CN1381943A

CN1381943A - Supply unit

Info

Publication number: CN1381943A
Application number: CN02118111A
Authority: CN
Inventors: 京极章弘
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2001-04-17
Filing date: 2002-04-17
Publication date: 2002-11-27
Anticipated expiration: 2022-04-17
Also published as: KR20020081083A; CN1221071C; CN2590271Y; KR100418127B1

Abstract

A power supply device, provided with a switch SW1 connected between one input terminal of a rectifier circuit 2 and a connection point between capacitors 4 and 5 for voltage doubler rectification, and a switch SW1 connected to the other input terminal of the rectifier circuit 2 and capacitors 4 and 5 for voltage doubler rectification. Switch SW2 between the connection point between capacitors 4,5. In operation mode 1, the control switch SW1 is continuously turned on from the zero-crossing moment of the power supply voltage, only during the conduction period corresponding to the output voltage change, and the control switch SW2 is always turned off. In the operation mode 2, the control switch SW1 is continuously turned on from the zero-crossing time of the power supply voltage, only during the conduction period corresponding to the output voltage change, and the control switch SW2 is always turned on.

Description

Supply unit

Technical field

The present invention relates to a kind of supply unit that certain AC power is transformed into desired DC power supply.

Background technology

At the supply unit that is used for electric equipments such as aircondition, be necessary to solve requirement for restriction to high order harmonic component, as a kind of method that solves this high order harmonic component restriction, in the spy opens flat 10-111028 number bulletin, a kind of method of using active filter to improve power factor is disclosed.By active filter, can reach when improving power factor, can realize the effect of boosting of supply voltage by way of parenthesis.But there is the problem that circuit scale increases, manufacturing cost increases in its reverse side.

So,, open in 2000-188867 number bulletin the spy and to record and narrate to some extent as the technology that realizes with simple formation with the active filter effect same.Figure 14 represents that its circuit constitutes.As shown in figure 14, supply unit comprises: be connected between the input of rectification circuit 2, between the tie point between the mid point that make short circuit or the switch SW 11 that opens circuit between this input, is connected the diode bridge that constitutes rectification circuit 2 and the voltage multiplying

rectifier usefulness capacitor

4,5, the switch SW 12 that makes short circuit between 2 or open circuit.

In this supply unit, make switch SW 11 conductings, disconnection by control impuls width (PWM), realized identical power factor and the boost function of improving when using active filter.And, by by the conducting of switch SW 12, the switching that full-wave rectification and voltage multiplying rectifier are implemented in disconnection, enlarged the variable range of output voltage.Also promptly, by when load is less, switch SW 12 is disconnected move, and when load is bigger, switch SW 12 conductings are moved in the voltage multiplying rectifier mode, thereby enlarged the variable range of output voltage with way of full-wave rectification.

But supply unit shown in Figure 14 exists the following stated problem.

Because switch SW 11 is controlled by pulse duration, and the carrier frequency of pulse duration control at this moment to compare with supply frequency be very high frequency, so the problem of high-frequency noise occurred producing.Therefore, just need other filter circuit, thereby caused the increase of manufacturing cost as the noise reduction countermeasure.In addition, when carrying out the switching of full-wave rectification and voltage multiplying rectifier by switch SW 12, the change of output voltage is big.Just, exist pattern will switch preceding output voltage, and the big problem of the voltage difference between the output voltage after the firm switching.

Summary of the invention

The invention provides a kind of supply unit, its purpose is to solve the above problem, improves power factor with simple formation, and satisfies the requirement for restriction to high order harmonic component.In the sudden change of carrying out suppressing when pattern is switched output voltage.

Supply unit of the present invention comprises: have two inputs and two outputs, be connected with AC power by reactor, AC supply voltage is transformed to the rectification circuit of direct voltage; Form by a plurality of capacitors that are connected in series, be connected the capacitor circuit between two outputs of rectification circuit; Be connected an input of rectification circuit, and the 1st switching device between the tie point between the capacitor in the capacitor circuit; Be connected another input of rectification circuit, and the 2nd switching device between the same tie point between the capacitor in the described capacitor circuit.

Supply unit can also comprise by any one pattern in the 1st and the 2nd pattern, controls the described the 1st and the control device of the 2nd switching device.At this moment, in the 1st pattern, control the 1st switching device, in the half period of supply voltage, only conducting continuously in the 1st conduction period that the output voltage with supply unit changes often disconnects and control the 2nd switching device.In the 2nd pattern, control the 1st switching device, in the half period of supply voltage, only conducting continuously in the 1st conduction period that the output voltage with supply unit changes, and control the conducting often of the 2nd switching device.

