidirectional resonant switching power converter. In one embodiment, the voltage conversion ratio of the input voltage Vin to the output voltage Vout of the resonant switching power converter 30 may be 4:1, 3:1, or 2:1. In one embodiment, the voltage conversion ratio of the resonant switching power converter 30 can be flexibly adjusted. For example, in the charging process and the discharging process, the switch Q7 is selected to be kept on, and the switches Q10 and Q4 are selected to be kept off. Turning on, the voltage conversion ratio of the resonant switching power converter 30 can be adjusted to 3:1. Similarly, for example, the switch Q6 can be selected to be kept on, and the switches Q9, Q3, Q7, Q10, and Q4 can be selected to be kept off, and the voltage conversion ratio of the resonant switching power converter 30 can be adjusted to 2:1.

Please refer to FIG. 4, which is a schematic circuit diagram of a resonant switching power converter according to another embodiment of the present invention. The difference between this embodiment and the embodiment in FIG. 3 is that this embodiment adds a front-end converter 401 to convert the input voltage Vin into a voltage V1. The front-end converter 401 is coupled between the input voltage Vin and the capacitor C1. The converter 401 includes a front-end inductor Lb and a switch Q1. The front-end inductor Lb is connected in series with the switch Q1. The front-end inductor Lb is set as an inductive energy storage element in the front-end converter 401 for front-end power conversion. During the duration (Ton1), the front-end inductor Lb is also connected in series with the inductor L1 to become a part of the charging inductor. The switch Q1 can be used as the switch Q1 in the embodiment of FIG. 3, and other components are similar to those of FIG. In one embodiment, the front-end converter 401 includes a buck converter, a boost converter, a back-voltage converter, a buck-boost converter, and a boost-back converter as shown in FIGS. 6A-6J.

FIG. 5A is a schematic diagram showing the corresponding operation signal of a charging process and a discharging process and the signal waveform of the corresponding inductor current according to an embodiment of the present invention. Please also refer to Figure 2A. In the embodiment shown in Figure 5A, the operating signals G1~G4 of the switches Q1~Q4 are high during the charging process, and the operating signals G5~G10 of the switches Q5~Q10 are high during the discharging process allow. In the embodiment of FIG. 5A, the duration of the charging process is approximately 50% of the duty cycle; thereby, the switch Q1 can be switched at the time when the current flowing through the switch is at a relatively low level of the positive half wave , It is also switched when the current of the inductor L1 is zero current to achieve flexible switching. In a preferred embodiment, zero current switching can be achieved.

5B and 5C are schematic diagrams showing the corresponding operation signals of a charging process and a discharging process and the corresponding signal waveforms of the inductor current according to another embodiment of the present invention. Please also refer to Figure 2A. In the embodiment shown in Figure 5B, the operating signals G1~G4 of the switches Q1~Q4 are high during the charging process, and the operating signals G5~G10 of the switches Q5~Q10 are high during the discharging process allow. In the embodiment of FIG. 5B, the duration of the charging process is substantially less than 50% of the duty cycle for a predetermined period T1; thereby, even after the switches Q1-Q4 are not turned on in advance, a small current flows through The charging inductor L1, therefore, can discharge the accumulated charge of the parasitic capacitance stored in the switch Q10 through the parasitic diode of the switch Q4, thereby reducing the cross voltage of the switch Q10 to achieve flexible switching. In a preferred embodiment, the preset period T1 is adjusted to achieve zero voltage switching. Please also refer to Figure 2A. In the embodiment shown in Figure 5C, the operating signals G1~G4 of the switches Q1~Q4 are high during the charging process, and the operating signals G5~G10 of the switches Q5~Q10 are high during the discharging process. . In the embodiment of FIG. 5C, the duration of the discharge process is substantially greater than 50% of the duty cycle for a predetermined period T2+T3; thereby, the negative of the inductance L2 is discharged after the non-conducting switch Q5-Q10 is delayed. The current will charge the parasitic capacitance of the switch Q1 through the parasitic diode of the switch Q5, and reduce the cross voltage of the switch Q1 to achieve flexible switching. In a preferred embodiment, the preset periods T2 and T3 are adjusted to achieve zero voltage switching. In one embodiment, it should be noted that the embodiments of FIGS. 5B and 5C can be implemented together or only one of them can be implemented. In addition, please refer to FIG. 5D, which is a schematic diagram showing the corresponding operation signal of a charging process and a discharging process and the signal waveform of the corresponding capacitor current according to another embodiment of the present invention. Please refer to FIG. 2A at the same time. As shown in FIG. 5D, the duration of the charging process and the duration of the discharging process can be adjusted, such as adding a delay time Td, and the ratio of the input voltage Vin to the output voltage Vout can be adjusted more flexibly.

