Step-up / step-down devices and systems

Abstract

An embodiment of the present disclosure discloses a buck-boost device and system, the buck-boost device including: a buck-boost circuit configured to output a first output voltage under a first control of the transistor controller, the first output voltage being greater than or less than a first input voltage, the first input voltage being a voltage of an externally connected power battery, and the first output voltage being for powering an inverter of a vehicle motor; and a transistor controller configured to output a first control to the buck-boost circuit when the vehicle is in a driving mode, the first control meaning to control whether a controllable device of the buck-boost circuit itself is turned on or off.

Description

Technical Field

[0001] This application claims the priority of a Chinese patent application filed with the China National Intellectual Property Administration on January 9, 2023, with the application number 202310026367.X and the title of the invention being "Buck-Boost Device and System", and the content thereof should be understood to be incorporated herein by reference.

[0002] Embodiments of the present disclosure relate to the technical field of power electronics, but are not limited thereto, and particularly relate to buck-boost devices and systems.

Background Art

[0003] In power electronics equipment, there are some devices that realize specific functions due to an increase or decrease in input voltage, and these devices are usually called boost devices or buck devices. These devices are represented as BOOST boost and BUCK buck in new energy vehicles. However, currently, only a boost discharge function or only a buck discharge function can be realized by the same device.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The following is a brief description of the topics described in detail in the text. This brief description is not intended to limit the scope of protection of the claims.

Means for Solving the Problems

[0005] Embodiments of the present disclosure provide a buck-boost device applied to a new energy vehicle, and the buck-boost device includes a buck-boost circuit and a transistor controller. The buck-boost circuit is arranged to output a first output voltage under the first control of the transistor controller, the first output voltage is greater than or less than a first input voltage, the first input voltage is the voltage of an externally connected power battery, and the first output voltage is for supplying power to an inverter of a motor of the vehicle. The transistor controller is installed to output a first control to the buck-boost circuit when the vehicle is in a driving mode, where the first control means conducting and interrupting control of a controllable device of the buck-boost circuit itself.

[0006] In an exemplary embodiment, the buck-boost circuit is further installed to output a second output voltage with a second control of the transistor controller, where the second output voltage is greater than a second input voltage, the second input voltage is the voltage of an externally connected charging post, and the second output voltage is for charging an externally connected power battery. The transistor controller is further installed to output a second control to the buck-boost circuit when the vehicle is in a charging mode, where the second control means conducting and interrupting control of a controllable device of the buck-boost circuit itself.

[0007] In an exemplary embodiment, the buck-boost circuit includes a first capacitor, an inductance, a diode, a first transistor, a second transistor, a third transistor, and a second capacitor. The first end of the first capacitor is the first negative terminal of the buck-boost device, the second end of the first capacitor is the first positive terminal of the buck-boost device, the first end of the second capacitor is the second positive terminal of the buck-boost device, and the second end of the second capacitor is the second negative terminal of the buck-boost device. The first end of the first capacitor is connected to the anode of the diode and the first end of the second transistor respectively. The second end of the second transistor is connected to the first end of the inductance and the first end of the second capacitor respectively. The second end of the first capacitor is connected to the first end of the third transistor. The second end of the third transistor is connected to the first end of the first transistor and the second end of the inductance respectively. The second end of the first transistor is connected to the cathode of the diode and the second end of the second capacitor respectively.

[0008] In one exemplary embodiment, the transistor controller is specifically configured to control the first transistor to shut off, the second transistor to conduct, and the third transistor to conduct when the vehicle is in drive mode, that is, after the first positive terminal and the first negative terminal of the step-up / step-up device are connected to the positive and negative terminals of the power battery, and to control the first conduction coefficient, so that when the first conduction coefficient is less than 1 / 2, the voltage between the second positive terminal and the second negative terminal of the step-up / step-up device is less than the voltage of the power battery, and when the first conduction coefficient is greater than 1 / 2, the voltage between the second positive terminal and the second negative terminal of the step-up / step-up device is greater than the voltage of the power battery. Of these, the first conduction coefficient refers to the ratio of the sum of the conduction time during which the second transistor and the third transistor are conducted, the conduction time during which the second transistor and the third transistor are conducted, and the cutoff time during which the second transistor and the third transistor are cut off.

[0009] In one exemplary embodiment, the transistor controller is specifically configured to control the second transistor to shut off and the first and third transistors to conduct alternately when the vehicle is in charging mode, that is, after the second positive terminal and second negative terminal of the step-up / step-up device are connected to the positive and negative terminals of the charging post, and to control the second conduction coefficient, so that when the second conduction coefficient is greater than zero, the voltage between the first positive terminal and first negative terminal of the step-up / step-up device becomes greater than the voltage of the charging post. Of these, the second conduction coefficient refers to the ratio of the sum of the conduction time during which the first transistor is conductive, the conduction time during which the first transistor is conductive, and the cutoff time during which the first transistor is disconnected.