When the 1st conduction period during greater than set-point, control device also can be controlled the pattern that the 1st and the 2nd switching device is adopted with being used to, and switches to the 2nd pattern from the 1st pattern.

In addition, when described the 1st conduction period vanishing, control device also can be controlled the pattern that the 1st and the 2nd switching device is adopted with being used to, and switches to the 1st pattern from the 2nd pattern.

In addition, be zero when described the 1st conduction period, and keep this state that control device also can be controlled the pattern that the 1st and the 2nd switching device is adopted with being used to, and switches to the 1st pattern from the 2nd pattern through after preset time.

In addition, when the control of described the 2nd pattern surpasses preset time constantly, and during the 1st conduction period vanishing, control device also can switch to the 1st pattern with the 2nd pattern.

In addition, in the half period of power supply, control device also can further be provided with and be different from the 2nd conduction period the 1st conduction period, that make the 1st switching device conducting.

Control device also can carry out the conducting of the 2nd switching device constantly and disconnect switching in the zero crossing of supply voltage.

Control device also can begin for the 1st conduction period constantly in the zero crossing of supply voltage.

Control device also can begin for the 1st conduction period after the zero crossing of supply voltage is passed through preset time constantly.

The 2nd switching device also can be made of relay.

In addition, the pattern that in supply unit, also can be set as follows.Just, in described the 1st pattern, control the 1st switching device, in the half period of supply voltage, only conducting continuously in the 1st conduction period that the output voltage with supply unit changes often disconnects and control described the 2nd switching device.In the 2nd pattern, make the conducting often of the 1st switching device, and control the 2nd switching device, in the half period of supply voltage, only conducting continuously in the 2nd conduction period that the output voltage with supply unit changes.

And, the also pattern that can be set as follows.Just, in the 1st pattern, than also short cycle half period of supply voltage as carrier cycle, the 1st switching device is carried out pulse duration control, often disconnect and control the 2nd switching device.In the 2nd pattern,, the 1st switching device is carried out pulse duration control, and control the conducting often of the 2nd switching device with this carrier cycle.

In addition, control device also can make the variable quantity of the 1st conduction period that is equivalent to the supply voltage half period in the 1st pattern, greater than the variable quantity of the 2nd pattern.

And when a kind of mode switch from the 1st or the 2nd pattern was another kind of pattern, control device also can be in the half period of supply voltage or during greater than this half period, made after the 1st and the 2nd switching device temporarily disconnects together, the change action pattern again.

Description of drawings

Fig. 1 is for the circuit diagram of supply unit principle of the present invention is described.

Fig. 2 is the circuit diagram that the supply unit of the expression embodiment of the invention 1 constitutes.

Fig. 3 is the oscillogram ((a) output voltage, (b) change in duty cycle of switch SW 1, (c) conducting/off-state of switch SW 2) of a kind of pattern (with duty ratio 100% switch mode) of the supply unit of explanation embodiment 1.

Fig. 4 is illustrated in the pattern 1 of supply unit of embodiment 1, conducting/the disconnection of switch, graph of a relation (waveform such as (a) output voltage with various waveforms (waveforms such as supply voltage, output voltage, input current), (b) control impuls of switch SW 1, (c) control impuls of switch SW 2).

Fig. 5 is illustrated in the pattern 2 of supply unit of embodiment 1, conducting/the disconnection of switch, graph of a relation (waveform such as (a) input current with various waveforms (waveforms such as supply voltage, output voltage, input current), (b) control impuls of switch SW 1, (c) control impuls of switch SW 2).

Fig. 6 is the input current waveform figure of a kind of pattern of the supply unit of expression embodiment 1 when switching waveforms such as (, (b) change in duty cycle of switch SW 1, (c) conducting/off-state of switch SW 2) (a) input currents.

Fig. 7 is the oscillogram ((a) output voltage, (b) change in duty cycle of switch SW 1, (c) conducting/off-state of switch SW 2) of another kind of pattern (with duty ratio 90% switch mode) of the supply unit of explanation embodiment 1.

Fig. 8 is the input current waveform figure of the another kind of pattern of the supply unit of expression embodiment 1 when switching waveforms such as (, (b) control impuls of switch SW 1, (c) conducting/off-state of switch SW 2) (a) input currents.

