Parallel hybrid power converter

Abstract

The application discloses a parallel hybrid power converter. The parallel hybrid power converter comprises a first input capacitor and a second input capacitor connected in series between an input terminal and a ground and forming a first node, the input terminal receiving a direct current input voltage; and a switched inductor module and a switched capacitor module, respectively converting voltage components of the first input capacitor and the second input capacitor, and being commonly connected to an output terminal to provide a direct current output voltage. The switched inductor module and the switched capacitor module in the parallel hybrid power converter form a parallel power supply scheme, which can not only reduce the size of the inductor to realize miniaturization, but also improve the conversion efficiency of the circuit and reduce the voltage stress of the switching element.

Description

TECHNICAL FIELD

[0001] The present application relates to a power converter, and more particularly, to a parallel hybrid power converter with both inductors and capacitors as energy storage elements. BACKGROUND

[0002] A power converter is a power module that converts an input voltage into a desired output voltage or output current. The power converter includes switching elements that are periodically turned on and off according to a control signal, and energy storage elements that store and release energy accordingly, thereby providing an output voltage signal at the output terminal of the power converter.

[0003] In a power converter using inductors as energy storage elements, the duty cycle of the control signal is adjusted using a feedback loop to obtain a substantially constant output voltage or output current, and the value of the output voltage or output current is adjusted using a regulating element to adjust the duty cycle of the control signal. In a power converter using capacitors as energy storage elements, the on-time and off-time of the switching elements are greater than the charging time constant and the discharging time constant, and a fixed ratio output voltage to the input voltage is obtained at steady state.

[0004] Figure 1a and Figure 1b A schematic circuit diagram of a switched-capacitor power converter and a waveform diagram of a control signal according to the prior art are shown, respectively. In the power converter, switching elements Q1 and Q2 are alternately turned on and off, and capacitor C1 is periodically charged and discharged to transfer electrical energy from the input terminal to the output terminal. An output capacitor Co is connected to the output terminal to filter out ripples to obtain a stable output voltage, for example, a fixed ratio output voltage of 1:1 to the input voltage. Compared with a power converter using inductors, a power converter using a switched-capacitor topology has the advantages of small capacitor size, high circuit conversion efficiency and power density, and low voltage stress of switching elements, but has the disadvantages of difficulty in flexible adjustment of the output voltage, a large number of switching elements, and difficulty in control circuit design.

[0005] Therefore, it is necessary to develop a new parallel hybrid power converter circuit that takes into account the advantages of traditional inductors and capacitors used in power converters, thereby providing a power solution with high conversion efficiency and high power density. SUMMARY

[0006] In view of the above, the purpose of the present application is to provide a parallel hybrid power converter in which a parallel power supply scheme of a switched inductor module and a switched capacitor module is implemented using an input capacitor connected in series to reduce the size of the inductor for miniaturization, and to improve the conversion efficiency of the circuit and reduce the voltage stress of the switching elements.

[0007] According to an embodiment of the present application, a parallel hybrid power converter is provided, comprising: a first input capacitor and a second input capacitor connected in series with each other between an input terminal and a ground terminal and forming a first node, the input terminal receiving a DC input voltage; and a switched-inductor module and a switched-capacitor module, respectively performing voltage conversion on voltage components of the first input capacitor and the second input capacitor, and being commonly connected to an output terminal to provide a DC output voltage.

[0008] Preferably, the switched-inductor module and the switched-capacitor module are both step-up modules.

[0009] Preferably, the switched-inductor module has a step-up topology and the switched-capacitor module has a capacitor series power supply topology.

[0010] Preferably, the switched-capacitor module comprises: a first group of switching elements connected in series between the output terminal and the first node; a second group of switching elements comprising a first switching element and a second switching element connected in series between the first node and the ground terminal, and a third switching element and a fourth switching element connected in series between the first node and the ground terminal; and a plurality of first capacitors, first ends of which are connected to intermediate nodes of adjacent switching elements of the first group of switching elements, and second ends of which are connected to intermediate nodes of adjacent switching elements of the second group of switching elements.

[0011] Preferably, the second end of an odd-numbered capacitor of the plurality of first capacitors is connected to an intermediate node of the first switching element and the second switching element, and the second end of an even-numbered capacitor of the plurality of first capacitors is connected to an intermediate node of the third switching element and the fourth switching element.

[0012] Preferably, the on-off states of the first group of switching elements and the second group of switching elements are controlled by one of a first control signal and a second control signal, the first control signal and the second control signal being complementary periodic signals.

[0013] Preferably, a switching period of the first control signal comprises a first time period and a second time period of consecutive different voltage levels, in the first time period, the plurality of first capacitors are connected in series with the first input capacitor to charge, and in the second time period, the plurality of first capacitors are connected in series with the second input capacitor to supply power to the output terminal.

[0014] Preferably, in a steady state of a continuous switching period of the parallel hybrid power converter, the output voltage is as follows,

[0015] Vo=(N+1)*Vi / (1+N(1-D1))

[0016] Where Vo represents the DC output voltage, Vi represents the DC input voltage, D1 represents the duty cycle of the control signal of the switching inductor module, and N represents the number of first capacitors in the switching capacitor module.

[0017] Preferably, the switching inductor module is a buck-boost module; and the switching capacitor module is a buck module.

[0018] Preferably, the switching inductor module has a buck-boost topology, and the switching capacitor module has a capacitor series charging topology.

[0019] Preferably, the switched capacitor module includes: a first set of switching elements, the first set of switching elements being connected in series between the first node and the output terminal; a second set of switching elements, the second set of switching elements including a first switching element and a second switching element connected in series between the output terminal and ground, and a third switching element and a fourth switching element connected in series between the output terminal and ground; and a plurality of first capacitors, the first end of the plurality of first capacitors being connected to the intermediate node of the adjacent switching element of the first set of switching elements, and the second end being connected to the intermediate node of the adjacent switching element of the second set of switching elements.

[0020] Preferably, the second end of the odd-numbered capacitors of the plurality of first capacitors is connected to the intermediate node between the first switching element and the second switching element, and the second end of the even-numbered capacitors of the plurality of first capacitors is connected to the intermediate node between the third switching element and the fourth switching element.

