Active switching device circuit and power electronic device

Abstract

The present application discloses an active switching device circuit and a power electronic device, which include an inductor L1 and a switching device Q1 connected in series between a power supply Vcc and the ground in sequence, and a freewheeling circuit connected in parallel with the inductor L1; a first electrode terminal of the switching device Q1 is connected to the inductor L1, a second electrode terminal of the switching device Q1 is grounded, and a control terminal of the switching device Q1 is configured to receive a control signal to achieve disconnection or conduction; a short-circuit protection circuit is further included; the short-circuit protection circuit is configured to remove the switching device Q1 from the active switching device circuit when a fault that the switching device Q1 cannot be normally turned off occurs. The present application can quickly cut off the fault loop through the short-circuit protection circuit, avoiding the circuit failure problem caused by the short-circuit failure of the active switching device itself or the abnormal control signal.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and particularly to an active switch device circuit and a power electronic device. Background Art

[0002] As Figure 1 shown, an active switch device circuit includes an inductor L1 and a switch device Q1 connected in series between a power supply Vcc and ground in sequence, and a freewheeling circuit connected in parallel with the inductor L1.

[0003] As Figure 2 shown, for Figure 1 the active switch device circuit shown, in some important application scenarios (such as excitation control, safety control, etc.), in order to improve the application reliability of the active switch device, generally two switch devices (shown as Q1 and Q2 in the figure) are connected in series in the circuit to provide redundancy, and it is required that these two switch devices be selected from different manufacturers as much as possible to avoid device consistency failure.

[0004] Although this treatment can effectively provide the reliability of the hardware circuit, since the control signal sources are the same, if the control signal is abnormal (for example, continuously conducting), both switch devices cannot be turned off, which will cause circuit application risks. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide an active switch device circuit and a power electronic device to solve the problem of circuit failure caused by the short - circuit failure of the active switch device itself or abnormal control signals.

[0006] The technical solutions adopted by this application to solve the above - mentioned technical problems are as follows:

[0007] On the one hand, this application provides an active switch device circuit, including an inductor L1 and a switch device Q1 connected in series between a power supply Vcc and ground in sequence, and a freewheeling circuit connected in parallel with the inductor L1;

[0008] The first electrode terminal of the switch device Q1 is connected to the inductor L1, the second electrode terminal of the switch device Q1 is grounded, and the control terminal of the switch device Q1 is used to receive a control signal to achieve disconnection or conduction;

[0009] The active switch device circuit further includes a short - circuit protection circuit; the short - circuit protection circuit is configured to cut off the switch device Q1 from the active switch device circuit when a fault occurs that the switch device Q1 cannot be normally turned off.

[0010] On the other hand, this application provides a power electronic device, including the active switch device circuit.

[0011] The active switch device circuit and the power electronic device provided by the embodiment of the present application can quickly cut off the faulty loop through the short-circuit protection circuit, avoiding the circuit failure problem caused by the short-circuit failure of the active switch device itself or the abnormal control signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 FIG. 7 is a schematic diagram of an existing active switch device circuit;

[0013] Figure 2 FIG. 11 is a schematic diagram of another existing active switch device circuit;

[0014] Figure 3 FIG. 15 is a schematic diagram of an active switch device circuit provided by the first embodiment of the present application;

[0015] Figure 4 FIG. 19 is a schematic diagram of a freewheeling circuit provided by the first embodiment of the present application;

[0016] Figure 5 FIG. 23 is a schematic diagram of another freewheeling circuit provided by the first embodiment of the present application;

[0017] Figure 6 FIG. 27 is a schematic diagram of an active switch device circuit provided by the second embodiment of the present application;

[0018] Figure 7 FIG. 31 is a schematic diagram of a freewheeling circuit provided by the second embodiment of the present application;

[0019] Figure 8 FIG. 35 is a schematic diagram of another freewheeling circuit provided by the second embodiment of the present application.

[0020] The implementation, functional features and advantages of the object of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0022] In the description of the present application, it should be understood that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "front", "rear", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application. In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance.

[0023] Embodiment 1

[0024] As Figure 3 shown, the first embodiment of the present application provides an active switch device circuit, including an inductor L1 and a switch device Q1 connected in series between a power supply Vcc and ground in sequence, and a freewheeling circuit connected in parallel with the inductor L1;

[0025] The first electrode terminal of the switch device Q1 is connected to the inductor L1, the second electrode terminal of the switch device Q1 is grounded, and the control terminal of the switch device Q1 is used to receive a control signal to achieve disconnection or conduction;

[0026] The active switch device circuit further includes a short - circuit protection circuit; the short - circuit protection circuit is configured to remove the switch device Q1 from the active switch device circuit when a fault occurs that the switch device Q1 cannot be normally turned off.