Fig. 9 is the oscillogram ((a) output voltage, (b) change in duty cycle of switch SW 1, (c) conducting/off-state of switch SW 2) of a kind of pattern (with duty ratio 100% switch mode) of the supply unit of explanation embodiment 2.

Figure 10 is the oscillogram ((a) output voltage, (b) change in duty cycle of switch SW 1, (c) change in duty cycle of switch SW 2) of another kind of pattern (with duty ratio 90% switch mode) of the supply unit of explanation embodiment 2.

Figure 11 is 2 pulse controlled oscillograms waveforms such as (, (b) control impuls of switch SW 1, (c) conducting/off-state of switch SW 2) (a) input currents of the supply unit of explanation embodiment 3.

Figure 12 is a kind of pattern of the supply unit of expression embodiment 4 input current waveform figure waveforms such as (, (b) change in duty cycle of switch SW 1, (c) conducting/off-state of switch SW 2) (a) input currents of (switching to pattern 2 from pattern 1) when switching.

Figure 13 is a kind of pattern of the supply unit of expression embodiment 4 input current waveform figure waveforms such as (, (b) change in duty cycle of switch SW 1, (c) conducting/off-state of switch SW 2) (a) input currents of (switching to pattern 1 from pattern 2) when switching.

Figure 14 is existing supply unit circuit diagram.

Symbol description among the figure

1-AC power; 2-rectification circuit; 3-reactor; 4,5,11-capacitor; 8-load; 12-power phase test section; 13-pulse duration control part; 14-relay ON/OFF control part; 15-output voltage test section; SW1, SW2-switch.

Embodiment

Below, the embodiment to supply unit of the present invention at length is illustrated with reference to accompanying drawing.

Embodiment 1

As shown in the drawing, supply unit comprises: through the voltage of reactor 3 input ac powers 1 and the rectification circuit 2 that carries out rectification; Voltage multiplying

rectifier capacitor

4,5; Connect each half-bridge mid point of rectification circuit 2 and switch SW 1, the SW2 that voltage multiplying rectifier is used the tie point between the capacitor 4,5.Supply unit will be from the voltage commutation that exchanges power supply 1, and to the direct voltage of the desired size of load 8 outputs.In load 8, comprise and be used for driving the compressor of aircondition, refrigerator etc. or the transformer of the employed d.c. motor of washing machine etc.

Rectification circuit 2 is made up of the half-bridge of two diodes.Capacitor 4 is connected in series with capacitor 5, and is connected the output of rectification circuit 2.Switch SW 1, SW2 are connected to each input (mid point of each half-bridge of rectification circuit 2) of rectification circuit 2, and between the tie point between capacitor 4 and the capacitor 5.In addition, voltage multiplying rectifier is not limited to 2 with capacitor, and even number can be set.

The supply unit of Gou Chenging as mentioned above, the conducting of corresponding switch SW 1, SW2 and the state of disconnection are in two kinds of patterns (pattern 1, pattern 2) action down.(a) pattern 1: switch SW 2 is controlled under the state that often disconnects, and switch SW 1 is controlled by pulse duration.In pattern 1, can obtain being approximately supply voltage Doubly arrive

The output voltage of times scope.(b) pattern 2: switch SW 2 is in conducting often or be subjected under the state of pulse duration control, and switch SW 1 is controlled by pulse duration.In pattern 2,, just can obtain greater than supply voltage owing to become the circuit of voltage doubling rectifing circuit form to constitute Output voltage doubly.

The pulse duration control of switch SW 1, SW2 is by control the pulse duration of the control impuls of their output to be carried out.At this, control impuls only is output one in the half period of each supply voltage.Below, the switch control of only being exported a pulse this each half period calls " 1 pulse control ".This 1 pulse control with the carrier cycle of pulse width control, the control when being set at half period of supply voltage is identical.

In 1 pulse control, based on 2 times the 100Hz or the such low speed switch action of 120Hz of supply frequency.Thereby, the not speed-sensitive switch of tens kHz as active filter action, the noise that is produced is little.Therefore, can simplify the circuit that is used for the noise reduction countermeasure, the advantage that no matter have aspect the space, still aspect cost, all becomes favourable.

In addition, in the present invention, any pattern in pattern 1, pattern 2 no matter, switch SW 2 are controlled in to be kept conducting or keeps a kind of state in the disconnection, so except switch mode, there is no need to carry out switch motion basically.Therefore, can be as switch SW 2 with relay etc. comparatively speaking than the switch element of low speed.

