CN112260546A - Power supply open-circuit voltage adjusting method, power supply circuit, power supply device and electric welding machine - Google Patents
Power supply open-circuit voltage adjusting method, power supply circuit, power supply device and electric welding machine Download PDFInfo
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- CN112260546A CN112260546A CN202011108421.8A CN202011108421A CN112260546A CN 112260546 A CN112260546 A CN 112260546A CN 202011108421 A CN202011108421 A CN 202011108421A CN 112260546 A CN112260546 A CN 112260546A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
- H02M3/33576—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
- H02M3/33592—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer
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Abstract
The application belongs to the technical field of power supplies, and provides a method for adjusting the open-circuit voltage of a power supply, a power supply circuit, a power supply device and an electric welding machine, wherein a first power tube switch module and a second power tube switch module are driven to be alternately conducted, so that a transformer module works in an extremely low energy density state, the purpose of adjusting the open-circuit voltage of the power supply in a large range is realized, the equivalent driving frequency of upper and lower switch tubes of a double-tube forward topological structure circuit in the power supply is reduced by a frequency hopping technology, the energy transfer density of the transformer is further reduced, the equivalent resistance of a power output end is controlled by a voltage adjusting module, an auxiliary voltage is provided by an auxiliary voltage reducing module, the purpose of compositely adjusting the open-circuit voltage of the power supply is achieved, finally, a voltage signal output by the transformer module is rectified and follow current by a rectifying module, the open-circuit voltage of the existing, or the problem that the adjustment range is small although the adjustment can be rarely carried out, and the adaptability of the welding process is poor.
Description
Technical Field
The application belongs to the technical field of power supplies, and particularly relates to an open-circuit voltage adjusting method of a power supply, a power supply circuit, a power supply device and an electric welding machine.
Background
The output voltage of the welding power supply is divided into a circuit voltage and a working voltage, wherein the open circuit voltage refers to the output voltage measured when the power output end is not connected with any load under the condition of electrifying, namely the voltage when the welding power supply does not work, and the voltage is generally between 50V and 90V; the operating voltage is the voltage at which normal welding occurs after ignition of the arc, and is typically around 15V to 40V. In order to meet the arc starting requirement during welding, the open circuit voltage of a welding power supply is generally designed to be much higher than the working voltage, but the higher open circuit voltage cannot meet the requirements of various safety regulations and different welding process procedures on the output voltage, so that a method for adjusting the output open circuit voltage of the welding power supply is required to be designed.
In order to adjust the output open circuit voltage of the welding power supply, the following schemes are adopted:
1. the general method is to increase the turn ratio of a main transformer of the welding power supply, and then connect a suitable non-variable load in parallel at the secondary output end of the transformer, as shown in fig. 1, VA is the welding power supply, and RA1 is a load resistor with the output end connected in parallel. However, the scheme can only meet partial safety requirements, for example, the national standard 'arc welding equipment safety requirement' specifies that the rated no-load voltage does not exceed the peak value of direct current 103V, and the scheme cannot comply with the more strict safety rules and has certain personal safety hazard because no Voltage Reduction Device (VRD) measures exist; secondly, the high and low open-circuit voltage greatly affects the arc starting and arc stabilizing performance, the higher the open-circuit voltage is, the easier the arc starting and arc stabilizing are, and particularly for some special welding processes, certain requirements are required on the size of the open-circuit voltage.
2. As shown in fig. 2, VB1 is a welding main power supply, the output no-load voltage is generally 50V to 90V, VB2 is a group of independent safe voltage sources, the recognized safe voltage is not higher than 36V, and the continuous contact safe voltage is not higher than 24V; the positive pole of VB2 is connected to the positive pole output end of VB1 through an electronic switch SB1, a current-limiting resistor RB1 and a forward diode DB1, and the negative poles of VB2 and VB1 are connected to serve as a common reference; when the welding loop enters an open circuit state, the output current of the welding power supply is zero, the system immediately turns off the output of the main power supply VB1 after recognizing the zero current, and simultaneously turns on SB1, so that the VB2 voltage is loaded to the output end of the welding power supply through RB1 and DB1, and a lower open circuit voltage for judging whether welding is required or not is formed; when welding is started, the output end is changed from open circuit to short circuit, the open circuit voltage for judging whether welding is required to be carried out is pulled down, the welding machine control system immediately disconnects SB1 after identifying the low voltage, simultaneously starts the welding main power supply VB1 to provide the no-load voltage or working voltage required by welding, the welding loop enters an open circuit state again after arc breakage or arc completion of welding, and then outputs lower open circuit voltage for judging whether welding is required to be carried out according to the process, so that the adjustment process of the open circuit voltage of the welding power supply is realized. The scheme can well solve all common safety problems, but needs to add a group of independent safe voltage source VB2, an electronic switch SB1(MOS tube, BJT, relay contact and the like), a current-limiting resistor RB1 and a diode DB1 with higher voltage resistance, increases the hardware cost, also adds the complexity of a circuit and brings great burden to debugging. Secondly, this solution does not enable the open circuit voltage adjustment in the welding operation state, and therefore the optimal open circuit arcing voltage cannot be applied in a targeted manner according to different welding process characteristics to achieve the optimal configuration of the arcing voltage. Thirdly, because the open circuit voltage is low, when welding is started, if the transition treatment from the open circuit state to the welding working state is not good, the arc striking performance is seriously influenced, and poor welding experience is brought.
