CN1056485C - Invertor power supply containing magnetic amplifier and method for controlling its output - Google Patents
Invertor power supply containing magnetic amplifier and method for controlling its output Download PDFInfo
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- CN1056485C CN1056485C CN98100504A CN98100504A CN1056485C CN 1056485 C CN1056485 C CN 1056485C CN 98100504 A CN98100504 A CN 98100504A CN 98100504 A CN98100504 A CN 98100504A CN 1056485 C CN1056485 C CN 1056485C
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Abstract
The present invention discloses an inverse power supply containing a magnetic amplifier, and a method for controlling the output of the inverse power supply. The magnetic amplifier 21 in the inverse power supply has the functions of reducing the switching loss of a switch element and controlling the output of the inverse power supply. A control device 3 outputs a control signal with variable frequencies so as to control the switching frequency of an inverter 12. When the switching frequency of the inverter is changed from a low frequency to a high frequency, the output of the inverter is changed from high level to a low level. The inverse power supply containing a magnetic amplifier has the advantages of little switching loss, high response speed, high output power, wide selection range of electrical inductance, etc. The present invention introduces an embodiment for welding and cutting a power supply, which is made from the power supply.
Description
The present invention relates to the inverter technical field, particularly a kind of inverter that contains magnetic amplifier.
Inverter switching device type DC power supply is called for short inverter, has plurality of advantages such as volume is little, in light weight and energy-conservation, but its when using as large power supply reliability still be not so good as the power supply of other type, so not seen widespread use so far.This is mainly to use VMOS pipe or IGBT pipe because inverter switching frequency during greater than 10KHz, constitutes the switch element of inverter, and this class switching tube is applied in the large power supply reliability still not as controllable silicon.Switching tube damages multiple reason, but switching tube is in that change on off state moment switching loss is big, and damage that cause instantaneous overload to cause accounts for considerable quantity, especially have welding or cutting power supply than high non-load voltage, as plasma welding or cutting power supply, the switch element instantaneous overload is just bigger to the reliability effect of inverter.For reducing switching loss, improve the reliability of inverter, it is a kind of effective method that magnetic amplifier is inserted inverter power circuit.Magnetic amplifier claims the saturable reactor again, its as the electro permanent magnetic control element utilize saturable core before saturated, have high inductance value and saturated after have low inductance value control power output, its operation principle is similar to controllable silicon.Magnetic amplifier is operated in the unsaturation attitude for some time in exchanging half cycle, and all the other time services are at saturated mode.Pilot angle when the unsaturation attitude duration, suitable controllable silicon was worked, because there is the dead band in magnetic amplifier, the unsaturation attitude duration can not be zero.The suitable silicon controlled angle of flow of saturated mode duration.For making to exchange in every half cycle the magnetic amplifier saturation conduction is arranged all, often magnetic amplifier is used in pairs.As magnetic amplifier is inserted in the inverter power circuit,,, therefore the switching loss of switch element is significantly descended because magnetic amplifier can not enter saturated mode at once when the switch element that constitutes inverter changes on off state constantly.Prior art is under the constant prerequisite of ac frequency, changes the saturated mode or the unsaturation attitude duration of magnetic amplifier in each cycle, thereby plays the purpose of control power output.High-power magnetic amplifier power supply can adopt the magnetic amplifier control power output of no FEEDBACK CONTROL, part internal feedback control and whole internal feedback control.The magnetic amplifier of this several types is to twine the multiturn control coil and pass to Control current on the iron core of magnetic amplifier, by regulating the magnetic saturation working point that Control current changes magnetic amplifier, reaches the purpose of control power output.This control method, not only increased the volume and weight of magnetic amplifier, and the power supply response speed is reduced, output power of power supply is big more, require the control coil number of turn many more, this contradiction is also outstanding more, so existing capacity is used power supply greater than the power supply of 2 kilovolt-amperes high power contravariant device type as welding or cutting, does not see and uses magnetic amplifier control power output.
