Thyristor driving circuit and power equipment

Abstract

The invention discloses a driving circuit of a thyristor and power equipment. The driving circuit of the thyristor comprises a switching device, an isolation transformer, a rectification circuit and a variable resistance device. A first end of a primary winding of the isolation transformer is used for connecting a positive pole of a power supply, a second end of the primary winding is connected with a negative pole of the power supply through a switching device, a first end of a secondary winding of the isolation transformer is connected with a first end of a variable resistance device through a rectifying circuit, and a second end of the variable resistance device is used for connecting a gate pole of a thyristor. The second end of the secondary winding is used for connecting the cathode of the thyristor; and the variable resistance device is used for changing the impedance of a branch connected to the gate pole of the thyristor under the condition that the switching device is switched on so as to change the driving current supplied to the gate pole of the thyristor. In the embodiment of the invention, the driving current of the thyristor is changed by changing the resistor connected to the gate pole of the thyristor, so that the driving current approaches an ideal driving current waveform of the thyristor, and the reliability of the thyristor is improved.

Description

Technical Field

[0001] The present application relates to the field of circuit electronic technology, and in particular to a thyristor drive circuit and power equipment. Background Art

[0002] Thyristors, also known as silicon-controlled rectifiers, are mainly used in the fields of power control and power conversion. In order to reduce the gate loss of thyristors, the drive circuit of thyristors is usually driven in pulse form.

[0003] In the related art, the driving current waveform output by the driving circuit of the thyristor is approximately a square wave, such as Figure 1 However, the thyristor driving current waveform in the related art is significantly different from the ideal thyristor driving current waveform, resulting in reduced reliability of the thyristor. Summary of the invention

[0004] Based on the above problems, the present application provides a thyristor drive circuit and power equipment, so that the output current waveform of the thyristor drive circuit approaches the ideal drive current waveform, thereby improving the reliability of the thyristor.

[0005] In a first aspect, an embodiment of the present application provides a thyristor driving circuit, including: a switching device, an isolation transformer, a rectifier circuit and a variable resistance device;

[0006] The first end of the primary winding of the isolation transformer is used to connect to the positive electrode of the power supply, the second end of the primary winding is connected to the negative electrode of the power supply via the switch device, the first end of the secondary winding of the isolation transformer is connected to the gate of the thyristor via the rectifier circuit and the variable resistance device, and the second end of the secondary winding is used to connect to the cathode of the thyristor;

[0007] The resistance changing device is used to change the impedance of the branch connected to the gate of the thyristor when the switching device is turned on, so as to change the driving current provided to the gate of the thyristor.

[0008] Optionally, the variable resistance device includes: a first resistor and a capacitor;

[0009] A first end of the first resistor is connected to the rectifier circuit, and a second end of the first resistor is used to connect to the gate of the thyristor;

[0010] The capacitor is connected in parallel with the first resistor; wherein the capacitor is charged when the switch device is turned on to change the impedance of the variable resistance device.

[0011] Optionally, the thyristor driving circuit further includes: a discharge circuit;

[0012] The discharge circuit is used to discharge the capacitor when the switch device is turned off to reduce the impedance of the variable resistance device.

[0013] Optionally, the discharge circuit includes: a second resistor and a control circuit;

[0014] The second resistor is connected in parallel to both ends of the capacitor;

[0015] The control circuit is used to control the capacitor to discharge through the second resistor when the secondary winding outputs a negative voltage.

[0016] Optionally, the control circuit includes a first diode, a photocoupler and a triode;

[0017] The anode of the first diode is connected to the second end of the secondary winding, the cathode of the first diode is connected to the anode of the photoelectric coupler; the cathode of the photoelectric coupler is connected to the first end of the secondary winding, the collector of the photoelectric coupler is connected to the base of the transistor, the emitter of the photoelectric coupler is connected to the second end of the second resistor, the emitter of the transistor is connected to the first end of the capacitor, the collector of the transistor is connected to the first end of the second resistor, and the second end of the second resistor is connected to the second end of the capacitor; or

[0018] The positive electrode of the photoelectric coupler is connected to the second end of the secondary winding, the negative electrode of the photoelectric coupler is connected to the positive electrode of the first diode, the collector of the photoelectric coupler is connected to the base of the transistor, the emitter of the photoelectric coupler is connected to the second end of the second resistor, the emitter of the transistor is connected to the first end of the capacitor, the collector of the transistor is connected to the first end of the second resistor, and the second end of the second resistor is connected to the second end of the capacitor; the cathode of the first diode is connected to the first end of the secondary winding.

