CN102005940A

CN102005940A - Power supply device

Info

Publication number: CN102005940A
Application number: CN2010102672236A
Authority: CN
Inventors: 横沟保久
Original assignee: Juki Corp
Current assignee: Juki Corp
Priority date: 2009-08-28
Filing date: 2010-08-27
Publication date: 2011-04-06
Also published as: JP2011050207A

Abstract

The invention relates to a power supply device capable of reducing the loss and increasing the powder factor in improvement control of the power factor of the power supply. The power supply device comprises: a transfer circuit with a rectifier, a switch element, a reactor and a diode, wherein the preset direct-current voltage is obtained from the alternative-current power supply using the switch element; a detection unit of alternative-current voltage; a detection unit of direct-current voltage of the transfer circuit; and a switch action control unit for controlling the action of the switch element based on the alternative-current voltage and the direct-current voltage detected by each detection unit, thus the direct-current voltage is formed into the preset control voltage and the switch action control unit is controlled and when the detected direct-current voltage exceeds the first level of the protection circuit or load, the switch control is immediately stopped and when the detected direct-current voltage exceeds the second level smaller than the first level, the timing is performed at the zero crossing of the alternative-current voltage to stop the switch control.

Description

Supply unit

Technical field

The present invention relates to a kind of supply unit, it will be a direct voltage from the AC voltage conversion that exchanges power supply, supply with to follow-up circuit.

Background technology

For example, for disclosed existing power supply device in patent documentation 1 and 2, as shown in Figure 6, have: single phase alternating current power supply 1, rectifier 2, reactor 3, diode 4, switch element 5, current sense resistor 6, smmothing capacitor 7, load 8, comparator 20, overvoltage detection reference voltage source 21, overvoltage detect with divider resistance 22,23, output voltage and detect with divider resistance 24,25, input voltage detection resistance 26 and control circuit 27.

In above-mentioned supply unit, be the input voltage vin of direct current with the output transform of single phase alternating current power supply 1 by rectifier 2.And control circuit 27 is corresponding with the magnitude of voltage of input voltage vin and switch element 5 is carried out switch, will be stored in energy in the reactor 3 to capacitance 7 chargings via diode 4.And output voltage V o is controlled as, and is higher and remain the control setting than input voltage vin.Alternating current Iin was controlled as with input voltage vin and became sine wave synchronously this moment.

Import to control circuit 27: input voltage vin; The control detection voltage Vs of output voltage V o; Current signal as the current sense resistor 6 of the monitor of alternating current Iin; And the output signal OVL of the comparator 20 that the overvoltage of output voltage V o is detected.

The overvoltage of 20 couples of output voltage V o of comparator detects voltage Vov and overvoltage reference voltage V ref (stopping voltage) compares, comparing with overvoltage reference voltage V ref under the overvoltage detection voltage Vov condition with higher, output voltage is judged as stops magnitude of voltage, and output OVL signal " H ".In addition, comparator 20 has hysteresis, as shown in Figure 7, with overvoltage reference voltage V ref compare low, compare higher voltage with the control setting and promptly be less than or equal under the beginning voltage, carry out the releasing that overvoltage detects.

On the other hand, control circuit 27 for according to from OVL " H " signal of comparator 20 with the power-factor improvement control break, and the switching signal SWP of switch element 5 is stopped.If output voltage V o descends thus, become " L " from the OVL signal of comparator 20, then recover power-factor improvement control.

Patent documentation 1: Japan speciallys permit communique No. 3242672

Patent documentation 2: No. 3740946 communique of Japan's patent

Summary of the invention

But; in the power-factor improvement control of existing power supply device; owing to only in circuit protection, use overvoltage to detect; so even output voltage V o rises to more than or equal to the needed voltage of control; if but be less than or equal to overvoltage reference voltage V ref (stopping voltage) with regard to Sustainable Control, exist to make load drive device produce the problem of control loss.That is, under control voltage condition with higher, the switching loss of switch drive element becomes big with comparing under the lower situation of control voltage.Because the control voltage more than or equal to the control required voltage increases loss, so can become unnecessary loss.In addition, except switch control, load current also increases, and loss increases.

