Dummy load circuit for soft switching inverter welding power supply

Abstract

The utility model discloses a dummy load circuit for a soft switching inverter welding power supply. The dummy load circuit comprises a high-frequency transformer B1, a load inductance loop, a load transformer B2, a full-bridge rectifier circuit D1 and a switching tube Q1, a primary winding of the high-frequency transformer B1 is used as an input end of the dummy load circuit for the soft switching inverter welding power supply; a secondary winding of the high-frequency transformer B1 is connected with a load inductance loop; the load inductance loop is connected with the full-bridge rectifier circuit D1 through a load transformer B2; according to the dummy load circuit for the soft switching inverter welding power supply, the implementation circuit is simple, the number of devices is small, the load effect under the no-load condition is guaranteed, the efficiency of the whole machine is improved, the energy efficiency level of the whole machine is improved, and the dummy load circuit for the soft switching inverter welding power supply is suitable for large-scale popularization and application. And the energy-saving purpose is achieved.

Description

Technical Field

[0001] The present application relates to the field of inverter power supplies, and particularly to a dummy load circuit for a soft-switching inverter welding power supply. Background Art

[0002] Currently, the dummy load methods adopted by IGBT full-bridge soft-switching inverter welding power supplies are all in the way of directly connecting a load inductor to a single or one of the output windings of a high-frequency transformer. This method has been stable and reliable during long-term actual use, and no problems have been found.

[0003] However, after the implementation of the energy efficiency grade system in the electric welding machine industry, this load inductor causes serious power loss, seriously affecting the energy efficiency grade rating of the welding machine. Utility Model Content

[0004] In view of the above deficiencies in the prior art, a dummy load circuit for a soft-switching inverter welding power supply provided by the present utility model solves the problems of having a certain requirement for a dummy load under no-load conditions of the welding power supply and reducing the additional load loss of the dummy load under load conditions.

[0005] In order to achieve the above utility model purpose, the technical solution adopted by the present utility model is: a dummy load circuit for a soft-switching inverter welding power supply, including a high-frequency transformer B1, a load inductor circuit, a load transformer B2, a full-bridge rectifier circuit D1, and a switching transistor Q1;

[0006] The primary winding of the high-frequency transformer B1 serves as the input end of the dummy load circuit for the soft-switching inverter welding power supply; the secondary winding of the high-frequency transformer B1 is connected to the load inductor circuit;

[0007] The load inductor circuit is connected to the full-bridge rectifier circuit D1 through the load transformer B2;

[0008] The full-bridge rectifier circuit D1 is also connected to the collector and emitter of the switching transistor Q1, and the base of the switching transistor Q1 serves as the output end of the dummy load circuit for the soft-switching inverter welding power supply and is connected to the welding power supply.

[0009] Further: The load inductor circuit includes a load inductor L1. One end of the load inductor L1 is connected to one end of the secondary winding of the high-frequency transformer B1, the other end of the load inductor L1 is connected to one end of the primary winding of the load transformer B2, and the other end of the primary winding of the load transformer B2 is connected to the other end of the secondary winding of the high-frequency transformer B1.

[0010] Further: The turns ratio of the load transformer B2 is 1, and both ends of the secondary winding of the load transformer B2 are connected to the AC end of the full-bridge rectifier circuit D1.

[0011] Further: The full-bridge rectifier circuit D1 includes 4 diodes connected in series in sequence.

[0012] Further: The V+ terminal of the full-bridge rectifier circuit D1 is connected to the collector of the switching transistor Q1, and the V- terminal of the full-bridge rectifier circuit D1 is connected to the emitter of the switching transistor Q1.

[0013] Further: The high-frequency transformer B1 further includes a secondary output winding, and the secondary output winding serves as the inverter output winding.

[0014] The beneficial effects of the present utility model are as follows:

[0015] 1. The problem of reducing the additional load loss of the dummy load under the load condition of the welding power source is solved, and the purpose of improving the efficiency of the welding power source is achieved;

[0016] 2. The implementation circuit is simple, with few components. It not only ensures the load effect under no-load conditions, but also improves the overall efficiency of the machine, enhances the energy efficiency level of the whole machine, and achieves the purpose of energy conservation. Description of the Drawings

[0017] Figure 1 It is the schematic diagram of the dummy load circuit for the soft-switching inverter welding power source. Specific Embodiments

[0018] The specific embodiments of the present utility model will be described below to facilitate those skilled in the art of this technology to understand the present utility model. However, it should be clear that the present utility model is not limited to the scope of the specific embodiments. For those of ordinary skill in the art of this technology, as long as various changes are within the spirit and scope of the present utility model defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present utility model are within the scope of protection.