[0019] Optionally, the resistance variable device further comprises: a resistance device;

[0020] The resistor device is connected in series with the capacitor;

[0021] The resistor device is used to adjust the rising rate of the driving current of the gate of the thyristor and the upper limit value of the driving current of the gate of the thyristor.

[0022] Optionally, the variable resistance device includes any one of a digital potentiometer and a digital resistance box.

[0023] Optionally, the rectifying circuit comprises a second diode.

[0024] Optionally, the thyristor driving circuit further includes: a third diode;

[0025] The anode of the third diode is connected to the second end of the secondary winding, and the cathode of the third diode is connected to the cathode of the second diode.

[0026] Optionally, the driving circuit of the thyristor further includes: an absorption circuit;

[0027] The absorption circuit is connected in parallel to the first end of the primary winding and the second end of the primary winding.

[0028] In a second aspect, an embodiment of the present application provides an electric power device, comprising: a power conversion circuit, a thyristor module, and a thyristor driving circuit as described in any embodiment of the first aspect.

[0029] The driving circuit of the thyristor in the embodiment of the present application includes: a switching device, an isolation transformer, a rectifier circuit and a variable resistance device; the first end of the primary winding of the isolation transformer is used to connect to the positive electrode of the power supply, the second end of the primary winding is connected to the negative electrode of the power supply through the switching device, the first end of the secondary winding of the isolation transformer is connected to the gate of the thyristor through the rectifier circuit and the variable resistance device, and the second end of the secondary winding is used to connect to the cathode of the thyristor; the variable resistance device is used to change the impedance of the branch connected to the gate of the thyristor when the switching device is turned on, so as to change the driving current provided to the gate of the thyristor. In the embodiment of the present application, by connecting the variable resistance device between the secondary side of the isolation transformer and the gate of the thyristor, and changing the impedance of the branch connected to the gate of the thyristor through the variable resistance device, the gate driving current of the thyristor is changed, so that the gate driving current of the thyristor approaches the ideal driving current, thereby improving the reliability of the thyristor. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0031] Figure 1 A waveform diagram of a thyristor driving current provided for related technology;

[0032] Figure 2 A schematic diagram of an ideal thyristor drive current waveform provided in an embodiment of the present application;

[0033] Figure 3 A schematic diagram of a thyristor drive circuit provided in an embodiment of the present application;

[0034] Figure 4 A schematic diagram of the structure of another thyristor driving circuit provided in an embodiment of the present application;

[0035] Figure 5 A schematic diagram of the structure of another thyristor driving circuit provided in an embodiment of the present application;

[0036] Figure 6 A schematic diagram of the structure of another thyristor driving circuit provided in an embodiment of the present application;

[0037] Figure 7A schematic diagram of a thyristor drive circuit provided in an embodiment of the present application;

[0038] Figure 8 A schematic diagram of the structure of another thyristor driving circuit provided in an embodiment of the present application;

[0039] Fig. 9 A schematic diagram of the structure of another thyristor driving circuit provided in an embodiment of the present application;

[0040] Fig.10 A schematic diagram of the structure of another thyristor driving circuit provided in an embodiment of the present application;

[0041] Fig.11 A schematic diagram of the structure of an on-grid and off-grid switching system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] The terms "first", "second", and "third" in the specification and claims of this application are used to distinguish different objects rather than to describe a specific order of the objects. For example, a first diode, a second diode, and a third diode are used to distinguish different diodes rather than to describe a specific order of the diodes.

[0044] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0045] In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more than two. For example, multiple processing units refer to two or more processing units, etc.; multiple elements refer to two or more elements, etc.