3. The software regulation scheme can realize the function of regulating the open-circuit voltage within a certain range by adopting a digital regulator to carry out flat characteristic closed-loop control on the output voltage in an open-circuit state, and the premise that the software regulation scheme needs to be connected with a proper constant-resistance load in parallel at the output end of a power supply like the scheme 1 so as to reduce the open-circuit voltage. In the scheme, a pure software control mode is adopted, constant-voltage closed-loop control is carried out in an open-circuit state, the method can only adjust average open-circuit voltage, peak voltage cannot meet the safety regulation requirement, the linear adjustment range is limited, and the larger the load resistance value is, the smaller the adjustable range is, and the smaller the load resistance value is, the larger the adjustable range is; however, the smaller load resistance results in larger standby power consumption, so from the viewpoint of energy efficiency, the load resistance cannot be too small, which results in that the linear adjustment range of the average open-circuit voltage is not too large, and the range is close to the rated no-load voltage, in which case the peak voltage also exceeds the safety requirement. Since the linear adjustment range of the open-circuit voltage is small and large (close to the rated no-load voltage), the optimal configuration of the arcing voltage cannot be realized.
Disclosure of Invention
The application aims to provide a power supply open-circuit voltage adjusting method, a power supply circuit, a power supply device and an electric welding machine, and can solve the problems that an existing welding power supply is small in open-circuit voltage adjusting range and poor in welding process adaptability.
A first aspect of the embodiments of the present application provides a method for adjusting an open-circuit voltage of a power supply, where the power supply includes a first power tube switch module, a transformer module, a second power tube switch module, and a rectification and follow current module, a current input end of the first power tube switch module is connected to a positive polarity end of a dc bus, a current output end of the first power tube switch module is connected to a first end of a primary winding of the transformer module, a current input end of the second power tube switch module is connected to a second end of the primary winding of the transformer module, and a current output end of the second power tube switch module is connected to a negative polarity end of the dc bus;
the open circuit voltage adjustment method comprises the following steps:
driving the first power tube switch module and the second power tube switch module to be alternately conducted;
rectifying and freewheeling the voltage signal output by the transformer module through a rectifying and freewheeling module; the rectification and follow current module is connected with the secondary winding of the transformer module.
In one embodiment, the open circuit voltage adjustment method further includes:
and adjusting the switching frequency of the first power tube switch module and the second power tube switch module by adopting a frequency hopping technology so as to adjust the energy transfer density of the transformer module.
In one embodiment, the open circuit voltage adjustment method further includes:
and adjusting the equivalent resistance of the output end of the power supply by adopting a voltage adjusting module so as to adjust the open-circuit voltage of the power supply.
In one embodiment, the open circuit voltage adjustment method further includes:
and outputting the auxiliary voltage according to the input auxiliary power supply control signal by adopting an auxiliary voltage reduction module.
A second aspect of embodiments of the present application provides a power supply circuit, including:
the current input end of the first power tube switch module is connected with the positive polarity end of the direct current bus;
the first end of the primary winding of the transformer module is connected with the current output end of the first power tube switch module;
a current input end of the second power tube switch module is connected with a second end of the primary winding of the transformer module, and a current output end of the second power tube switch module is connected with a negative polarity end of the direct current bus;
the first gate driving module is used for receiving a first original driving signal and generating a first gate driving signal according to the first original driving signal;
the second gate driving module is used for receiving a second original driving signal and generating a second gate driving signal according to the second original driving signal; the first gate driving signal and the second gate driving signal drive the first power tube switch module and the second power tube switch module to be alternatively conducted;
and the rectification and follow current module is connected with the secondary winding of the transformer module and is used for rectifying and follow current of the voltage signal output by the transformer module.
In one embodiment, the power supply circuit further includes:
and the voltage regulating module is connected with the rectifying and follow current module and is used for regulating the open-circuit voltage output by the rectifying and follow current module according to the input voltage control signal.
In one embodiment, the power supply circuit further includes:
and the auxiliary voltage reduction module is connected with the rectification and follow current module and is used for outputting auxiliary voltage according to an input auxiliary power supply control signal.
In one embodiment, the first gate drive module comprises: the circuit comprises a first resistor, a second resistor, a first voltage regulator tube and a first capacitor;
the first end of the first resistor is connected with the positive polarity end of a first original driving signal source, the second end of the first resistor and the first end of the second resistor are connected with the control end of the first power tube circuit in a sharing mode, the second end of the second resistor, the anode of the first voltage-regulator tube and the first end of the first capacitor are connected with the negative polarity end of the first original driving signal source in a sharing mode, and the cathode of the first voltage-regulator tube and the second end of the first capacitor are connected with the first end of a primary winding of the transformer module in a sharing mode;
the second gate driving module includes: the first resistor, the second resistor, the third capacitor and the fourth capacitor are connected in series;
the first end of the third resistor is connected with the positive polarity end of a second original driving signal source, the second end of the third resistor and the first end of the fourth resistor are connected to the control end of the second power tube module in a shared mode, the second end of the fourth resistor, the first end of the second capacitor and the anode of the second voltage regulator tube are connected to the negative polarity end of the second original driving signal source in a shared mode, and the cathode of the second voltage regulator tube and the second end of the second capacitor are connected to the second end of a primary winding of the transformer module in a shared mode.
The third aspect of the embodiments of the present application also provides a power supply apparatus including the power supply circuit described in any one of the above.