In addition, in above-mentioned existing power circuit, surpassed the state that stops voltage,, all stopped control, so become the reason that power factor is worsened then regardless of the phase place of AC power if detect.Particularly, with load be the regenerated electric power of AC servomotor etc. under the situation of power supply feedback, surpass when regeneration that to stop voltage condition more, the stop frequency of alternating current increases, and becomes the reason that power factor is obviously worsened especially.

In addition, as mentioned above, in order to realize reducing the wastage, also consider to set overvoltage reference voltage V ref (stopping voltage) lower, but be that the regenerated electric power of AC servomotor etc. is under the situation of power supply feedback with load, because the stop frequency of alternating current also increases, frequency factor is further worsened, so be difficult to set lowlyer with stopping voltage.

The objective of the invention is to, in the power-factor improvement control of power circuit, reduce the wastage, realize the raising of power factor.

The invention of technical scheme 1 record is a kind of supply unit, and it has: translation circuit, and it has rectifier, switch element, reactor and diode at least, utilizes the switch motion of described switch element, the direct voltage that is obtained stipulating by AC power; The input voltage detecting unit, its alternating voltage to described AC power detects; The direct voltage detecting unit, its direct voltage to described translation circuit output detects; And switch motion control unit; its basis is by detected alternating voltage of described each detecting unit and direct voltage; control the action of described switch element; so that direct voltage becomes the control voltage of regulation; it is characterized in that; described switch motion control unit carries out following control: surpassed under the situation of the 1st level by the detected direct voltage of described direct voltage detecting unit; utilize described switch element at once energising to be stopped; the 1st level is the big value of comparing with described control voltage; the load that is used to protect described translation circuit or is applied in described direct voltage; surpassing under the situation of the 2nd level by the detected direct voltage of described direct voltage detecting unit; zero crossing at described alternating voltage regularly utilizes described switch element that energising is stopped, and the 2nd level is to compare with described control voltage to compare less value greatly and with described the 1st level.

The invention of technical scheme 2 records, it is characterized in that, has the identical structure of invention with technical scheme 1 record, and described switch motion control unit carries out following control: utilize surpassing described the 1st level or the 2nd level by the detected direct voltage of described direct voltage detecting unit under the state that described switch element stops energising, utilizing the detected direct voltage of described direct voltage detecting unit to become under the situation less than the assigned voltage of described the 2nd level, regularly utilizing the recovery of will switching on of described switch element at the zero crossing of described alternating voltage.

The invention of technical scheme 3 record is characterized in that, has the invention identical mechanism with described technical scheme 2 records, and will utilize that described switch element makes that energising recovers less than the assigned voltage of described the 2nd level as described control voltage.

The effect of invention

The invention of technical scheme 1 record; corresponding with the direct voltage of circuit output and set two level; under the situation that surpasses the 1st bigger level be used for protective circuit etc.; by at once switch control being stopped; and realize protecting same as the prior artly; and,, regularly carry out the control that switch control is stopped so waiting for the zero crossing of alternating voltage because emergency is lower above being set under the situation of the 2nd level of comparing smaller value with the 1st level.

Thus, needn't wait for the 1st level value that is used for protective circuit etc. to reaching, just energising can be stopped, reducing switching loss.

In addition and since utilize the 2nd level stop to be that zero crossing at alternating voltage regularly carries out, so can avoid the reduction of power factor effectively.Especially, even because load-side regeneration and taking place continually under the situation that direct voltage increases, also can avoid since each switch stop to make power factor decline, can provide power factor higher supply unit.

And, owing to utilize the two-stage level to carry out stopping of switch, thus compare the 2nd big slightly level with the control power supply and stop control by utilizing, thus can use the reverse power of regeneration overvoltage etc. effectively, reduce consuming electric power.

For the inventions of technical scheme 2 and 3 records, owing to utilize switch element will switch on, also be that the zero crossing at alternating voltage regularly carries out, so can also provide power factor higher supply unit from the recovery of halted state.

Description of drawings

Fig. 1 is the circuit diagram of the supply unit of expression an embodiment of the invention.