[0019] As Figure 1 shown, in an embodiment of the present utility model, a dummy load circuit for a soft-switching inverter welding power source is provided, including a high-frequency transformer B1, a load inductor circuit, a load transformer B2, a full-bridge rectifier circuit D1, and a switching transistor Q1;

[0020] The primary winding of the high-frequency transformer B1 serves as the input terminal of the dummy load circuit for the soft-switching inverter welding power source; the secondary winding of the high-frequency transformer B1 is connected to the load inductor circuit;

[0021] The load inductor circuit is connected to the full-bridge rectifier circuit D1 through the load transformer B2;

[0022] The full-bridge rectifier circuit D1 is also connected to the collector and emitter of the switching transistor Q1. The base of the switching transistor Q1 serves as the output terminal of the dummy load circuit for the soft-switching inverter welding power source and is connected to the welding power source.

[0023] The load inductor loop includes a load inductor L1. One end of the load inductor L1 is connected to one end of the secondary winding of the high-frequency transformer B1, and the other end of the load inductor L1 is connected to one end of the primary winding (N1 side) of the load transformer B2. The other end of the primary winding of the load transformer B2 is connected to the other end of the secondary winding of the high-frequency transformer B1.

[0024] The turns ratio of the load transformer B2 is 1. Both ends of the secondary winding (N2 side) of the load transformer B2 are connected to the AC terminals of the full-bridge rectifier circuit D1.

[0025] The full-bridge rectifier circuit D1 includes 4 diodes connected in series in sequence. The model of the diode used in this embodiment is MB60200PT.

[0026] The V+ terminal of the full-bridge rectifier circuit D1 is connected to the collector of the switching transistor Q1, and the V- terminal of the full-bridge rectifier circuit D1 is connected to the emitter of the switching transistor Q1.

[0027] The model of the switching transistor Q1 used in this embodiment is IRFB3077.

[0028] In this application, the switching and turning off of the switching transistor Q1 are controlled by the output current of the welding power source. When the output current of the welding power source is less than the set value (such as 5A), the switching transistor Q1 conducts. At this time, it is equivalent to short-circuiting the secondary winding of the load transformer B2. The load transformer B2 is equivalent to a small-inductance inductor with an inductance equal to its leakage inductance. This inductance is much smaller than the inductance of the load inductor L1, so the influence on the current loaded by the load inductor L1 is small.

[0029] When the output current of the welding power source is greater than the set value, the switching transistor Q1 turns off. The secondary winding of the load transformer N2 is equivalent to being in an open-circuit state. At this time, the load transformer B2 is equivalent to a large-inductance inductor. By being connected in series with the load inductor L1, the current in the load inductor L1 loop is greatly reduced, its loop loss is greatly reduced, the efficiency of the welding power source is improved, and its energy efficiency level is increased.

[0030] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by terms such as "center", "thickness", "upper", "lower", "horizontal", "top", "bottom", "inner", "outer", "radial", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model 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. Therefore, it cannot be understood as a limitation to the present utility model. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of technical features. Therefore, the features defined by "first", "second", "third" may explicitly or implicitly include one or more of such features.

Claims

1. A dummy load circuit for a soft-switching inverter welding power supply, characterized in that: It includes a high-frequency transformer B1, a load inductor circuit, a load transformer B2, a full-bridge rectifier circuit D1 and a switch tube Q1; The primary winding of the high-frequency transformer B1 serves as the input end of the dummy load circuit for the soft-switching inverter welding power supply; the secondary winding of the high-frequency transformer B1 is connected to the load inductor loop; The load inductance loop is connected to the full-bridge rectifier circuit D1 through the load transformer B2; The full-bridge rectifier circuit D1 is also connected to the collector and emitter of the switch tube Q1. The base of the switch tube Q1 is connected to the welding power source as the output end of the dummy load circuit for the soft-switching inverter welding power source.

2. The dummy load circuit for a soft-switching inverter welding power supply according to claim 1, characterized in that: The load inductance circuit includes a load inductor L1, one end of the load inductor L1 is connected to one end of the secondary winding of the high-frequency transformer B1, the other end of the load inductor L1 is connected to one end of the primary winding of the load transformer B2, and the other end of the primary winding of the load transformer B2 is connected to the other end of the secondary winding of the high-frequency transformer B1.

3. The dummy load circuit for a soft-switching inverter welding power supply according to claim 1, characterized in that: The transformation ratio of the load transformer B2 is 1, and both ends of the secondary winding of the load transformer B2 are connected to the AC end of the full-bridge rectifier circuit D1.

4. The dummy load circuit for a soft-switching inverter welding power supply according to claim 1, characterized in that: The full-bridge rectifier circuit D1 includes four diodes connected in series.

5. The dummy load circuit for a soft-switching inverter welding power supply according to claim 4, characterized in that: The V+ terminal of the full-bridge rectifier circuit D1 is connected to the collector of the switch tube Q1 , and the V- terminal of the full-bridge rectifier circuit D1 is connected to the emitter of the switch tube Q1 .

6. The dummy load circuit for a soft-switching inverter welding power supply according to claim 1, characterized in that: The high-frequency transformer B1 further includes a secondary output winding, which serves as an inverter output winding.

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