Step-up / step-down device and system

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 priority from a Chinese patent application bearing application number 202310026367.X and entitled "Step-Up / Step-Down Device and System" filed with the China Patent Office on January 9, 2023, the contents of which are hereby incorporated by reference.

[0002] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate to the field of power electronics technology, particularly but not exclusively to buck-boost devices and systems. [Background technology]

[0003] In power electronics equipment, there are some devices that achieve specific functions by increasing or decreasing the input voltage, and these devices are usually called boost devices or buck devices. These devices are referred to as boost and buck devices in new energy vehicles. However, currently, the same device can only achieve the boost discharge function or only the buck discharge function. Summary of the Invention [Problem to be solved by the invention]

[0004] The following is a brief summary of the topics described in detail in the text, which is not intended to limit the scope of protection of the claims. [Means for solving the problem]

[0005] An embodiment of the present disclosure provides a step-up / step-down device applicable to a new energy vehicle, the step-up / step-down device including 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 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 the voltage of an externally connected power battery, and the first output voltage being for supplying power to an inverter of a motor of a vehicle; The transistor controller is configured to output a first control to the step-up / step-down circuit when the vehicle is in a driving mode, and the first control means that the controllable device of the step-up / step-down circuit itself is controlled to be turned on or off.

[0006] In one exemplary embodiment, the buck-boost circuit is further configured to output a second output voltage under a second control of the transistor controller, the second output voltage being greater than a second input voltage, the second input voltage being a voltage of an externally connected charging post, and the second output voltage being 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 a charging mode, and the second control means to control the conduction / cut-off of a controllable device of the buck-boost circuit itself.

[0007] In one 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; a first end of the first capacitor is a first negative terminal of the step-up / step-down device, a second end of the first capacitor is a first positive terminal of the step-up / step-down device, a first end of the second capacitor is a second positive terminal of the step-up / step-down device, and a second end of the second capacitor is a second negative terminal of the step-up / step-down device; A first end of the first capacitor is connected to the anode of the diode and the first end of the second transistor, respectively; a second end of the second transistor is connected to the first end of the inductance and the first end of the second capacitor, respectively; a second end of the first capacitor is connected to the first end of the third transistor, a second end of the third transistor is connected to the first end of the first transistor and the second end of the inductance, respectively; and a 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 an exemplary embodiment, the transistor controller is specifically configured to control the first transistor to be turned off, the second transistor to be turned on, and the third transistor to be turned on when the vehicle is in a driving mode, i.e., after the first positive terminal and the first negative terminal of the step-up / step-down device are respectively connected to the positive terminal and the negative terminal of the power battery, and to control a 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 means the ratio of the conduction time during which the second transistor is turned on and the third transistor is turned on to the sum of the conduction time during which the second transistor is turned on and the third transistor is turned on, and the cut-off time during which the second transistor is turned off and the third transistor is cut off.

[0009] In one exemplary embodiment, the transistor controller is specifically configured to: when the vehicle is in a charging mode, i.e., after the second positive terminal and the second negative terminal of the buck-boost device are respectively connected to the positive terminal and the negative terminal of the charging post, control the second transistor to be turned off and the first transistor and the third transistor to be turned on alternately, and control a 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 is greater than the voltage of the charging post; The second conduction coefficient means the ratio of the conduction time during which the first transistor is turned on to the sum of the conduction time during which the first transistor is turned on and the cut-off time during which the first transistor is cut off.

[0010] An embodiment of the present disclosure is a step-up / step-down system applied to a new energy vehicle, The power supply includes a step-up / step-down device, a transfer switch, an inverter, a charging post, a power battery, and a transfer switch controller, and 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 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 the voltage of the power battery, and the first output voltage supplying power to the inverter of the vehicle motor; the transistor controller is configured to output a first control to the step-up / step-down circuit when the vehicle is in a driving mode, and the first control means that the step-up / step-down circuit itself controls a controllable device to turn on or off; The 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 a driving 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 a 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 a second control of the transistor controller, the second output voltage being greater than a second input voltage, the second input voltage being the voltage of the charging post, and the second output voltage being 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 a charging mode, and the second control means to control the conduction / cut-off of a controllable device of the buck-boost circuit itself.