[0046] The ideal thyristor drive current waveform is as follows: Figure 2 As shown, Figure 2 The vertical coordinate i in GKis the driving current of the thyristor, and the horizontal axis t is time. In the t0-t1 stage, the driving current i of the thyristor GK Rapidly rises and reaches the peak current I peak ; During the t1-t2 phase, the thyristor drive current i GK Slowly decrease to the platform current I flat , t2-t3 stage, the thyristor drive current i GK Maintain the platform current I flat ; During the t3-t4 phase, the thyristor drive current i GK Slowly decreases to 0.

[0047] It should be understood that by Figure 2 The driving current of the thyristor shown drives the thyristor, so that the state of the thyristor can be switched from the blocking state to the conducting state when needed, thereby improving the reliability of the thyristor.

[0048] The technical content of this application will be described below in conjunction with embodiments.

[0049] See also Figure 3 , which is a structural schematic diagram of a thyristor driving circuit provided in an embodiment of the present application.

[0050] like Figure 3 As shown, the driving circuit includes: a switch device 310, an isolation transformer T, a rectifier circuit 320 and a variable resistance device 330;

[0051] The first end of the primary winding of the isolation transformer T is used to connect to the positive electrode V+ of the power supply, and the second end of the primary winding is connected to the negative electrode V- of the power supply via the switching device 310. The first end of the secondary winding of the isolation transformer T is connected to the gate G of the thyristor via the rectifier circuit 320 and the variable resistor device 330, and the second end of the secondary winding is used to connect to the cathode K of the thyristor.

[0052] The rectifier circuit 320 is used to convert the AC signal output by the secondary winding of the isolation transformer T into a DC signal. The rectifier circuit 320 can be any one of a half-wave rectifier circuit, a full-wave rectifier circuit, a bridge rectifier circuit and a voltage doubler rectifier circuit.

[0053] Exemplarily, when the rectifier circuit 320 is a half-wave rectifier circuit, the structural diagram of the thyristor drive circuit is as follows: Figure 4 As shown. Figure 4 In the embodiment, the anode of the second diode D2 is connected to one end of the secondary winding, and the cathode of the second diode D2 is connected to the gate of the thyristor via the resistance changing device.

[0054] In a possible implementation, the variable resistance device 330 includes any one of a digital potentiometer and a digital resistance box.

[0055] By controlling the resistance of the digital potentiometer or digital resistor box, the impedance of the branch connected to the gate of the thyristor is changed, thereby changing the drive current i supplied to the gate of the thyristor. GK , improving the reliability of the thyristor. Furthermore, by controlling the resistance of the digital potentiometer or the resistance box, the driving current of the thyristor can be extended within I peak duration, further making the thyristor drive current i GK Approaching the ideal driving current waveform.

[0056] The variable resistance device 330 is used to change the impedance of the branch connected to the gate of the thyristor when the switch device 310 is turned on, so as to change the driving current i provided to the gate of the thyristor. GK .

[0057] The switching device 310 described in the embodiment of the present application can be any one of the switching tubes such as a bipolar junction transistor (BJT), a field effect transistor (FET), a metal-oxide-semiconductor field-effect transistor (MOSFET) and an insulated gate bipolar transistor (IGBT).

[0058] When the switch device 310 is any of the above-mentioned devices, the embodiment of the present application can control the on or off of the switch device 310 by outputting a PWM signal through the driving circuit of the switch device.

[0059] Illustratively, the driving circuit of the switching device 310 in the embodiment of the present application may be any one of a power IC direct driving circuit, a push-pull driving circuit, an accelerated shutdown driving circuit, and an isolation driving circuit. The embodiment of the present application does not limit the driving circuit of the switching device 310.

[0060] In order to make the gate drive current of the thyristor close to Figure 2 In this embodiment, during the period t0-t1, the switch device 310 is closed, the impedance of the resistance changing device 330 is in a low impedance state, and the gate drive current i GK The current rises and reaches the peak value I at t1 peak ; During the t1-t2 phase, the impedance of the variable resistor device 330 increases, so that the gate drive current i of the thyristor GK The current I drops and reaches the platform at t2. flatDuring the t2-t3 phase, the impedance of the variable resistor device 330 remains unchanged, so that the gate drive current i of the thyristor GK Maintain the platform current I flat ; During the t3-t4 phase, the switch device 310 is turned off, so that the gate drive current i of the thyristor GK From the platform current I flat Down to 0.

