Boost circuit and inverter

Abstract

The present application relates to a boost circuit and an inverter comprising the same. The boost circuit according to an aspect of the present application comprises an input link, a charge-discharge circuit block and an output link connected in sequence. The charge-discharge circuit block comprises an inductor, a switch selection device and a storage capacitor. The switch selection device is configured to form a charging loop of the inductor and the storage capacitor with the input link when the boost circuit is to perform a boost charging, and disconnect the output link from the charging loop to charge the storage capacitor; and form a discharging loop of the inductor and the storage capacitor with the input link and the output link when the boost circuit is to perform a boost discharging, to discharge the storage capacitor.

Description

Technical Field

[0001] This invention relates to the field of circuits, and more particularly to a boost circuit and an inverter having the same. Background Technology

[0002] Currently, inductors are commonly used as energy storage components in boost circuits, especially in automotive inverter circuits, where almost all high-power voltage conversion circuits employ inductors. Compared to boost circuits using inductors, charge pump boost circuits offer advantages such as high efficiency and low noise, while also providing significant advantages in cost, integration, and manufacturing. However, traditional charge pump boost circuits are limited by circuit current and cannot meet the demands of high-power drives. Furthermore, traditional charge pump boost circuits cannot achieve reverse energy recovery. Summary of the Invention

[0003] To address or at least alleviate one or more of the above problems, the following technical solutions are provided.

[0004] According to a first aspect of the present invention, a boost circuit is provided, which may include an input link, a charging / discharging circuit block, and an output link connected in sequence. The charging / discharging circuit block includes an inductor, a switching selection device, and a storage capacitor.

[0005] The switch selection device can be configured to form a charging circuit with the inductor and the storage capacitor and the input link when the boost circuit needs to perform boost charging, and to disconnect the output link from the charging circuit to charge the storage capacitor; and to form a discharge circuit with the inductor and the storage capacitor and the input link and the output link when the boost circuit needs to perform boost discharging, so as to discharge the storage capacitor.

[0006] According to an embodiment of the present invention, the boost circuit wherein the switch selection device may be further configured to allow the input voltage of the input link to be directly output to the output link when the boost circuit is to be driven without boosting.

[0007] According to an embodiment of the boost circuit of the present invention, the switch selection device may include a first switch, a second switch, a third switch, and a fourth switch, and the inductor may include a first inductor and a second inductor. The first inductor and the third switch are connected between a first terminal of the input link and a first terminal of the storage capacitor; the second inductor and the first switch are connected between the first terminal of the input link and a second terminal of the storage capacitor; the second switch is connected between the second terminal of the storage capacitor and a second terminal of the input link; the fourth switch is connected between the first terminal of the storage capacitor and a first terminal of the output link; and the second terminal of the output link is connected to the second terminal of the input link.

[0008] Furthermore, the boost circuit can be configured to enable the second switch and the third switch and disable the first switch and the fourth switch when the boost circuit is to perform boost charging; and to enable the first switch and the fourth switch and disable the second switch and the third switch when the boost circuit is to perform boost discharging.

[0009] According to an embodiment of the present invention, the boost circuit can be further configured to enable the third switch and the fourth switch and disable the first switch and the second switch when the boost circuit is to perform direct drive without boosting.

[0010] According to an embodiment of the present invention, in a boost circuit, the third switch and the fourth switch may be diodes.

[0011] According to an embodiment of the present invention, the boost circuit can also be configured to directly connect the two ends of the input link to the two ends of the output link when energy recovery is required.

[0012] According to an embodiment of the present invention, the boost circuit may further include a recycling switch, the second end of the input link is connected to the second end of the output link, and the first end of the input link is connected to the recycling switch and then connected to the first end of the output link.

[0013] According to an embodiment of the present invention, the boost circuit may further include a voltage-regulating capacitor connected between the first and second terminals of the output link.

[0014] According to an embodiment of the present invention, in a boost circuit, the first switch, the second switch, the third switch and the fourth switch may be insulated gate bipolar transistors (IGBTs).

[0015] According to an embodiment of the present invention, the boost circuit can utilize an external controller to control each switch. The controller can adjust the duty cycle of the enable and disable signals of the first switch, the second switch, the third switch, and the fourth switch according to the output voltage requirements of the output link.