Fig. 2 is the circuit diagram that the supply unit of the expression embodiment of the invention 1 constitutes.In Fig. 2, switch SW 1 is made of ovonic switch, and switch SW 2 is made of relay.By using relay, compare the decay in the time of to reduce switch conduction with the situation of using semiconductor switchs such as IGBT as switch SW 2.Supply unit shown in Figure 2 is to add in formation shown in Figure 1: smmothing capacitor 11, the power phase test section 12 that detects the supply voltage phase place, the pulse duration control part 13 that carries out the pulse duration control of switch SW 1, the relay ON/OFF control part 14 of control switch SW2 conducting/disconnection and the output voltage test section 15 that detects output voltage.In addition, by inserting smoothing capacity 11, the capacity that can suppress to switch with pattern changes, and can realize more stable voltage supply.

In aforesaid supply unit, pulse duration control part 13 is according to the output voltage testing result of output voltage test section 15 and the power phase testing result output control pulse of power phase test section 12, the moment of conducting/disconnection of control switch SW1.Pulse duration control part 13 is the moment of zero cross point at power phase, output control pulse.In addition, relay ON/OFF control part 14 output control pulses, the moment of conducting/disconnection of control switch SW2.

With Fig. 3 action in each pattern of supply unit is described.In addition, the situation of change of the duty ratio of Fig. 3 (b) expression switch SW 1, (c) conducting/off-state of expression switch SW 2.The output voltage of the state of each switch of (about 400W) changed when Fig. 3 (a) expression was exported certain load should be arranged.

The transverse axis of this figure is represented the state of a control taked, when explanation during with status transition that target output voltage produced, also can regard transverse axis as time shaft, and from left to right or from right to left state of a control changes.

As shown in Figure 3, in pattern 1, switch SW 2 is in the state that often disconnects, and switch SW 1 corresponding desired output voltage is subjected to pulse duration control (the P point among the figure).Also promptly, in pattern 1, in the time of expecting higher output voltage, will make the pulse duration of control impuls of switch SW 1 bigger.At this moment, the duty ratio of switch SW 1 reaches 100% (at this moment, control switch SW1 is conducting in the half period of supply frequency), if when being desirably in output voltage on this again, because the pulse duration of uncontrollable switch SW 1 strengthens again, so pattern is switched to pattern 2 from pattern 1.

In the front and back that switch to pattern 2 from pattern 1, the duty ratio of switch SW 1 switches to 0% from 100%, and switch SW 2 switches to conducting (the Q point the figure) from disconnection.At this moment and since the circuit before and after switching be voltage doubling rectifing circuit himself, so do not produce the change of the output voltage before and after switching.Have, in pattern 2, switch SW 2 is controlled to be conducting often again, and switch SW 1 corresponding output voltage is subjected to pulse duration control (the R point among the figure).In pattern 2, constitute owing to become the circuit of voltage doubling rectifing circuit form, so the about 2 times output voltage can obtain being pattern 1 time.

Make in pattern 2 under the situation that output voltage reduces gradually, when the duty ratio of switch SW 1 arrives 0%, switch to disconnection by making switch SW 2 from conducting, the duty ratio that makes switch SW 1 becomes 100% from 0%, carries out from the switching of pattern 2 to pattern 1.

And in the pattern 1 of Fig. 3, control impuls is not greatly to a certain degree the time, and output voltage does not rise, and this is because supply voltage is also little in the little interval of control impuls, and the reason that does not have input current to flow.In addition control impuls near 100% near the time, output voltage does not rise yet, reason also is the same.

In addition, in pattern 1, the recruitment of the output voltage that increases with respect to the duty ratio of switch SW 1 is owing on its circuit constitutes, compare low with the pattern 2 that constitutes the short loop of AC power 1 because of switch SW 1 conducting.Therefore, as shown in Figure 3, the recruitment of the duty ratio by making the switch SW 1 in the pattern 1 is set at recruitment greater than pattern 2 (among the figure for setting big slope), and the output voltage tracking velocity of Control and Feedback action makes its approximately equal between two patterns.Thus, in the gamut of output voltage, can make the tracking velocity approximately constant of output voltage.

Have, in described example, switch SW 2 is to make duty ratio become for 0% stage, switching to pattern 1 from pattern 2 at once again.But also can be under duty ratio become 0% state, switch through the stage of certain hour (for example more than 1 hour).Because of carrying out this control, though temporarily liken to, between pattern 1 and pattern 2, can change continually under the situation of such load considering to the high state of the output voltage of target can continue, just can suppress the frequency of diverter switch SW2 significantly.