[0012] In one 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; a first end of the first capacitor is a first negative terminal of the step-up / step-down device, a second end of the first capacitor is a first positive terminal of the step-up / step-down device, a first end of the second capacitor is a second positive terminal of the step-up / step-down device, and a second end of the second capacitor is a second negative terminal of the step-up / step-down device; A first end of the first capacitor is connected to the anode of the diode and the first end of the second transistor, respectively; a second end of the second transistor is connected to the first end of the inductance and the first end of the second capacitor, respectively; a second end of the first capacitor is connected to the first end of the third transistor, a second end of the third transistor is connected to the first end of the first transistor and the second end of the inductance, respectively; and a second end of the first transistor is connected to the cathode of the diode and the second end of the second capacitor, respectively.

[0013] In an exemplary embodiment, the transistor controller is specifically configured to control the first transistor to be turned off, the second transistor to be turned on, and the third transistor to be turned on when the vehicle is in a driving mode, i.e., after the first positive terminal and the first negative terminal of the step-up / step-down device are respectively connected to the positive terminal and the negative terminal of the power battery, and to control a 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 means the ratio of the conduction time during which the second transistor is turned on and the third transistor is turned on to the sum of the conduction time during which the second transistor is turned on and the third transistor is turned on, and the cut-off time during which the second transistor is turned off and the third transistor is cut off.

[0014] In one exemplary embodiment, the transistor controller is specifically configured to: when the vehicle is in a charging mode, i.e., after the second positive terminal and the second negative terminal of the buck-boost device are respectively connected to the positive terminal and the negative terminal of the charging post, control the second transistor to be turned off and the first transistor and the third transistor to be turned on alternately, and control a 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 is greater than the voltage of the charging post; The second conduction coefficient means the ratio of the conduction time during which the first transistor is turned on to the sum of the conduction time during which the first transistor is turned on and the cut-off time during which the first transistor is cut off.

[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 stationary end, a first movable end, and a second movable end; a fixed end of the first selector switch is connected to a second positive terminal of the step-up / step-down device, a first movable end of the first selector switch is connected to a positive terminal of the charging post, and a second movable end of the first selector switch is connected to a positive input terminal of the inverter; The fixed end of the second selector switch is connected to the second negative terminal of the step-up / step-down device, the first movable end of the second selector switch is connected to the negative terminal of the charging post, and the second movable end of the second selector switch is connected to the negative input terminal of the inverter.

[0016] In one exemplary embodiment, the transfer switch controller is configured to connect the fixed end of the first transfer switch to the second movable end of the first transfer switch and connect the fixed end of the second transfer switch to the second movable end of the second transfer switch when the vehicle is in a driving mode, and to connect the fixed end of the first transfer switch to the first movable end of the first transfer switch and connect the fixed end of the second transfer switch to the first movable end of the second transfer switch when the vehicle is in a charging mode.

[0017] Other aspects of the related art may be understood after reading and understanding the accompanying drawings and detailed description. The accompanying drawings are intended to provide an understanding of the technical solution of the present disclosure and to constitute a part of the specification, and are used to interpret the technical solution of the present disclosure in conjunction with the embodiments of the present disclosure, and are not intended to constitute limitations on the technical solution of the present disclosure. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic diagram of a step-up / step-down device according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a schematic diagram of a step-up / step-down system according to an embodiment of the present disclosure. [Figure 3] FIG. 1 is a schematic diagram of another buck-boost system according to an embodiment of the present disclosure. [Figure 4] 4 is a structural schematic diagram of a step-up / step-down device in the system shown in FIG. 3. FIG. [Figure 5] FIG. 4 is a circuit diagram showing the system shown in FIG. 3 in which S2 and S3 are turned on and S1 is turned off. [Figure 6] FIG. 4 is a circuit diagram showing the system shown in FIG. 3 in which S3 and S2 are cut off and S1 is made conductive. [Figure 7] FIG. 4 is a circuit diagram showing the system shown in FIG. 3 in which S3 and S2 are cut off and S1 is made conductive. [Figure 8]FIG. 4 is a circuit diagram showing the system shown in FIG. 3 in which S1 is cut off and S3 and S2 are turned on. DETAILED DESCRIPTION OF THE INVENTION