[0016] According to an embodiment of the present invention, the duty cycle of the boost circuit can be 50%.

[0017] According to a second aspect of the invention, an inverter is provided that may include a boost circuit as described in any of the foregoing embodiments.

[0018] The boost circuit according to one or more embodiments of the present invention uses a storage capacitor as an energy storage element and can use a low-inductance inductor as a current limiting device, resulting in higher boost efficiency, lower system inductance loss, switching loss, and noise, making it suitable for high-power drive requirements; the circuit topology is simpler and the implementation cost is lower; it has efficient energy recovery function; and since there is no high-frequency charging and discharging with a large inductor, electromagnetic interference problems are almost negligible. The boost circuit of the present invention can be used, particularly in high-voltage, high-power applications such as automotive motor drives and battery pack charging and discharging. Attached Figure Description

[0019] The above and / or other aspects and advantages of the present invention will become clearer and more readily understood from the following description taken in conjunction with the accompanying drawings, in which the same or similar elements are denoted by the same reference numerals. In the drawings: Figure 1 This is a circuit diagram of a boost circuit 1000 according to an embodiment of the present invention; Figure 2 This is a circuit diagram of a boost circuit 2000 according to another embodiment of the present invention; Figure 3 A circuit diagram of a boost circuit 3000 according to another embodiment of the present invention. Figure 4 This is a schematic diagram of the potential, current and voltage of the main components according to an embodiment of the present invention during operation. Detailed Implementation

[0020] The following detailed description is merely exemplary in nature and is not intended to limit the disclosed technology or its application and use. Furthermore, it is not intended to be bound by any express or implied theory presented in the foregoing technical fields, background art, or the following detailed description.

[0021] In the following detailed description of the embodiments, numerous specific details are set forth in order to provide a more thorough understanding of the disclosed technology. However, it will be apparent to those skilled in the art that the disclosed technology can be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0022] Terms such as “comprising” and “including” indicate that, in addition to the units and steps that are directly and explicitly stated in the specification, the technical solution of the present invention does not exclude the presence of other units and steps that are not directly or explicitly stated.

[0023] In the following, various exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0024] Figure 1 This is a circuit diagram of a boost circuit 1000 according to an embodiment of the present invention. Figure 1 In the boost circuit 1000, an input link 1100 (e.g., a battery), a charge / discharge circuit block 1300, and an output link 1200 (e.g., a load) are connected in sequence. The charge / discharge circuit block 1300 may further include an inductor 1310, a switch selection device 1320, and a storage capacitor 1330. The switch selection device 1320 is configured to form a charging circuit between the inductor 1310 and the storage capacitor 1330 and the input link 1100 when the boost circuit 1000 needs to boost charge the storage capacitor 1330, and to disconnect the output link 1200 from the charging circuit to charge the storage capacitor 1330. For example, the switch selection device 1320 can be configured with one or more internal switching elements such that the inductor 1310 and the storage capacitor 1330 are connected in series across the input link 1100, and the one or more switching elements can disconnect other components and circuits (e.g., the output link 1200) from the series loop, so that the input link 1100 (e.g., a power supply) charges the storage capacitor 1330. The switch selection device 1320 is also configured to form a discharge loop with the inductor 1310 and the storage capacitor 1330, the input link 1100, and the output link 1200 when the boost circuit 1000 needs to perform boost discharge, so that the storage capacitor 1330 can be discharged. For example, the switch selection device 1320 can be configured with one or more internal switching elements such that an inductor 1310, a storage capacitor 1330 and an output link 1200 are connected in series from one end of the input link 1100 to the other end, and the one or more switching elements can disconnect other components and circuits from the series loop so that the storage capacitor 1330 is discharged and the output voltage of the output link 1200 is increased.