Fig. 2 is that the output voltage of circuit is because the temporary transient generation of underload or regeneration relaxes the sequential chart of the overvoltage retentive control under the situation about rising.

Fig. 3 is that the output voltage of circuit is because than heavy duty or regeneration and the temporary transient sequential chart that produces the overvoltage protection under the situation about sharply rising.

Fig. 4 be the output voltage of circuit because temporary transient generation of underload or regeneration relaxed situation about rising, needn't wait for zero detection of handing over and the sequential chart of overvoltage protection control under the situation that output voltage is descended.

Fig. 5 is the flow chart of the processing of the corresponding overvoltage protection control of carrying out when supply power with load of expression control circuit.

Fig. 6 realizes the existing block diagram that improves the supply unit of power factor and overvoltage protection.

Fig. 7 is the output voltage of translation circuit in existing supply unit produces the overvoltage protection control under the situation of rising owing to underload or regeneration a sequential chart.

Embodiment

Utilize Fig. 1 that the circuit structure of the supply unit 10 of expression one embodiment of the present of invention is described.In the explanation of following supply unit 10, for the structure mark identical label identical with described supply unit shown in Figure 6 100.

Supply unit 10 is for example to carry out the supply unit that power supply is supplied with to motor even load 8, and has: single phase alternating current (A.C.) source power supply 1; Rectifier 2, it utilizes the single-phase full wave rectification that exchange conversion is direct current; Boost chopper, it is made up of reactor 3, diode 4, switch element 5 and smmothing capacitor 7; As the current sense resistor 6 of current detecting unit, it is used to obtain current detection signal Vaci as the monitor of alternating current Iin; Load current detects resistance 9, and it is used to obtain current detection signal VL; As the overvoltage of direct voltage detecting unit detect with divider resistance 22 and 23 and output voltage detect with divider resistance 24 and 25, this overvoltage detects with divider resistance 22 and 23 in order to be used for the superpotential supervision of protective circuit and load 8, the direct voltage that is used to obtain circuit output is that overvoltage detects voltage Vov, this output voltage detection in order to be used for the superpotential supervision of protective circuit and load 8, is used to obtain the output voltage V o of circuit with divider resistance 24 and 25; Input voltage detects resistance 26, and it is used to obtain the input voltage vin of circuit; First comparator 20, it monitors superpotential for protective circuit; The first overvoltage detection reference voltage source 21, it is to comparator 20 input regeneration overvoltage reference voltage V ref1, and superpotential benchmark (the first overvoltage reference voltage) takes place as judging in this regeneration overvoltage reference voltage V ref1; Second comparator 30, it monitors underload is superpotential in order to lower circuit loss; The second overvoltage detection reference voltage source 31, it is to comparator 30 input underload overvoltage reference voltage V ref2, and the superpotential benchmark of underload (the second overvoltage reference voltage) takes place as judging in this underload overvoltage reference voltage V ref2; And control circuit 50, it carries out power-factor improvement control and overvoltage protection in the circuit control of AC power in the DC power supply conversion.

Comparator 20 is connected with the first overvoltage detection reference voltage source 21 that is used for circuit is carried out overvoltage protection.And, to the regeneration overvoltage reference voltage V ref1 that applies by the first overvoltage detection reference voltage source 21, with detect the overvoltage detection voltage Vov that obtains with divider resistance 22 and 23 from overvoltage and compare, comparing under the overvoltage detection voltage Vov condition with higher OVL signal of output " H " with regeneration overvoltage reference voltage V ref1.

The value of above-mentioned regeneration overvoltage reference voltage V ref1 is set at following magnitude of voltage, that is, and and with the corresponding magnitude of voltage of higher limit of judging the circuit output voltage Vo that circuit and load destruction etc. can not taken place.That is, be no more than regeneration overvoltage reference voltage V ref1 as long as overvoltage detects the value of voltage Vov, circuit and load just can stably be moved.