In addition, also can be determined at the control duration of pattern 2, surpass preset time in this duration, and the duty ratio of switch SW 1 become for 0% the moment, switches to pattern 1 from pattern 2.In this case, even the duty ratio of switch SW 1 becomes 0%, as long as be no more than preset time in the control duration of pattern 2, the switching of pattern can not carried out, then, surpass moment of preset time, carry out from the switching of pattern 2 to pattern 1 in control duration of pattern 2.

Generally, under the situation of d.c. motor load,, even temporarily make output voltage be higher than desired value, but also can make the motor rotation, so its influence is little with desired rotating speed by this control even the output voltage height also can make the motor rotation by PWM control.Otherwise when making the d.c. motor high speed rotating, respective load is the induced voltage of d.c. motor, just needs to improve output voltage.

In described control, because the restriction that when pattern 1 switches to pattern 2, has no time, so, output voltage is risen even motor load increases suddenly.On the other hand, when constituting switch SW 2, reduced the switching frequency of switch SW 2 owing to carry out described control, so can guarantee the needed contact life-span on the life of product index with relay.

Fig. 4 is in the expression present embodiment supply unit pattern 1, to the various waveforms such as voltage of the tie point of the control impuls of switch SW1, SW2, supply voltage, input current, output voltage (smoothly putting the both end voltage of container 11), capacitor 4,5.As shown in the drawing, the control impuls of switch SW 1 is exported on the zero cross point position of supply voltage, only exports one in the half period of each supply voltage.As shown in the figure, because of this control impuls, input current began to flow from the moment of supply voltage greater than the mid-point voltage of capacitor 4,5.Just, during A in, can make the input current conducting extraly, because of during can expanding current lead-through like this, so can improve power factor.Have again, because of making input current waveform, so can satisfy requirement for restriction high order harmonic component near mains voltage waveform.

And when carrying out mode switch, switch SW 2 is in the position of the zero cross point of supply voltage switched conductive/be broken as ideal.In addition, in example shown in Figure 4,, be in the output of the zero cross point position of supply voltage, but also can be from the moment of the zero cross point of supply voltage to the control impuls of switch SW1, export after only postponing preset time.

Fig. 5 represents in the supply unit pattern 2 of the present invention, to the waveform of control impuls, supply voltage and the input current of switch SW1, SW2.In the figure, the control impuls of switch SW 1 is the moment from the zero cross point of supply voltage, only postpones given time of delay and exports behind the Td.Be necessary time of delay Td be set on the value that can solve the requirement for restriction of high order harmonic component.Might not be time of delay Td to be set at more little then its value of load output big more, just easy more solution is to the requirement for restriction of high order harmonic component, so, even time of delay, Td=0 also can (that is, also can make the control impuls of switch SW 1 export constantly in zero crossing).In pattern 1, even control impuls becomes conducting, but when supply voltage surpasses moment of mid-point voltage of capacitor 4,5, input current can not flow, in contrast, and in pattern 2, when the control impuls of switch SW 1 became conducting, input current just began to flow.As previously discussed, during the pulse duration that makes switch SW 1 conducting in the Tw, owing to can make the input current conducting extraly, so during can enlarging current lead-through equally with pattern 1, thereby can improve power factor.Have again, can make input current waveform, thereby can satisfy requirement for restriction high order harmonic component near mains voltage waveform.

The oscillogram that supply voltage when Fig. 6 is the explanation mode switch and input current change.As shown in the drawing, before and after the moment of mode switch, the variation of output voltage does not almost have.

Though the input current among the mains half-cycle X after mode switch just finishes, its peak value is slightly little, and big slightly in next half period Y, its change degree is enough little.Input current becomes the reason of this waveform in addition, it is phase place because of corresponding input supply voltage before and after mode switch, the multiplication of voltage that is recharged is replacing with

capacitor

4,5, also be because during among the X, in the half period before it will switch, because capacitor 5 has been recharged, so almost do not flow to the charging current of capacitor 5, and in next half period Y, because the voltage of capacitor 4 reduced, so charging current is big.

Thus, when mode switch, there is not the variation of current waveform, transition output voltage glossily in output voltage range.Also promptly, even when carrying out the change of the target output voltage between two kinds of patterns, also can suppress the sudden change of output voltage.