As everyone knows, the output of inverter need connect dc inductance.Use as Arc Welding Power as inverter, the value of inductance will exert an influence to welding procedure, the welding process requirement inductance value that has more greatly, the welding procedure that has then requires the inductance value littler.Think the requirement of satisfying arc load, the outputting inductance of inverter should have the range of choice of broad.The existing inverter that uses as Arc Welding Power, the inductance value is between 25～80 microhenrys.Under some welding condition, the inertia that the inductance in this scope has electric power outputting current is difficult to satisfy the load that some requires rapid conversion output current.For example existing variable polarity welding power supply can use bridge-type or semi-bridge type inverter, as for the DC power supply of inverter power supply is an inverter, just constitute so-called two converter type sources of welding current.Primary connects first inverter, and transformer secondary output connects second inverter.The common feature of two inverter sources of welding current is in the prior art: at the output termination dc inductance of DC power supply, the effect of inductance is except the outputting inductance as first inverter, it also is the shaping of second inverter output current, obtain so-called square wave alternating-current current waveform, so the inductance value is bigger.Because the inductance storage power can not be suddenlyd change, during second inverter commutation, the turn-off power loss of the switch element of second inverter of formation is also bigger, and this is the main cause that causes inverter failure.Consider that from welding procedure the Variable Polarity power supply should change the ratio that is just connecing polarity output current duration and reversal connection polarity output current duration, also should be able to change the ratio that is just connecing polarity output current value and reversal connection polarity output current value.But because the inductive current value can not suddenly change, as the current value difference of output opposed polarity, the current value that the current value of electric current before by commutation is transformed into after the commutation needs long transit time.For overcoming this shortcoming, can adopt the power supply plan of patent US 4,180,720 disclosed two dc power supplies, shortcoming is the equipment complexity, needs two power transformers.Certainly, on the angle that adapts to load, some load request output current has bigger inertia, promptly requires power supply that bigger outputting inductance is arranged, as is used for the source of welding current or the cutting power supply of consumable electrode short circuiting transfer.But increasing inductance only is the volume and weight that has increased inverter, does not have technical problem, and reduces the problem that there is some technology soil in inductance.Inverter is continuous for keeping output current, and the bottom line of inductance value is relevant with output minimum average B configuration electric current and inverter switching frequency.Constant as output frequency, the output average current is more little, and required inductance is big more; As changing frequency, inductance value and frequency are inversely proportional to.So, for reducing inductance, can increase frequency, but increase frequency the switching loss of the switch element of inverter is increased, frequency height then switching loss is big, and the power output of inverter is big more, and the influence of switching loss is also outstanding more.Because the inverter that can regulate as power output need have the certain power adjustable range, both otherwise the switching loss when increasing the big electric current of output, the current continuity when satisfying the little electric current of output again just had been difficult to reduce the inductance value with the method that increases frequency.
The objective of the invention is: the inverter that contains magnetic amplifier of provide a kind of switching loss of switch element little, response speed is fast, power output is big and inductance numeric area is wide and control the device of this inverter output.
For achieving the above object, the unsaturation time when the present invention utilizes magnetic amplifier work is reduced the switching loss of switch element, improves the reliability of inverter.Many in order to overcome the magnetic amplifier control coil number of turn, the slow shortcoming of high-power magnetic amplifier power supply response speed, the present invention improves the control method of the inverter that contains magnetic amplifier, do not rely on the saturated or unsaturation time of adjusting magnetic amplifier in exchanging half cycle to control power output merely, but rely on magnetic amplifier and the switch element that constitutes inverter to control power output jointly.Owing in containing the inverter of magnetic amplifier, have only magnetic amplifier at saturated mode, the switch element that constitutes inverter is at conducting state, and magnetic amplifier and switch element could transmission of power.So, after the unsaturation time of magnetic amplifier and the Dead Time of inverter were determined, the switching frequency that changes inverter had promptly quite changed the time of interior magnetic amplifier of each cycle and the common conducting of switch element; The unsaturation time that also changes magnetic amplifier when perhaps, changing inverter switching frequency also can change the time of these two common conducting.The present invention is according to these character, controls the output of inverter with the method that changes inverter switching frequency, promptly exports big electric current or high voltage during low frequency, exports little electric current or low-voltage during high frequency.Because this control method need not twined the multiturn control coil on magnetic