The fourth aspect of the embodiment of the present application further provides an electric welding machine, including the power supply circuit as described in any one of the above.
The embodiment of the application provides a method for adjusting the open-circuit voltage of a power supply, a power supply circuit, a power supply device and an electric welding machine, wherein a first power tube switch module and a second power tube switch module are driven to be alternately conducted, so that a transformer module works in an extremely low energy density state, the purpose of adjusting the open-circuit voltage of the power supply in a large range is realized, the equivalent driving frequency of upper and lower switch tubes of a double-tube forward topological structure circuit in the power supply is reduced through a frequency hopping technology, the energy transfer density of the transformer is further reduced, the equivalent resistance of a power supply output end is controlled by a voltage adjusting module, an auxiliary voltage is provided by an auxiliary voltage reducing module, the purpose of compositely adjusting the open-circuit voltage of the power supply is achieved, finally, a voltage signal output by the transformer module is rectified and follow current by a rectifying and follow current module, the problem that the open-circuit voltage, or the problem that the adjustment range is small although the adjustment can be rarely carried out, and the adaptability of the welding process is poor.
Drawings
FIG. 1 is a schematic diagram of a welding power supply according to the present disclosure;
FIG. 2 is a schematic diagram of another welding power supply configuration provided herein;
fig. 3 is a schematic structural diagram of a power supply circuit according to an embodiment of the present disclosure;
fig. 4 is a schematic structural diagram of another power circuit provided in the embodiment of the present application;
fig. 5 is a schematic structural diagram of another power circuit provided in the embodiment of the present application;
fig. 6 is a schematic structural diagram of another power supply circuit according to an embodiment of the present disclosure.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application more clearly apparent, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.
It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, refer to an orientation or positional relationship illustrated in the drawings for convenience in describing the present application and to simplify description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present application.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.
The embodiment of the present application provides a method for adjusting an open-circuit voltage of a power supply in a first aspect of the embodiment of the present application, where the power supply includes a first power tube switch module, a transformer module, a second power tube switch module, and a rectification and follow current module, a current input end of the first power tube switch module is connected to a positive polarity end of a dc bus, a current output end of the first power tube switch module is connected to a first end of a primary winding of the transformer module, a current input end of the second power tube switch module is connected to a second end of the primary winding of the transformer module, and a current output end of the second power tube switch module is connected to a negative polarity end of the dc bus.
Specifically, the open-circuit voltage adjustment method in this embodiment includes:
driving the first power tube switch module and the second power tube switch module to be alternately conducted;
rectifying and freewheeling the voltage signal output by the transformer module through a rectifying and freewheeling module; the rectification and follow current module is connected with the secondary winding of the transformer module.
In this embodiment, the first power tube switch module, the transformer module, and the second power tube switch module form a dual-tube forward topology circuit, and in the adjustment of the open-circuit voltage of the power supply, the transformer module can work in an extremely low energy transfer density state by driving the upper and lower power tubes in the dual-tube forward topology circuit to be alternately turned on and utilizing the source-drain parasitic capacitance in the power tubes, so that the open-circuit voltage of the power supply can be adjusted in a large range by controlling the main power tubes (the first power tube switch module and the second power tube switch module), and the optimal configuration of the output voltage is realized.
In one embodiment, the driving the first power tube switch module and the second power tube switch module to be alternately turned on includes:
when the control end of the first power tube switch module is set to be a low level signal, the control end of the second power tube switch module is set to be a high level signal;
and when the control end of the first power tube switch module is set to be a high level signal, the control end of the second power tube switch module is set to be a low level signal.
As an embodiment of the present application, the first original driving signal source is configured to provide a first gate driving signal for a control end of a first power transistor switch module, the second original driving signal source is configured to provide a second gate driving signal for a control end of a second power transistor switch module, and the equivalent driving frequency of the first power transistor switch module and the equivalent driving frequency of the second power transistor switch module can be adjusted by adjusting a level or a duty ratio of the first gate driving signal and the second gate driving signal, for example, if the first power transistor switch module and the second power transistor switch module are both N-type MOS transistors, in a specific application, the first gate driving signal is a low level signal, the second gate driving signal is a high level signal, and the first gate driving signal is a high level signal, the second gate driving signal is a low level signal.
Furthermore, a first gate drive module may be disposed between the first original drive signal source and the first power transistor switch module, and a second gate drive module may be disposed between the second original drive signal source and the second power transistor switch module, so that the first power transistor switch module and the second power transistor switch module realize a negative pressure preset function in an alternate conduction process, so that the first power transistor switch module and the second power transistor switch module have reliable negative pressure turn-off.
In one embodiment, the driving the first power tube switch module and the second power tube switch module to be alternately turned on includes: and adjusting the switching frequency of the first power tube switch module and the second power tube switch module by adopting a frequency hopping technology so as to adjust the energy transfer density of the transformer module.
Specifically, in this embodiment, the duty ratios of the first gate driving signal and the second gate driving signal are adjusted by using a frequency hopping technique, so as to adjust the energy transfer density of the transformer module, for example, the frequency hopping technique is used to reduce the equivalent driving frequencies of the upper and lower switching tubes of the double-tube forward topology circuit in the power supply, so as to further reduce the energy transfer density of the transformer, and thus, the open-circuit voltage can be controlled to reach a lower voltage by using the main power switching tube, so that the welding power supply can more easily meet various safety requirements.