[0021] Preferably, the conduction state of the first group of switching elements and the second group of switching elements is controlled by one of a first control signal and a second control signal, wherein the first control signal and the second control signal are complementary periodic signals.

[0022] Preferably, the switching cycle of the first control signal includes a first time period and a second time period with continuous different level states. During the first time period, the plurality of first capacitors are connected in series with the input capacitor for charging. During the second time period, the plurality of first capacitors are connected with the second input capacitor to provide a discharge path.

[0023] Preferably, the steady-state output voltage of the parallel hybrid power converter during continuous switching cycles is as follows:

[0024] Vo = Vi / (N+1 + N*(1-D1) / D1)

[0025] Where Vo represents the DC output voltage, Vi represents the DC input voltage, D1 represents the duty cycle of the control signal of the switching inductor module, and N represents the number of first capacitors in the switching capacitor module.

[0026] Preferably, the switched capacitor module further includes: at least one first inductor, wherein the at least one inductor is connected in series with the odd-numbered capacitors of the plurality of first capacitors to form at least one resonant circuit.

[0027] Preferably, the switching cycles of the first set of switching elements and the second set of switching elements correspond to the resonant frequency of the at least one resonant circuit.

[0028] Preferably, the switched capacitor module further includes: at least one first inductor, wherein the at least one inductor is connected in series with the even-numbered capacitors of the plurality of first capacitors to form at least one resonant circuit.

[0029] Preferably, the switching cycles of the first set of switching elements and the second set of switching elements correspond to the resonant frequency of the at least one resonant circuit.

[0030] The beneficial effects of this invention are as follows: The parallel hybrid power converter provided by this invention can provide an output voltage Vo that is proportional to the input voltage Vi. By changing the duty cycles of the first set of control signals and the second set of control signals respectively, a desired output voltage within a predetermined voltage range can be obtained. Therefore, this parallel hybrid power converter can improve the output voltage regulation capability of the circuit and obtain the desired conversion ratio.

[0031] According to the parallel hybrid power converter provided by this invention, inductors and capacitors are used together as energy storage elements, with the energy density of capacitors being much higher than that of inductors. Compared with conventional power converters that only use inductors, the parallel hybrid power converter has a higher power density. Compared with conventional power converters that only use capacitors, the hybrid converter can utilize inductors to achieve output voltage regulation, smooth startup, and scalability among multiple circuits.

[0032] According to the parallel hybrid power converter provided by the present invention, the parallel hybrid power converter includes a first input capacitor and a second input capacitor connected in series. The switching inductor module and the switching capacitor module of the power converter respectively convert the voltage components of the first input capacitor and the second input capacitor. The switching inductor module and the switching capacitor module in this power converter form a parallel power supply scheme. Since the voltage stress of the switching element is less than the input voltage, it is permissible to use switching elements with low rated voltage. Compared with high rated voltage switching elements, using low rated voltage switching elements has the advantages of low switching losses and low conduction losses. Therefore, this parallel hybrid power converter can operate at a high switching frequency while also improving the circuit's conversion efficiency.

[0033] According to the parallel hybrid power converter provided by the present invention, the switched capacitor module includes a first inductor connected in series with a first capacitor, and the two form a resonant circuit. The switching period of the control signal of the switching element in the switched capacitor module corresponds to the resonant frequency of the resonant circuit. Therefore, the charging and discharging process of the first capacitor in the switched capacitor module will generate a sinusoidal resonant current. Since the maximum current value of the switching element is correspondingly reduced in the sinusoidal case, it is possible to use a low-power rated switching element. Compared with a high-power rated switching element, using a low-power rated switching element has the advantage of allowing for a reduction in element size. Therefore, this parallel hybrid power converter can operate at a high switching frequency while also achieving miniaturization. Attached Figure Description

[0034] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings.

[0035] Figure 1a and Figure 1b Schematic circuit diagrams of switched capacitor power converters according to the prior art and waveform diagrams of control signals are shown respectively.

[0036] Figure 2a and Figure 2b The schematic circuit diagram of the parallel hybrid power converter according to the first embodiment of the present invention and the working waveform diagram of the control signal are shown respectively.

[0037] Figure 3a and Figure 3b The schematic circuit diagram of the parallel hybrid power converter according to the second embodiment of the present invention and the working waveform diagram of the control signal are shown respectively.

[0038] Figure 4a and Figure 4b The schematic circuit diagram of the parallel hybrid power converter according to the third embodiment of the present invention and the working waveform diagram of the control signal are shown respectively.

[0039] Figure 5a and Figure 5b The schematic circuit diagram of the parallel hybrid power converter according to the fourth embodiment of the present invention and the working waveform diagram of the control signal are shown respectively. Detailed Implementation

[0040] The present invention is described below based on embodiments, but the invention is not limited to these embodiments. In the detailed description of the invention below, certain specific details are described in detail. Those skilled in the art will fully understand the invention even without these details. To avoid obscuring the essence of the invention, well-known methods, processes, flows, elements, and circuits are not described in detail.

[0041] Furthermore, those skilled in the art should understand that the accompanying drawings provided herein are for illustrative purposes and are not necessarily drawn to scale. It should also be understood that, in the following description, "circuit" refers to a conductive loop formed by at least one element or sub-circuit connected by an electrical or electromagnetic link. When an element or circuit is said to be "connected" to another element or "connected" between two nodes, it can be directly coupled or connected to the other element, or there may be intermediate elements; the connection between elements can be physical, logical, or a combination thereof. Conversely, when an element is said to be "directly coupled to" or "directly connected" to another element, it means that there are no intermediate elements between them.

[0042] Unless the context explicitly requires it, the terms "comprising," "including," and similar terms throughout the specification and claims should be interpreted as encompassing rather than exclusive or exhaustive; that is, meaning "including but not limited to." In the description of this invention, it should be understood that terms such as "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0043] The present invention will now be described in detail with reference to the accompanying drawings.