[0019] FIG. 1 is a schematic diagram of a step-up / step-down device according to an embodiment of the present disclosure. As shown in FIG. 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 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 the voltage of an externally connected power battery, and the first output voltage being for supplying power to an inverter of a motor of a vehicle; The transistor controller is configured to output a first control to the step-up / step-down circuit when the vehicle is in a driving mode, and the first control means that a first conduction / cut-off control is performed on a controllable device 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 a second control of the transistor controller, the second output voltage being greater than a second input voltage, the second input voltage being a voltage of an externally connected charging post, and the second output voltage being 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 a charging mode, the second control meaning that a second conduction / cut-off control is performed on a controllable device of the buck-boost circuit itself.

[0021] In one 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; a first end of the first capacitor is a first negative terminal of the step-up / step-down device, a second end of the first capacitor is a first positive terminal of the step-up / step-down device, a first end of the second capacitor is a second positive terminal of the step-up / step-down device, and a second end of the second capacitor is a second negative terminal of the step-up / step-down device; A first end of the first capacitor is connected to the anode of the diode and the first end of the second transistor, respectively; a second end of the second transistor is connected to the first end of the inductance and the first end of the second capacitor, respectively; a second end of the first capacitor is connected to the first end of the third transistor, a second end of the third transistor is connected to the first end of the first transistor and the second end of the inductance, respectively; and a second end of the first transistor is connected to the cathode of the diode and the second end of the second capacitor, respectively.

[0022] In an exemplary embodiment, the transistor controller is configured to control the first transistor to be turned off, the second transistor to be turned on, and the third transistor to be turned on when the vehicle is in a driving mode, i.e., 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 a 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; The first conduction coefficient means the ratio of the conduction time during which the second transistor and the third transistor are turned on to the sum of the conduction time during which the second transistor and the third transistor are turned on and the cut-off time during which the second transistor and the third transistor are cut off.

[0023] The first control may mean controlling the first transistor to be turned off, controlling the second transistor and the third transistor to be turned on, and controlling a first conduction coefficient. The control of the first conduction coefficient may mean controlling a conduction time for which the second transistor and the third transistor are turned on.

[0024] In one exemplary embodiment, the first transistor, the second transistor, and the third transistor may be silicon carbide thyristors, with the first terminal of the transistor being the anode of the silicon carbide thyristor, the second terminal being the cathode of the silicon carbide thyristor, and the gate of the silicon carbide thyristor being the control electrode.

[0025] In one exemplary embodiment, the first transistor, the second transistor, and the third transistor may be silicon carbide triodes, where the first terminals of the transistors may be source / drain electrodes of the silicon carbide triodes, the second terminals of the transistors may be drain / source electrodes of the silicon carbide triodes, and the grid electrode of the silicon carbide triodes is the control electrode.

[0026] For example, the first conduction coefficient is D d =t on1 / (t on1 +t off1 ), among which, t on1 is the time that 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 turned off. The third transistor and the second transistor are turned on and turned off at the same time. The voltage U between the second positive terminal and the second negative terminal of the step-up / step-down device is o , and a voltage U between the first positive terminal and the first negative terminal of the step-up / step-down device in The relationship between U o =[D d / (1-D d )]U in .

[0027] In one exemplary embodiment, the transistor controller is configured to, when the vehicle is in a charging mode, i.e., 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, control the second transistor to be turned off and the first transistor and the third transistor to be turned on alternately, and control a 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 is greater than the voltage of the charging post; The second conduction coefficient means the ratio of the conduction time during which the first transistor is turned on to the sum of the conduction time during which the first transistor is turned on and the cut-off time during which the first transistor is cut off.