Please refer to FIG. 7, which shows a schematic diagram of a controller in a power converter according to an embodiment of the present invention. As shown in FIG. 7, the power converter of the present invention may include a controller 701, which is coupled to the switch Q1-10, for generating operation signals G1-G4, G5-G10, and output to the switches Q1-Q4, Q5-Q10, thereby switching the switches Q1-Q4, Q5-Q10 respectively.

It should be noted that the so-called switch conduction time and non-conduction time point are synchronized with the start time and end time of the positive half wave of the charging resonant current of the charging process, and refer to the switch conduction time and non-conduction time point and the charging resonant current The start time and end time of the positive half-wave are the same, or there is a fixed interval; and the on-time and non-conduction time of the switch are synchronized with the start and end of the positive half-wave of the discharge resonant current of the discharge program. It means that the switch's conduction time and non-conduction time are the same as the start time and end time of the positive half-wave of the discharge resonant current, or are separated by a fixed period.

As described above, the present invention provides a resonant switching power converter, which can reduce the number of inductances through a special circuit design to only require one inductance to be used as a charging inductance and a discharging inductance in different periods of time, which can reduce voltage stress and make all The resonant capacitors have the same rated current and rated voltage, and can use smaller-volume capacitors, can resonate to achieve flexible switching with zero current switching (ZCS) or zero voltage switching (ZVS), and can adjust the voltage more flexibly Conversion ratio, can be combined with resonant inductor and front-end converter, and can be operated in both directions.

The present invention has been described above with reference to preferred embodiments, but the above description is only for making it easier for those skilled in the art to understand the content of the present invention, and is not intended to limit the broadest scope of rights of the present invention. The illustrated embodiments are not limited to individual applications, but can also be combined. For example, two or more embodiments can be used in combination, and part of the composition of one embodiment can also be used to replace another embodiment. Corresponding component parts. In addition, under the same spirit of the present invention, those skilled in the art can think of various equivalent changes and various combinations. For example, the “processing or calculation based on a certain signal or generating a certain output result” in the present invention is not limited to According to the signal itself, it also includes, when necessary, performing voltage-current conversion, current-voltage conversion, and/or ratio conversion on the signal, and then process or calculate an output result according to the converted signal. It can be seen that, under the same spirit of the present invention, those skilled in the art can think of various equivalent changes and various combinations, and there are many combinations of them, which will not be listed here. Therefore, the scope of the present invention should cover all the above and other equivalent changes.

20, 30, 40: resonant switching power converter 401: front-end converter 701: Controller C1~C3, C1(CR), C2(CF), C3(CR): capacitance Co: output capacitance G1~G10: Operation signal Ic1: Capacitor C1 current IL1: Charging resonance current IL2: Discharge resonance current Io: output current IS7: Switch Q7 current IS9: Switch Q9 current L1: Charging inductance L2: discharge inductance L1(LR), L2(LR), Lb: inductance Q1~Q10, Q1(S1A), Q2(S2A), Q3(S1B), Q4(S2B), Q5(S1A), Q6(S2A), Q7(S2A), Q8(S1B), Q9(S1B), Q10 (S2B), Qb: switch RL: Load resistance T1, T2, T3: period Td: Delay time V1: Voltage Vc1: Capacitor C1 DC bias Vc2: Capacitor C2 DC bias Vc3: Capacitor C3 DC bias Vin: input voltage Vout: output voltage

Figure 1 is a conventional power converter.

2A and 2B are schematic diagrams showing the signal waveforms of the circuit and related signals of a resonant switching power converter according to an embodiment of the present invention.

FIG. 3 is a schematic diagram showing a circuit of a resonant switching power converter according to another embodiment of the present invention.

4 is a schematic diagram showing a circuit of a resonant switching power converter according to another embodiment of the present invention.

5A, 5B, and 5C are schematic diagrams showing the corresponding operation signals of a charging process and a discharging process and the corresponding signal waveforms of the inductor current according to an embodiment of the present invention.