[0044] <First Embodiment>

[0045] Figure 2a and Figure 2b A schematic circuit diagram and a waveform diagram of the control signal of the parallel hybrid power converter according to the first embodiment of the present invention are shown respectively. The parallel hybrid power converter 20 receives an input voltage Vi between its input terminal and ground, and provides an output voltage Vo between its output terminal and ground. The parallel hybrid power converter 20 includes a switched inductor module 21, a switched capacitor module 22, input capacitors Ci1 and Ci2, and an output capacitor Co. The switched inductor module 21 includes an inductor Ls and switching elements Qx and Qy, and the switched capacitor module 22 includes capacitors C1 to C3 and switching elements Q1 to Q4 and Q11 to Q14.

[0046] Input capacitors Ci1 and Ci2 are connected in series between the input terminal of the parallel hybrid power converter 20 and ground, with node N1 being the intermediate node between them. Output capacitor Co is connected between the output terminal of the parallel hybrid power converter 20 and ground.

[0047] In the switching inductor module 21, the inductor Ls and the switching element Qy are connected in series between the input and output terminals of the parallel hybrid power converter 20. The switching element Qx is connected between the intermediate node of the inductor Ls and the switching element Qy and node N1.

[0048] The switching inductor module 21 controls the charging and discharging process of inductor Ls through the complementary conduction of switching elements Qx and Qy, thus achieving an output voltage Vo higher than the input voltage Vi. When switching element Qx is on, switching element Qy is off, and the DC power supply provides the input voltage Vi to charge inductor Ls and input capacitor Ci2. When switching element Qx is off, switching element Qy is on, and the inductor current of inductor Ls freewheels and discharges, generating the output voltage Vo at the output terminal. Therefore, the switching inductor module 21 can adjust the magnitude of the output voltage Vo by changing the duty cycle of the control signals for switching elements Qx and Qy.

[0049] In the switched capacitor module 22, switching elements Q1 to Q4 are connected in series between the output terminal of the parallel hybrid power converter 20 and node N1. Switches Q11 and Q12 are connected in series between node N1 and ground, and switches Q13 and Q14 are connected in series between node N1 and ground. Furthermore, capacitor C1 is connected between the intermediate node of switching elements Q1 and Q2 and the intermediate node of switching elements Q11 and Q12; capacitor C2 is connected between the intermediate node of switching elements Q2 and Q3 and the intermediate node of switching elements Q13 and Q14; and capacitor C3 is connected between the intermediate node of switching elements Q3 and Q4 and the intermediate node of switching elements Q11 and Q12.

[0050] The switched capacitor module 22 controls the charging and discharging process of capacitors C1 to C3 through the complementary conduction of switching elements Q1, Q3, Q11, Q14 and Q2, Q4, Q12, Q13, thus obtaining an output voltage Vo higher than the input voltage Vi. When switching elements Q2, Q4, Q12, Q13 are on, switching elements Q1, Q3, Q11, Q14 are off, the DC power supply provides the input voltage Vi, capacitor C2 charges capacitor C1, and input capacitor Ci2 charges capacitor C3. When switching elements Q2, Q4, Q12, Q13 are off, switching elements Q1, Q3, Q11, Q14 are on, capacitor C1 discharges, capacitor C2 charges capacitor C3, generating the output voltage Vo at the output terminal. The switched capacitor module 22 is used to perform voltage multiplication and boosting on the voltage drop across the input capacitor Ci2. The circuit efficiency of the switched capacitor module 22 is related to the duty cycle of the control signals of the switching elements Q1, Q3, Q11, Q14 and Q2, Q4, Q12, Q13. In order to optimize the circuit efficiency, the duty cycle of the control signals of the switching elements Q1, Q3, Q11, Q14 and Q2, Q4, Q12, Q13 is, for example, a fixed value of 0.5.

[0051] The switching elements in the parallel hybrid power converter 20 include any one selected from field-effect transistors and bipolar transistors. In this embodiment, the switching elements are, for example, N-type MOSFETs; however, the invention is not limited thereto. The gate of switching element Qx receives control signal Gx, and the gate of switching element Qy receives control signal Gy. The gates of switching elements Q1, Q3, Q11, and Q13 receive control signal G1, and the gates of switching elements Q2, Q4, Q12, and Q14 receive control signal G2. For clarity, in Figure 2a The control circuits used to generate control signals Gx and Gy, G1 and G2 are not shown.

[0052] The control signals Gx and Gy are periodic signals with the same and complementary switching periods. This switching period is denoted as T1. Each of the control signals Gx and Gy includes an on-time Ton1 and an off-time Toff1 in its respective switching period. That is, when the control signal Gx is active, the control signal Gy is inactive, and vice versa.

[0053] Control signals G1 and G2 are periodic signals with the same and complementary switching periods. This switching period is denoted as T2. Each of the control signals G1 and G2 includes an on-time Ton2 and an off-time Toff2 in its respective switching period. That is, when control signal G1 is active, control signal G2 is inactive, and vice versa.

[0054] In this embodiment, the switching periods and duty cycles of control signals Gx and Gy are the same as those of control signals G1 and G2, and the triggering of control signals Gx and Gy is delayed by a certain time compared to control signals G1 and G2. However, the invention is not limited to this. For example, the switching period T1 of control signals Gx and Gy can be the same as or different from the switching period T2 of control signals G1 and G2, and the duty cycle D1 of control signal Gx can be the same as or different from the duty cycle D2 of control signal G1. The parallel hybrid power converter 20 adjusts the output voltage Vo by changing the duty cycle D1 of control signal Gx, and sets the duty cycle D2 of control signal G1 to a fixed value to optimize circuit efficiency.

[0055] In the following description, combined with Figure 2b The waveform diagrams of the control signals shown illustrate the operation of the parallel hybrid power converter 20 and the method for calculating the proportional relationship between the output voltage Vo and the input voltage Vi. However, as mentioned above, the specific signal relationships between control signals Gx and Gy and control signals G1 and G2 should not be construed as limiting the invention.

[0056] During the first time interval of switching cycle T1, control signal Gx is valid and control signal Gy is invalid; switching element Qx is turned on and switching element Qy is turned off. The first terminal of inductor Ls is connected to the input terminal, and the second terminal is grounded via input capacitor Ci2, and is disconnected from the output terminal. The DC input voltage Vi provided by the DC power supply charges inductor Ls.