As an embodiment of the present application, the open circuit voltage adjustment method further includes: and adjusting the equivalent resistance of the output end of the power supply by adopting a voltage adjusting module so as to adjust the open-circuit voltage of the power supply.
In this embodiment, a voltage regulation module is provided at the power output end, for example, an electronic switch is connected in series to a constant resistance load connected in parallel to the output end of the existing welding power supply, and an unchangeable "dead load" is changed into a changeable "live load" by flexibly controlling the electronic switch, so that the effect of the constant resistance load is achieved. In one embodiment, the voltage regulating module may be an OVA circuit module.
As an embodiment of the present application, the open circuit voltage adjustment method further includes: and outputting the auxiliary voltage according to the input auxiliary power supply control signal by adopting an auxiliary voltage reduction module.
In this embodiment, an auxiliary voltage-reducing module is disposed at the output end of the power supply, and the auxiliary voltage-reducing module outputs an auxiliary voltage according to an input auxiliary power supply control signal, further, the load change of the output end can be sensed, and in addition, the auxiliary voltage-reducing module can be mixed with a negative voltage preset mode of the power supply and cooperatively work to achieve the purpose of compositely adjusting the open-circuit voltage of the power supply. In one embodiment, the auxiliary voltage reduction module may be a VES circuit module.
Referring to fig. 3, as an embodiment of the present application, the power circuit in this embodiment includes a first power transistor switch module 10, a transformer module 20, a second power transistor switch module 30, a first gate driver module 40, a second gate driver module 50, and a rectification and freewheeling module 60. Specifically, the current input end of the first power tube switch module 10 is connected to the positive polarity end VBUS + of the dc bus; the first end of the primary winding of the transformer module 20 is connected with the current output end of the first power tube switch module 10; the current input end of the second power tube switch module 30 is connected with the second end of the primary winding of the transformer module 20, and the current output end of the second power tube switch module 30 is connected with the negative polarity end VBUS-of the direct current bus; the first gate driving module 40 is configured to receive a first original driving signal and generate a first gate driving signal according to the first original driving signal; the second gate driving module 50 is configured to receive the second original driving signal and generate a second gate driving signal according to the second original driving signal; the first gate driving signal and the second gate driving signal may respectively drive the first power transistor switch module 10 and the second power transistor switch module 30 to be alternately turned on; the rectifying and freewheeling module 60 is connected to the secondary winding of the transformer module 20 for rectifying and freewheeling the voltage signal output by the transformer module 20.
In this embodiment, the first power tube switch module 10, the transformer module 20, the second power tube switch module 30, the first gate drive module 40, and the second gate drive module 50 form an inverter portion of a double-tube forward topology circuit, which is used to convert direct current provided by a direct current bus into alternating current, and in cooperation with the gate drive circuits (i.e., the first gate drive module 40 and the second gate drive module 50) with the function of driving negative voltage generation, the first power tube switch module 10 and the second power tube switch module 30 can realize a negative voltage preset function in the alternate conducting process, so that the first power tube switch module 10 and the second power tube switch module 30 can realize reliable negative voltage turn-off. Specifically, parasitic capacitances (for example, drain-source parasitic capacitances) exist in the first power tube switch module 10 and the second power tube switch module 30, and the first power tube switch module 10 and the second power tube switch module 30 are driven to be alternately conducted, so that the transformer module 20 operates in an extremely low energy transfer density state, and the maximum peak voltage drop of the secondary winding thereof is about half of that during normal operation, which enables the open-circuit voltage of the welding power source to be adjusted in a wide range directly by adjusting the switching frequencies of the first power tube switch module 10 and the second power tube switch module 30, and the optimal open-circuit arcing voltage can be applied specifically according to different welding process characteristics, so as to achieve the optimal configuration of the arcing voltage.
As an embodiment of the present application, a frequency hopping technique may be further used to reduce the equivalent driving frequency of the upper and lower switching tubes in the two-tube forward topology circuit formed by the first power tube switching module 10 and the second power tube switching module 30, so as to further reduce the average energy transfer density of the transformer module 20, and thus, the open-circuit voltage may be controlled to reach a lower voltage by the main power switching tube (i.e., the first power tube switching module 10 and the second power tube switching module 30), so that the welding power supply may more easily meet various safety requirements. Specifically, the open-circuit voltage of the power circuit is adjusted by adjusting the duty ratio of the first original driving signal and the second original driving signal.
In one embodiment, referring to fig. 4, the power circuit further includes a voltage regulating module 70, and the voltage regulating module 70 is connected to the rectifying and freewheeling module 60 and is configured to regulate the open-circuit voltage output by the rectifying and freewheeling module 60 according to the input voltage control signal.
In this embodiment, the open circuit voltage output by the rectifying and freewheeling module 60 is regulated by providing a voltage regulation module 70 and an input voltage control signal at the output of the power circuit. For example, the voltage regulation module 70 connected in parallel at the output end of the power circuit may be formed by connecting a resistive load and an electronic switch in series, and by controlling the switching state of the electronic switch, the resistance output by the power supply is changed from a non-adjustable "dead load" to an adjustable "live load", which not only can realize the effect of a constant resistive load, but also can control the switching frequency of the power switch tube by the voltage control signal to control the equivalent resistance connected to the output end of the power circuit in the negative pressure preset working mode of the welding power supply, thereby reducing the open-circuit voltage and realizing the adjustment of the open-circuit voltage. In one embodiment, the voltage control signal may be a PWM drive signal.