amplifier, so can improve the response speed of the inverter that contains magnetic amplifier, reduced the own wt and the cost of manufacture of magnetic amplifier again.The switching frequency that changes inverter relies on the control circuit of inverter to realize, promptly replaces the pwm circuit that has now in the inverter power source control circuit with FM circuit.FM circuit realizes that with the voltage-frequency change-over circuit characteristics of voltage-frequency change-over circuit are among the present invention: the high output frequency of control voltage is low, the low output frequency height of control voltage.This frequency modulation type inverter that is connected to magnetic amplifier of the present invention is regulated the inverter of power output and is compared with the prior PWM mode, can more select inductance value in the wide region, to adapt to the unequally loaded requirement.Though this is because outputting inductance can have different design principles, only consider that inductance upper limit value can be different different because of load characteristic from the angle that satisfies load request, electric current was continuous when the lower limit value generally will guarantee power supply output minimum average B configuration electric current.According to this principle, constant as the switching frequency of inverter, output current is more little, and inductance just should be big more; As changing the switching frequency of inverter, inductance value and frequency are inversely proportional to so.So, be to reduce inductance value, must improve the switching frequency of inverter, but switching frequency when improving the switching loss of switch element also increase thereupon, be restricted so improve frequency.On the other hand, to not connecing the inverter of magnetic amplifier, the little switching loss that also will increase switch element of the value of inductance.Inverter of the present invention not only can utilize magnetic amplifier to reduce switching loss, and is by the frequency modulation control power output, promptly exports big electric current during low frequency, and power supply does not increase switching loss when exporting big electric current; Export little electric current during high frequency, current continuity was good when power supply was exported little electric current, therefore can reduce inductance lower limit value effectively.As electric power output voltage 50V, minimum average B configuration electric current 10A, load pressure drop 10V, frequency is 100KHz during output minimum average B configuration electric current, allowing the minimum value of dc inductance is 5 μ H.The output cable length of the general source of welding current is not less than 3m, and the distributed inductance of cable is about 4～5 μ H.Promptly with this understanding, adopt inverter of the present invention, satisfy some requirement of arc load, can cancel dc inductance, and only utilize the distributed inductance of cable just passable as desire.As in two inverter variable polarity welding power supplies, adopt the above-mentioned frequency modulation type inverter that is connected to magnetic amplifier with low outputting inductance as being the DC power supply of second inverter power supply in two inverter power supplies, the switch element of second inverter is changing on off state constantly, because the inductance energy stored is low, the turn-off power loss of switch element also decreases, after the output current commutation, the climbing speed of electric current is proportional to the floating voltage of power supply and the ratio of inductance, as power supply floating voltage 50V, load pressure drop 10V, inductance is 5 μ H, and the electric current initial ramp rate is about every microsecond 8A.These data can satisfy the requirement of rapid conversion output current, and do not need two power transformers.Certainly, as it is constant to desire to keep the electric current climbing speed, improves floating voltage, the also corresponding raising of inductance value.
Technical scheme of the present invention is: the inverter that contains magnetic amplifier is made of DC power supply, inverter, voltage changer, AC/DC converting means and control device.DC power supply is generally obtained through current rectifying and wave filtering circuit by electrical network; Inverter is connected between DC power supply and the voltage changer, and the direct current that the DC power supply power supply is exported converts high-frequency alternating current to; Voltage changer is connected between inverter and the AC/DC converting means; The AC/DC converting means is connected between voltage changer and the power transmitting device, and the high-frequency alternating current that voltage changer is exported is converted to direct current; Power transmitting device is connected between load and the AC/DC converting means, and the direct current that the AC/DC converting means is exported transfers to load.Voltage changer is made of magnetic amplifier and transformer, magnetic amplifier be connected between primary and the inverter or be connected on transformer secondary output and the AC/DC converting means between.Control device is connected with inverter, the power output of control inverter, control device produces the control signal of changeable frequency, control signal is added in the control end of inverter switch element, be used for the switching frequency of control inverter, the power output of inverter is controlled by the switching frequency of inverter, and the power output of inverter and the switching frequency of inverter are inversely proportional to.
The output current of control device control inverter, it also is connected with the AC/DC converting means, and the output current of inverter is controlled by the switching frequency of inverter, is inversely proportional to the switching frequency of inverter.
The variation of the switching frequency of control device control inverter is between 20KHz～125KHz.