[0057] During the first time period described above, if control signal G1 is invalid and control signal G2 is valid, capacitors C1 and C2 are connected in series. The second terminal of capacitor C2 is connected to node N1, and the second terminal of capacitor C1 is grounded. The DC input voltage Vi provided by the DC power supply charges the series circuit of capacitors C1 and C2. The first terminal of capacitor C3 is connected to node N1, and the second terminal is grounded. The DC input voltage Vi provided by the DC power supply charges the series circuit of capacitors C1 and C2, as well as capacitor C3. During the first time period described above, if control signal G1 is valid and control signal G2 is invalid, capacitors C1 to C3 are connected in series. The first terminal of capacitor C1 is connected to the output terminal, and the second terminal of capacitor C3 is grounded. Capacitors C1 to C3 discharge, providing electrical energy to the output terminal of the parallel hybrid power converter 20.

[0058] During the second time interval of switching cycle T1, control signal Gx is invalid and control signal Gy is valid; switching element Qx is turned off and switching element Qy is turned on. The first terminal of inductor Ls is connected to the input terminal, and the second terminal is connected to the output terminal. DC current supplies power to the output terminal of the parallel hybrid power converter 20 via inductor Ls, and inductor Ls discharges to supply power to the output terminal of the parallel hybrid power converter 20.

[0059] During the second time period described above, if control signal G1 is invalid and control signal G2 is valid, capacitors C1 and C2 are connected in series. The second terminal of capacitor C2 is connected to node N1, and the second terminal of capacitor C1 is grounded. The DC input voltage Vi provided by the DC power supply charges the series circuit of capacitors C1 and C2. The first terminal of capacitor C3 is connected to node N1, and the second terminal is grounded. The DC input voltage Vi provided by the DC power supply charges the series circuit of capacitors C1 and C2, as well as capacitor C3. During the second time period described above, if control signal G1 is valid and control signal G2 is invalid, capacitors C1 to C3 are connected in series. The first terminal of capacitor C1 is connected to the output terminal, and the second terminal of capacitor C3 is grounded. Capacitors C1 to C3 discharge, providing electrical energy to the output terminal of the parallel hybrid power converter 20.

[0060] During continuous switching cycles, the charging and discharging processes of the inductor Ls and capacitors C1 to C3 in the parallel hybrid power converter 20 tend to reach a steady state, providing a stable DC output voltage Vo at the output terminal of the parallel hybrid power converter 20. This DC output voltage Vo has a voltage value that is higher than the DC input voltage Vi. As described below, the desired voltage value can be obtained by changing the duty cycle of the control signal G1 in the parallel hybrid power converter 20.

[0061] See Figure 2b The duty cycle D1 of the control signal Gx and the duty cycle D2 of the control signal G1 are shown in equations (1) and (2) respectively:

[0062] D1=Ton1 / (Ton1+Toff1) (1)

[0063] D2=Ton2 / (Ton2+Toff2)=0.5 (2)

[0064] Based on the voltage relationship at the input terminal of the parallel hybrid power converter 20, the following equation (3) can be obtained:

[0065] Vi = Vci1 + Vci2 (3)

[0066] Where Vi represents the DC input voltage, and Vci1 and Vci2 represent the voltage drops across the input capacitors Ci1 and Ci2, respectively.

[0067] Based on the connection relationship of inductor Ls and capacitors C1 to C3 in the parallel hybrid power converter 20 during the discharge stage, it can be seen that the switching inductor module 21 and the switching capacitor module 22 form a parallel hybrid power converter with parallel power supply. Therefore, the switching inductor module 21 and the switching capacitor module 22 perform voltage conversion according to their respective voltage conversion ratios.

[0068] Based on the working principle of the switching inductor module 21, the voltage conversion of the switching inductor module 21 under steady state is as shown in the following equation (4):

[0069] (Vo-Vci2) / Vci1=1 / (1-D1) (4)

[0070] Where Vo represents the DC output voltage, Vci1 and Vci2 represent the voltage drops across the input capacitors Ci1 and Ci2, respectively, and D1 represents the duty cycle of the control signal Gx.

[0071] Based on the working principle of the switched capacitor module 22, the voltage conversion of the switched capacitor module 22 under steady state is as shown in the following equation (5):

[0072] Vo / Vci2= 4 (5)

[0073] Vc1 / Vci2=3

[0074] Vc2 / Vci2=2

[0075] Vc3 / Vci2=1

[0076] Where Vo represents the DC output voltage, Vci2 represents the voltage drop across the input capacitor Ci2, and Vc1, Vc2, and Vc3 represent the voltage drops across capacitors C1 to C3, respectively.

[0077] In summary, from equation (2) to equation (5), the output voltage Vo of the parallel hybrid power converter 20 in steady state during a continuous switching cycle is shown in equation (6) below:

[0078] Vo = 4 * Vi / (4 - 3 * D1) (6)

[0079] Where Vo represents the DC output voltage, Vi represents the DC input voltage, and D1 represents the duty cycle of the control signal Gx.

[0080] According to the first embodiment, the parallel hybrid power converter operates as a boost converter, providing an output voltage Vo proportional to the input voltage Vi. With three capacitors in the switched capacitor module, the parallel hybrid power converter can achieve a predetermined voltage conversion ratio greater than or equal to 1 and less than or equal to 4. Within this predetermined voltage range, the desired output voltage is obtained by adjusting the duty cycle D1 of the control signal Gx. Therefore, this parallel hybrid power converter can improve the output voltage regulation capability of the circuit and achieve the desired conversion ratio.

[0081] Furthermore, the parallel hybrid power converter includes a first input capacitor and a second input capacitor connected in series. The switched inductor module and the switched capacitor module of the parallel hybrid power converter convert the voltage components of the first input capacitor and the second input capacitor, respectively. The switched inductor module and the switched capacitor module in this parallel hybrid power converter form a parallel power supply scheme, which not only utilizes inductors and capacitors together as energy storage elements to improve power density, but also leverages the characteristics of capacitor-switched converters to improve circuit efficiency, making it applicable to small-size, high-power power supply products.