[0025] Thus, through the alternating control of the switch selection device 1320, the charge-discharge cycle of the boost circuit 1000 can be realized, thereby increasing and maintaining the output voltage at the output link 1200 at a higher voltage value. Compared to inductive boost circuits (such as Boost converters), during the boost and discharge process, the boost circuit 1000 of this invention uses a storage capacitor 1230 as an energy storage element and a low-inductance inductor 1210 as a current limiting device. This allows for voltage multiplication using a lower switching frequency, resulting in lower system inductance and switching losses, and thus higher overall boost efficiency. By optimizing various circuit parameters, the low-inductance components further reduce circuit current, making it suitable for high-voltage, high-power applications, particularly in automotive motor drives and battery pack charging and discharging. Due to the absence of high-frequency charging and discharging with large inductance, electromagnetic interference is almost negligible.

[0026] In some embodiments, the switch selection device 1320 is further configured to directly output the voltage of the input link 1100 to the output link 1200 when the boost circuit 1000 is to be driven without boosting. Specifically, the switch selection device 1320 may, for example, directly short-circuit the input link 1100 to the output link 1200, making the input voltage the same as the output voltage. Alternatively, the input link 1100 may be connected to the output link 1200 via an inductor 1310, and an inductor 1310 with a small inductance value may be selected, making the input voltage substantially the same as the output voltage. In this way, a direct drive mode without boosting can be realized.

[0027] Figure 2 A circuit diagram of a boost circuit 2000 according to another embodiment of the present invention is shown. Figure 1 This is a specific structure of a boost circuit. It can be understood that... Figure 2 The input link 2100, charge / discharge circuit block 2300, and output link 2200 in the boost circuit 2000 correspond to respectively Figure 1 The boost circuit 1000 includes input link 1100, charge / discharge circuit block 1300, and output link 1200. Figure 2 The charging and discharging circuit block 2300 may further include an inductor 2310 and a switch selection device 2320 (for simplicity, Figure 2 (shown in dashed box) and storage capacitor 2330. Switch selection device 2320 may include a first switch 2322, a second switch 2324, a third switch 2326, and a fourth switch 2328 (shown in dashed box). Figure 2 The diode is shown in the diagram, but is not limited to it; it could also be any active or passive switch, for example. Inductor 2310 includes a first inductor 2312 and a second inductor 2314. This arrangement simplifies the structure of the boost circuit 2000, making it easy to integrate and reducing circuit costs.

[0028] like Figure 2 As shown, the first inductor 2312 and the third switch 2326 are connected between the first end (e.g., the positive terminal) of the input link 2100 and the first end of the storage capacitor 2330. The second inductor 2314 and the first switch 2322 are connected between the first end of the input link 2100 and the second end of the storage capacitor 2330. The second switch 2324 is connected between the second end of the storage capacitor 2330 and the second end (e.g., the negative terminal) of the input link 2100. The fourth switch 2328 is connected between the first end of the storage capacitor 2330 and the first end of the output link 2200. The second end of the output link 2200 is connected to the second end of the input link 2100.

[0029] Therefore, the switch selection device 2320 can enable or disable four switches (i.e., the first switch 2322, the second switch 2324, the third switch 2326, and the fourth switch 2328) to perform charging and discharging operations on the storage capacitor 2330. Specifically, when the boost circuit 2000 needs to perform a boost charging operation, the second switch 2324 and the third switch 2326 can be enabled and the first switch 2322 and the fourth switch 2328 can be disabled; similarly, when the boost circuit 2000 needs to perform a boost discharging operation, the first switch 2322 and the fourth switch 2328 can be enabled and the second switch 2324 and the third switch 2326 can be disabled. Thus, the following configuration can be formed respectively: (See reference) Figure 1 The charging and discharging circuits described herein enable the charging and discharging of the storage capacitor 2330.

[0030] Furthermore, when the boost circuit 2000 needs to perform direct drive without boosting, the third switch 2326 and the fourth switch 2328 can be enabled while the first switch 2322 and the second switch 2324 can be disabled. In this way, the input link 2100 (e.g., power supply) can output voltage to the output link 2200 through the first inductor 2312, and the input voltage is basically equal to the output voltage, thereby realizing the direct drive process without boosting.