[0061] In the embodiment of the present application, the impedance of the variable resistance device 330 is changed in different stages (t0-t1 stage, t1-t2 stage and t2-t3 stage), so that the driving current i of the corresponding stage is GK The waveform approaches the ideal driving current waveform. GK The thyristor is driven so that the state of the thyristor is switched from a blocking state to a conducting state when needed, thereby improving the reliability of the thyristor.

[0062] See also Figure 5 , which is a structural schematic diagram of another thyristor driving circuit provided in an embodiment of the present application.

[0063] In this embodiment, a specific implementation method of the resistance changing device in the driving circuit of the thyristor will be introduced.

[0064] like Figure 5 As shown, the variable resistance device 330 includes: a first resistor R1 and a capacitor C1;

[0065] The first end of the first resistor R1 is connected to the rectifier circuit, and the second end of the first resistor R1 is used to connect the gate G of the thyristor; the capacitor C1 is connected in parallel with the first resistor R1; wherein the capacitor C1 is charged when the switch device is turned on to change the impedance of the variable resistor device 330.

[0066] It should be noted that the first resistor R1 and the capacitor C1 are connected in parallel, and the first resistor R1 and the capacitor C1 together constitute a variable resistance device. When the impedance of the capacitor C1 after charging is much larger than the resistance value of the first resistor R1, the branch where the capacitor C1 is located is equivalent to an open circuit. At this time, the equivalent impedance of the variable resistance device 330 is equivalent to the resistance value of the first resistor R1, thereby keeping the gate drive current in this stage unchanged.

[0067] Exemplarily, the rectifier circuit is a half-wave rectifier circuit, the anode of the second diode D2 is connected to the secondary winding, and the cathode of the second diode D2 is connected to the first resistor R1.

[0068] In order to make the gate drive current i GK The waveform approaches Figure 2In this embodiment, during the t0-t1 phase, the switch device is closed. Since the capacitor C1 has not been charged at this time, the impedance of the capacitor C1 is low. Correspondingly, the equivalent impedance of the variable resistance device 330 is also in a low impedance state, so that the gate drive current i GK It rises rapidly and reaches the peak current I at t1 peak During the t1-t2 phase, as the capacitor C1 is charged, the impedance of the capacitor C1 gradually increases, and the equivalent impedance of the variable resistance device 330 increases accordingly, causing the gate drive current i GK As the capacitor C1 is charged, the impedance of the capacitor C1 continues to increase. When the impedance of the capacitor C1 increases to a value much larger than the resistance of the first resistor R1, the capacitor C1 is equivalent to an open circuit, and the equivalent impedance of the variable resistor device 330 is equivalent to the resistance of the first resistor R1. The gate drive current i GK At time t2, the platform current I flat ; During the t2-t3 phase, since the resistance of the first resistor R1 is fixed, the gate drive current i of the thyristor GK Maintain the platform current I flat ; In the t3-t4 phase, the switching device is switched at time t3, so that the gate drive current i of the thyristor GK From the platform current I flat Down to 0.

[0069] In this embodiment, the impedance of the capacitor C1 can be changed in different stages (t0-t1 stage, t1-t2 stage and t2-t3 stage), and the equivalent impedance of the first resistor R1 and the capacitor C1 (that is, the equivalent impedance of the variable resistance device 330) can also be changed accordingly, so that the driving current i GK The waveform approaches the ideal driving current waveform. Compared with the method of changing the impedance of the variable resistance device 330 by the controller, this embodiment automatically adjusts the equivalent impedance of the variable resistance device 330, simplifies the thyristor driving circuit, and reduces the control difficulty of the thyristor driving circuit.

[0070] Furthermore, in order to adjust the gate drive current i of the thyristor GK In the t0-t1 phase, the rising rate and the peak current Ipeak are considered. The embodiment of the present application provides another thyristor driving circuit, and its corresponding structural schematic diagram is shown in FIG. Figure 6 shown.