[0010] Embodiments of this disclosure are step-up / step-down systems applicable to new energy vehicles, The system includes a step-up / step-down device, a changeover switch, an inverter, a charging post, a power battery, and a changeover switch controller, wherein the step-up / step-down device includes a step-up / step-down circuit and a transistor controller. The step-up / step-down circuit is configured to output a first output voltage under the first control of the transistor controller, wherein the first output voltage is greater than or less than the first input voltage, the first input voltage is the voltage of the power battery, and the first output voltage is used to supply power to the inverter of the vehicle's motor. The transistor controller is configured to output a first control to the step-up / step-down circuit when the vehicle is in drive mode, and the first control means that it performs conduction / disconnection control on the controllable devices of the step-up / step-down circuit itself. The aforementioned changeover switch controller is installed to switch the changeover switch to the inverter side so that the step-up / step-down device is connected to the inverter when the vehicle is in drive mode, and to switch the changeover switch to the charging post side so that the step-up / step-down device is connected to the charging post when the vehicle is in charging mode, thereby providing a step-up / step-down system.

[0011] In one exemplary embodiment, the buck-boost circuit is further configured to output a second output voltage under second control of the transistor controller, wherein the second output voltage is greater than the second input voltage, the second input voltage is the voltage of the charging post, and the second output voltage is for charging the power battery. The transistor controller is further configured to output a second control to the buck-boost circuit when the vehicle is in charging mode, and the second control means that it performs conduction / disconnection control on the controllable devices of the buck-boost circuit itself.

[0012] In one exemplary embodiment, the step-up / step-down circuit includes a first capacitor, an inductance, a diode, a first transistor, a second transistor, a third transistor, and a second capacitor. The first terminal of the first capacitor is connected to the first negative terminal of the buck-boost device, the second terminal of the first capacitor is connected to the first positive terminal of the buck-boost device, the first terminal of the second capacitor is connected to the second positive terminal of the buck-boost device, and the second terminal of the second capacitor is connected to the second negative terminal of the buck-boost device. The first terminal of the first capacitor is connected to the anode of the diode and the first terminal of the second transistor, respectively; the second terminal of the second transistor is connected to the first terminal of the inductance and the first terminal of the second capacitor, respectively; the second terminal of the first capacitor is connected to the first terminal of the third transistor; the second terminal of the third transistor is connected to the first terminal of the first transistor and the second terminal of the inductance, respectively; and the second terminal of the first transistor is connected to the cathode of the diode and the second terminal of the second capacitor, respectively.

[0013] In one exemplary embodiment, the transistor controller is specifically configured to control the first transistor to shut off, the second transistor to conduct, and the third transistor to conduct when the vehicle is in drive mode, that is, after the first positive terminal and the first negative terminal of the step-up / step-up device are connected to the positive and negative terminals of the power battery, and to control the first conduction coefficient, so that when the first conduction coefficient is less than 1 / 2, the voltage between the second positive terminal and the second negative terminal of the step-up / step-up device is less than the voltage of the power battery, and when the first conduction coefficient is greater than 1 / 2, the voltage between the second positive terminal and the second negative terminal of the step-up / step-up device is greater than the voltage of the power battery. Of these, the first conduction coefficient refers to the ratio of the sum of the conduction time during which the second transistor and the third transistor are conducted, the conduction time during which the second transistor and the third transistor are conducted, and the cutoff time during which the second transistor and the third transistor are cut off.

[0014] In one exemplary embodiment, the transistor controller is specifically configured to control the second transistor to shut off and the first and third transistors to conduct alternately when the vehicle is in charging mode, that is, after the second positive terminal and second negative terminal of the step-up / step-up device are connected to the positive and negative terminals of the charging post, and to control the second conduction coefficient, so that when the second conduction coefficient is greater than zero, the voltage between the first positive terminal and first negative terminal of the step-up / step-up device becomes greater than the voltage of the charging post. Of these, the second conduction coefficient refers to the ratio of the conduction time during which the first transistor is conductive, the sum of the conduction time during which the first transistor is conductive, and the cutoff time during which the first transistor is disconnected.

[0015] In one exemplary embodiment, the changeover switch includes two changeover switches, a first changeover switch and a second changeover switch, each changeover switch including a fixed end, a first movable end and a second movable end, The immovable end of the first changeover switch is connected to the second positive terminal of the step-up / step-down device, the first movable end of the first changeover switch is connected to the positive terminal of the charging post, and the second movable end of the first changeover switch is connected to the positive input terminal of the inverter. The immovable end of the second changeover switch is connected to the second negative terminal of the step-up / step-down device, the first movable end of the second changeover switch is connected to the negative terminal of the charging post, and the second movable end of the second changeover switch is connected to the negative input terminal of the inverter.