Comparator 30 is connected with the second overvoltage detection reference voltage source 31, this second overvoltage detection reference voltage source 31 apply with the overvoltage reference voltage V ref1 that regenerates compare low, with control assigned voltage Vss (control voltage) compare higher underload overvoltage reference voltage V ref2 (the second overvoltage reference voltage).And, the underload overvoltage reference voltage V ref2 (the second overvoltage reference voltage) that applies from the second overvoltage detection reference voltage source 31 is detected voltage Vov with described overvoltage to be compared, comparing under the overvoltage detection voltage Vov condition with higher OVC signal of output " H " with underload overvoltage reference voltage V ref2.

Value for above-mentioned underload overvoltage reference voltage V ref2, will with regeneration overvoltage reference voltage V ref1 compare low, compare higherly as necessary condition with control assigned voltage Vss, preferably compare the value of more approaching control assigned voltage Vss with regeneration overvoltage reference voltage V ref1.Wherein, be preferably formed into, under deregenerative situation about changing up and down when common, compare higher value at control assigned voltage Vss with this common amplitude of fluctuation.

Above-mentioned supply unit 10 utilizes boost chopper to constitute with rectifier 2 and exchanges a DC transfer circuit, and this boost chopper is made up of reactor 3, diode 4, switch element 5 and smmothing capacitor 7.And, by in ac-dc conversion circuit, increasing the control circuit 50 that the switch motion of switch element 5 is controlled, and constitute so-called boost chopper type High Power Factor comparator.

Above-mentioned rectifier 2 will be a direct current from the AC rectification that exchanges source power supply 1, and smmothing capacitor 7 carries out the smoothing of direct current after the rectification.

In addition, control circuit 50 utilizes the duty ratio of the switch element 5 in the control boost chopper, can at random control its output voltage V o.

And, utilizing the control of the 5 pairs of duty ratios of switch element in the boost chopper, control circuit 50 can at random be controlled the increase and decrease of reactor current, thereby can at random control alternating current Iin.Specifically, the control by carrying out switch element 5 is controlled thereby carry out power-factor improvement to form the sinusoidal waveform identical with AC-input voltage.

To control circuit 50 input via input voltage detect the output voltage V o of input voltage vin that resistance 26 obtains, circuit control detection voltage Vs, alternating current Iin, detect current detection signal VL, the output signal OVL of comparator 20 of resistance 9 and the output signal OVC of comparator 30 as current detection signal Vaci, the load current of the current sense resistor 6 of the monitor of this alternating current Iin.

Below, according to Fig. 2～each sequential chart shown in Figure 4, the output voltage V o that illustrates at circuit produces the above-mentioned overvoltage protection control under the situation of various state variation.

Control circuit 50 carries out following control; promptly; detect voltage Vov for the overvoltage that shows the variation corresponding with output voltage V o; setting is used for the regeneration overvoltage reference voltage V ref1 of protective circuit and load; with the low value of comparing with it be the threshold value of this two-stage of underload overvoltage reference voltage V ref2; under the situation of overvoltage detection voltage Vov, cut off alternating current Iin at once above regeneration overvoltage reference voltage V ref1; detect voltage Vov in overvoltage and surpass regeneration overvoltage reference voltage V ref1 and only surpass under the situation of underload voltage Vref2, wait for zero crossing (zero crossing) ZC of input voltage vin and cut off alternating current Iin.

Utilize Fig. 2, the output voltage V o that circuit is described is because underload or regeneration and the temporary transient sequential chart that produces the overvoltage protection control that relaxes under the situation about rising.

In this case, detect the value that voltage Vov surpasses underload overvoltage reference voltage V ref2 if detect overvoltage constantly at the A of Fig. 2, underload excess voltage detection signal OVC switches to " H " from " L ", then control circuit 50 is waited for the detection of the zero crossing ZC of input voltage vin, if detect zero crossing ZC constantly at B, then switch element 5 disconnects, and alternating current Iin is cut off.

Its result, overvoltage detects voltage Vov and descends, become and be less than or equal to underload overvoltage reference voltage V ref2 (C point), and, drop to control assigned voltage Vss (D point) if overvoltage detects voltage Vov, then control circuit 50 is waited for the detection of the zero crossing ZC of input voltage vin, if detect zero crossing ZC constantly at E, then switch element 5 is connected, and recovers the energising of alternating current Iin.

Utilize Fig. 3, the output voltage V o that circuit is described is because than heavy duty or regeneration and the temporary transient sequential chart that produces the overvoltage protection control under the situation about sharply rising.