In one embodiment, referring to fig. 5, the power circuit further includes an auxiliary voltage-reducing module 80, where the auxiliary voltage-reducing module 80 is configured to output an auxiliary voltage according to an input auxiliary power control signal.
In this embodiment, the auxiliary voltage-reducing module 80 may input an auxiliary power control signal according to a user requirement, so that the auxiliary voltage is output by the auxiliary voltage-reducing module 80, and the auxiliary voltage may be a safe voltage, for example, the auxiliary voltage is 36V.
In specific application, the high and low degree of open circuit voltage influences the performance of arcing and arc stabilization, and the higher the open circuit voltage is, the easier the arc striking and arc stabilization are, especially for some special welding processes, have certain requirement to open circuit voltage size, through supplementary step-down module 80 output auxiliary voltage, can switch between open circuit state and welding operation state, not only can guarantee good arcing performance, the common problem that can not satisfy the ann rule requirement of solution that moreover can be fine.
As a preferred embodiment of the present application, the auxiliary voltage-dropping module 80 may also sense a load change of the output terminal and output a corresponding open-circuit voltage according to the load change of the output terminal. Furthermore, the device can also be mixed with a negative pressure preset mode of a power circuit to work cooperatively so as to achieve the purpose of compositely adjusting the open-circuit voltage of the welding power supply.
In one embodiment, referring to FIG. 6, the first gate drive module 40 comprises: the circuit comprises a first resistor R1, a second resistor R2, a first voltage regulator tube Z1 and a first capacitor C1; a first end of the first resistor R1 is connected to a positive polarity end of the first original driving signal source, a second end of the first resistor R1 and a first end of the second resistor R2 are connected to a control end of the first power transistor module 10 in common, a second end of the second resistor R2, an anode of the first regulator tube Z1 and a first end of the first capacitor C1 are connected to a negative polarity end of the first original driving signal source in common, and a cathode of the first regulator tube Z1 and a second end of the first capacitor C1 are connected to a first end of a primary winding of the transformer module 20 in common.
In this embodiment, the first gate driving module 40 is configured to receive a first original driving signal Vgs1, and the first original driving signal Vgs1 is adjusted by a negative voltage generating circuit composed of a gate resistor (i.e., a first resistor R1), a pull-down resistor (i.e., a second resistor R2), a first voltage regulator Z1 and a first capacitor C1 to generate a first gate driving signal, so as to control the on and off of the first power transistor switch module 10.
As an embodiment of the present application, referring to fig. 6, the second gate driving module 50 includes: a third resistor R3, a fourth resistor R4, a second capacitor C2 and a second voltage regulator tube Z2; a first end of the third resistor R3 is connected to the positive polarity end of the second original driving signal source, a second end of the third resistor R3 and a first end of the fourth resistor R4 are commonly connected to the control end of the second power transistor module 30, a second end of the fourth resistor R4, a first end of the second capacitor C2 and an anode of the second regulator tube Z2 are commonly connected to the negative polarity end of the second original driving signal source, and a cathode of the second regulator tube Z2 and a second end of the second capacitor C2 are commonly connected to the second end of the primary winding of the transformer module 20.
In this embodiment, the second gate driving module 50 is configured to receive a second original driving signal Vgs2, and the second original driving signal Vgs2 is adjusted by a negative voltage generating circuit composed of a gate resistor (i.e., a third resistor R3), a pull-down resistor (i.e., a fourth resistor R4), a second voltage regulator Z2 and a second capacitor C2 to generate a second gate driving signal, so as to control the second power transistor switch module 30 to turn on and off.
As an embodiment of the present application, referring to fig. 6, the first power transistor switch module 10 includes a first power transistor M1, a drain of the first power transistor M1 is connected to the positive polarity terminal VBUS + of the dc bus as a current input terminal of the first power transistor module 10, a source of the first power transistor M1 is connected to the first terminal of the primary winding of the transformer module 20 as a current output terminal of the first power transistor module 10, and a gate of the first power transistor M1 is connected to the first gate driving module 40 as a control terminal of the first power transistor module 10.
As an embodiment of the present application, referring to fig. 4, the second power transistor switch module 30 includes a second power transistor M2, a drain of the second power transistor M2 is connected to the second end of the primary winding of the transformer module 20 as a current input end of the second power transistor switch module 30, a source of the second power transistor M2 is connected to the negative polarity end VBUS-of the dc bus as a current output end of the second power transistor module 30, and a gate of the second power transistor M2 is connected to the second gate driving module 50 as a control end of the second power transistor module 30.
As an embodiment of the present application, the first power transistor M1 and the second power transistor M2 are both N-type MOS transistors.
Referring to fig. 6, the transformer module 20 includes a transformer T1, a primary winding of the transformer T1 is used as the primary winding of the transformer module 20, and a secondary winding of the transformer T1 is used as the secondary winding of the transformer module 20.
In this embodiment, the drain of the first power tube M1 is connected to the positive polarity terminal VBUS + of the dc bus, the source of the first power tube M1 is connected to the first terminal of the primary winding of the transformer T1, the drain of the second power tube M2 is connected to the second terminal of the primary winding of the transformer T1, and the source of the second power tube M2 is connected to the negative polarity terminal VBUS-of the dc bus.