[0016] In one exemplary embodiment, the changeover switch controller is configured to connect the immovable end of the first changeover switch to the second movable end of the first changeover switch and connect the immovable end of the second changeover switch to the second movable end of the second changeover switch when the vehicle is in drive mode, but to connect the immovable end of the first changeover switch to the first movable end of the first changeover switch and connect the immovable end of the second changeover switch to the first movable end of the second changeover switch when the vehicle is in charge mode.

[0017] Other embodiments of the related technologies can be understood after reading and understanding the attached drawings and detailed descriptions. The attached drawings are intended to provide an understanding of the proposed technical invention of this disclosure and to constitute part of the specification, and are to be used together with the embodiments of this disclosure for the interpretation of the proposed technical invention of this disclosure, and do not constitute any limitation on the proposed technical invention of this disclosure. [Brief explanation of the drawing]

[0018] [Figure 1] This is a schematic diagram of a step-up / step-down device according to an embodiment of the present disclosure. [Figure 2] This is a schematic diagram of a step-up / step-down system according to an embodiment of the present disclosure. [Figure 3] This is a schematic diagram of another step-up / step-down system according to an embodiment of the present disclosure. [Figure 4] Figure 3 is a schematic diagram of the structure of the step-up / step-down device in the system shown. [Figure 5] Figure 3 is a schematic circuit diagram showing the system in which S2 and S3 are conductive and S1 is blocked. [Figure 6] This is a schematic circuit diagram of the system shown in Figure 3, where S3 and S2 are shut off and S1 is made conductive. [Figure 7] This is a schematic circuit diagram of the system shown in Figure 3, where S3 and S2 are shut off and S1 is made conductive. [Figure 8]This is a schematic circuit diagram of the system shown in Figure 3, where S1 is shut off and S3 and S2 are made conductive. [Modes for carrying out the invention]

[0019] Figure 1 is a schematic diagram of a step-up / step-down device according to an embodiment of the present disclosure, and as shown in Figure 1, the step-up / step-down device of this embodiment is applied to a new energy vehicle. The step-up / step-down device includes a step-up / step-down circuit and the transistor controller, The step-up / step-down circuit is configured to output a first output voltage under the first control of the transistor controller, wherein the first output voltage is greater than or less than the first input voltage, the first input voltage is the voltage of an externally connected power battery, and the first output voltage is used to supply power to the inverter of the vehicle's motor. The transistor controller is configured to output a first control to the step-up / step-down circuit when the vehicle is in drive mode, and the first control means that a first conduction / disconnection control is performed on the controllable devices of the step-up / step-down circuit itself.

[0020] In one exemplary embodiment, the buck-boost circuit is further configured to output a second output voltage under second control of the transistor controller, wherein the second output voltage is greater than the second input voltage, the second input voltage is the voltage of an externally connected charging post, and the second output voltage is for charging an externally connected power battery. The transistor controller is further configured to output a second control to the buck-boost circuit when the vehicle is in charging mode, and the second control means that a second conduction / disconnection control is performed on the controllable devices of the buck-boost circuit itself.

[0021] In one exemplary embodiment, the step-up / step-down circuit includes a first capacitor, an inductance, a diode, a first transistor, a second transistor, a third transistor, and a second capacitor. The first terminal of the first capacitor is connected to the first negative terminal of the buck-boost device, the second terminal of the first capacitor is connected to the first positive terminal of the buck-boost device, the first terminal of the second capacitor is connected to the second positive terminal of the buck-boost device, and the second terminal of the second capacitor is connected to the second negative terminal of the buck-boost device. The first terminal of the first capacitor is connected to the anode of the diode and the first terminal of the second transistor, respectively; the second terminal of the second transistor is connected to the first terminal of the inductance and the first terminal of the second capacitor, respectively; the second terminal of the first capacitor is connected to the first terminal of the third transistor; the second terminal of the third transistor is connected to the first terminal of the first transistor and the second terminal of the inductance, respectively; and the second terminal of the first transistor is connected to the cathode of the diode and the second terminal of the second capacitor, respectively.

[0022] In one exemplary embodiment, the transistor controller is configured to control the first transistor to shut off, the second transistor to conduct, and the third transistor to conduct when the vehicle is in drive mode, that is, after the first positive terminal of the step-up / step-up device is connected to the positive terminal of the power battery and the first negative terminal of the step-up / step-up device is connected to the negative terminal of the power battery, and to control the first conduction coefficient, so that when the first conduction coefficient is less than 1 / 2, the voltage between the second positive terminal and the second negative terminal of the step-up / step-up device is less than the voltage of the power battery, and when the first conduction coefficient is greater than 1 / 2, the voltage between the second positive terminal and the second negative terminal of the step-up / step-up device is greater than the voltage of the power battery. Of these, the first conduction coefficient refers to the ratio of the sum of the conduction time during which the second and third transistors conduct, the conduction time during which the second and third transistors conduct, and the cutoff time during which the second and third transistors are cut off.