The present invention is further detailed explanation below in conjunction with drawings and Examples.
Fig. 1 is the inverter schematic diagram of open loop control of the present invention.
Fig. 2 is the inverter schematic diagram of closed-loop control of the present invention.
Fig. 3 is the schematic diagram of of the present invention pair of inverter power supply.
Fig. 4 is the schematic diagram of the two inverter power supplies that can regulate respectively of positive reversal connection polarity output current of the present invention.
Fig. 5, Fig. 6 are that magnetic amplifier of the present invention is connected on schematic diagram and the power supply output external characteristic among the inverter embodiment of primary, open loop control.
Fig. 7 to Fig. 9 is that magnetic amplifier of the present invention is connected on primary, schematic diagram, magnetic amplifier method for winding and power supply output external characteristic among the inverter embodiment of closed loop current control.
Figure 10 is that magnetic amplifier of the present invention is connected on primary, is used for the inverter output external characteristic of air plasma cutting.
Figure 11 to Figure 14 is that magnetic amplifier of the present invention is connected on transformer secondary output, schematic diagram, magnetic amplifier method for winding and power supply output external characteristic among the inverter embodiment of employing voltage close loop feedback.
Figure 15 to Figure 19 is of the present invention pair of schematic diagram and the power supply output external characteristic in the inverter power supply.
The inverter of open loop shown in Figure 1 control is by DC power supply 11, inverter 12, and voltage changer 2, control device 3 and AC/DC converting means 4 constitute.Voltage changer 2 is made of transformer 22 and magnetic amplifier 21, and magnetic amplifier can be connected between the elementary and inverter 12 of transformer 22, also can be connected between transformer secondary output and the AC/DC converting means 4.Power transmitting device 6 joins with AC/DC converting means 4.
Fig. 2 is the inverter with closed loop feedback character.Can select the output current of AC/DC converting means 4 or voltage output variable among Fig. 2 as power-supply system, between AC/DC converting means 4 and control device 3, set up closed loop current negative feedback or voltage negative feedback, make power supply have the character of current source or voltage source.
As shown in Figure 3, with respect to single inverter, the direct current that two inverter power supplies have just increased by 5 pairs of previous inverter outputs of second DC-to-AC converter carries out the secondary inversion, direct current is converted to be fit to the alternating current that welding procedure is used.The present invention uses Fig. 1 or inverter shown in Figure 2 as first inverter in two inverters.Two inverters shown in Figure 3 are to adopt the current source with Current Negative Three-Point Capacitance character shown in Figure 2 as first inverter.
Fig. 4 is two inverter power supply schematic diagrams that positive reversed polarity output current can be regulated respectively.The output current of the positive reversal connection polarity of control device 3 controls among Fig. 4, its function are that control device 3 can be exported the signal of different frequency, controls the size of opposed polarity output current respectively when the electric current of power supply output opposed polarity.Output current can adopt open loop or closed-loop control, and this figure is the schematic diagram that adopts closed loop current control.As adopt open loop control, disconnect between AC/DC converting means 4 and the control device 3.