[0027] Specifically, the short - circuit protection circuit includes a resistor R2, a diode D2, a capacitor C1, and a relay K1;

[0028] One end of the resistor R2 is connected to the power supply Vcc, and the other end is connected to the anode terminal of the diode D2 and the first electrode terminal of the switch device Q1; the cathode terminal of the diode D2 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is grounded;

[0029] The control part of the relay K1 is connected in parallel with the capacitor C1, and the normally - open contact of the relay K1 is connected between the inductor L1 and the first electrode terminal of the switch device Q1.

[0030] In this example, the capacitor C1 is configured such that when the charging voltage on the capacitor C1 is greater than or equal to the starting voltage of the relay K1, the normally - open contact of the relay K1 conducts.

[0031] In this example, the capacitor C1 is further configured such that when the switch device Q1 is normally conducting, the minimum voltage value on the capacitor C1 is greater than the release voltage of the relay K1.

[0032] In this example, the switching device Q1 is selected from one of IGBT, MOSFET, and BJT.

[0033] The working principle of the active switching device circuit is illustrated by the following example:

[0034] After Vcc is powered on, Vcc charges the capacitor C1 through the resistor R2 and the diode D2. When the charging voltage on the capacitor C1 is greater than or equal to the starting voltage of the coil of the relay K1, the normally open contact of the relay K1 conducts, and at this time, the switching device Q1 can receive the control signal and work normally. When the switching device Q1 is normally controlled to conduct or disconnect according to the PWM pulse, the capacitor C1 is continuously charged and discharged. Through reasonable circuit design (including reasonable selection of device parameters), when it works at the maximum duty cycle, the minimum voltage value on the capacitor C1 is greater than the release voltage of the coil of the relay K1. When the switching device Q1 itself is short-circuited and fails or the drive signal is at 100% duty cycle, at this time, the diode D2 is cut off, and the capacitor C1 will continuously discharge automatically through the coil of the relay K1. When its voltage is less than the release voltage of the coil of the relay K1, the normally open contact of the relay K1 disconnects, thus cutting off the circuit.

[0035] Further, please refer to Figure 4 As shown, the freewheeling circuit of the active switching device circuit provided by the embodiment of the present application includes a diode D1; the diode D1 is connected in parallel with the inductor L1, and the cathode end of the diode D1 is connected to the power supply Vcc.

[0036] Further, please refer to Figure 5 As shown, different from Figure 4 the freewheeling circuit of the active switching device circuit provided by the embodiment of the present application further includes a resistor R1 connected in series to the anode end of the diode D1.

[0037] Embodiment 2

[0038] As Figure 6 shown, the second embodiment of the present application provides an active switching device circuit. Different from Figure 3 it: the short-circuit protection circuit includes a resistor R2, a diode D2, a capacitor C1, a switching device Q2, and a resistor R3; one end of the resistor R2 is connected to the power supply Vcc, and the other end is connected to the anode end of the diode D2, the second electrode end of the switching device Q2, and the first electrode end of the switching device Q1; the cathode end of the diode D2 is connected to one end of the capacitor C1, the control end of the switching device Q2, and one end of the resistor R3, and the other ends of the capacitor C1 and the resistor R3 are grounded; the first electrode end of the switching device Q2 is connected to the inductor L1.

[0039] In this example, the capacitor C1 is configured such that when the voltage across the capacitor C1 is greater than or equal to the turn-on voltage of the switching device Q2, the switching device Q2 turns on.

[0040] In this example, the capacitor C1 is further configured such that when the switching device Q1 is conducting normally, the minimum voltage value across the capacitor C1 is greater than the turn-on voltage of the switching device Q2.

[0041] In this example, both the switching device Q1 and the switching device Q2 are selected from one of IGBT, MOSFET, and BJT.

[0042] The working principle of the active switching device circuit in this example is described as follows:

[0043] When Vcc is powered on, Vcc charges the capacitor C1 through the resistor R2 and the diode D2. When the charging voltage across the capacitor C1 is greater than or equal to the turn-on voltage of the switching device Q2, the switching device Q2 turns on. At this time, the switching device Q1 can receive a control signal to operate normally. When the switching device Q1 is controlled to turn on or off normally according to PWM pulses, the capacitor C1 is constantly charging and discharging. Through reasonable circuit design (including reasonable selection of device parameters), when it operates at the maximum duty cycle, the minimum voltage value across the capacitor C1 can be made greater than the turn-on voltage of the switching device Q2. When the switching device Q1 itself fails short-circuited or the drive signal has a 100% duty cycle, at this time the diode D2 is cut off, and the capacitor C1 will continuously discharge automatically through the resistor R3. When its voltage is less than the turn-on voltage of the switching device Q2, the switching device Q2 turns off, thus cutting off the circuit.