In described example, as Fig. 3, shown in Figure 6,2 the switching from pattern 1 to pattern is that duty ratio in the switch SW 1 of pattern 1 arrives moment of 100% and carries out.But even arrived before 100% in the duty ratio of switch SW 1, when arriving given duty ratio near 100% (for example about 80%), it is also passable to carry out mode switch.Fig. 7 represents that the duty ratio of switch SW 1 arrives at 80% o'clock, carries out the variation of duty ratio of switch SW 1, the SW2 of mode switch, and the variation of the output voltage of corresponding each on off state.Fig. 8 is that explanation is the oscillogram of the variation of the control impuls, supply voltage and the input current that carried out mode switch at 80% o'clock in duty ratio.In this case, also be that to carry out the situation of mode switch at 100 o'clock the same in duty ratio, before and after the moment of mode switch, can obtain current waveform much at one, in the output voltage range when carrying out mode switch, can make output voltage transition smoothly.

And, in Fig. 7, though in the front and back of carrying out mode switch, the output voltage that has produced about 10V is poor, if but make reactor 3 is that the output voltage difference in the time of just can making mode switch is almost nil about 4～6mH, when

capacitor

4,5 is 90% left and right sides for the duty ratio about 1000F, when switching.This be because, as illustrated like that with Fig. 3, duty ratio is 90% o'clock, the interval input current remaining about 10% is zero, has become the circuit with the voltage doubling rectifing circuit equivalence.At this moment, even be the interval that near produced 100% the duty ratio output voltage that improves switch SW 1 does not also rise, reduce with when duty ratio is the control of switching at 100% o'clock, comparing to some extent in duty ratio.Therefore, when pattern 1 switches to pattern 2, output voltage is followed the tracks of quickly towards target output voltage.

Embodiment 2

With Fig. 9 the switch SW 1 of supply unit pattern, another example of SW2 control method are described.

Fig. 9 is the oscillogram of the control of each switch SW 1 of explanation present embodiment, SW2.As shown in Figure 9, the control of present embodiment pattern 1 is the same with the situation of embodiment 1 shown in Figure 3.But, in the control of pattern 2, embodiment 1 makes switch SW 2 conducting often, make switch SW 1 controlled by pulse duration, and in the present embodiment, be to make switch SW 1 conducting often (just, duty ratio being set at 100%), make the change of the corresponding output voltage of bidirectional switch SW2 that adopts formations such as semiconductor switch controlled by pulse duration.

The same during with embodiment 1, even control each switch SW 1, SW2 as described above, also can connect the input current waveform that carries out before and after the mode switch smoothly, the change of the output voltage when also can suppression mode switching.In order to carry out above-mentioned control, though have any problem as switch SW 2 with relay, its advantage is to be easier to realize making switch SW 2 to carry out high accuracy in the position of the zero cross point of supply voltage switch.

In addition, when carrying out aforesaid mode switch, the moment that also can arrive near duty ratio given 100% in the duty ratio of switch SW 1 switches.Also promptly, as shown in Figure 9, also can make from pattern 1 to pattern 2 switching, arrive moment of 90% carries out in the duty ratio of switch SW 1.At this moment, for switch SW 1,, before arriving 100%, its duty ratio still is subjected to pulse duration control even after switching to pattern 2.

Even control as described above, also the same with foregoing situation, before and after mode switch, can obtain same effect.

In addition, in

embodiment

1,2, though only being applied " the 1 pulse control " of a control impuls half period at supply voltage is illustrated, but also can make carrier frequency be set at the frequency more much higher than supply frequency (just compares with the half period of supply voltage, set very short carrier cycle), with this carrier frequency switch SW1 is carried out pulse duration control.

Embodiment 3

In embodiment 1, as shown in Figure 4, carried out in the half period of supply voltage, switch SW1 only being applied " the 1 pulse control " of a control impuls.And in the present embodiment, as shown in figure 11, carry out in the half period of supply voltage, switch SW1 is applied the control (hereinafter referred to as " 2 pulses control ") of two control impuls.At this moment, last pulse being applied when the zero cross point of supply voltage occurs, is to apply near zero moment and make the back input current of one pulse when 1 pulse control.In addition, the pulse duration that makes back one pulse little than last pulse.By carrying out this 2 pulses control, not only during A and also during B also can make the input current conducting, thereby can improve power factor more, can improve power-efficient.

Embodiment 4

In embodiment 1, when the another kind of pattern transition, control switch SW1 and switch SW 2 were switched in the half period of same supply voltage from a kind of pattern.And in the present embodiment, as Figure 12 and shown in Figure 13, when carrying out the switching of described two kinds of patterns, at first in the half period of supply voltage, after control switch SW1, SW2 disconnect, change action pattern again.In addition, (hereinafter referred to as " dead band ") is bigger than the half period of supply voltage during can making also that switch SW 1, SW2 disconnect.