[0071] like Figure 6 As shown, the variable resistance device 330 in the thyristor driving circuit may further include: a resistor device RG;

[0072] Among them, the first end of the first resistor R1 is connected to the cathode of the second diode D2, and the second end of the first resistor R1 is used to connect the gate of the thyristor; the first end of the resistance device RG is connected to the first end of the first resistor R1, the second end of the resistance device RG is connected to the first end of the capacitor C1, and the second end of the capacitor C1 is connected to the second end of the first resistor R1.

[0073] In a possible implementation, the rising rate of the thyristor gate drive current and the magnitude of the peak current Ipeak are adjusted by adjusting the resistance value of the resistor RG and the capacitance of the capacitor C1.

[0074] For example, as the resistance value of the resistor RG decreases, the rate of change of the current increases, and the gate drive current i GK In the t0-t1 stage, the slope becomes steeper and the interval between t0-t1 becomes smaller, the peak current Ipeak increases; the resistance value of the resistor RG increases, the current conversion rate decreases, and the gate drive current i GK The t0-t1 phase becomes more gradual and the interval between t0-t1 becomes larger, and the peak current Ipeak decreases.

[0075] Exemplarily, the resistor device RG may be any one of a digital potentiometer and a digital resistor box.

[0076] In this embodiment, a resistor device RG is connected in series on one side of the capacitor C1, and the gate drive current i of the thyristor can be more flexibly controlled through the thyristor drive circuit. GK Adjust so that the gate drive current i GK The waveform is closer to the ideal driving current waveform.

[0077] It should be understood that the thyristor drive signal i GK It is periodic. When the variable resistance device 330 includes the capacitor C1, after one cycle ends, in order to make the waveform of the thyristor driving current of the next cycle approach the ideal thyristor driving current waveform, the capacitor C1 needs to be discharged to reduce the impedance of the capacitor C1, so that the capacitor C1 is in a low impedance state in the t0-t1 stage of the next cycle, thereby making the gate driving current i GK It rises during the t0-t1 phase and reaches the peak current I at t1. peak To this end, the present application embodiment provides a thyristor driving circuit, and its corresponding schematic diagram is as follows: Figure 7 shown.

[0078] like Figure 7 As shown, the thyristor driving circuit further includes: a discharge circuit 340;

[0079] The discharge circuit 340 is connected in parallel to two ends of the variable resistance device.

[0080] In a possible implementation, the discharge circuit 340 may be a second resistor R2, which is connected in parallel to two ends of the variable resistance device. When the switch device is turned off, the capacitor C1 is discharged to reduce the impedance of the variable resistance device.

[0081] In this embodiment, by introducing the discharge circuit 340 into the thyristor driving circuit, after outputting a cycle of the thyristor driving current signal, the discharge circuit 340 discharges the capacitor C1 to reduce the impedance of the variable resistance device, so that in the t0-t1 stage of the next cycle, the variable resistance device is in a low impedance state, thereby making the driving current i output by the thyristor driving circuit GK Approaching the ideal driving current improves the reliability of the thyristor.

[0082] It should be understood that when the switch device is turned off, the capacitor C1 in the variable resistance device should be discharged through the discharge circuit. To this end, an embodiment of the present application provides a discharge circuit, which includes a control circuit and a second resistor R2. When the switch device is turned off, the control circuit connects the second resistor R2 in parallel with both ends of the capacitor C1, and discharges the capacitor C1 through the second resistor R2.

[0083] In a possible implementation, the discharge circuit includes a switch tube and a second diode R2 (the switch tube serves as a control circuit). The first end of the switch tube is connected to the first end of the capacitor C1, the second end of the switch tube is connected to the first end of the second resistor R2, and the second end of the second resistor R2 is connected to the second end of the capacitor C1.

[0084] Exemplarily, when the switch device connected to the primary winding of the isolation transformer T is turned off, the switch tube is controlled to be turned on, so that the second resistor R2 is connected in parallel with the capacitor, and then the capacitor C1 is discharged through the second resistor R2.