[0031] In some embodiments, such as Figure 2As shown, the third switch 2326 and the fourth switch 2328 can be diodes. When the second switch 2324 is enabled and the first switch 2322 is disabled, the formed charging circuit is: input link 2100 first terminal (e.g., power supply positive terminal) - first inductor 2312 - third switch 2326 - storage capacitor 2330 - second switch 2324 - input link 2100 second terminal (e.g., power supply negative terminal). At this time, diode 2326 is turned on while diode 2328 is reverse-biased and cut off. Similarly, when the first switch 2322 is enabled and the second switch 2324 is disabled, diode 2326 is reverse-biased and diode 2328 is turned on. In this way, the charging and discharging of the boost circuit can also be realized. Furthermore, in this embodiment, two fewer switches can be controlled (i.e., the third switch 2326 and the fourth switch 2328 using diodes).

[0032] In some embodiments, the boost circuit 2000 is further configured to directly connect the two ends of the input link 2100 to the two ends of the output link 2200 when energy recovery is required. Figure 2 As shown in the example, the boost circuit 2000 can further include a recovery switch 2400. The second terminal of the input link 2100 is connected to the second terminal of the output link 2200, while the first terminal of the input link 2100 is connected to the recovery switch 2400 and then to the first terminal of the output link 2200. In this case, the original input link 2100 can be converted into an energy receiving device (e.g., a battery), and the original output link 2200 can be converted into an energy source (e.g., a generator / grid). The energy source and the recovery switch 2400 form an energy feedback loop. When the recovery switch 2400 is activated, the entire boost circuit is short-circuited. Thus, the problem of the boost circuit's inability to be reverse-engineered is solved with a simple structure, and energy recovery efficiency is greatly improved. Furthermore, by using a bypass recovery switch to short-circuit the boost circuit 2000, there is no need for high-frequency control of the switching on and off of each switch, and the current does not pass through the boost circuit section, resulting in higher system efficiency and lower heat generation.

[0033] In some embodiments, the boost circuit further includes a voltage-regulating capacitor disposed in the output link, connected between the first and second terminals of the output link. (Reference) Figure 2 The voltage regulator capacitor 2500 is connected to both ends (e.g., positive and negative terminals) of the output link 2200 to stabilize the output voltage.

[0034] Figure 3 The circuit diagram shown is for a boost circuit 3000 according to another embodiment of the present invention, illustrating a circuit structure using an insulated-gate bipolar transistor (IGBT) as the switching element. It is understood that... Figure 3 The various figures and symbols in the figure Figure 2 One-to-one correspondence. In Figure 3In this design, the first switch 3322, the second switch 3324, the third switch 3326, and the fourth switch 3328 all employ Insulated Gate Bipolar Transistors (IGBTs). However, it is understandable that only one, two, or three of these four switches could also be configured as IGBT switches. Using IGBTs as switches requires very little drive power, offers fast switching speeds, and increases the current-carrying capacity and voltage resistance of the switches.

[0035] Furthermore, when using IGBTs, when IGBT 3326 (the third switch) and IGBT 3328 (the fourth switch) are turned on simultaneously, the input link 3100 can also be connected to the output link 3200 through the first inductor 3312 to achieve direct drive without boosting.

[0036] It is understood that the activation and deactivation of the above switches can be accomplished by a controller located either inside or outside the boost circuit. The controller adjusts the duty cycle of the activation and deactivation signals of the first, second, third, and fourth switches according to the output voltage requirements of the output link. Depending on the actual circuit design and output requirements, the duty cycle of the high and low potentials formed by the alternating activation / deactivation of the switches can be adjusted within a certain range to control the output voltage (e.g., not exceeding twice the input voltage). Preferably, the controller does not perform precise voltage control. And preferably, the duty cycle of the switch control can be 50%.

[0037] Figure 4 This is a schematic diagram showing the waveforms of the potential, current, and voltage of the main components during operation according to an embodiment of the present invention over time. Figure 4 As shown, this illustrates the charge-discharge cycle of a storage capacitor under approximately 50% duty cycle switch control. During boost charging, the first switch is disabled and the second switch is enabled. Since the fourth switch is also disabled (or its diode is reverse-biased), the current flowing through the second inductor and / or the first switch can be considered zero, while the current flowing through the first inductor and / or the second switch exhibits the waveform shown in the figure. Taking boost discharging as an example, the first switch is enabled and the second switch is disabled. Since the third switch is also disabled (or its diode is reverse-biased), the current flowing through the first inductor and / or the second switch can be considered zero, while the current flowing through the second inductor and / or the first switch exhibits the waveform shown in the figure. This charge-discharge process causes the storage capacitor to generate a sinusoidal current change. With appropriate circuit parameter settings, the boost circuit can achieve voltage multiplication.