[0023] The first control may mean controlling to cut off the first transistor, controlling to turn on the second transistor and the third transistor, and controlling a first conduction coefficient. The control of the first conduction coefficient may mean controlling the conduction time for turning on the second transistor and the third transistor.

[0024] In an exemplary embodiment, the first transistor, the second transistor, and the third transistor may be silicon carbide thyristors. At this time, the first end of the transistor may be the anode of the silicon carbide thyristor, the second end may be the cathode of the silicon carbide thyristor, and the gate of the silicon carbide thyristor is used as the control electrode.

[0025] In an exemplary embodiment, the first transistor, the second transistor, and the third transistor may be silicon carbide triodes. At this time, the first end of the transistor may be the source electrode / drain electrode of the silicon carbide triode, the second end may be the drain electrode / source electrode of the silicon carbide triode, and the grid electrode of the silicon carbide triode is used as the control electrode.

[0026] For example, the first conduction coefficient is D d =t on1 / (t on1 +t off1 ), where t on1 is the time when the third transistor and the second transistor are turned on, and t off1 is the time when the third transistor and the second transistor are cut off. The third transistor and the second transistor are turned on and cut off simultaneously. The voltage U o between the second positive terminal and the second negative terminal of the buck-boost device, and the voltage U in between the first positive terminal and the first negative terminal of the buck-boost device have the following relationship, that is, U o =[D o / (1-D d )]U d ). in

[0027] In one exemplary embodiment, the transistor controller is configured to control the second transistor to shut off and the first and third transistors to conduct alternately when the vehicle is in charging mode, that is, after the second positive terminal of the buck-boost device is connected to the positive terminal of the charging post and the second negative terminal of the buck-boost device is connected to the negative terminal of the charging post, and to control the second conduction coefficient, so that when the second conduction coefficient is greater than zero, the voltage between the first positive terminal and the first negative terminal of the buck-boost device becomes greater than the voltage of the charging post. Of these, the second conduction coefficient refers to the ratio of the conduction time during which the first transistor is conductive, the sum of the conduction time during which the first transistor is conductive, and the cutoff time during which the first transistor is disconnected.

[0028] The second control may mean controlling the second transistor to shut off, controlling the first transistor and the third transistor to conduct alternately, and controlling the second conduction coefficient. Controlling the second conduction coefficient may mean controlling the conduction time for which the first transistor conducts. For example, the second conduction coefficient is D g =t on1 / (t on1 +t off1 ) and among them, t on1 is the time during which the first transistor is conductive, and t off1 is the time during which the first transistor is shut off. The voltage U between the second positive terminal and the second negative terminal of the step-up / step-down device. o , and the voltage U between the first positive terminal and the first negative terminal of the step-up / step-down device. in The relationship is as follows, that is, U in =[1 / (1-D g )]U o .

[0029] The step-up / step-down device according to the embodiment of this disclosure can realize both a step-up discharge function and a step-down discharge function in the same device.

[0030] Figure 2 is a schematic diagram of a step-up / step-down system according to an embodiment of the present disclosure, and as shown in Figure 2, the step-up / step-down system includes a step-up / step-down device, a changeover switch, an inverter, a charging post, a power battery, and a changeover switch controller, wherein the step-up / step-down device includes a step-up / step-down circuit and the transistor controller, The step-up / step-down circuit is configured to output a first output voltage under the first control of the transistor controller, wherein the first output voltage is greater than or less than the first input voltage, the first input voltage is the voltage of the power battery, and the first output voltage is used to supply power to the inverter of the vehicle's motor. The transistor controller is configured to output a first control to the step-up / step-down circuit when the vehicle is in drive mode, and the first control means that a first conduction / disconnection control is performed on the controllable device of the step-up / step-down circuit itself. The aforementioned changeover switch controller is installed to switch the changeover switch to the inverter side when the vehicle is in drive mode so that the step-up / step-down device is connected to the inverter, and to switch the changeover switch to the charging post side when the vehicle is in charging mode so that the step-up / step-down device is connected to the charging post.

[0031] In one exemplary embodiment, the buck-boost circuit is further configured to output a second output voltage under second control of the transistor controller, wherein the second output voltage is greater than the second input voltage, the second input voltage is the voltage of the charging post, and the second output voltage is for charging the power battery. The transistor controller is further configured to output a second control to the buck-boost circuit when the vehicle is in charging mode, and the second control means that a second conduction / disconnection control is performed on the controllable devices of the buck-boost circuit itself.

