A method for suppressing small current oscillation of fast recovery diode based on saturated reactor

Abstract

The present invention provides a method for suppressing small current oscillation of a fast recovery diode based on a saturated reactor, wherein a saturated reactor with a magnetic core is used to construct a semiconductor device power module, and the saturated reactor with a magnetic core is obtained by the following steps: A. For the semiconductor device power module, an air-core adjustable reactor is used as a commutation reactor, and the reactance value of the air-core adjustable reactor is adjusted to a first expected value that does not damage the semiconductor device power module during commutation when a switching behavior occurs; B. The inductance value of the air-core adjustable reactor is repeatedly increased until the switching behavior under any current does not cause low current oscillation, and the inductance value L of the air-core adjustable reactor is confirmed at this time; C. Based on the inductance value L obtained in the step B, the inductance value of the saturated reactor with a magnetic core when it is not saturated is determined to design the saturated reactor with a magnetic core. The IGCT module realized by the present invention has a small volume, good oscillation suppression effect, and high efficiency.

Description

Technical Field

[0001] The invention belongs to the field of power electronic devices, and in particular relates to a method for suppressing small current oscillation of a fast recovery diode based on a saturated reactor. Background Art

[0002] When a fast recovery diode enters a blocking state at a high di / dt in a low current density flow state, the reverse recovery tail current decays too quickly, resulting in severe oscillation (referred to as low current oscillation), which in turn causes device damage. In addition, in the integrated gate-commutated thyristor (IGCT) modules (such as half-bridge modules, full-bridge modules, and diode-clamped three-level modules) used in the field of flexible power transmission, since the IGCT device turn-on process is positive feedback and the turn-on speed is very fast, a module commutation reactor is usually required to limit the di / dt of the IGCT device during the switching process.

[0003] In high-voltage and high-capacity applications, when large-size fast recovery diodes are used in IGCT modules, the aforementioned oscillation phenomenon is particularly serious, and a large-value module commutation reactor is required to limit di / dt to a very low level to ensure device safety. However, the energy stored in the anode reactance is proportional to its inductance, and a large-value reactance stores more energy, which increases the action loss of the clamping circuit and reduces the module efficiency. Summary of the invention

[0004] In view of the above problems, the present invention proposes a method for suppressing small current oscillation of a fast recovery diode based on a saturated reactor.

[0005] The invention discloses a method for suppressing small current oscillation of a fast recovery diode based on a saturated reactor, which adopts a saturated reactor with a magnetic core to construct a semiconductor device power module.

[0006] The saturated reactor with a magnetic core is obtained by the following steps:

[0007] A. For the semiconductor device power module, an air-core adjustable reactance is used as a commutation reactor, and the reactance value of the air-core adjustable reactance is adjusted to a first expected value that does not cause damage to the semiconductor device power module during commutation when a switching behavior occurs;

[0008] B. Repeatedly increase the inductance of the air-core adjustable reactance until the switching behavior does not cause low current oscillation under any current, and confirm the inductance L of the air-core adjustable reactance at this time;

[0009] C. Based on the inductance value L obtained in the step B, determine the inductance value of the saturated reactor with a magnetic core when it is unsaturated, so as to design the saturated reactor with a magnetic core.

[0010] further,

[0011] In the step A, at the highest operating voltage of the semiconductor device power module, the reactance value of the air-core adjustable reactance is adjusted to a first expected value that does not damage the semiconductor device power module during commutation when a switching behavior occurs.

[0012] further,

[0013] In step A, the maximum current I of the semiconductor device power module causing low current oscillation phenomenon is obtained through a pulse test. m .

[0014] further,

[0015] In the step B, the inductance value of the air-core adjustable reactance is repeatedly increased, and a pulse test is performed to confirm the inductance value L of the air-core adjustable reactance at this time.

[0016] further,

[0017] In step C, at the maximum current I m Based on the above, the saturation critical current value of the saturated inductor with a magnetic core is determined; the inductance value of the saturated inductor with a magnetic core when it is unsaturated is determined to design the saturated inductor with a magnetic core.

[0018] further,

[0019] At the maximum current I m An expected margin is left on this basis as the saturation critical current value of the saturated inductor with a magnetic core.

[0020] further,

[0021] The expected margin is the maximum current I m 0.5 times or 1 times.

[0022] further,

[0023] When designing the saturated reactor with a magnetic core, the inductance value of the saturated reactor with a magnetic core when unsaturated is set to be higher than the inductance value L.

[0024] further,

[0025] The semiconductor device power module is an IGCT module.

[0026] further,

[0027] The maximum current I m It is the maximum current when the fast recovery diode in the IGCT module enters the blocking state when the current is flowing at a low current density.

[0028] The IGCT module realized by the method for suppressing small current oscillation of a fast recovery diode based on a saturated reactor of the present invention has a small volume. To achieve the same inductance value, the volume of a saturated reactor with a magnetic core is much smaller than that of an air-core reactor, which is conducive to miniaturization of the module; the oscillation suppression effect is good, and di / dt is suppressed to a very low level under low current, thereby effectively avoiding oscillation phenomenon, extending the life of the device and the module, and improving the operation stability; the efficiency is high, and the saturated reactor requires fewer turns to achieve the same inductance value, thereby reducing the copper loss when the reactor is passed through the current, and the reactor core is saturated under large current, presenting a low inductance value, storing less energy, thereby reducing the action loss of the clamping circuit.