[0085] In a possible implementation, another structural diagram of a thyristor driving circuit is as follows: Figure 8 As shown. Figure 8 In the embodiment, the discharge circuit 340 includes a photocoupler U1, a transistor Q1, a first diode D1 and a second resistor R2 (the photocoupler U1, the transistor Q1 and the first diode D1 are used as a control circuit). The anode of the first diode D1 is connected to the second end of the secondary winding, and the cathode of the first diode D1 is connected to the positive electrode of the photocoupler U1; the negative electrode of the photocoupler U1 is connected to the first end of the secondary winding, the collector of the photocoupler U1 is connected to the base of the transistor Q1, and the emitter of the photocoupler U1 is connected to the second end of the second resistor R2; the emitter of the transistor Q1 is connected to the first end of the capacitor C1, and the collector of the transistor Q1 is connected to the first end of the second resistor R2; the second end of the second resistor R2 is connected to the second end of the capacitor C1.

[0086] It should be understood that when the switch device is in the on state, the first end of the secondary winding of the isolation transformer T outputs a positive voltage, and the second end of the secondary winding outputs a negative voltage; when the switch device is in the off state, the first end of the secondary winding of the isolation transformer T outputs a negative voltage, and the second end of the secondary winding outputs a positive voltage. Therefore, the first diode D1 is in the off state when the switch device is on, and is in the on state when the switch device is off.

[0087] When the switch device is turned off, the first diode D1 is turned on, the light-emitting diode in the photocoupler U1 emits light of a certain wavelength, the photosensitive element in the photocoupler U1 generates current when illuminated by light, and the transistor Q1 is turned on due to the increase in the current of the base, so that the second resistor R2 is connected in parallel with the capacitor C1, thereby realizing the discharge of the capacitor C1 through the second resistor R2.

[0088] In a possible implementation, a schematic diagram of another thyristor driving circuit is shown as follows: Fig. 9 As shown. Fig. 9 In the embodiment, the discharge circuit 340 includes a photocoupler U1, a transistor Q1, a first diode D1 and a second resistor R2 (the photocoupler U1, the transistor Q1 and the first diode D1 are used as a control circuit). The positive electrode of the photocoupler U1 is connected to the first end of the secondary winding, the negative electrode of the photocoupler is connected to the anode of the first diode D1, the cathode of the first diode D1 is connected to the first end of the secondary winding, the collector of the photocoupler U1 is connected to the base of the transistor Q1, and the emitter of the photocoupler U1 is connected to the second end of the second resistor R2; the emitter of the transistor Q1 is connected to the first end of the capacitor C1, and the collector of the transistor Q1 is connected to the first end of the second resistor R2; the second end of the second resistor R2 is connected to the second end of the capacitor C1.

[0089] The first diode D1 is in an off state when the switch device is turned on, and is in an on state when the switch device is turned off.

[0090] It should be understood that Fig. 9 The principle and Figure 8 The principle of the discharge circuit is the same as that of the conventional discharge circuit, and will not be described in detail here.

[0091] See also Fig.10 , this figure is a structural schematic diagram of another thyristor driving circuit provided in an embodiment of the present application.

[0092] like Fig.10 As shown, the driving circuit of the thyristor includes: a switch device 310 , an isolation transformer T, a first diode D1 , a second diode D2 , a third diode D3 , a resistance variable device 330 , a discharge circuit 340 and an absorption circuit 350 .

[0093] Among them, the first end of the primary winding of the isolation transformer T is connected to the positive electrode V+ of the power supply, and the second end of the primary winding of the isolation transformer T is connected to the negative electrode V- of the power supply via the switching device 310; the first end of the secondary winding of the isolation transformer T is connected to the gate G of the thyristor via the second diode D2 and the variable resistor device 330, and the second end of the secondary winding of the isolation transformer T is connected to the cathode K of the thyristor.

[0094] The variable resistance device 330 includes a first resistor R1, a resistor element RG and a capacitor C1. The first end of the first resistor R1 is connected to the cathode of the first diode D1, and the second end of the first resistor R1 is connected to the gate G of the thyristor; the first end of the resistor element RG is connected to the first end of the first resistor R1, the second end of the resistor element RG is connected to the first end of the capacitor C1, and the second end of the capacitor C1 is connected to the second end of the first resistor R1.