[0032] In one exemplary embodiment, the step-up / step-down circuit includes a first capacitor, an inductance, a diode, a first transistor, a second transistor, a third transistor, and a second capacitor. The first terminal of the first capacitor is connected to the first negative terminal of the buck-boost device, the second terminal of the first capacitor is connected to the first positive terminal of the buck-boost device, the first terminal of the second capacitor is connected to the second positive terminal of the buck-boost device, and the second terminal of the second capacitor is connected to the second negative terminal of the buck-boost device. The first terminal of the first capacitor is connected to the anode of the diode and the first terminal of the second transistor, respectively; the second terminal of the second transistor is connected to the first terminal of the inductance and the first terminal of the second capacitor, respectively; the second terminal of the first capacitor is connected to the first terminal of the third transistor; the second terminal of the third transistor is connected to the first terminal of the first transistor and the second terminal of the inductance, respectively; and the second terminal of the first transistor is connected to the cathode of the diode and the second terminal of the second capacitor, respectively.

[0033] In one exemplary embodiment, the first transistor, the second transistor, and the third transistor may be silicon carbide thyristors. In this case, the first end of the transistor may be the anode of the silicon carbide thyristor, the second end may be the cathode of the silicon carbide thyristor, and the gate of the silicon carbide thyristor is the control electrode.

[0034] In one exemplary embodiment, the first, second, and third transistors may be silicon carbide triodes. In this case, the first terminal of the transistor may be the source / drain electrode of the silicon carbide triode, the second terminal may be the drain / source electrode of the silicon carbide triode, and the grid electrode of the silicon carbide triode serves as the control electrode.

[0035] In one exemplary embodiment, the transistor controller is specifically configured to control the first transistor to shut off and the second and third transistors to conduct when the vehicle is in drive mode, that is, after the first positive terminal of the buck-boost device is connected to the positive terminal of the power battery and the first negative terminal of the buck-boost device is connected to the negative terminal of the power battery, and to control the first conduction coefficient, so that when the first conduction coefficient is less than 1 / 2, the voltage between the second positive terminal and the second negative terminal of the buck-boost device is less than the voltage of the power battery, and when the first conduction coefficient is greater than 1 / 2, the voltage between the second positive terminal and the second negative terminal of the buck-boost device is greater than the voltage of the power battery. Of these, the first conduction coefficient refers to the ratio of the sum of the conduction time during which the second transistor and the third transistor are conducted, the conduction time during which the second transistor and the third transistor are conducted, and the cutoff time during which the second transistor and the third transistor are cut off.

[0036] The first control may mean controlling the first transistor to shut off, controlling the second and third transistors to conduct, and controlling the first conduction coefficient. Controlling the first conduction coefficient may mean controlling the conduction time for which the second and third transistors conduct.

[0037] In one exemplary embodiment, the transistor controller is specifically configured to control the second transistor to shut off and the first and third transistors to conduct alternately when the vehicle is in charging mode, that is, after the second positive terminal of the buck-boost device is connected to the positive terminal of the charging post and the second negative terminal of the buck-boost device is connected to the negative terminal of the charging post, and to control the second conduction coefficient, so that when the second conduction coefficient is greater than zero, the voltage between the first positive terminal and the first negative terminal of the buck-boost device becomes greater than the voltage of the charging post. Of these, the second conduction coefficient refers to the ratio of the conduction time during which the first transistor is conductive, the sum of the conduction time during which the first transistor is conductive, and the cutoff time during which the first transistor is disconnected.

[0038] The second control may mean controlling the second transistor to shut off, controlling the first transistor and the third transistor to conduct alternately, and controlling the second conduction coefficient. Controlling the second conduction coefficient may mean controlling the conduction time for which the first transistor conducts.

[0039] In one exemplary embodiment, the changeover switch includes two changeover switches, a first changeover switch and a second changeover switch, each changeover switch including a fixed end, a first movable end and a second movable end, The immovable end of the first changeover switch is connected to the second positive terminal of the step-up / step-down device, the first movable end of the first changeover switch is connected to the positive terminal of the charging post, and the second movable end of the first changeover switch is connected to the positive input terminal of the inverter. The immovable end of the second changeover switch is connected to the second negative terminal of the step-up / step-down device, the first movable end of the second changeover switch is connected to the negative terminal of the charging post, and the second movable end of the second changeover switch is connected to the negative input terminal of the inverter.

[0040] In one exemplary embodiment, the changeover switch controller is configured to connect the immovable end of the first changeover switch to the second movable end of the first changeover switch and connect the immovable end of the second changeover switch to the second movable end of the second changeover switch when the vehicle is in drive mode, but to connect the immovable end of the first changeover switch to the first movable end of the first changeover switch and connect the immovable end of the second changeover switch to the first movable end of the second changeover switch when the vehicle is in charge mode.