FIG. 5D is a schematic diagram showing the corresponding operation signal of a charging process and a discharging process and the signal waveform of the corresponding capacitor current according to an embodiment of the present invention.

Figures 6A-6J show a buck converter, a boost converter, a back-voltage converter, a buck-boost converter, and a boost-back converter.

FIG. 7 is a schematic diagram showing a controller in a power converter according to an embodiment of the present invention.

20: Resonant switching power converter

C1~C3: Capacitance

Co: output capacitance

L1: Charging inductance

L2: discharge inductance

Q1~Q10: switch

RL: Load resistance

Vin: input voltage

Vout: output voltage

Claims (15)

A resonant switching power converter for converting an input voltage into an output voltage. The resonant switching power converter includes: Complex capacitance A plurality of switches are correspondingly coupled to the plurality of capacitors, and respectively switch the electrical connection relationship of the corresponding capacitors according to a corresponding operation signal; At least one charging inductor in series with at least one of the plurality of capacitors; and At least one discharge inductor in series with at least one of the plurality of capacitors; Wherein, in a charging process, by switching the plurality of switches, the plurality of capacitors and the at least one charging inductor are connected in series with each other between the input voltage and the output voltage to form a charging path corresponding to the plurality of The conduction time and non-conduction time of the switch are synchronized with the start time and end time of the positive half wave of the resonant charging current of one of the charging procedures; Wherein, in a discharge process, by switching the plurality of switches, each of the capacitors and the corresponding discharge inductance are connected in series between the output voltage and a ground potential to form a plurality of discharge paths corresponding to the plurality of switches The conduction time point and the non-conduction time point are synchronized with the start time point and the end time point of the positive half wave of the discharge resonant current of one of the discharge procedures; Wherein, the charging procedure and the discharging procedure are alternately sequenced repeatedly to convert the input voltage into the output voltage. The resonant switching power converter according to claim 1, wherein the at least one charging inductance is a single charging inductance, and the at least one discharging inductance is a single discharging inductance, and in the discharging process, the switching of the plurality of switches , The multiple capacitors are connected in parallel with each other and then the single discharge inductor is connected in series. The resonant switching power converter according to claim 2, wherein the inductance value of the single charging inductor is equal to the inductance value of the single discharging inductor. The resonant switching power converter according to claim 1, wherein the at least one charging inductance and the at least one discharging inductance are a single same inductance, and in the discharging process, the plurality of switches are switched to make the plurality of capacitors After connecting in parallel with each other, the single same inductance is connected in series. The resonant switching power converter according to claim 1, wherein the resonant switching power converter keeps conducting at least one of the plurality of switches during the charging process and the discharging process, and keeps being non-conducting At least two of the plurality of switches are specified to change the voltage conversion ratio between the input voltage and the output voltage. The resonant switching power converter described in 2, 3 or 4 further includes a front-end converter, wherein the front-end converter has a front-end inductor to assist the charging inductor. The resonant switching power converter according to claim 6, wherein the front-end converter includes a buck converter, a boost converter, a buck-boost converter, a back-voltage converter, or a boost-back converter. The resonant switching power converter according to claim 1 or 2, wherein the charging procedure has a charging resonance frequency, and the discharging procedure has a discharging resonance frequency, and the charging resonance frequency is the same as the discharging resonance frequency. The resonant switching power converter according to 2, 3 or 4, wherein the charging procedure has a charging resonance frequency, and the discharging procedure has a discharging resonance frequency, and the charging resonance frequency is different from the discharging resonance frequency. The resonant switching power converter according to 2, 3 or 4, wherein the duration of the charging process is adjusted to achieve soft switching (zero voltage switching). The resonant switching power converter according to 2, 3 or 4, wherein the duration of the discharge process is adjusted to achieve soft switching (zero voltage switching). The resonant switching power converter according to 2, 3 or 4, wherein the resonant switching power converter is a bidirectional resonant switching power converter. The resonant switching power converter according to 2, 3 or 4, wherein the voltage conversion ratio of the input voltage to the output voltage of the resonant switching power converter is 4:1, 3:1 or 2:1. The resonant switching power converter according to 2, 3 or 4, wherein the duration of the charging process and the duration of the discharging process do not overlap with each other. The power converter according to claim 1 further includes a controller coupled to the plurality of switches for generating the operation signal.

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