[0044] Further, please refer to Figure 7 As shown, the freewheeling circuit of the active switching device circuit provided in the embodiment of the present application includes a diode D1; the diode D1 is connected in parallel with the inductor L1, and the cathode terminal of the diode D1 is connected to the power supply Vcc.

[0045] Further, please refer to Figure 8 As shown, different from Figure 7 the freewheeling circuit of the active switching device circuit provided in the embodiment of the present application further includes a resistor R1 connected in series to the anode terminal of the diode D1.

[0046] Embodiment 3

[0047] The third embodiment of the present application provides a power electronic device, including the active switching device circuit described in the first embodiment or the second embodiment.

[0048] In this example, the power electronic device includes, but is not limited to, an inverter.

[0049] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, and thus do not limit the scope of the rights of the present application. Any modifications, equivalent replacements, and improvements made by those skilled in the art without departing from the scope and essence of the present application shall fall within the scope of the rights of the present application.

Claims

1. An active switching device circuit includes an inductor L1 and a switching device Q1 connected in series between a power supply Vcc and ground in sequence, and a freewheeling circuit connected in parallel with the inductor L1; A first electrode terminal of the switching device Q1 is connected to the inductor L1, a second electrode terminal of the switching device Q1 is grounded, and a control terminal of the switching device Q1 is configured to receive a control signal to achieve disconnection or conduction; the freewheeling circuit includes a diode D1; the diode D1 is connected in parallel with the inductor L1, and a cathode terminal of the diode D1 is connected to the power supply Vcc; characterized in that, The active switching device circuit further includes a short-circuit protection circuit; the short-circuit protection circuit is configured to remove the switching device Q1 from the active switching device circuit when a fault that the switching device Q1 cannot be normally turned off occurs; The short-circuit protection circuit includes a resistor R2, a diode D2, a capacitor C1, and a relay K1; one end of the resistor R2 is connected to the power supply Vcc, and the other end is connected to an anode terminal of the diode D2 and a first electrode terminal of the switching device Q1; a cathode terminal of the diode D2 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is grounded; a control part of the relay K1 is connected in parallel with the capacitor C1, and a normally open contact of the relay K1 is connected between the inductor L1 and the first electrode terminal of the switching device Q1; or, The short-circuit protection circuit includes a resistor R2, a diode D2, a capacitor C1, a switching device Q2, and a resistor R3; one end of the resistor R2 is connected to the power supply Vcc, and the other end is connected to an anode terminal of the diode D2, a second electrode terminal of the switching device Q2, and a first electrode terminal of the switching device Q1; a cathode terminal of the diode D2 is connected to one end of the capacitor C1, a control terminal of the switching device Q2, and one end of the resistor R3, and the other ends of the capacitor C1 and the resistor R3 are grounded; a first electrode terminal of the switching device Q2 is connected to the inductor L1; Wherein, both the switching device Q1 and the switching device Q2 are selected from one of IGBT, MOSFET, and BJT.

2. The active switching device circuit according to claim 1, characterized in that, The capacitor C1 is configured such that when a charging voltage on the capacitor C1 is greater than or equal to a starting voltage of the relay K1, a normally open contact of the relay K1 is turned on.

3. The active switching device circuit according to claim 2, wherein The capacitor C1 is further configured such that when the switching device Q1 is normally conducting, a minimum voltage value on the capacitor C1 is greater than a release voltage of the relay K1.

4. The active switching device circuit according to claim 1, wherein The capacitor C1 is configured such that when a voltage on the capacitor C1 is greater than or equal to a starting voltage of the switching device Q2, the switching device Q2 is turned on.

5. The active switching device circuit according to claim 4, characterized in that, The capacitor C1 is further configured such that when the switching device Q1 is normally conducting, a minimum voltage value on the capacitor C1 is greater than a starting voltage of the switching device Q2.

6. The active switching device circuit according to claim 1, characterized in that, The freewheeling circuit further includes a resistor R1 connected in series to an anode terminal of the diode D1.

7. A power electronic device, characterized in that, An active switching device circuit according to any one of claims 1-6 is included.

Images