[0041] Figure 3 is a schematic diagram of another step-up / step-down system according to an embodiment of the present disclosure, and as shown in Figure 3, U in This is the input voltage in drive mode (i.e., the output voltage of the power battery), U o is the output voltage, D1 is a diode, S1, S2, S3 are silicon carbide (SiC) thyristors (SiC is bidirectional), L is the inductance, C1, C2 are automotive film capacitors, S a1 S a2 These are two thyristor IGBT groups on the half-bridge corresponding to the three-phase motor A, and similarly, S b1 S b2 This corresponds to phase B, S c1 S c2 The C phase corresponds to the stator winding of the three-phase motor M, which is connected in a star configuration, with point N being the neutral point of the three-phase winding. SW1 and SW2 are toggle switches; when in the up position, the entire vehicle is in charging mode and is connected to the charging post to charge the power battery of the charging post. When in the down position, the entire vehicle is in driving mode and is connected to the motor's inverter to supply input voltage to the motor.

[0042] The step-up / step-down circuit shown in Figure 4 includes capacitors C1 and C2, thyristors S1, S2, and S3, diode D1, and inductance L. The voltage across capacitor C2 is U o That is the case.

[0043] In drive mode, the description of the BOOST / BUCK function is as follows: At this time, power battery U in When the voltage is stepped up or down, the voltage U o The output is as follows, and the control methods for S1, S2, and S3 are as follows: When S2 and S3 are made to conduct and S1 is blocked, the inductance L stores energy, as shown in Figure 5 below, and the flow of current I is shown in the figure. When S2 and S3 are blocked and S1 is opened, the inductance L releases its energy, and the circuit becomes as shown in Figure 6. The control method is described as follows: The switching frequencies of the three silicon carbide thyristors S1, S2, and S3 are the same, i.e., the switching period T d The same (d indicates Driving), and the control duty cycles of S2 and S3 are D d Set the duty cycle of S1 to (1-D d In other words, when S3 and S2 are made to conduct, S1 is blocked, and when S3 and S2 are blocked, S1 is made to conduct, and they complement each other.

[0044] Voltage U in and U o The calculation relationship is as follows: When S3 and S2 are made to conduct and S1 is made to block, the inductance L is U in The energy from is stored, and the current that flows through L is,

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[0045] In charging or energy recovery mode, the description of the BOOST boost function is as follows: In this mode, U o The battery pack U is used as the energy input terminal. in When charging, S2 is in a permanently shut-off state, and the control methods for S1 and S3 are as follows: When S3 and S2 are blocked and S1 is opened, the inductance L stores energy, and the schematic diagram is shown in Figure 7. When S1 and S2 are blocked and S3 is made conductive, U in After charging, the schematic diagram is as shown in Figure 8. The control method is described as follows: Of the three silicon carbide thyristors, S2 is always shut off in this mode, and the switching frequencies of S1 and S3 are the same, i.e., the switching period T g The same (g indicates Generating), and the duty cycle of S1 is D g Set the duty cycle of S3 to (1-D g In other words, when S1 is made to conduct, S3 is blocked, and when S1 is blocked, S3 is made to conduct, and they complement each other.

[0046] Voltage U in and U o The calculation relationship is as follows: When S1 is made to conduct and S3 is made to stop, the inductance L is equal to the power supply U o With the energy stored, the current flowing through L is, ​

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[0047] As can be seen from the above, when a vehicle equipped with this device is in drive mode, the bus voltage input of the inverter can be boosted and bucked by controlling the conduction duty cycle of a specific SiC in the boost / buck device, and the target values ​​for boosting and bucking can be calculated based on formula (1). When a vehicle equipped with this device is in charging or energy recovery mode, boost charging can be achieved by controlling the conduction duty cycle of a specific SiC in the boost / buck device with respect to the voltage input of the power battery, and the target value of the boost is calculated based on formula (2).

[0048] While this disclosure describes several embodiments, this description is illustrative and not restrictive, and it will be obvious to those skilled in the art that there may be many more embodiments and implementations within the scope of those described herein. Although many possible combinations of features are shown in the accompanying drawings and specific embodiments have been considered, many other combinations of the disclosed features are also possible. Unless otherwise specified, any feature or element in any embodiment may be used in combination with any other feature or element in any other embodiment, or may substitute for any other feature or element in any other embodiment.

[0049] In embodiments of this disclosure, any illustrated and / or discussed feature can be realized individually or in any suitable combination.

[0050] Furthermore, when describing representative embodiments, the specification may present the method and / or process as a specific step sequence. However, the method or process should not be limited to the steps in the aforementioned specific sequence unless it does not depend on such a specific order as described above. Other steps and sequences are possible, as those skilled in the art will understand.