In this case, detect overvoltage constantly at a of Fig. 3 and detect the value that voltage Vov surpasses underload overvoltage reference voltage V ref2, underload excess voltage detection signal OVC switches to " H " from " L ".And, if before detecting zero crossing ZC, detect overvoltage constantly at b and detect the value that voltage Vov surpasses regeneration overvoltage reference voltage V ref1, regeneration excess voltage detection signal OVL switches to " H " from " L ", then control circuit 50 is not waited for the detection of the zero crossing ZC of input voltage vin, at once switch element 5 is disconnected, cut off alternating current Iin.

Its result, overvoltage detects voltage Vov and descends, become and be less than or equal to regeneration overvoltage reference voltage V ref1 (c point), be less than or equal to underload overvoltage reference voltage V ref2 (d point), if and then drop to control deboost Vss (e point), then control circuit 5 is waited for the detection of the zero crossing ZC of input voltage vin, if detect zero crossing ZC constantly at f, then recovers the energising of alternating current Iin.

Utilize Fig. 4, the output voltage V o that circuit is described is because underload or regeneration and temporary transient the generation relaxed under the situation about rising, and do not wait until to detect zero crossing and the sequential chart of the overvoltage protection control of output voltage V o when descending.

In this case, detect the value that voltage Vov surpasses underload overvoltage reference voltage V ref1 if detect overvoltage constantly at the I of Fig. 4, underload excess voltage detection signal OVC switches to " H " from " L ", then control circuit 50 is waited for the detection of the zero crossing ZC of input voltage vin as mentioned above, but do not cut off energising, if detecting voltage Vov, overvoltage transfers decline (timing of II) to via peak value, and become and be less than or equal to underload overvoltage reference voltage V ref2, underload excess voltage detection signal OVC switches to " L " (time point of III) from " H ", and then control circuit 50 does not carry out the cut-out of switch element 5.

As mentioned above; control circuit 50 is corresponding with various states and carry out the overvoltage retentive control; but during except the cut-out alternating current in this overvoltage protection control, constantly carry out and utilize described switch element 5 that output voltage V o is remained the control and the power-factor improvement control of desired value arbitrarily.

Below, utilize Fig. 5, the contents processing of the overvoltage retentive control that control circuit 50 carries out to load 8 supply powers the time is described.

At first, control circuit 50 judges whether the OVC signal that overvoltage that expression is obtained by comparator 30 detects the comparative result of voltage Vov and underload overvoltage reference voltage V ref2 is " H " (step S1).

At this moment, detect voltage Vov in overvoltage and do not surpass under the situation of underload overvoltage reference voltage V ref2, handle jumping to step S5.

On the other hand, under the regenerated electric power and underloaded situation that have produced from load, output voltage V in begins to rise from control assigned voltage Vss.Thus, detect voltage Vov in overvoltage and surpass under the situation of underload overvoltage reference voltage V ref2 (Vov＞Vref2), it is 1 or 0 (step S2) that the underload overvoltage of judging control circuit 50 detects sign FG2, detects under the situation that indicates FG2=0 in the underload overvoltage and switches to FG2=1 (step S3).

On the other hand, switch under 1 the situation for underload overvoltage under the situation of FG2=1 or in step S3 detects sign FG2 in the judgement of step S2, control circuit 50 is judged the voltage waveform of the input voltage vin that whether obtains from detecting resistance 26 via input voltage and is detected zero crossing ZC (step S4).

Its result, under the situation that does not detect zero crossing ZC, control circuit 50 judges whether the OVL signal of representing overvoltage detection voltage Vov that is obtained by comparator 20 and the comparative result of regenerating overvoltage reference voltage V ref1 is " H " (step S5).

And, be under the situation of " H " that (Vov＞Vref1), handle and jump to step S6 be (Vov＜Vref1 or Vov=Vref1) under the situation of " H " at the OVL signal, and processing jumping to step S7 at the OVL signal.

In addition, in step S4, under the situation of the zero crossing ZC that detects input voltage vin, handle also jumping to step S6.