[0082] <Second Embodiment>

[0083] Figure 3a and Figure 3bA schematic circuit diagram and a waveform diagram of the control signal of a parallel hybrid power converter according to a second embodiment of the present invention are shown respectively. The parallel hybrid power converter 30 receives an input voltage Vi between its input terminal and ground, and provides an output voltage Vo between its output terminal and ground. The parallel hybrid power converter 30 includes a switched inductor module 31, a switched capacitor module 32, input capacitors Ci1 and Ci2, and an output capacitor Co. The switched inductor module 31 includes an inductor Ls and switching elements Qx and Qy, and the switched capacitor module 32 includes inductors L1 and L3, capacitors C1 to C3, switching elements Q1 to Q4, and switching elements Q11 to Q14.

[0084] The circuit structure of the parallel hybrid power converter 30 according to the second embodiment is basically the same as that of the parallel hybrid power converter 20 according to the first embodiment. The detailed description of the similarities between the two is omitted below.

[0085] The main difference between the circuit structure of the parallel hybrid power converter 30 according to the second embodiment and the circuit structure of the parallel hybrid power converter 20 according to the first embodiment is that the switched capacitor module 32 also includes inductors L1 and L3. Capacitor C1 and inductor L1 are connected in series between the intermediate nodes of switching elements Q1 and Q2 and the intermediate nodes of switching elements Q11 and Q12, forming a resonant circuit. Capacitor C3 and inductor L3 are connected in series between the intermediate nodes of switching elements Q3 and Q4 and the intermediate nodes of switching elements Q11 and Q12, forming a resonant circuit.

[0086] According to the resonant characteristics of the resonant circuit, in the switched capacitor module 32, the switching period T2 of the control signal G1 of the switching element is a fixed value corresponding to the resonant frequency of the resonant circuit, as shown in the following equation (19):

[0087] (7)

[0088] Where Ton2 and Toff2 represent the on-time and off-time of control signal G1, respectively, L represents the inductance values ​​of inductors L1 and L3, and C represents the capacitance values ​​of capacitors C1 and C3.

[0089] According to the second embodiment, the parallel hybrid power converter operates as a boost converter, providing an output voltage Vo proportional to the input voltage Vi. With three capacitors in the switched capacitor module, the parallel hybrid power converter can achieve a predetermined voltage conversion ratio greater than or equal to 1 and less than or equal to 4. Within this predetermined voltage range, the desired output voltage is obtained by adjusting the duty cycle D1 of the control signal Gx. Therefore, this parallel hybrid power converter can improve the output voltage regulation capability of the circuit and achieve the desired conversion ratio.

[0090] Furthermore, the capacitors and inductors in the switched capacitor module form a resonant circuit, and the charging and discharging process of the capacitors generates a sinusoidal resonant current. Since the maximum current value of the switching element decreases accordingly under sinusoidal conditions, low-power rated switching elements can be used. Compared to high-power rated switching elements, using low-power rated switching elements has the advantage of allowing for smaller component size. Therefore, this parallel hybrid power converter can operate at a high switching frequency while also achieving miniaturization.

[0091] In the first and second embodiments described above, it was shown that when the number of capacitors in the switched capacitor module is 3, the parallel hybrid power converter can achieve a predetermined voltage conversion ratio greater than or equal to 1 and less than or equal to 4. It can be understood that in the first and second embodiments described above, by increasing the number of capacitors in the switched capacitor module, the voltage regulation range can be expanded. At this time, the output voltage Vo of the parallel hybrid power converter in steady state is as shown in equation (8):

[0092] Vo=(N+1)*Vi / (1+N(1-D1)) (8)

[0093] Where Vo represents the DC output voltage, Vi represents the DC input voltage, D1 represents the duty cycle of the control signal of the switching inductor module, and N represents the number of capacitors in the switching capacitor module.

[0094] <Third Embodiment>

[0095] Figure 4a and Figure 4b Schematic circuit diagrams and control signal waveforms of a parallel hybrid power converter according to a third embodiment of the present invention are shown. The parallel hybrid power converter 40 receives an input voltage Vi between its input terminal and ground, and provides an output voltage Vo between its output terminal and ground. The parallel hybrid power converter 40 includes a switched inductor module 41, a switched capacitor module 42, input capacitors Ci1 and Ci2, and an output capacitor Co. The switched inductor module 41 includes an inductor Ls and switching elements Qx and Qy, and the switched capacitor module 42 includes capacitors C1 to C3 and switching elements Q1 to Q4 and Q11 to Q14.

[0096] Input capacitors Ci1 and Ci2 are connected in series between the input terminal of the parallel hybrid power converter 40 and ground, with node N1 being the intermediate node between them. Output capacitor Co is connected between the output terminal of the parallel hybrid power converter 40 and ground.

[0097] In the switching inductor module 41, switching elements Qx and Qy are connected in series between the input and output terminals of the parallel hybrid power converter 40. Inductor Ls is connected between the intermediate node of switching elements Qx and Qy and node N1.

[0098] The switching inductor module 41 controls the charging and discharging process of inductor Ls through the complementary conduction of switching elements Qx and Qy, thus achieving an output voltage Vo lower than the input voltage Vi. When switching element Qx is on, switching element Qy is off, and the DC power supply provides the input voltage Vi to charge inductor Ls and input capacitor Ci2. When switching element Qx is off, switching element Qy is on, and the inductor current of inductor Ls freewheels and discharges, generating the output voltage Vo at the output terminal. Therefore, the switching inductor module 41 can adjust the magnitude of the output voltage Vo by changing the duty cycle of the control signals for switching elements Qx and Qy.

[0099] In the switched capacitor module 42, switching elements Q1 to Q4 are connected in series between the intermediate node N1 of input capacitors Ci1 and Ci2 and the output terminal of the parallel hybrid power converter 40. Switches Q11 and Q12 are connected in series between the output terminal and ground, and switches Q13 and Q14 are connected in series between the output terminal and ground. Further, capacitor C1 is connected between the intermediate node of switching elements Q1 and Q2 and the intermediate node of switching elements Q11 and Q12, capacitor C2 is connected between the intermediate node of switching elements Q2 and Q3 and the intermediate node of switching elements Q13 and Q14, and capacitor C3 is connected between the intermediate node of switching elements Q3 and Q4 and the intermediate node of switching elements Q11 and Q12.