[0051] As those skilled in the art will understand, all or some steps, systems, or devices in the methods disclosed in the Preamble can be implemented as software, firmware, hardware, or appropriate combinations thereof. In hardware embodiments, the distinctions between the functional modules / units referred to above do not necessarily correspond to distinctions between physical components; for example, one physical component may have multiple functions, or one function or step may be performed by the cooperation of several physical components. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or microprocessor, or as hardware, or as an integrated circuit, such as a dedicated integrated circuit. Such software may be distributed on computer-readable media, which may include computer storage media (or non-temporary media) and communication media (or temporary media). As those skilled in the art will know, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technique for storing information (e.g., computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital multifunction disk (DVD) or other optical disc storage devices, magnetic cassettes, magnetic tapes, magnetic disk storage devices or other magnetic storage devices, or any other media used for storing desired information and accessible by a computer. Furthermore, as is well known to those skilled in the art, communication media typically include computer-readable instructions, data structures, program modules or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

Claims

1. A step-up / step-down device applicable to new energy vehicles, Includes a step-up / step-down circuit and a transistor controller, The step-up / step-down circuit is configured to output a first output voltage under the first control of the transistor controller, wherein the first output voltage is greater than or less than the first input voltage, the first input voltage is the voltage of an externally connected power battery, and the first output voltage is used to supply power to the inverter of the vehicle's motor. The transistor controller is installed to output a first control to the step-up / step-down circuit when the vehicle is in drive mode, and the first control means that a first conduction / disconnection control is performed on the controllable device of the step-up / step-down circuit itself. The step-up / step-down circuit includes a first capacitor, an inductance, a diode, a first transistor, a second transistor, a third transistor, and a second capacitor. The first terminal of the first capacitor is connected to the first negative terminal of the buck-boost device, the second terminal of the first capacitor is connected to the first positive terminal of the buck-boost device, the first terminal of the second capacitor is connected to the second positive terminal of the buck-boost device, and the second terminal of the second capacitor is connected to the second negative terminal of the buck-boost device. The first terminal of the first capacitor is connected to the anode of the diode and the first terminal of the second transistor, respectively; the second terminal of the second transistor is connected to the first terminal of the inductance and the first terminal of the second capacitor, respectively; the second terminal of the first capacitor is connected to the first terminal of the third transistor; the second terminal of the third transistor is connected to the first terminal of the first transistor and the second terminal of the inductance, respectively; and the second terminal of the first transistor is connected to the cathode of the diode and the second terminal of the second capacitor, respectively. Step-up / step-down converter.

2. The step-up / step-down circuit is further configured to output a second output voltage under the second control of the transistor controller, wherein the second output voltage is greater than the second input voltage, the second input voltage is the voltage of an externally connected charging post, and the second output voltage is for charging an externally connected power battery. The transistor controller is further configured to output a second control to the buck-boost circuit when the vehicle is in charging mode, and the second control means that a second conduction / disconnection control is performed on the controllable device of the buck-boost circuit itself. The step-up / step-down device according to claim 1.

3. The transistor controller is configured to control the first transistor to shut off and the second and third transistors to conduct when the vehicle is in drive mode, that is, after the first positive terminal of the step-up / step-down device is connected to the positive terminal of the externally connected power battery and the first negative terminal of the step-up / step-down device is connected to the negative terminal of the externally connected power battery, and to control the first conduction coefficient, so that when the first conduction coefficient is less than 1 / 2, the voltage between the second positive terminal and the second negative terminal of the step-up / step-down device is less than the voltage of the externally connected power battery, and when the first conduction coefficient is greater than 1 / 2, the voltage between the second positive terminal and the second negative terminal of the step-up / step-down device is greater than the voltage of the externally connected power battery. The first conduction coefficient is the ratio of the sum of the conduction time during which both the second and third transistors conduct, the conduction time during which both the second and third transistors conduct, and the cutoff time during which both the second and third transistors are cut off. The step-up / step-down device according to claim 1.

4. The transistor controller is configured to control the second transistor and alternately conduct the first and third transistors when the vehicle is in charging mode, that is, after the second positive terminal of the step-up / step-up device is connected to the positive terminal of the charging post and the second negative terminal of the step-up / step-up device is connected to the negative terminal of the charging post, thereby controlling the second conduction coefficient, so that when the second conduction coefficient is greater than zero, the voltage between the first positive terminal and the first negative terminal of the step-up / step-up device becomes greater than the voltage of the charging post. The second conduction coefficient refers to the ratio of the conduction time during which the first transistor is conductive to the sum of the conduction time during which the first transistor is conductive and the cutoff time during which the first transistor is cut off. The step-up / step-down device according to claim 1.