Ideally, only when the first power tube M1 and the second power tube M2 are simultaneously turned on, a current flows through the primary winding of T1 to drive the transformer T1 to operate, but when the first power tube M1 or the second power tube M2 is separately turned on due to the parasitic capacitance Cds existing between the drain and source electrodes of the first power tube M1 and the second power tube M2, a loop for charging the parasitic capacitance Cds through the primary winding of the transformer T1 is formed, and the parasitic capacitance Cds does not disappear until the loop is filled with the parasitic capacitance Cds, and this process also transfers energy to the secondary winding of the transformer T1. For example, assume that the on-resistance of the first power tube M1 is Rds1, the drain-source parasitic capacitance of the first power tube M1 is Cds1, the on-resistance of the second power tube M2 is Rds2, and the drain-source parasitic capacitance of the second power tube M2 is Cds 2; the first power tube M1 and the second power tube M2 work in an alternating conduction mode, when the first power tube M1 is conducted, the second power tube M2 is in an off state, a charging loop is formed at this time, the charging loop is formed, the positive polarity end VBUS + of the direct current bus sequentially flows through the Rds1, the primary winding of the transformer T1, the Cds2 to the negative polarity end VBUS-of the direct current bus, the Cds1 close to zero voltage is charged, and meanwhile, the Cds1 is rapidly discharged to the zero voltage by the Rds 1; when the second power tube M2 is turned on, the first power tube M1 is in an off state, and a charging loop is formed from the positive polarity end VBUS + of the dc bus bar to the negative polarity end VBUS-of the dc bus bar, which sequentially flows through Cds1, the primary winding of the transformer T1, and Rds2, to charge Cds1 which is discharged to a voltage close to zero during the turn-on period of the first power tube M1, and at the same time, Cds2 is rapidly discharged to a voltage close to zero by Rds2, so as to prepare for forming the charging loop when the first power tube M1 is turned on. Because the charging process is completed instantly, and the charging current is reduced along with the gradual rise of the voltage of Cds1 or Cds2, the energy transferred to the secondary winding of the transformer T1 is much smaller than the working condition that the upper power tube and the lower power tube are conducted simultaneously during normal operation, and meanwhile, the working voltage of the primary winding of the transformer T1 is about 50% lower than that during normal operation, so that the peak value of the secondary rectification output voltage is about 50% lower than that during normal operation; then, the duty ratio of the gate driving signals of the first power tube M1 and the second power tube M2 is adjusted, so that the energy and the voltage transmitted to the secondary side of the transformer can be controlled.
Furthermore, the power circuit in the embodiment can also reduce the driving frequency of the gate driving signal by using a frequency hopping technology, and can further reduce the energy density transmitted to the secondary side of the transformer, so that the open-circuit voltage of the power supply is easier to control and lower in power consumption, and the adjustment of the output open-circuit voltage is realized.
As an embodiment of the present application, in cooperation with a gate driving circuit having a function of driving negative voltage generation, the first power transistor M1 and the second power transistor M2 can implement a negative voltage presetting function during an alternate conduction process, so that the first power transistor M1 and the second power transistor M2 implement reliable negative voltage shutoff. For example, taking the driving circuit of the first power tube M1 as an example, when the first original driving signal Vgs1 is at a high level, the first original driving signal Vgs1 charges the gate-source capacitor Cgs1 of the first power tube M1 through the first resistor R1, and when the first original driving signal Vgs1 is charged to be higher than or equal to the conduction voltage Vgsth of the first power tube M1, the first power tube M1 is turned on, and at the same time, the first capacitor C1 is also charged until the voltage value of the voltage regulator tube connected in parallel with the first power tube is charged, at this time, the source terminal of the first power tube M1 is positive, and the Vgs1 terminal is negative; when Vgs1 becomes low, Vgs1+ is equipotential with Vgs1 —, the gate terminal of the first power tube M1 is equipotential with Vgs1+, and since the voltage of the first capacitor C1 remains unchanged for a short time, the gate voltage of the first power tube M1 is negative with respect to the source of the first power tube M1, and the magnitude of the voltage is equal to the voltage across the first capacitor C1, and the negative voltage of the first power tube M1 is turned off, so the operation mode in which the gates of the first power tube M1 and the second power tube M2 are alternately turned on is called a negative voltage preset mode in which the gates of the power tubes are set to be negative.
In one embodiment, referring to fig. 6, the rectification and freewheeling module 60 includes: a first diode D1, a second diode D2, and a first inductor L1; an anode of the first diode D1 is connected to a first end of the secondary winding of the transformer module 20, a cathode of the first diode D1 and a cathode of the second diode D2 are commonly connected to a first end of the first inductor L1, a second end of the first inductor L1 serves as a positive polarity output end of the power circuit, and an anode of the second diode D2 is connected to a second end of the secondary winding of the transformer module 20.
In the embodiment, the secondary winding of the transformer T1, the rectifying diode (i.e., the first diode D1), the freewheeling diode (i.e., the second diode D2) and the output inductor (i.e., the first inductor L1) form a rectifying and freewheeling portion of a dual-transistor forward topology circuit, during the operation of the transformer T1, the first diode D1 is turned on in the forward direction, the second diode D2 is turned off in the reverse direction, the first inductor L1 is charged to store energy, during the intermittence of the transformer T1, the first diode D1 is turned off in the reverse direction, the second diode D2 is turned on in the forward direction to freewheel, and the first inductor L1 releases energy.