In this step S6, control circuit 50 makes switching signal SWP for " L " (disconnections) and to switch element 5 output, and the energising of alternating current Iin is stopped, and stops power-factor improvement control, makes to control to stop to indicate FG1=1.

Then, in step S7, control circuit 50 judges that it is 1 or 0 that the underload overvoltage detects sign FG2, detects in the underload overvoltage under the situation of sign FG2=0, thinks not produce the rising that overvoltage detects voltage Vov, end process.

In addition, detect in the underload overvoltage under the situation of sign FG2=1, control circuit 50 judges that control stops to indicate that FG1 is 1 or 0 (step S8).

In step S8, owing to judging that control stops to indicate under the situation of FG1=1, energising by alternating current Iin stops to become and stops the power-factor improvement state of a control, so whether judge the value of overvoltage detection voltage Vov becomes less than control assigned voltage Vss (step S10), detect voltage Vov in overvoltage and do not drop under the situation of controlling voltage Vss, handle being back to step S1.

In addition, under overvoltage detection voltage Vov dropped to less than the situation of controlling assigned voltage Vss, control circuit 50 judged whether detect zero crossing ZC (step S11) from the voltage waveform of input voltage vin.And, under the situation that does not detect zero crossing ZC, handle being back to step S1.

In addition, under the situation that detects zero crossing ZC, control circuit 50 makes switching signal SWP be " H " (connection), and to switch element 5 outputs, recover the energising of alternating current Iin, recover power-factor improvement control, make control stop to indicate FG1=0 (step S12).And, make the underload overvoltage detect sign FG2=0 (step S13), end process.

In addition, in step S8, judging that control stops to indicate under the situation of FG1=0, whether the OVL signal that the overvoltage that control circuit 50 judgement expressions are obtained by comparator 30 detects the comparative result of voltage Vov and underload overvoltage reference voltage V ref2 is " L " (step S9).Its result is not (Vref2＜Vov or Vref2=Vov) under the situation of " L " at the OVL signal, handles being back to step S1.

In addition, at the OVL signal be (Vref2＞Vov), make the underload overvoltage detect sign FG2=0 (step S13), end process under the situation of " L ".

Here, the processing of the sequential chart of the processing shown in the flow chart of contrast Fig. 5 and described Fig. 2 describes.

At first, surpass underload overvoltage reference voltage V ref2 (A point) if overvoltage detects voltage Vov, then being judged to be of step S1 is, in step S2, S3 the underload overvoltage detected sign and is set at FG2=1.

And if detect zero crossing ZC at the B point, then being judged to be of step S4 is, utilizes step S6 that the energising of alternating current Iin is stopped.And because each sign FG1=1, so FG2=1 is step S7,8 be judged to be and be.

And, drop to less than control assigned voltage Vss if detect voltage Vov in D point overvoltage, then being judged to be of step S10 is, and if detect zero crossing ZC at the E point, then being judged to be of step S11 is.

And, by the processing of step S12, recover the energising of alternating current Iin, and control is stopped sign resetting (FG1=0), and, by the processing of step S13, also the underload overvoltage is detected sign and reset (FG2=0), finish a series of processing.

Below, the processing of the sequential chart of the processing shown in the flow chart of contrast Fig. 5 and described Fig. 3 describes.

At first, surpass underload overvoltage reference voltage V ref2 (a point) if overvoltage detects voltage Vov, then being judged to be of step S1 is, in step S2,3 the underload overvoltage detected sign and is set at FG2=1.

And, do not detect voltage Vov and surpass regeneration overvoltage reference voltage V ref1 (b point) if detect zero crossing ZC and overvoltage, being judged to be not of step S4 then, being judged to be of step S5 be, utilizes step S6, the energising with alternating current Iin at once stops.

And, because each sign FG1=1, FG2=1, so step S7,8 be judged to be and be.And, drop to less than control assigned voltage Vss if detect voltage Vov in e point overvoltage, then being judged to be of step S10 is, and if detect zero crossing ZC at the f point, then being judged to be of step S11 is.

And, by the processing of step S12, recover the energising of alternating current Iin, and control is stopped sign resetting (FG1=0), and, utilize the processing of step S13, also the underload overvoltage is detected sign and reset (FG2=0), finish a series of processing.