Fig. 5 is the inverter embodiment that magnetic amplifier is connected on primary, open loop control.Its schematic diagram is seen Fig. 1.In Fig. 5, DC power supply 11 input AC 220V line voltages.Inverter 12 is a full-bridge inverter.Magnetic amplifier 21 adopts two amorphous annular cores, and core section is 0.35cm
2, iron circuit length is 17.3cm, turn number N
1Be 15N; N
2Be 15N.R is 10 Ω.22 level floating voltages of transformer are 65V.AC/DC converting means 4 is made of rectification circuit 41 and inductance 42, and inductance value is 10 μ H.The cable of output device 6 is long to be 4m.Control device 3 is made of inverter driving circuit 32, voltage-frequency change-over circuit 31, output control circuit 33.Output control circuit 33 output control voltages, control voltage converts frequency signal to through voltage-frequency change-over circuit 31, when control voltage changes from low to high, the signal frequency of voltage-frequency change-over circuit 31 outputs changes from high to low, and the frequency signal of voltage-frequency change-over circuit 31 outputs is fed to the switching frequency of the control end control inverter 12 of the controllable switch element that constitutes inverter 12 after drive circuit 32 is isolated amplification.When the switching frequency of inverter changes from high to low, the ascending variation of the power output of inverter.In voltage-frequency change-over circuit 31, resistance R
1: 10K Ω; R
2: 10K Ω; R
3: 20K Ω; R
4: 10K Ω; R
5: 2K Ω; Adjustable resistance W
1: 2K Ω; W
2: 40K Ω; W
3: 40K Ω; Capacitor C
1: 1000pF; C
2: 1000pF; C
3: 1 μ F; C
4: 200pF; C
5: 200pF; T
1Be metal-oxide-semiconductor, I
C1Comparator; I
C2Be operational amplifier; I
C3Be d type flip flop, I
C3Export two groups of signals that phase place is opposite; I
C4Be two inverters; I
C5Be two with door.The a of voltage-frequency change-over circuit 31 outputs and c signal and drive circuit 32 output A and C signal same-phases; The B and the D signal same-phase of the b of voltage-frequency change-over circuit 31 outputs and d signal and drive circuit 32 outputs.Regulate the Dead Time that variable resistor W2 and W3 can set inverter 12.Generator characteristic curve under three different frequency conditions shown in Figure 6.Frequency condition is respectively: 1. frequency is 100KHz, and 2. frequency is 50KHz, and 3. frequency is 20KHz.This example can be used as the manual electric arc welding power supply.
Fig. 7 to Fig. 9 is the embodiment of schematic diagram shown in Figure 2.This example is to adopt the current source of closed loop current feedback.In this example, DC power supply 11 input AC 220V line voltages.Inverter 12 adopts full-bridge inverter.Magnetic amplifier 21 adopts two annular amorphous iron cores, and core section is 0.35cm
2, iron circuit length is 17.3cm.The magnetic amplifier coil is divided into Nc and Nd two parts among the figure, and Nc flows through symmetrical alternating current, and Nd flows through half-wave rectified current, Nc
1: 30N; Nc
2: 30N; Nd
1: 15N; Nd
2: 15N.22 level output of transformer floating voltage is 50V.The cable of output device is long to be 4m.AC/DC converting means 4 is made of rectification circuit 41, current measuring device 43, and this example does not connect inductance 42.Control device 3 is by inverter driving circuit 32, voltage-frequency change-over circuit 31, and current control circuit 331, error amplifier 36 constitutes.The control voltage that the measurement signal voltages of current measuring device 43 output and current control circuit 331 are exported after error amplifier 36 computings output voltage to voltage-frequency change-over circuit 31, the current source that this example is become have Current Negative Three-Point Capacitance character.Fig. 8 a, Fig. 8 b are two kinds of method for winding realizing this routine magnetic amplifier.Shown in Fig. 8 a, the Nc coil twines two iron cores, Nd simultaneously with a lead
1, Nd
2Coil is to twine separately iron core, Nd respectively with two leads
1, Nd
2With the intersection of Nc a public wiring point is arranged.In Fig. 8 b, Nc
1, Nc
2The number of turn of coil is to twine two iron cores, Nd simultaneously with two leads
1, Nd
2The number of turn of coil is to have twined Nc at these two leads
1, Nc
2After the number of turn, twine one of them iron core more separately.Fig. 9 is this exception characteristic curve of output, output current adjustable range: 10A～130A.Frequency range: 125KHz～20KHz.This example can be used as the DC TIG welding power supply.Among Fig. 7, Fig. 8 a and Fig. 8 b the 210, the 211st, node number.
Inverter adopts power principle figure shown in Figure 2 as the embodiment that air plasma cuts with power supply.In Fig. 2, DC power supply 11 input AC 220V line voltages, inverter 12 adopts full-bridge inverter, and magnetic amplifier 21 adopts magnetic amplifier shown in Figure 5, and the magnetic amplifier core section is 0.35cm
2, iron circuit length is 17.3cm, the magnetic amplifier turn number N
1: 65N; N
2: 65N.R：10Ω。It is elementary that magnetic amplifier is connected on transformer 22.Transformer secondary output floating voltage: 200V.AC/DC converting means 4 is made of rectification circuit 41, inductance 42 and current measuring device 43.Inductance 42 is 625 μ H.Control device 3 is identical with control device 3 among Fig. 7.Cable is long to be 4m.The power supply output external characteristic is seen Figure 10.Current Regulation scope: 10A～30A.Frequency range: 100KHz～20KHz.