[0029] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention 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 some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 It shows a schematic structural diagram of an IGCT module using the present invention according to an embodiment of the present invention;

[0032] Figure 2 A flow chart of obtaining a saturable reactor with a magnetic core according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Figure 1 The figure shows the schematic diagram of the IGCT module structure using this method. Figure 1 In the IGCT module, the first capacitor C0 and the reactor L s , resistor R s , diode D s , the second capacitor C s, a first IGCT T1 and a second IGCT T2, and T1 and T2 are respectively connected in anti-parallel with diodes D1 and D2. Among them, one electrode of the first capacitor C0 is connected to the reactor L s One end and resistor R s One end of the reactor L s The other end of the diode D s anode and the anode of the first IGCT T1, diode D s The cathode connection resistance R s The other end of the second capacitor C s One electrode, the second capacitor C s The other electrode of the first IGCT T1 is connected to the other electrode of the first capacitor C0, the cathode of the first IGCT T1 is connected to the anode of the second IGCT T2, and the cathode of the second IGCT T2 is connected to the second capacitor C s the other electrode.

[0035] In the method for suppressing small current oscillation of a fast recovery diode based on a saturated reactor of the present invention, a saturated reactor with a magnetic core is used to construct the reactor L in the above IGCT module. s See also Figure 2 , the saturated reactor with a magnetic core is obtained by the following steps:

[0036] (1) For the IGCT module, an air-core adjustable reactance is used as a commutation reactor. Under the highest operating voltage of the IGCT module, the reactance value of the air-core adjustable reactance is adjusted to a first expected value that does not cause damage to the IGCT module during commutation when a switching behavior occurs, wherein the fast recovery diode (i.e. Figure 1 Middle diode D s ) can cause the maximum current I of the low current oscillation phenomenon m ;

[0037] (2) repeatedly increasing the inductance of the air-core adjustable reactance and performing a pulse test until the switching behavior under any current does not cause the fast recovery diode in the IGCT module to generate low current oscillation, and confirming the inductance L of the air-core adjustable reactance at this time;

[0038] (3) At the maximum current I m A certain margin is left on the basis (for example, 0.5 times I m or 1 times I m ) as the saturation critical current value of the saturated inductor with a magnetic core, and make the inductance of the saturated inductor with a magnetic core when unsaturated slightly larger than the inductance L confirmed in step (2), and design the saturated inductor with a magnetic core.

[0039] (4) Use the saturated inductor with a magnetic core designed in step (3) as a module commutation inductor, and verify by pulse test or continuous operation test whether the switching behavior of any current value at the highest module operating voltage will not cause low current oscillation that may affect the operation of the IGCT module.

[0040] The fast recovery diode small current oscillation suppression method based on saturated reactor of the present invention adopts saturated reactor with magnetic core as commutation reactor in IGCT module. Saturated reactor presents high inductance value at low current, and can suppress di / dt at a very low level when switching at low current, thereby effectively avoiding low current oscillation phenomenon, extending module service life and improving operation stability. At high current, saturated reactor presents low inductance value, and stores less energy, thereby reducing clamping circuit loss.

[0041] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for suppressing small current oscillation of fast recovery diode based on saturated reactor, It is characterized in that The semiconductor device power module is constructed using a saturated reactor with a magnetic core. The saturated reactor with a magnetic core is obtained by the following steps: A. For the semiconductor device power module, an air-core adjustable reactance is used as a commutation reactor, and the reactance value of the air-core adjustable reactance is adjusted to a first expected value that does not cause damage to the semiconductor device power module during commutation when a switching behavior occurs; B. Repeatedly increase the inductance of the air-core adjustable reactance until the switching behavior does not cause low current oscillation under any current, and confirm the inductance L of the air-core adjustable reactance at this time; C. Based on the inductance value L obtained in the step B, determine the inductance value of the saturated reactor with a magnetic core when it is unsaturated, so as to design the saturated reactor with a magnetic core; In the step A, at the highest operating voltage of the semiconductor device power module, the reactance value of the air-core adjustable reactance is adjusted to a first expected value that does not cause damage to the semiconductor device power module during commutation when a switching behavior occurs; In step A, the maximum current I of the semiconductor device power module causing low current oscillation phenomenon is obtained through a pulse test. m ; In the step B, the inductance value of the air-core adjustable reactance is repeatedly increased, and a pulse test is performed to confirm the inductance value L of the air-core adjustable reactance at this time; In step C, at the maximum current I m Based on the above, the saturation critical current value of the saturated inductor with a magnetic core is determined; the inductance value of the saturated inductor with a magnetic core when it is unsaturated is determined to design the saturated inductor with a magnetic core.

2. According to claim 1, a method for suppressing small current oscillation of a fast recovery diode based on a saturated reactor, It is characterized in that At the maximum current I m An expected margin is left on this basis as the saturation critical current value of the saturated inductor with a magnetic core.

3. According to claim 2, a method for suppressing small current oscillation of a fast recovery diode based on a saturated reactor, It is characterized in that The expected margin is the maximum current I m 0.5 times or 1 times.

4. A method for suppressing small current oscillation of a fast recovery diode based on a saturable inductor according to any one of claims 1 to 3, It is characterized in that When designing the saturated reactor with a magnetic core, the inductance value of the saturated reactor with a magnetic core when unsaturated is set to be higher than the inductance value L.

5. A method for suppressing small current oscillation of a fast recovery diode based on a saturable inductor according to any one of claims 1 to 3, It is characterized in that The semiconductor device power module is an IGCT module.

6. A method for suppressing small current oscillation of a fast recovery diode based on a saturated reactor according to claim 5, It is characterized in that The maximum current I m It is the maximum current when the fast recovery diode in the IGCT module enters the blocking state when the current is flowing at a low current density.

Images