In one embodiment, referring to fig. 6, the auxiliary voltage-reducing module 80 includes: a third diode D3, a fifth resistor R5, a first switching unit S1, and an auxiliary voltage source V1; a cathode of the third diode D3 is connected to the positive output terminal of the rectification and freewheeling module 60, an anode of the third diode D3 is connected to a first terminal of a fifth resistor R5, a second terminal of the fifth resistor R5 is connected to a first terminal of a first switching unit S1, a second terminal of the first switching unit S1 is connected to a positive terminal of an auxiliary voltage source V1, and a negative terminal of the auxiliary voltage source V1 is connected to a negative output terminal of the rectification and freewheeling module 60.
In this embodiment, the auxiliary voltage-reducing module 80 utilizes an independent safety voltage source (i.e., the auxiliary voltage source V1) to output an open-circuit voltage (i.e., an auxiliary voltage) meeting the safety requirements, for example, the auxiliary voltage-reducing module 80 may be activated when an open-circuit voltage lower than the dc 36V needs to be output, and the auxiliary voltage-reducing module 80 may adjust the open-circuit voltage of the power circuit when the main power output circuit is turned off (e.g., the first power transistor M1 and the second power transistor M2 are turned off), that is, the auxiliary voltage-reducing module 80 may operate independently based on the auxiliary voltage source V1 and the first switching unit S1, or may operate cooperatively after being mixed with a negative voltage preset mode of the power circuit, so as to achieve the purpose of compositely adjusting the open-circuit voltage of the welding power supply.
As an example of the application, the first switching unit S1 may be a MOS Transistor, a Bipolar Junction Transistor (BJT), a relay contact, or the like.
In one embodiment, referring to fig. 6, the voltage regulation module 70 includes: a sixth resistor R6 and a second switching unit S2; a first terminal of the sixth resistor R6 is connected to the positive polarity output terminal of the rectification and freewheeling module 60, a second terminal of the sixth resistor R6 is connected to a first terminal of the second switching unit S2, and a second terminal of the second switching unit S2 is connected to the negative polarity output terminal of the rectification and freewheeling module 60.
In this embodiment, the voltage regulating module 70 may have two operation modes, one is to control the second switch unit S2 to be normally open, so that the sixth resistor R6 is used as a fixed load of the power output terminal, and then the duty ratio of the gate driving signals of the first power transistor M1 and the second power transistor M2 is adjusted in a closed loop in the negative preset mode to achieve the purpose of adjusting the open-circuit voltage; in the other mode, in the negative-pressure preset mode, according to the magnitude of the target open-circuit voltage, a trip frequency number and a proper duty ratio are preset for gate driving signals of the first power tube M1 and the second power tube M2, and then the second switching unit S2 is driven by a voltage control signal to control an equivalent resistor connected to the output end of the power supply, so that the open-circuit voltage is reduced, and the open-circuit voltage is adjusted.
As an embodiment of the application, the gate driving signals of the first power transistor M1 and the second power transistor M2 are pulse width modulation signals (PWM signals), wherein the gate of the first power transistor M1 is connected to the first gate driving signal, the gate of the second power transistor M2 is connected to the second gate driving signal, and the open-circuit voltage of the power circuit can be automatically adjusted by adjusting the duty ratio of the first gate driving signal and the second gate driving signal in a closed loop in the negative preset mode.
Further, as a preferred embodiment of the present application, the voltage control signal for controlling the switching state of the second switching unit S2 is a pulse width modulation signal, and the switching frequency of the second switching unit S2 can be adjusted by adjusting the duty ratio of the voltage control signal, so as to adjust the equivalent resistance that is connected to the output terminal of the power supply, thereby implementing the adjustment of the open-circuit voltage.
In one embodiment, referring to fig. 6, the second switch unit S2 includes an electronic switch, a first terminal of the electronic switch is connected to the second terminal of the sixth resistor R6, a second terminal of the electronic switch is connected to the negative polarity output terminal of the rectification and freewheeling module 60, and a control terminal of the electronic switch is connected to a voltage control signal, wherein the voltage control signal is used for controlling a switching state of the electronic switch.
As an embodiment of the present application, the electronic switch may be a MOS Transistor, a Bipolar Junction Transistor (BJT), a relay contact, or the like.
An embodiment of the present application further provides a power supply apparatus, which includes the power supply circuit described in any one of the above.
The embodiment of the application also provides an electric welding machine, which comprises the power supply circuit.
In specific implementation, the electric welding machine is an inverter electric welding machine and can be loaded and used for welding.
The embodiment of the application adopts an innovative main power driving circuit and a working mode, novel VES (auxiliary voltage reduction module 80) and OVA (voltage regulation module 70) modules, unique frequency hopping control technology, and open-circuit voltage software control strategies set for different welding process requirements, and realizes large-range adjustment of the open-circuit voltage of the welding power supply in multiple modes, thereby solving the problems that the existing welding power supply open-circuit voltage cannot meet various safety regulations and the requirements of different welding process procedures on the open-circuit voltage due to the fact that the existing welding power supply open-circuit voltage cannot be adjusted or adjusted in a limited range, and the like, and achieving the effects of avoiding the common problem that the safety regulations cannot be met and realizing the optimal configuration of arcing and arc stabilizing voltage of different welding process procedures.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-mentioned division of the functional units and modules is illustrated, and in practical applications, the above-mentioned function distribution may be performed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-mentioned functions. Each functional unit and module in the embodiments may be integrated in one processing unit, or each unit may exist alone physically, or two or more units are integrated in one unit, and the integrated unit may be implemented in a form of hardware, or in a form of software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working processes of the units and modules in the system may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.