Figure 11 to Figure 14 is another embodiment that adopts Fig. 2 schematic diagram.These routine DC power supply 11 input AC 220V line voltages.Inverter 12 is a full-bridge inverter.Transformer 22 has two pairs of outputs except that centre cap, the relative centre cap of output end voltage is respectively 48V and 84V.This routine magnetic amplifier 21 has two pairs of magnetic amplifiers.A pair of magnetic amplifier is connected with transformer 48V output, and another is connected with transformer 84V output magnetic amplifier.The magnetic amplifier winding parameter that is connected with transformer 84V output is: Nc
1: 4N; Nc
2: 4N; Nd
1: 1N; Nd
2: 1N.Core section is 0.35cm
2, iron circuit length is 10.1cm.Method for winding is seen Figure 13.The magnetic amplifier winding parameter that is connected with transformer 48V output is: N
11: 2N; N
12: 2N; N
21: 20N; N
22: 20N.Core section: 0.35cm
2, iron circuit length: 17.3cm, method for winding is seen Figure 12.This routine AC/DC converting means 4 is made of rectification circuit 41, inductance 42 and voltage measuring apparatus 43.Inductance 42 is 20 μ H.Power transmission cable is long to be 3m.Control device 3 is made of inverter driving circuit 32, voltage-frequency change-over circuit 31, voltage control circuit 332, error amplifier 36.The control voltage of the voltage measurement signal of voltage measuring apparatus 43 outputs and voltage-operated device 332 outputs output voltage after error amplifier 36 computings becomes this example and has the voltage source that voltage negative is fed back character to voltage-frequency change-over circuit 31.Magnetic amplifier operation principle shown in Figure 12 is identical with Fig. 8 a, 8b, and just winding method is had any different.Among Figure 12, use two leads to twine Nc
1, Nd
1And Nc
2, Nd
2Because D
1And D
2Be the rectifying tube of transformer secondary output, D
1And D
2Can only be common cathode or common anode connection, twine Nc
1And Nc
2Should make D during coil
1Flow direction that in iron core, produces during conducting and D
2The flow direction that produces in iron core during conducting is opposite.For the purpose of difference, two leads are drawn with heavy line and fine line respectively.Twine Nc
1, Nc
2The number of turn be to twine two annular cores with opposite direction with two leads, twine Nd
1, Nd
2Twine an iron core separately with one in these two leads during the number of turn of coil.N among Figure 13
11, N
12Winding method and the Nc among Figure 12
1, Nc
2Winding method identical.For preventing N
11Or N
12In when the electric current at N
21And N
22On induce high voltage, N
21And N
22Coil is cascaded, N
21Induced voltage direction on the coil should with N
22Induced voltage direction on the coil is opposite.Figure 14 is this routine output external characteristic, and the voltage-regulation scope is 15V～24V; Frequency range is 20KHz～100KHz.In Figure 11～13 the 210,220,221,222,223, the 410th, node number.This example can be used as the source of welding current of consumable electrode short circuiting transfer.