[0028] The second control may mean controlling the second transistor to be turned off, controlling the first transistor and the third transistor to be turned on alternately, and controlling a second conduction coefficient. The control of the second conduction coefficient may mean controlling the conduction time for which the first transistor is turned on. For example, the second conduction coefficient is D g =t on1 / (t on1 +t off1 ), among which, t on1 is the time that the first transistor is turned on, and t off1 is the time when the first transistor is turned off. The voltage U between the second positive terminal and the second negative terminal of the step-up / step-down device o , and a voltage U between the first positive terminal and the first negative terminal of the step-up / step-down device in The relationship between U in =[1 / (1-D g )]U o .

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

[0030] FIG. 2 is a schematic diagram of a buck-boost system according to an embodiment of the present disclosure. As shown in FIG. 2, the buck-boost system includes a buck-boost device, a transfer switch, an inverter, a charging post, a power battery, and a transfer switch controller. The buck-boost device includes a buck-boost circuit and the transistor controller. the step-up / step-down circuit is 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 the voltage of the power battery, and the first output voltage supplying power to the inverter of the vehicle motor; the transistor controller is configured to output a first control to the step-up / step-down circuit when the vehicle is in a driving mode, and the first control means performing a first conduction / cut-off control on a controllable device of the step-up / step-down circuit itself; The 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 a driving 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 a charging mode.

[0031] In one exemplary embodiment, the buck-boost circuit is further configured to output a second output voltage under a second control of the transistor controller, the second output voltage being greater than a second input voltage, the second input voltage being a voltage of the charging post, and the second output voltage being 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 a charging mode, the second control meaning that a second conduction / cut-off control is performed on a controllable device of the buck-boost circuit itself.

[0032] In one 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; a first end of the first capacitor is a first negative terminal of the step-up / step-down device, a second end of the first capacitor is a first positive terminal of the step-up / step-down device, a first end of the second capacitor is a second positive terminal of the step-up / step-down device, and a second end of the second capacitor is a second negative terminal of the step-up / step-down device; A first end of the first capacitor is connected to the anode of the diode and the first end of the second transistor, respectively; a second end of the second transistor is connected to the first end of the inductance and the first end of the second capacitor, respectively; a second end of the first capacitor is connected to the first end of the third transistor, a second end of the third transistor is connected to the first end of the first transistor and the second end of the inductance, respectively; and a second end of the first transistor is connected to the cathode of the diode and the second end 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, with the first terminal of the transistor being the anode of the silicon carbide thyristor, the second terminal being the cathode of the silicon carbide thyristor, and the gate of the silicon carbide thyristor being the control electrode.

[0034] In one exemplary embodiment, the first transistor, the second transistor, and the third transistor may be silicon carbide triodes, where the first terminals of the transistors may be source / drain electrodes of the silicon carbide triodes, the second terminals of the transistors may be drain / source electrodes of the silicon carbide triodes, and the grid electrode of the silicon carbide triodes is the control electrode.

[0035] In an exemplary embodiment, the transistor controller is specifically configured to, when the vehicle is in a driving mode, i.e., after the first positive terminal of the buck-boost device is connected to the positive electrode of the power battery and the first negative terminal of the buck-boost device is connected to the negative electrode of the power battery, control the first transistor to be turned off and the second transistor and the third transistor to be turned on, and control a 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; 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; The first conduction coefficient means the ratio of the conduction time during which the second transistor is turned on and the third transistor is turned on to the sum of the conduction time during which the second transistor is turned on and the third transistor is turned on, and the cut-off time during which the second transistor is turned off and the third transistor is cut off.

[0036] The first control may mean controlling the first transistor to be turned off, controlling the second transistor and the third transistor to be turned on, and controlling a first conduction coefficient. The control of the first conduction coefficient may mean controlling a conduction time for which the second transistor and the third transistor are turned on.

[0037] In an exemplary embodiment, the transistor controller is specifically configured to: when the vehicle is in a charging mode, i.e., after the second positive terminal of the buck-boost device is connected to the positive pole of the charging post and the second negative terminal of the buck-boost device is connected to the negative pole of the charging post, control the second transistor to be turned off and the first transistor and the third transistor to be turned on alternately, and control a 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 is greater than the voltage of the charging post; The second conduction coefficient means the ratio of the conduction time during which the first transistor is turned on to the sum of the conduction time during which the first transistor is turned on and the cut-off time during which the first transistor is cut off.