5. A step-up / step-down system applicable to new energy vehicles, Includes a step-up / step-down converter, changeover switch, inverter, charging post, power battery and changeover switch controller, The aforementioned buck-boost device includes a buck-boost circuit and a transistor controller. The step-up / step-down circuit is configured to output a first output voltage under the first control of the transistor controller, wherein the first output voltage is greater than or less than the first input voltage, the first input voltage is the voltage of the power battery, and the first output voltage supplies power to the inverter of the vehicle's motor. The transistor controller is installed to output a first control to the step-up / step-down circuit when the vehicle is in drive mode, and the first control means that a first conduction / disconnection control is performed on the controllable device of the step-up / step-down circuit itself. The aforementioned changeover switch controller is installed to switch the changeover switch to the inverter side when the vehicle is in drive mode so that the step-up / step-down device is connected to the inverter, and to switch the changeover switch to the charging post side when the vehicle is in charging mode so that the step-up / step-down device is connected to the charging post. The step-up / step-down circuit includes a first capacitor, an inductance, a diode, a first transistor, a second transistor, a third transistor, and a second capacitor. The first terminal of the first capacitor is connected to the first negative terminal of the buck-boost device, the second terminal of the first capacitor is connected to the first positive terminal of the buck-boost device, the first terminal of the second capacitor is connected to the second positive terminal of the buck-boost device, and the second terminal of the second capacitor is connected to the second negative terminal of the buck-boost device. The first terminal of the first capacitor is connected to the anode of the diode and the first terminal of the second transistor, respectively; the second terminal of the second transistor is connected to the first terminal of the inductance and the first terminal of the second capacitor, respectively; the second terminal of the first capacitor is connected to the first terminal of the third transistor; the second terminal of the third transistor is connected to the first terminal of the first transistor and the second terminal of the inductance, respectively; and the second terminal of the first transistor is connected to the cathode of the diode and the second terminal of the second capacitor, respectively. Step-up / step-down system.

6. The step-up / step-down circuit is further configured to output a second output voltage under the second control of the transistor controller, wherein the second output voltage is greater than the second input voltage, the second input voltage is the voltage of the charging post, and the second output voltage is for charging the power battery. The transistor controller is further configured to output a second control to the buck-boost circuit when the vehicle is in charging mode, and the second control means that a second conduction / disconnection control is performed on the controllable device of the buck-boost circuit itself. The step-up / step-down system according to claim 5.

7. The transistor controller is configured to control the first transistor to shut off and the second and third transistors to conduct when the vehicle is in drive mode, that is, after the first positive terminal of the step-up / step-down device is connected to the positive terminal of the power battery and the first negative terminal of the step-up / step-down device is connected to the negative terminal of the power battery, and to control the first conduction coefficient, so that when the first conduction coefficient is less than 1 / 2, the voltage between the second positive terminal and the second negative terminal of the step-up / step-down device is less than the voltage of the power battery, and when the first conduction coefficient is greater than 1 / 2, the voltage between the second positive terminal and the second negative terminal of the step-up / step-down device is greater than the voltage of the power battery. The first conduction coefficient is the ratio of the sum of the conduction time during which both the second and third transistors conduct, the conduction time during which both the second and third transistors conduct, and the cutoff time during which both the second and third transistors are cut off. The step-up / step-down system according to claim 5.

8. Specifically, the transistor controller is configured to control the second transistor to shut off and the first and third transistors to conduct alternately when the vehicle is in charging mode, that is, after the second positive terminal and second negative terminal of the step-up / step-down device are connected to the positive and negative terminals of the charging post, and to control the second conduction coefficient, so that when the second conduction coefficient is greater than zero, the voltage between the first positive terminal and first negative terminal of the step-up / step-down device becomes greater than the voltage of the charging post. The second conduction coefficient refers to the ratio of the sum of the conduction time during which the first transistor is conductive, the conduction time during which the first transistor is conductive, and the cutoff time during which the first transistor is cut off. The step-up / step-down system according to claim 5.

9. The aforementioned changeover switch includes two changeover switches, a first changeover switch and a second changeover switch, each changeover switch including a fixed end, a first movable end and a second movable end, The immovable end of the first changeover switch is connected to the second positive terminal of the step-up / step-down device, the first movable end of the first changeover switch is connected to the positive terminal of the charging post, and the second movable end of the first changeover switch is connected to the positive input terminal of the inverter. The immovable end of the second changeover switch is connected to the second negative terminal of the step-up / step-down device, the first movable end of the second changeover switch is connected to the negative terminal of the charging post, and the second movable end of the second changeover switch is connected to the negative input terminal of the inverter. The step-up / step-down system according to claim 5.

10. The aforementioned changeover switch controller is configured to connect the immovable end of the first changeover switch to the second movable end of the first changeover switch, and the immovable end of the second changeover switch to the second movable end of the second changeover switch, when the vehicle is in drive mode, but to connect the immovable end of the first changeover switch to the first movable end of the first changeover switch, and the immovable end of the second changeover switch to the first movable end of the second changeover switch when the vehicle is in charging mode. The step-up / step-down system according to claim 9.

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