Claims (10)
1. The method for adjusting the open-circuit voltage of the power supply is characterized in that the power supply comprises a first power tube switch module, a transformer module, a second power tube switch module and a rectification and follow current module, wherein the current input end of the first power tube switch module is connected with the positive polarity end of a direct current bus, the current output end of the first power tube switch module is connected with the first end of a primary winding of the transformer module, the current input end of the second power tube switch module is connected with the second end of the primary winding of the transformer module, and the current output end of the second power tube switch module is connected with the negative polarity end of the direct current bus;
the open circuit voltage adjustment method comprises the following steps:
driving the first power tube switch module and the second power tube switch module to be alternately conducted;
rectifying and freewheeling the voltage signal output by the transformer module through a rectifying and freewheeling module; the rectification and follow current module is connected with the secondary winding of the transformer module.
2. The open circuit voltage adjustment method according to claim 1, further comprising:
and adjusting the switching frequency of the first power tube switch module and the second power tube switch module by adopting a frequency hopping technology so as to adjust the energy transfer density of the transformer module.
3. The open circuit voltage adjustment method according to claim 1, further comprising:
and adjusting the equivalent resistance of the output end of the power supply by adopting a voltage adjusting module so as to adjust the open-circuit voltage of the power supply.
4. The open circuit voltage adjustment method according to claim 1, further comprising:
and outputting the auxiliary voltage according to the input auxiliary power supply control signal by adopting an auxiliary voltage reduction module.
5. A power supply circuit, characterized in that the power supply circuit comprises:
the current input end of the first power tube switch module is connected with the positive polarity end of the direct current bus;
the first end of the primary winding of the transformer module is connected with the current output end of the first power tube switch module;
a current input end of the second power tube switch module is connected with a second end of the primary winding of the transformer module, and a current output end of the second power tube switch module is connected with a negative polarity end of the direct current bus;
the first gate driving module is used for receiving a first original driving signal and generating a first gate driving signal according to the first original driving signal;
the second gate driving module is used for receiving a second original driving signal and generating a second gate driving signal according to the second original driving signal; the first gate driving signal and the second gate driving signal drive the first power tube switch module and the second power tube switch module to be alternatively conducted;
and the rectification and follow current module is connected with the secondary winding of the transformer module and is used for rectifying and follow current of the voltage signal output by the transformer module.
6. The power supply circuit of claim 5, wherein the power supply circuit further comprises:
and the voltage regulating module is connected with the rectifying and follow current module and is used for regulating the open-circuit voltage output by the rectifying and follow current module according to the input voltage control signal.
7. The power supply circuit of claim 5, wherein the power supply circuit further comprises:
and the auxiliary voltage reduction module is connected with the rectification and follow current module and is used for outputting auxiliary voltage according to an input auxiliary power supply control signal.
8. The power circuit of claim 5, wherein the first gate drive module comprises: the circuit comprises a first resistor, a second resistor, a first voltage regulator tube and a first capacitor;
the first end of the first resistor is connected with the positive polarity end of a first original driving signal source, the second end of the first resistor and the first end of the second resistor are connected with the control end of the first power tube switch module in a sharing mode, the second end of the second resistor, the anode of the first voltage-regulator tube and the first end of the first capacitor are connected with the negative polarity end of the first original driving signal source in a sharing mode, and the cathode of the first voltage-regulator tube and the second end of the first capacitor are connected with the first end of a primary winding of the transformer module in a sharing mode;
the second gate driving module includes: the first resistor, the second resistor, the third capacitor and the fourth capacitor are connected in series;
the first end of the third resistor is connected with the positive polarity end of a second original driving signal source, the second end of the third resistor and the first end of the fourth resistor are connected to the control end of the second power tube module in a shared mode, the second end of the fourth resistor, the first end of the second capacitor and the anode of the second voltage regulator tube are connected to the negative polarity end of the second original driving signal source in a shared mode, and the cathode of the second voltage regulator tube and the second end of the second capacitor are connected to the second end of a primary winding of the transformer module in a shared mode.
9. A power supply device for performing the open circuit voltage adjustment method according to any one of claims 1-4 or comprising a power supply circuit according to any one of claims 5-8.
10. A welding bug for performing an open circuit voltage adjustment method as claimed in any of claims 1-4 or comprising a power supply circuit as claimed in any of claims 5-8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011108421.8A CN112260546A (en) | 2020-10-16 | 2020-10-16 | Power supply open-circuit voltage adjusting method, power supply circuit, power supply device and electric welding machine |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011108421.8A CN112260546A (en) | 2020-10-16 | 2020-10-16 | Power supply open-circuit voltage adjusting method, power supply circuit, power supply device and electric welding machine |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114789285A (en) * | 2022-04-22 | 2022-07-26 | 深圳市爱达思技术有限公司 | Welding waveform generation method, device, equipment and storage medium |
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2020
- 2020-10-16 CN CN202011108421.8A patent/CN112260546A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114789285A (en) * | 2022-04-22 | 2022-07-26 | 深圳市爱达思技术有限公司 | Welding waveform generation method, device, equipment and storage medium |
| CN114789285B (en) * | 2022-04-22 | 2023-12-05 | 深圳市爱达思技术有限公司 | Welding waveform generation method, device, equipment and storage medium |
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