[0100] The switched capacitor module 42 controls the charging and discharging process of capacitors C1 to C3 through the complementary conduction of switching elements Q1, Q3, Q11, Q14 and Q2, Q4, Q12, Q13, thus obtaining an output voltage Vo lower than the input voltage Vi. When switching elements Q2, Q4, Q12, Q13 are off, switching elements Q1, Q3, Q11, Q14 are on, capacitor C1 is connected to node N1 for charging, and capacitor C2 charges capacitor C3. When switching elements Q2, Q4, Q12, Q13 are on, switching elements Q1, Q3, Q11, Q14 are off, the series circuit of capacitors C1 and C2 is connected between the output terminal of the parallel hybrid power converter 40 and ground for discharging, and capacitor C3 is connected between the output terminal of the parallel hybrid power converter 40 and ground for discharging, generating an output voltage Vo at the output terminal. The switched capacitor module 42 is used to double and reduce the voltage drop across the input capacitor Ci2. The circuit efficiency of the switched capacitor module 42 is related to the duty cycle of the control signals of the switching elements Q1, Q3, Q11, Q14 and Q2, Q4, Q12, Q13. In order to optimize the circuit efficiency, the duty cycle of the control signals of the switching elements Q1, Q3, Q11, Q14 and Q2, Q4, Q12, Q13 is, for example, a fixed value of 0.5.

[0101] The switching elements in the parallel hybrid power converter 40 include any one selected from field-effect transistors and bipolar transistors. In this embodiment, the switching elements are, for example, N-type MOSFETs; however, the invention is not limited thereto. The gate of switching element Qx receives control signal Gx, and the gate of switching element Qy receives control signal Gy. The gates of switching elements Q1, Q3, Q11, and Q13 receive control signal G1, and the gates of switching elements Q2, Q4, Q12, and Q14 receive control signal G2. For clarity, in Figure 4a The control circuits used to generate control signals Gx and Gy, G1 and G2 are not shown.

[0102] The control signals Gx and Gy are periodic signals with the same and complementary switching periods. This switching period is denoted as T1. Each of the control signals Gx and Gy includes an on-time Ton1 and an off-time Toff1 in its respective switching period. That is, when the control signal Gx is active, the control signal Gy is inactive, and vice versa.

[0103] Control signals G1 and G2 are periodic signals with the same and complementary switching periods. This switching period is denoted as T2. Each of the control signals G1 and G2 includes an on-time Ton2 and an off-time Toff2 in its respective switching period. That is, when control signal G1 is active, control signal G2 is inactive, and vice versa.

[0104] In this embodiment, the switching periods and duty cycles of control signals Gx and Gy are the same as those of control signals G1 and G2, and the triggering of control signals Gx and Gy is delayed by a certain time compared to control signals G1 and G2. However, the invention is not limited to this. For example, the switching period T1 of control signals Gx and Gy can be the same as or different from the switching period T2 of control signals G1 and G2, and the duty cycle D1 of control signal Gx can be the same as or different from the duty cycle D2 of control signal G1. The parallel hybrid power converter 40 adjusts the output voltage Vo by changing the duty cycle D1 of control signal Gx, and sets the duty cycle D2 of control signal G1 to a fixed value to optimize circuit efficiency.

[0105] In the following description, combined with Figure 4b The waveform diagrams of the control signals shown illustrate the operation of the parallel hybrid power converter 40 and the method for calculating the proportional relationship between the output voltage Vo and the input voltage Vi. However, as mentioned above, the specific signal relationships between control signals Gx and Gy and control signals G1 and G2 should not be construed as limiting the invention.

[0106] During the first time interval of switching cycle T1, control signal Gx is valid and control signal Gy is invalid; switching element Qx is turned on and switching element Qy is turned off. The first terminal of inductor Ls is connected to the input terminal, and the second terminal is grounded via input capacitor Ci2, and is disconnected from the output terminal. The DC input voltage Vi provided by the DC power supply charges inductor Ls.

[0107] During the first time period described above, if control signal G1 is valid and control signal G2 is invalid, capacitors C1 to C3 are connected in series. The first terminal of capacitor C1 is connected to the intermediate node N1 of input capacitors Ci1 and Ci2, and the second terminal of capacitor C3 is grounded. The DC input voltage Vi provided by the DC power supply charges the series circuit of capacitors C1 to C3. During the same first time period, if control signal G1 is invalid and control signal G2 is valid, capacitors C1 and C2 are connected in series. The second terminal of capacitor C2 is connected to the output terminal of the parallel hybrid power converter 40, and the second terminal of capacitor C1 is grounded. The output terminal of the parallel hybrid power converter 40 discharges through the series circuit of capacitors C1 and C2. The first terminal of capacitor C3 is connected to the output terminal of the parallel hybrid power converter 40, and the second terminal is grounded. The discharge of capacitors C1 to C3 draws electrical energy from the output terminal of the parallel hybrid power converter 40.

[0108] During the second time interval of switching cycle T1, control signal Gx is invalid and control signal Gy is valid; switching element Qx is turned off and switching element Qy is turned on. The first terminal of inductor Ls is connected to the input terminal, and the second terminal is connected to the output terminal. DC current supplies power to the output terminal of the parallel hybrid power converter 40 via inductor Ls, and inductor Ls discharges to supply power to the output terminal of the parallel hybrid power converter 40.

[0109] During the second time period described above, if control signal G1 is valid and control signal G2 is invalid, capacitors C1 to C3 are connected in series. The first terminal of capacitor C1 is connected to the intermediate node N1 of input capacitors Ci1 and Ci2, and the second terminal of capacitor C3 is grounded. The DC input voltage Vi provided by the DC power supply charges the series circuit of capacitors C1 to C3. During the same second time period, if control signal G1 is invalid and control signal G2 is valid, capacitors C1 and C2 are connected in series. The second terminal of capacitor C2 is connected to the output terminal of the parallel hybrid power converter 40, and the second terminal of capacitor C1 is grounded. The output terminal of the parallel hybrid power converter 40 discharges through the series circuit of capacitors C1 and C2. The first terminal of capacitor C3 is connected to the output terminal of the parallel hybrid power converter 40, and the second terminal is grounded. The discharge of capacitors C1 to C3 draws electrical energy from the output terminal of the parallel hybrid power converter 40.