[0038] The second control may mean controlling the second transistor to be turned off, controlling the first transistor and the third transistor to be turned on alternately, and controlling a second conduction coefficient. The control of the second conduction coefficient may mean controlling a conduction time for which the first transistor is turned on.

[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 stationary end, a first movable end, and a second movable end; a fixed end of the first selector switch is connected to a second positive terminal of the step-up / step-down device, a first movable end of the first selector switch is connected to a positive terminal of the charging post, and a second movable end of the first selector switch is connected to a positive input terminal of the inverter; The fixed end of the second selector switch is connected to the second negative terminal of the step-up / step-down device, the first movable end of the second selector switch is connected to the negative terminal of the charging post, and the second movable end of the second selector switch is connected to the negative input terminal of the inverter.

[0040] In one exemplary embodiment, the transfer switch controller is configured to connect the fixed end of the first transfer switch to the second movable end of the first transfer switch and connect the fixed end of the second transfer switch to the second movable end of the second transfer switch when the vehicle is in a driving mode, and to connect the fixed end of the first transfer switch to the first movable end of the first transfer switch and connect the fixed end of the second transfer switch to the first movable end of the second transfer switch when the vehicle is in a charging mode.

[0041] FIG. 3 is a schematic diagram of another buck-boost system according to an embodiment of the present disclosure. As shown in FIG. 3, in is the input voltage (i.e., the output voltage of the power battery) in driving mode, and U o is the output voltage, D1 is a diode, S1, S2, and S3 are silicon carbide (SiC) thyristors (SiC is capable of bidirectional conduction), L is an inductance, C1 and C2 are automotive film capacitors, and S a1 , S a2 are two thyristor IGBT groups on the corresponding half bridge of the three-phase motor A, and similarly, S b1 , S b2 corresponds to the B phase, and S c1 , S c2 corresponds to phase C. The stator winding of the three-phase motor M is star-connected, of which point N is the neutral point of the three-phase winding. SW1 and SW2 are change-over switches. When they are 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 they are in the down position, the entire vehicle is in driving mode and is connected to the motor inverter to supply input voltage to the motor.

[0042] The step-up / step-down circuit shown in Figure 4 includes a capacitor C1, a capacitor C2, a thyristor S1, a thyristor S2, a thyristor S3, a diode D1, and an inductance L. The voltage of the capacitor C2 is U o is.

[0043] In drive mode, the BOOST / BUCK function description is as follows: At this time, the power battery U in When the voltage is increased or decreased, the voltage U o The control method for S1, S2, and S3 is as follows: When S2 and S3 are turned on and S1 is turned off, the inductance L stores energy, as shown in Figure 5 below, which shows the flow of current I. When S2 and S3 are cut off and S1 is turned on, 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 are the same (d indicates Driving), and the control duty ratios of S2 and S3 are D d and set the duty ratio of S1 to (1-D d ) that is, when S3 and S2 are turned on, S1 is cut off, and when S3 and S2 are turned off, S1 is turned on, so they complement each other.

[0044] Voltage U in and U o The calculation relationship is as follows: When S3 and S2 are turned on and S1 is turned off, the inductance L is in The energy from the capacitor is stored, and the current flowing through L is

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[0045] In charging or energy recovery mode, the BOOST function description is as follows: In this mode, U o The battery pack U is used as the energy input terminal. in The control method for S1 and S3 is as follows: When S3 and S2 are cut off and S1 is turned on, the inductance L stores energy, as shown in Figure 7. When S1 and S2 are cut off and S3 is turned on, U in The schematic diagram is shown in Figure 8. The control method is described as follows: Of the three silicon carbide thyristors, S2 is always turned off in this mode, and the switching frequency of S1 and S3 is the same, that is, the switching period T g is the same (g indicates Generating), and the duty ratio of S1 is D g and set the duty ratio of S3 to (1-D g ) that is, when S1 is turned on, S3 is turned off, and when S1 is turned off, S3 is turned on, so they complement each other.