The two inverter power supplies of Variable Polarity shown in Figure 15 adopt the schematic diagram of Fig. 4.Because this example adopts open loop control output current, does not have between AC/DC converting means 4 and the control device 3 and gets in touch.In this example, DC power supply 11 input AC 220V line voltages.Inverter 12 is a full-bridge inverter.Transformer secondary output output voltage: 95V.The parameter of magnetic amplifier 21 is: Nc
1: 5N; Nc
2: 5N; Nd
1: 3N; Nd
2: 3N.Coil winding methods is identical with Figure 12.Adopt annular amorphous iron core, core section is 0.35cm
2, iron circuit length is 17.3cm.AC/DC converting means 4 is made of rectification circuit 41 and inductance 42.Rectification circuit 41 adopts 4 rectifying tubes, exports two the tunnel and has the DC power supply of common point.Inductance 42 is 10 μ H.Second DC-to-AC converter 5 is made of half-bridge inverter circuit 51, drive circuit 52, rectangle square wave generation circuit 53.Rectangle square wave generation circuit 53 generation frequency adjustable, the rectangle square wave voltage signal that pulse duration is adjustable, switching frequency and two switch transistor T of two switching tubes of this signal in drive circuit 52 control half-bridge inverter circuit 51
51, T
52The ratio of ON time.Control device 3 constitutes by just connecing polarity current control circuit 34, reversal connection polarity current control circuit 35, analog switch circuit 37, voltage-frequency change-over circuit 31 and inverter driving circuit 32.When power supply output is just connecing the polarity electric current, analog switch circuit 37 will just connect polarity current control circuit 34 and connect with voltage-frequency change-over circuit 31, and control is just connecing the polarity output current; When power supply output reversal connection polarity electric current, analog switch circuit 37 is connected reversal connection polarity current control circuit 35 and voltage-frequency change-over circuit 31, the output current of control reversal connection polarity.This routine analog switch circuit 37 is by metal-oxide-semiconductor T
31, T
32And Schottky tube D
31, D
32And inverter Ic constitutes T
31T in the control signal of a end and second inverter circuit
51The signal same-phase of pipe control end A end; T
32The control signal and the T of b end
52The control signal same-phase of pipe control end B end.Work as T
51Logical, T
52When ending, output reversal connection polarity electric current, T at this moment
31Conducting, T
32End; Work as T
52Logical, T
51When ending, T
32Conducting, T
31End, this moment, output just connect the polarity electric current.Figure 16 is this routine power supply output external characteristic.This example can be used as Variable Polarity and exchanges the microplasma power supply, and the Current Regulation scope is 5A～100A.Frequency range: 20KHz～100KHz.Article three, the frequency of external characteristic curve correspondence is respectively: 1. 100KHz; 2. 33KHz; 3. 20KHz.Figure 17 is the another kind of connection of half-bridge inverter 51 and plasma gun among Figure 15.In Figure 17 and Figure 15, the 7th, electrode, the 8th, welded piece, the 9th, plasma gun nozzle.The advantage of Figure 17 is when the two inverter power supply output of Variable Polarity reversal connection polarity electric current, because nozzle 9 is as anode, so can reduce the scaling loss degree of tungsten electrode effectively.Among Figure 17, D
51And D
52Be diode.The long 4m of this routine output cable.
Adopt another embodiment of shown in Figure 4 couple of inverter Variable Polarity power principle figure to see Figure 18.This example is a Variable Polarity argon tungsten-arc welding power supply.The character of first inverter and power supply output external characteristic are identical to inverter shown in Figure 9 with Fig. 7 in this example.In the drawings, DC power supply 11, inverter 12, magnetic amplifier 21, transformer 22, rectification circuit 41, current measurement circuit 43, error amplifier 36, voltage-frequency change-over circuit 31, drive circuit 32 and Fig. 7 to Fig. 8 a, 8b illustrated embodiment are identical, and generator characteristic is identical with Fig. 9.It is identical with Figure 15 embodiment just to connect polarity current control circuit 34, reversal connection polarity current control circuit 35, analog switch circuit 37.Rectangle square wave generation circuit 53, drive circuit 52 character are identical with Figure 15 embodiment, and just drive circuit 52 and rectangle square wave generation circuit 53 drive four switching tubes of full-bridge inverter for full-bridge inverter 51 provides two pairs of opposite signals of signal phase.When the output of Variable Polarity power supply is just connecing the polarity electric current, analog switch circuit 37 will just connect polarity current control circuit 34 and connect with error amplifier 36, output voltage is to voltage-frequency change-over circuit 31 after error amplifier 36 computings just to connect the control voltage of polarity current control circuit 34 outputs and the current signal voltage of current measurement circuit 43 outputs, and control is just connecing the polarity output current; When Variable Polarity power supply output reversal connection polarity electric current, analog switch circuit 37 is connected reversal connection polarity current control circuit 35 and error amplifier 36, control reversal connection polarity output current.The long 4m of this routine cable, inverter 12 frequency ranges are 20KHz～125KHz.
Figure 19 is the embodiment that adopts shown in Figure 3 pair of inverter schematic diagram.Adopt embodiment shown in Figure 7 as first inverter in two inverter power supplies among Figure 19, generator characteristic is identical with Fig. 9.