Figure 12 is the oscillogram of the variation of supply voltage, input current and the output voltage of explanation when pattern 1 switches to pattern 2.As shown in the drawing, in the mains half-cycle before mode switch will be carried out,, before and after mode switch, obtained almost same current waveform in the situation with embodiment 1 except input current becomes zero part.In addition control switch SW1, SW2 all disconnect during (dead band), though the output voltage peak value has descended about 20～30V, the size of same degree is also arranged from the fluctuation voltage of common state, output voltage can not produce change significantly.Therefore, in this control, also can make the output voltage transition smoothly when mode switch.Also promptly, can suppress voltage jump when the target output voltage transition.

Figure 13 represents from the waveform of pattern 2 when pattern 1 is switched.Same during with Figure 12, control switch SW1, SW2 all disconnect during (dead band), therefore though output voltage temporarily reduces, its peak value is about 20～30V, has suppressed the change of output voltage.

In addition, when switch SW 2 is relay, consider the operate time of switch SW 2, relay ON/OFF control part 14, in the forward moment of zero cross point that likens to the supply voltage that carries out mode switch, the control signal of output conducting/disconnection, but in this control, even just in case the disconnection of switch SW 2 action is during than the late 10ms of the TYP value left and right sides, so owing to be provided with dead band switch SW 1 and also not all conductings of SW2.Therefore, even when the operate time of switch SW 2, difference was big,, also can avoid reliably by the rise of output voltage that boosting produced of following AC power 1 short loop to form by implementing this control.

According to the present invention, tie point between a plurality of capacitors that output is connected in series, and between each input terminal of rectification circuit, be respectively equipped with in the formation of the 1st and the 2nd switching device, the conducting by switching each switch and the combination of disconnection can constitute based on power circuit full-wave rectifying circuit and voltage-multiplying circuit, that have boosting.Thus, can constitute and improve power factor and solve requirement for restriction, have the supply unit of the output voltage range of wide region (about 120～290V) again high order harmonic component.

In addition, invent according to claim 2, by making the 2nd switching device conducting/disconnection, carry out the switching of pattern, and by control the 1st switching device, make it only conducting continuously in the conduction period that changes with output voltage in mains half-cycle, just can accomplish with the requirement for restriction of simple control solution, and obtain desired output voltage high order harmonic component.Have again, because be the low frequency switch motion, so that the switching noise that is produced also can be suppressed to is smaller.

In addition, invention according to claim 3 when conduction period of the 1st pattern during greater than set-point, disconnects, makes the 2nd switching device conducting by making the 1st switching device, thereby carry out the transition to the 2nd pattern, can suppress in the past the change of the output voltage that produces because of mode switch.

In addition, invention according to claim 4, when becoming zero by conduction period in the 2nd pattern, conduction period by making the 1st switching device for maximum, the 2nd switching device is disconnected, thereby carry out the transition to the 1st pattern, can suppress in the past the change of the output voltage that produces because of mode switch.

In addition, invention according to claim 6 by additional period condition in the switching condition of two kinds of patterns, can reduce the switching frequency of the 2nd switching device, therefore, can prolong the contact life-span when using relay as the 2nd switching device.

In addition, invention according to claim 7, by be increased in the 1st conduction period, near the interval terminal point of input current energising, be set the 2nd conduction period, can further increase the energising angle of input current, thereby further improve power factor.

In addition, invention according to claim 8 is carried out the switching of pattern by the moment at the zero cross point of AC power, can make not have unwanted short circuit current when switching and flow, thereby carry out the switching of pattern smoothly.

In addition, invention according to claim 10 begins begin to pass through preset time constantly from zero crossing after by making for the 1st conduction period, can enlarge the improvement scope of input current waveform, its result can more easily satisfy the requirement for restriction to high order harmonic component.

In addition, invention according to claim 12, because when pattern is switched, there is no need to make the 1st switching device temporarily by being conducting to disconnection or switching by being disconnected to conducting ground, as long as the direction that associative mode is switched, make the conducting width of a switching device increase gradually or reduce and get final product, thereby, the disorder of the input current waveform in the time of can more easily being suppressed at mode switch.

In addition, invention according to claim 14, by in the 1st pattern, make the conducting change width amount of the 1st switching device that is equivalent to mains half-cycle, variable quantity greater than the 2nd pattern, can in output voltage range, make the output voltage tracking velocity approximately equal of corresponding target output voltage.