[0095] In a possible implementation, the discharge circuit 340 includes a photocoupler U1, a transistor Q1, a first diode D1, a second resistor R2, and a third resistor R3. The anode of the first diode D1 is connected to the second end of the secondary winding, and the cathode of the first diode D1 is connected to the positive electrode of the photocoupler U1 via the third resistor R3; the negative electrode of the photocoupler U1 is connected to the first end of the secondary winding, the collector of the photocoupler U1 is connected to the base of the transistor Q1, and the emitter of the photocoupler U1 is connected to the second end of the second resistor R2; the emitter of the transistor Q1 is connected to the first end of the capacitor C1, and the collector of the transistor Q1 is connected to the first end of the second resistor R2; the second end of the second resistor R2 is connected to the second end of the capacitor C1.

[0096] In another possible implementation, the discharge circuit 340 includes a photocoupler U1, a transistor Q1, a first diode D1, a second resistor R2, and a third resistor R3. The positive electrode of the photocoupler U1 is connected to the second end of the secondary winding, the negative electrode of the photocoupler U1 is connected to the anode of the first diode D1 via the third resistor R3, the cathode of the first diode D1 is connected to the first end of the secondary winding, the collector of the photocoupler U1 is connected to the base of the transistor Q1, and the emitter of the photocoupler U1 is connected to the second end of the second resistor R2; the emitter of the transistor Q1 is connected to the first end of the capacitor C1, and the collector of the transistor Q1 is connected to the first end of the second resistor R2; the second end of the second resistor R2 is connected to the second end of the capacitor C1.

[0097] It should be understood that in the process of the control circuit controlling the transistor Q1, the switch is prone to overload, thereby damaging the discharge circuit. In the embodiment of the present application, by connecting the third resistor R3 in series between the photocoupler U1 and the first diode D1, the switch can be prevented from being overloaded, and when the transistor Q1 is overloaded, the third resistor R3 will limit the current, thereby protecting the photocoupler U1 and other components.

[0098] The anode of the third diode D3 is connected to the second end of the secondary winding, and the cathode of the third diode D3 is connected to the cathode of the second diode D2. The third diode D3 mainly functions as freewheeling.

[0099] When current flows through the secondary winding of the isolation transformer T, an induced electromotive force is generated at both ends of the secondary winding; when no current flows through the secondary winding, the induced electromotive force may generate a reverse voltage on the components in the circuit. For example, when the reverse voltage is higher than the reverse breakdown voltage of the transistor, the transistor will be damaged. In this embodiment, by connecting the third diode D3 in parallel to both ends of the secondary winding, when no current flows through the secondary winding, the induced electromotive force is consumed by doing work through the loop formed by the third diode D3 and the secondary winding, thereby protecting other components in the driving circuit of the thyristor from damage.

[0100] The absorption circuit 350 is connected in parallel to both ends of the primary winding of the isolation transformer T.

[0101] In the embodiment of the present application, when the switch device is disconnected, the absorption circuit 350 can absorb the leakage inductance peak voltage to prevent the switch device from being damaged.

[0102] Exemplarily, the absorption circuit described in the embodiments of the present application can be any one of an RCD absorption circuit, a non-dissipative clamping circuit, a transient voltage suppressor (TVS) and a linear voltage stabilizing MOS absorption circuit.

[0103] In addition, an embodiment of the present application further provides an electric power device, including: a power conversion circuit, a thyristor module, and a thyristor driving circuit as described in any of the aforementioned embodiments.

[0104] By adopting the thyristor driving circuit described in the above embodiments, the reliability of the thyristor is improved, thereby improving the reliability of the power equipment.

[0105] Exemplarily, the power equipment includes a grid-connected and off-grid switching system, and its corresponding structural schematic diagram is as follows: Fig.11 shown.

[0106] like Fig.11 As shown, the on-grid and off-grid switching system includes: an energy storage device 1110, an inverter 1120, a thyristor module 1130, and a thyristor driving circuit 1140 described in the above embodiments;

[0107] Among them, the energy storage device 1110 is connected to the DC side of the inverter 1120, the AC side of the inverter 1120 is connected to the first end of the thyristor module 1130 and the load, and the second end of the thyristor module 1130 is used to connect to the power grid; the thyristor drive circuit 1140 is connected to the thyristor module 1130 to provide the thyristor module 1130 with a thyristor drive current that is close to the ideal.