[0046] Voltage U in and U o The calculation relationship is as follows: When S1 is turned on and S3 is turned off, the inductance L is o The current flowing through L due to the accumulation of energy is ​

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[0047] As can be seen from the above, when a vehicle equipped with this device is in driving mode, the input bus voltage of the inverter can be boosted and bucked by controlling the conduction duty ratio of a specific SiC boost / buck device, and the target value of the boost / buck voltage is 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 ratio of a specific SiC in the boost / buck device in relation to the input voltage of the power battery, and the target boost value is calculated based on formula (2).

[0048] While this disclosure has described several embodiments, this description is illustrative rather than limiting, and it will be apparent to those skilled in the art that many more embodiments and implementations are possible within the scope of the embodiments described in this disclosure. Although many possible combinations of features are shown in the accompanying drawings and discussed in specific embodiments, many other combinations of the disclosed features are possible. Unless otherwise limited, any feature or element of any embodiment can be used in combination with or substituted for any other feature or element in any other embodiment.

[0049] In the embodiments of the present disclosure, any of the features shown and / or discussed may be implemented singly or in any suitable combination.

[0050] Moreover, when describing exemplary embodiments, the specification may present a method and / or process as a particular sequence of steps. However, to the extent that the method or process does not rely on a particular order of the steps herein, the method or process should not be limited to the particular order of steps described. As one of ordinary skill in the art will appreciate, other steps and orders are possible.

[0051] As will be understood by those skilled in the art, all or some steps in the methods, systems, and functional modules / units in the apparatuses disclosed above can be implemented as software, firmware, hardware, or any suitable combination thereof. In hardware embodiments, the division between functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component may have multiple functions, or one function or step may be performed cooperatively by 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 across computer-readable media, which may include computer storage media (or non-transitory media) and communication media (or transitory media). As known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology 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 technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium used for storing the desired information and accessible by a computer. Additionally, as known to those skilled in the art, communication media typically include computer-readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Claims

1. A step-up / step-down device applied to a new energy vehicle, 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 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 the voltage of an externally connected power battery, and the first output voltage being for supplying power to an inverter of a motor of a vehicle; The transistor controller is configured to output a first control to the step-up / step-down circuit when the vehicle is in a driving mode, and the first control means performing a first conduction / cut-off control on a controllable device of the step-up / step-down circuit itself; Step-up / step-down device.

2. The step-up / step-down circuit is further configured to output a second output voltage under a second control of the transistor controller, the second output voltage being greater than a second input voltage, the second input voltage being a voltage of an externally connected charging post, and the second output voltage being 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 a charging mode, the second control meaning a second conduction / cut-off control for a controllable device of the buck-boost circuit itself. The step-up / step-down device according to claim 1 .

3. 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; a first end of the first capacitor serves as a first negative terminal of the step-up / step-down device, a second end of the first capacitor serves as a first positive terminal of the step-up / step-down device, a first end of the second capacitor serves as a second positive terminal of the step-up / step-down device, and a second end of the second capacitor serves as a second negative terminal of the step-up / step-down device; a first end of the first capacitor is connected to the anode of the diode and the first end of the second transistor, respectively; a second end of the second transistor is connected to the first end of the inductance and the first end of the second capacitor, respectively; a second end of the first capacitor is connected to the first end of the third transistor, a second end of the third transistor is connected to the first end of the first transistor and the second end of the inductance, respectively; and a second end of the first transistor is connected to the cathode of the diode and the second end of the second capacitor, respectively. The step-up / step-down device according to claim 1 or 2.

4. the transistor controller is configured to control the first transistor to be turned off and the second transistor and the third transistor to be turned on when the vehicle is in a driving mode, i.e., 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 a first conduction coefficient, such 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 means a ratio of a conduction time during which both the second transistor and the third transistor are turned on to a sum of a conduction time during which both the second transistor and the third transistor are turned on and a cut-off time during which both the second transistor and the third transistor are cut off. The step-up / step-down device according to claim 3 .