Below, the processing of the sequential chart of the processing shown in the flow chart of contrast Fig. 5 and described Fig. 4 describes.

At first, surpass underload overvoltage reference voltage V ref2 (I point) if overvoltage detects voltage Vov, then being judged to be of step S1 is, in step S2,3 the underload overvoltage detected sign and is set at FG2=1.

And, because not detecting zero crossing ZC and overvoltage detection voltage Vov drops to less than underload overvoltage reference voltage V ref2, so being judged to be not of step S4 and 5 is masked as FG2=1 because the underload overvoltage detects, so being judged to be of step S7 is.And, keep FG1=0 owing to stop sign, thus being judged to be not of step S8, so since Vov＜being judged to be of Vref2 step S9 be.Its result in step S13, detects sign with the underload overvoltage and resets (FG2=0), finishes a series of processing.

As mentioned above; in above-mentioned supply unit 10; overvoltage for the direct voltage of exporting based on translation circuit detects voltage Vov; set regeneration overvoltage reference voltage V ref1 and these two level of underload overvoltage reference voltage V ref2; by under the situation that surpasses the bigger regeneration overvoltage reference voltage V ref1 be used for protective circuit etc.; at once switch control is stopped, thereby can realize the protection of load same as the prior artly.

And, be set under the situation of the underload overvoltage reference voltage V ref2 that compares smaller value with the overvoltage reference voltage V ref1 that regenerates surpassing, because emergency is lower, regularly carry out the control that switch control is stopped so waiting for the zero crossing of alternating voltage, so can avoid the reduction of power factor effectively.Especially, even the direct voltage increase takes place continually in this case regenerating because of load-side, also can avoid owing to each switch stop power factor being descended, can provide power factor higher supply unit.In addition, owing to carry out stopping of switch with the two-stage level, thus compare the 2nd big slightly level with control voltage and stop control by utilizing, and can use the reverse power of regeneration overvoltage etc. effectively, reduce consuming electric power.

And owing to utilize switch element to make the recovery of energising from halted state, also the zero crossing at alternating voltage regularly carries out, so can realize the raising of power factor.

In addition, the situation of shutdown switch control and surpass each overvoltage reference voltage V ref1, Vref2 and make under the situation that switch control stopping back recovering surpassing underload overvoltage reference voltage V ref2, all make and recover regularly consistent, but above-mentioned stop or recovering also can be consistent with the zero crossing timing of alternating current and carry out with the zero crossing of alternating voltage.

Claims

1. supply unit, it has:

Translation circuit, it has rectifier, switch element, reactor and diode at least, utilizes the switch motion of described switch element, the direct voltage that is obtained stipulating by AC power;

The input voltage detecting unit, its alternating voltage to described AC power detects;

The direct voltage detecting unit, its direct voltage to described translation circuit output detects; And

The switch motion control unit, it controls the action of described switch element according to by detected alternating voltage of described each detecting unit and direct voltage, so that direct voltage becomes the control voltage of regulation,

It is characterized in that,

Described switch motion control unit carries out following control:

Surpassing under the situation of the 1st level by the detected direct voltage of described direct voltage detecting unit; utilize described switch element at once energising to be stopped; the 1st level is the big value of comparing with described control voltage, the load that is used to protect described translation circuit or is applied in described direct voltage

Surpassing under the situation of the 2nd level by the detected direct voltage of described direct voltage detecting unit, zero crossing at described alternating voltage regularly utilizes described switch element that energising is stopped, and the 2nd level is to compare with described control voltage to compare less value greatly and with described the 1st level.

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

Described switch motion control unit carries out following control:

Utilize surpassing described the 1st level or the 2nd level under the state that described switch element stops energising by the detected direct voltage of described direct voltage detecting unit, utilizing the detected direct voltage of described direct voltage detecting unit to become under the situation less than the assigned voltage of described the 2nd level, regularly utilizing the recovery of will switching on of described switch element at the zero crossing of described alternating voltage.

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

With utilize that described switch element makes that energising recovers less than the assigned voltage of described the 2nd level as described control voltage.