[0108] It should be understood that the embodiment of the present application takes the inverter as a three-phase inverter as an example. In addition, the inverter can also be a single-phase inverter, which will not be described in detail in this embodiment.

[0109] It should be noted that each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device and system embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiments. The device and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components indicated as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0110] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A thyristor driving circuit, characterized in that: include: Switching devices, isolation transformers, rectifier circuits and varistor devices; The first end of the primary winding of the isolation transformer is used to connect to the positive electrode of the power supply, the second end of the primary winding is connected to the negative electrode of the power supply via the switching device, the first end of the secondary winding of the isolation transformer is connected to the gate of the thyristor via the rectifier circuit and the variable resistance device, and the second end of the secondary winding is used to connect to the cathode of the thyristor; The resistance changing device is used to change the impedance of the branch connected to the gate of the thyristor when the switch device is turned on, so as to change the driving current provided to the gate of the thyristor.

2. The thyristor driving circuit according to claim 1, characterized in that: The variable resistance device comprises: a first resistor and a capacitor; The first end of the first resistor is connected to the rectifier circuit, and the second end of the first resistor is used to connect the gate of the thyristor; The capacitor is connected in parallel with the first resistor; wherein the capacitor is charged when the switch device is turned on to change the impedance of the variable resistance device.

3. The thyristor driving circuit according to claim 2, characterized in that: The thyristor driving circuit further includes: a discharge circuit; The discharge circuit is used to discharge the capacitor when the switch device is turned off, so as to reduce the impedance of the resistance changing device.

4. The thyristor driving circuit according to claim 3, characterized in that: The discharge circuit comprises: a second resistor and a control circuit; The second resistor is connected in parallel to both ends of the capacitor; The control circuit is used to control the capacitor to discharge through the second resistor when the secondary winding outputs a negative voltage.

5. The thyristor driving circuit according to claim 4, characterized in that: The control circuit includes a first diode, a photocoupler and a triode; The anode of the first diode is connected to the second end of the secondary winding, and the cathode of the first diode is connected to the anode of the photoelectric coupler; the cathode of the photoelectric coupler is connected to the first end of the secondary winding, the collector of the photoelectric coupler is connected to the base of the transistor, the emitter of the photoelectric coupler is connected to the second end of the second resistor, the emitter of the transistor is connected to the first end of the capacitor, the collector of the transistor is connected to the first end of the second resistor, and the second end of the second resistor is connected to the second end of the capacitor; or The positive electrode of the photoelectric coupler is connected to the second end of the secondary winding, the negative electrode of the photoelectric coupler is connected to the positive electrode of the first diode, the collector of the photoelectric coupler is connected to the base of the transistor, the emitter of the photoelectric coupler is connected to the second end of the second resistor, the emitter of the transistor is connected to the first end of the capacitor, the collector of the transistor is connected to the first end of the second resistor, and the second end of the second resistor is connected to the second end of the capacitor; the cathode of the first diode is connected to the first end of the secondary winding.

6. The thyristor driving circuit according to claim 2, characterized in that: The variable resistance device further comprises: a resistance device; The resistor is connected in series with the capacitor; The resistor device is used to adjust the rising rate of the driving current of the gate of the thyristor and the upper limit value of the driving current of the gate of the thyristor.

7. The thyristor driving circuit according to claim 1, characterized in that: The variable resistance device includes any one of a digital potentiometer and a digital resistance box.

8. The thyristor driving circuit according to any one of claims 1 to 7, characterized in that: The rectifying circuit includes a second diode.

9. The thyristor driving circuit according to claim 8, characterized in that: The thyristor driving circuit further includes: a third diode; An anode of the third diode is connected to the second end of the secondary winding, and a cathode of the third diode is connected to the cathode of the second diode.

10. The thyristor driving circuit according to claim 9, characterized in that: The driving circuit of the thyristor further comprises: an absorption circuit; The absorption circuit is connected in parallel to the first end of the primary winding and the second end of the primary winding.

11. An electric power device, characterized in that: include: A power conversion circuit, a thyristor module, and a thyristor driving circuit as claimed in any one of claims 1 to 10.

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