[0110] During continuous switching cycles, the charging and discharging processes of the inductor Ls and capacitors C1 to C3 in the parallel hybrid power converter 40 tend to reach a steady state, providing a stable DC output voltage Vo at the output terminal of the parallel hybrid power converter 40. This DC output voltage Vo has a voltage value that is lower than the DC input voltage Vi. As described below, the parallel hybrid power converter 40 can obtain the desired voltage value by changing the duty cycle of the control signal G1.

[0111] See Figure 4b The duty cycle D1 of the control signal Gx and the duty cycle D2 of the control signal G1 are shown in equations (9) and (10) respectively:

[0112] D1=Ton1 / (Ton1+Toff1) (9)

[0113] D2=Ton2 / (Ton2+Toff2)=0.5 (10)

[0114] Based on the voltage relationship at the input terminal of the parallel hybrid power converter 40, the following equation (11) can be obtained:

[0115] Vi = Vci1 + Vci2 (11)

[0116] Where Vi represents the DC input voltage, and Vci1 and Vci2 represent the voltage drops across the input capacitors Ci1 and Ci2, respectively.

[0117] Based on the connection relationship of inductor Ls and capacitors C1 to C3 in the parallel hybrid power converter 40 during the discharge stage, it can be seen that the switching inductor module 41 and the switching capacitor module 42 form a parallel hybrid power converter with parallel power supply. Therefore, the switching inductor module 41 and the switching capacitor module 42 perform voltage conversion according to their respective voltage conversion ratios.

[0118] Based on the working principle of the switching inductor module 41, the voltage conversion of the switching inductor module 41 under steady state is as shown in the following equation (12):

[0119] (Vcin2-Vo) / Vci1=D1 / (1-D1) (12)

[0120] Where Vo represents the DC output voltage, Vci1 and Vci2 represent the voltage drops across the input capacitors Ci1 and Ci2, respectively, and D1 represents the duty cycle of the control signal Gx.

[0121] Based on the working principle of the switched capacitor module 42, the voltage conversion of the switched capacitor module 42 under steady state is as shown in the following equation (13):

[0122] Vo / Vci2 = 1 / 4 (13)

[0123] Vo / Vc1=1 / 3

[0124] Vo / Vc2=1 / 2

[0125] Vo / Vc3=1

[0126] Where Vo represents the DC output voltage, Vci2 represents the voltage drop across the input capacitor Ci2, and Vc1, Vc2, and Vc3 represent the voltage drops across capacitors C1 to C3, respectively.

[0127] Combining equations (19) to (23), the output voltage Vo of the parallel hybrid power converter 40 in steady state during continuous switching cycles is shown in equation (14):

[0128] Vo=Vi / (4+3*(1-D1) / D1) (14)

[0129] Where Vo represents the DC output voltage, Vi represents the DC input voltage, and D1 represents the duty cycle of the control signal Gx.

[0130] According to the third embodiment, the parallel hybrid power converter operates as a buck converter, providing an output voltage Vo proportional to the input voltage Vi. With three capacitors in the switched capacitor module, the parallel hybrid power converter can achieve a predetermined voltage conversion ratio of less than or equal to 1 / 4. Within this predetermined voltage range, the desired output voltage is obtained by adjusting the duty cycle D1 of the control signal Gx. Therefore, this parallel hybrid power converter can improve the output voltage regulation capability of the circuit and achieve the desired conversion ratio.

[0131] Furthermore, the parallel hybrid power converter includes a first input capacitor and a second input capacitor connected in series. The switched inductor module and the switched capacitor module of the parallel hybrid power converter convert the voltage components of the first input capacitor and the second input capacitor, respectively. The switched inductor module and the switched capacitor module in this parallel hybrid power converter form a parallel power supply scheme, which not only utilizes inductors and capacitors together as energy storage elements to improve power density, but also leverages the characteristics of capacitor-switched converters to improve circuit efficiency, making it applicable to small-size, high-power power supply products.

[0132] <Fourth Embodiment>

[0133] Figure 5a and Figure 5b Schematic circuit diagrams and control signal waveforms of a parallel hybrid power converter according to a fourth embodiment of the present invention are shown. The parallel hybrid power converter 50 receives an input voltage Vi between its input terminal and ground, and provides an output voltage Vo between its output terminal and ground. The parallel hybrid power converter 50 includes a switched inductor module 51, a switched capacitor module 52, input capacitors Ci1 and Ci2, and an output capacitor Co. The switched inductor module 51 is a buck-boost module, including an inductor Ls and switching elements Qx and Qy. The switched capacitor module 52 is a buck module, including inductors L1 and L3, capacitors C1 to C3, switching elements Q1 to Q4, and switching elements Q11 to Q14.

[0134] The circuit structure of the parallel hybrid power converter 50 according to the fourth embodiment is basically the same as that of the parallel hybrid power converter 40 according to the third embodiment. The detailed description of the similarities between the two is omitted below.

[0135] The main difference between the circuit structure of the parallel hybrid power converter 50 according to the fourth embodiment and the circuit structure of the parallel hybrid power converter 40 according to the third embodiment is that the switched capacitor module 52 further includes inductors L1 and L3. Capacitor C1 and inductor L1 are connected in series between the intermediate nodes of switching elements Q1 and Q2 and the intermediate nodes of switching elements Q11 and Q12, forming a resonant circuit. Capacitor C3 and inductor L3 are connected in series between the intermediate nodes of switching elements Q3 and Q4 and the intermediate nodes of switching elements Q11 and Q12, forming a resonant circuit.

[0136] According to the resonance characteristics of the resonant circuit, in the switched capacitor module 52, the switching period T2 of the control signal G1 of the switching element is a fixed value corresponding to the resonant frequency of the resonant circuit, as shown in the following formula (15):

[0137] (15)

[0138] Where Ton2 and Toff2 represent the on-time and off-time of control signal G1, respectively, L represents the inductance values ​​of inductors L1 and L3, and C represents the capacitance values ​​of capacitors C1 and C3.

[0139] According to the fourth embodiment, the parallel hybrid power converter operates as a buck converter, providing an output voltage Vo proportional to the input voltage Vi. With three capacitors in the switched capacitor module, the parallel hybrid power converter can achieve a predetermined voltage conversion ratio of less than or equal to 1 / 4. Within this predetermined voltage range, the desired output voltage is obtained by adjusting the duty cycle D1 of the control signal Gx. Therefore, this parallel hybrid power converter can improve the output voltage regulation capability of the circuit and achieve the desired conversion ratio.