The main magnetic property of used magnetic amplifier iron core in the embodiment of the invention: saturated magnetic strength Bs=0.58T, squareness ratio Br/Bs 〉=0.9, coercivity H≤0.4A/m.The Dead Time that full-bridge inverter 12 adopts among the embodiment: 2.5 μ S.
In sum, because the present invention inserts inverter with magnetic amplifier, so inverter has reliably The property height, the advantage that the switching loss of switch element is little; Because the present invention contains magnetic amplifier with the control of frequency modulation method Inverter output is so power supply has the advantage of fast response time; Because frequency modulation method of the present invention is inversion The switching frequency of power supply is low, and output current is big; The switching frequency height of inverter, output current is little, so Inverter can be exported relatively high power and can select outputting inductance in wider scope.
Claims (4)
1. inverter that contains magnetic amplifier, it is made of DC power supply (11), inverter (12), voltage changer (2), AC/DC converting means (4) and control device (3), inverter (12) is connected between DC power supply (11) and the voltage changer (2), voltage changer (2) is connected between inverter (12) and the AC/DC converting means (4), and power transmitting device (6) is connected between AC/DC converting means (4) and the load;
Inverter (12) is converted to high-frequency alternating current with the direct current of DC power supply (11) output;
AC/DC converting means (4) is converted to direct current with the high-frequency alternating current of voltage changer (2) output;
Power transmitting device (6) transfers to load with the direct current of AC/DC converting means (4) output;
It is characterized in that:
Said voltage changer (2) is made of magnetic amplifier (21) and transformer (22), and magnetic amplifier (21) is connected between the elementary and inverter (12) of transformer (22);
The power output of said control device (3) control inverter, it is connected with inverter (12); Control device (3) produces the switching frequency of the control signal control inverter (12) of changeable frequency, and the power output of inverter is controlled by the switching frequency of inverter (12), and the switching frequency of the power output of inverter and inverter (12) is inversely proportional to.
2. as the said inverter that contains magnetic amplifier of claim 1, it is characterized in that: wherein said magnetic amplifier (21) is connected between the secondary and AC/DC converting means (4) of transformer (22).
3. as claim 1 or the 2 said inverters that contain magnetic amplifier, it is characterized in that: the output current of said control device (3) control inverter, it also is connected with AC/DC converting means (4), the output current of inverter is controlled by the switching frequency of inverter (12), and the switching frequency of the output current of inverter and inverter (12) is inversely proportional to.
4. as claim 1 or the 2 said inverters that contain magnetic amplifier, it is characterized in that: said control device (3) control inverter (12) switching frequency, frequency range is between 20KHz～125KHz.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN98100504A CN1056485C (en) | 1998-02-10 | 1998-02-10 | Invertor power supply containing magnetic amplifier and method for controlling its output |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN98100504A CN1056485C (en) | 1998-02-10 | 1998-02-10 | Invertor power supply containing magnetic amplifier and method for controlling its output |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1187064A CN1187064A (en) | 1998-07-08 |
| CN1056485C true CN1056485C (en) | 2000-09-13 |
Family
ID=5216064
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN98100504A Expired - Fee Related CN1056485C (en) | 1998-02-10 | 1998-02-10 | Invertor power supply containing magnetic amplifier and method for controlling its output |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1056485C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101179895B (en) * | 2007-12-06 | 2011-04-27 | 刘耘思 | AC magnetic controlled power regulation electrical inductance ballast |
| US20200306890A1 (en) * | 2019-03-27 | 2020-10-01 | The Esab Group Inc. | Multi-process welding and cutting machine |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4180720A (en) * | 1978-06-15 | 1979-12-25 | Hobart Brothers Company | Welding power supply |
| US4716515A (en) * | 1984-06-04 | 1987-12-29 | Solar Refining, Inc. | Switched capacitor induction motor drive |
-
1998
- 1998-02-10 CN CN98100504A patent/CN1056485C/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4180720A (en) * | 1978-06-15 | 1979-12-25 | Hobart Brothers Company | Welding power supply |
| US4716515A (en) * | 1984-06-04 | 1987-12-29 | Solar Refining, Inc. | Switched capacitor induction motor drive |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1187064A (en) | 1998-07-08 |
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