In addition, invention according to claim 15, in half period by the supply voltage when pattern is switched, controlling the 1st and the 2nd switching device disconnects, shortly under the situation of relay that the usage operation time difference is big as the 2nd switching device, also can prevent the conducting simultaneously of the 1st and the 2nd switching device, and then can prevent the disorder of the output voltage that the boosting because of the short loop of input power supply produces reliably.

Claims

1. supply unit is characterized in that: comprising:

Have two inputs and two outputs, be connected with AC power, AC supply voltage is transformed to the rectification circuit of direct voltage through reactor;

Form by a plurality of capacitors that are connected in series, be connected the capacitor circuit between two outputs of described rectification circuit;

Be connected an input of described rectification circuit, and the 1st switching device between the tie point between the capacitor in the described capacitor circuit;

Be connected another input of rectification circuit, and the 2nd switching device between the described tie point between the capacitor in the described capacitor circuit.

2. supply unit according to claim 1 is characterized in that:

Also comprise by any one pattern in the 1st and the 2nd pattern, control the described the 1st and the control device of the 2nd switching device,

Described the 1st pattern is controlled the 1st switching device, makes it in the half period of supply voltage, only conducting continuously in the 1st conduction period that the output voltage with supply unit changes, and described the 2nd switching device controlled, make it often to disconnect

Described the 2nd pattern is controlled the 1st switching device, makes it in the half period of supply voltage, only conducting continuously in the 1st conduction period that the output voltage with supply unit changes, and described the 2nd switching device controlled, make it often to disconnect

3. supply unit according to claim 2 is characterized in that:

When the 1st conduction period during greater than set-point, the pattern that described control device will adopt in order to control the 1st and the 2nd switching device switches to the 2nd pattern from the 1st pattern.

4. supply unit according to claim 2 is characterized in that:

When described the 1st conduction period vanishing, the pattern that described control device will adopt in order to control the 1st and the 2nd switching device switches to the 1st pattern from the 2nd pattern.

5. supply unit according to claim 2 is characterized in that:

In described the 1st conduction period is zero, and keeps this state through after preset time, and the pattern that described control device will adopt in order to control the 1st and the 2nd switching device switches to the 1st pattern from the 2nd pattern.

6. supply unit according to claim 2 is characterized in that:

More than the control of carrying out with described the 2nd pattern has continued preset time, and during the 1st conduction period vanishing, described control device switches to the 1st pattern with the 2nd pattern.

7. supply unit according to claim 2 is characterized in that:

Described control device also was provided with and is different from the 2nd conduction period the 1st conduction period, that make the 1st switching device conducting in the half period of power supply.

8. supply unit according to claim 2 is characterized in that:

Described control device carries out the conducting of the 2nd switching device constantly and disconnects switching in the zero crossing of supply voltage.

9. supply unit according to claim 2 is characterized in that:

Described control device made for the 1st conduction period from the zero crossing of supply voltage constantly.

10. supply unit according to claim 2 is characterized in that:

After described control device made for the 1st conduction period pass through preset time constantly from the zero crossing of supply voltage.

11. supply unit according to claim 1 and 2 is characterized in that:

Described the 2nd switching device is made of relay.

12. supply unit according to claim 1 is characterized in that:

Also comprise by any one pattern in the 1st and the 2nd pattern and control the described the 1st and the control device of the 2nd switching device,

Described the 2nd pattern, the 1st switching device is controlled, made it conducting often, and described the 2nd switching device is controlled, make it in the half period of supply voltage only conducting continuously in the 2nd conduction period that the output voltage with supply unit changes.

13. supply unit according to claim 1 is characterized in that:

Described the 1st pattern, than also short cycle half period of supply voltage as carrier cycle, the 1st switching device is carried out pulse duration control, and described the 2nd switching device is controlled, make it often to disconnect.

Described the 2nd pattern is carried out pulse duration control with described carrier cycle to the 1st switching device, and described the 2nd switching device is controlled, and makes it conducting often.

14. supply unit according to claim 2 is characterized in that:

Described control device is in described the 1st pattern, and the value of variable quantity that makes described the 1st conduction period in the supply voltage half period is greater than the value of the variable quantity in described the 2nd pattern.

15. supply unit according to claim 2 is characterized in that:

Described control device is in the described the 1st or the 2nd pattern, from a kind of pattern when another kind of pattern is switched, will the described the 1st and the 2nd switching device all be controlled at off-state during be set at the half period of supply voltage or more than the half period after, change action pattern again.