5. the transistor controller is configured to, when the vehicle is in a charging mode, i.e., 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, control the second transistor to be turned off and the first transistor and the third transistor to be turned on alternately, and to control a 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 is greater than the voltage of the charging post; The second conduction coefficient means a ratio of a conduction time during which the first transistor is turned on to a sum of a conduction time during which the first transistor is turned on and a cut-off time during which the first transistor is cut off. The step-up / step-down device according to claim 3 .

6. A voltage boosting system applied to a new energy vehicle, Includes a step-up / step-down device, a transfer switch, an inverter, a charging post, a power battery and a transfer switch controller. 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 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 the voltage of the power battery, and the first output voltage supplying power to the inverter of the motor of the vehicle; the transistor controller is configured to output a first control to the step-up / step-down circuit when the vehicle is in a driving mode, and the first control means performing a first conduction / cut-off control on a controllable device of the step-up / step-down circuit itself; the 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 a driving 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 a charging mode; Buck-boost system.

7. The step-up / step-down circuit is further configured to output a second output voltage under a second control of the transistor controller, the second output voltage being greater than a second input voltage, the second input voltage being the voltage of the charging post, and the second output voltage 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 a charging mode, the second control meaning a second conduction / cut-off control to a controllable device of the buck-boost circuit itself. The step-up / step-down system according to claim 6 .

8. 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; a first end of the first capacitor serves as a first negative terminal of the step-up / step-down device, a second end of the first capacitor serves as a first positive terminal of the step-up / step-down device, a first end of the second capacitor serves as a second positive terminal of the step-up / step-down device, and a second end of the second capacitor serves as a second negative terminal of the step-up / step-down device; a first end of the first capacitor is connected to the anode of the diode and the first end of the second transistor, respectively; a second end of the second transistor is connected to the first end of the inductance and the first end of the second capacitor, respectively; a second end of the first capacitor is connected to the first end of the third transistor, a second end of the third transistor is connected to the first end of the first transistor and the second end of the inductance, respectively; and a second end of the first transistor is connected to the cathode of the diode and the second end of the second capacitor, respectively. The step-up / step-down system according to claim 6 or 7.

9. the transistor controller is configured to control the first transistor to be turned off and the second transistor and the third transistor to be turned on when the vehicle is in a driving mode, i.e., 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 a first conduction coefficient, such 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 means a ratio of a conduction time during which both the second transistor and the third transistor are turned on to a sum of a conduction time during which both the second transistor and the third transistor are turned on and a cut-off time during which both the second transistor and the third transistor are cut off. The step-up / step-down system of claim 7 .

10. The transistor controller is specifically configured to control the second transistor to be turned off and the first transistor and the third transistor to be turned on alternately when the vehicle is in a charging mode, i.e., after the second positive terminal and the second negative terminal of the step-up / step-down device are respectively connected to the positive and negative terminals of the charging post, and to control a 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-down device is greater than the voltage of the charging post; The second conduction coefficient means a ratio of a conduction time during which the first transistor is turned on to a sum of a conduction time during which the first transistor is turned on and a cut-off time during which the first transistor is cut off. The step-up / step-down system of claim 7 .

11. 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; a fixed end of the first changeover switch is connected to a second positive terminal of the step-up / step-down device, a first movable end of the first changeover switch is connected to a positive terminal of the charging post, and a second movable end of the first changeover switch is connected to a positive input terminal of the inverter; a fixed end of the second selector switch is connected to a second negative terminal of the step-up / step-down device, a first movable end of the second selector switch is connected to a negative terminal of the charging post, and a second movable end of the second selector switch is connected to a negative input terminal of the inverter; The step-up / step-down system of claim 8 .

12. the changeover switch controller is installed so that, when the vehicle is in a driving mode, the changeover switch controller connects the fixed end of the first changeover switch to the second movable end of the first changeover switch and connects the fixed end of the second changeover switch to the second movable end of the second changeover switch, and when the vehicle is in a charging mode, the changeover switch controller connects the fixed end of the first changeover switch to the first movable end of the first changeover switch and connects the fixed end of the second changeover switch to the first movable end of the second changeover switch; The step-up / step-down system of claim 11.

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