[0140] Furthermore, the capacitors and inductors in the switched capacitor module form a resonant circuit, and the charging and discharging process of the capacitors generates a sinusoidal resonant current. Since the maximum current value of the switching element decreases accordingly under sinusoidal conditions, low-power rated switching elements can be used. Compared to high-power rated switching elements, using low-power rated switching elements has the advantage of allowing for smaller component size. Therefore, this parallel hybrid power converter can operate at a high switching frequency while also achieving miniaturization.

[0141] In the third and fourth embodiments described above, it is shown that when the number of capacitors in the switched capacitor module is 3, the parallel hybrid power converter can achieve a predetermined voltage conversion ratio of less than or equal to 1 / 4. It can be understood that in the third and fourth embodiments described above, by increasing the number of capacitors in the switched capacitor module, the voltage regulation range can be reduced. At this time, the output voltage Vo of the parallel hybrid power converter in steady state is shown in equation (16) below:

[0142] Vo=Vi / (N+1+N*(1-D1) / D1) (16)

[0143] Where Vo represents the DC output voltage, Vi represents the DC input voltage, D1 represents the duty cycle of the control signal of the switching inductor module, and N represents the number of capacitors in the switching capacitor module.

[0144] It should be noted that in the description of this invention, the terms "upper," "lower," "inner," etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0145] Furthermore, throughout this document, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0146] Finally, it should be noted that the above embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A parallel hybrid power converter, comprising: The first input capacitor and the second input capacitor are connected in series between the input terminal and ground to form a first node, and the input terminal receives a DC input voltage. as well as The switched inductor module and the switched capacitor module respectively convert the voltage components of the first input capacitor and the second input capacitor, and are jointly connected to the output terminal to provide a DC output voltage. The switched capacitor module includes: The first set of switching elements is connected in series between the output terminal and the first node; The second set of switching elements includes a first switching element and a second switching element connected in series between the first node and ground, and a third switching element and a fourth switching element connected in series between the first node and ground; or the second set of switching elements includes a first switching element and a second switching element connected in series between the output terminal and ground, and a third switching element and a fourth switching element connected in series between the output terminal and ground. A plurality of first capacitors, wherein the first end of the plurality of first capacitors is connected to the middle node of the adjacent switching element of the first group of switching elements, and the second end is connected to the middle node of the adjacent switching element of the second group of switching elements; A first inductor is connected in series with a first capacitor, and the two form a resonant circuit; the switching period of the control signal of the first set of switching elements or the second set of switching elements corresponds to the resonant frequency of the resonant circuit. Wherein, the second end of the odd-numbered capacitors of the plurality of first capacitors is connected to the intermediate node between the first switching element and the second switching element, and the second end of the even-numbered capacitors of the plurality of first capacitors is connected to the intermediate node between the third switching element and the fourth switching element.

2. The parallel hybrid power converter according to claim 1, wherein, Both the switching inductor module and the switching capacitor module are boost modules.

3. The parallel hybrid power converter according to claim 2, wherein, The switching inductor module has a boost topology, and the switching capacitor module has a capacitor series power supply topology.

4. The parallel hybrid power converter according to claim 1, wherein, The conduction state of the first group of switching elements and the second group of switching elements is controlled by one of a first control signal and a second control signal, wherein the first control signal and the second control signal are complementary periodic signals.

5. The parallel hybrid power converter according to claim 4, wherein, The switching cycle of the first control signal includes a first time period and a second time period with continuous different level states. During the first time period, the plurality of first capacitors are connected in series with the first input capacitor for charging. During the second time period, the plurality of first capacitors are connected in series with the second input capacitor to supply power to the output terminal.

6. The parallel hybrid power converter according to claim 5, wherein, The steady-state output voltage of the parallel hybrid power converter during continuous switching cycles is as follows: Vo=(N+1)*Vi / (1+N(1-D1)) Where Vo represents the DC output voltage, Vi represents the DC input voltage, D1 represents the duty cycle of the control signal of the switching inductor module, and N represents the number of first capacitors in the switching capacitor module.

7. The parallel hybrid power converter according to claim 1, wherein, The switching inductor module is a step-up / step-down module; the switching capacitor module is a step-down module.

8. The parallel hybrid power converter according to claim 7, wherein, The switching inductor module has a step-up / step-down topology, and the switching capacitor module has a capacitor series charging topology.

9. The parallel hybrid power converter according to claim 8, wherein, The conduction state of the first group of switching elements and the second group of switching elements is controlled by one of a first control signal and a second control signal, wherein the first control signal and the second control signal are complementary periodic signals.

10. The parallel hybrid power converter according to claim 9, wherein, The switching cycle of the first control signal includes a first time period and a second time period with continuous different level states. During the first time period, the plurality of first capacitors are connected in series with the first input capacitor for charging. During the second time period, the plurality of first capacitors are connected with the second input capacitor to provide a discharge path.

11. The parallel hybrid power converter according to claim 10, wherein, The steady-state output voltage of the parallel hybrid power converter during continuous switching cycles is as follows: Vo = Vi / (N+1 + N*(1-D1) / D1) Where Vo represents the DC output voltage, Vi represents the DC input voltage, D1 represents the duty cycle of the control signal of the switching inductor module, and N represents the number of first capacitors in the switching capacitor module.

12. The parallel hybrid power converter according to claim 3 or 9, wherein, The first inductor is at least one; At least one of the first inductors is connected in series with the odd-numbered capacitors of the plurality of first capacitors to form at least one resonant circuit.

13. The parallel hybrid power converter according to claim 12, wherein, The switching cycles of the first set of switching elements and the second set of switching elements correspond to the resonant frequency of the at least one resonant circuit.

14. The parallel hybrid power converter according to claim 3 or 9, wherein, The first inductor is at least one; At least one of the first inductors is connected in series with the even-numbered capacitors of the plurality of first capacitors to form at least one resonant circuit.

15. The parallel hybrid power converter according to claim 14, wherein, The switching cycles of the first set of switching elements and the second set of switching elements correspond to the resonant frequency of the at least one resonant circuit.

Images