[0038] On the other hand, as described above, the present invention can also be implemented as an inverter, including a boost circuit as described in any of the foregoing embodiments. It can be used for inverter boosting in various electric vehicles. For example, in automotive inverter boost circuits, the operating frequency is typically below 500kHz, the rated input voltage is typically in the range of approximately 200~400V, and it can be boosted to 200~800V. This can be used for motor drives in pure electric or hybrid vehicles. Typical power values ​​are between 10kW and 200kW, but can also be lower or higher, depending on the circuit design.

[0039] The embodiments and examples presented herein are provided to best illustrate embodiments of the invention and its particular applications, thereby enabling those skilled in the art to practice and use the invention. However, those skilled in the art will understand that the above description and examples are provided merely for ease of illustration and example. The descriptions presented are not intended to cover all aspects of the invention or to limit the invention to the precise forms disclosed.

Claims

1. A boost circuit, characterized in that, The boost circuit includes an input link, a charging / discharging circuit block, and an output link connected in sequence. The charging / discharging circuit block includes an inductor, a switch selection device, and a storage capacitor. The switch selection device is configured to: When the boost circuit needs to perform boost charging, the inductor and the storage capacitor are connected to the input link to form a charging circuit, and the output link is disconnected from the charging circuit to charge the storage capacitor. When the boost circuit needs to perform boost discharge, the inductor and the storage capacitor, along with the input link and the output link, form a discharge circuit to allow the storage capacitor to discharge. The switch selection device is further configured to: When the boost circuit needs to perform direct drive without boosting, the input voltage of the input link is directly output to the output link. Furthermore, the switch selection device includes a first switch, a second switch, a third switch, and a fourth switch; the inductor includes a first inductor and a second inductor; the first inductor and the third switch are connected between a first terminal of the input link and a first terminal of the storage capacitor; the second inductor and the first switch are connected between a first terminal of the input link and a second terminal of the storage capacitor; the second switch is connected between a second terminal of the storage capacitor and a second terminal of the input link; the fourth switch is connected between a first terminal of the storage capacitor and a first terminal of the output link; the second terminal of the output link is connected to a second terminal of the input link; and the boost circuit is configured as follows: When the boost circuit needs to perform boost charging, the second switch and the third switch are enabled, and the first switch and the fourth switch are disabled. When the boost circuit needs to perform boost discharge, the first switch and the fourth switch are enabled, and the second switch and the third switch are disabled.

2. The boost circuit according to claim 1, wherein, The boost circuit is configured to: When the boost circuit needs to be driven directly without boosting, the third switch and the fourth switch are enabled, and the first switch and the second switch are disabled.

3. The boost circuit according to claim 1, wherein, The third and fourth switches are diodes.

4. The boost circuit according to claim 1, wherein, The boost circuit is also configured to directly connect the two ends of the input link to the two ends of the output link when energy recovery is required.

5. The boost circuit according to claim 4, wherein, The boost circuit also includes a recycling switch, with the second end of the input link connected to the second end of the output link, and the first end of the input link connected to the recycling switch and then connected to the first end of the output link.

6. The boost circuit according to claim 1, wherein, The boost circuit also includes a voltage regulator capacitor connected between the first and second terminals of the output link.

7. The boost circuit according to claim 1, wherein, The first switch, the second switch, the third switch, and the fourth switch are all insulated gate bipolar transistors (IGBTs).

8. The boost circuit according to claim 1, wherein, The boost circuit uses an external controller to control each switch. The controller adjusts the duty cycle of the enable and disable signals of the first switch, the second switch, the third switch, and the fourth switch according to the output voltage requirements of the output link.

9. The boost circuit according to claim 8, wherein, The duty cycle is 50%.

10. An inverter, characterized in that, It includes a boost circuit as described in any one of claims 1-9.

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