CN204578375U - A kind of DC-DC switch power supply system based on three level DC bus - Google Patents
A kind of DC-DC switch power supply system based on three level DC bus Download PDFInfo
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- CN204578375U CN204578375U CN201520308915.9U CN201520308915U CN204578375U CN 204578375 U CN204578375 U CN 204578375U CN 201520308915 U CN201520308915 U CN 201520308915U CN 204578375 U CN204578375 U CN 204578375U
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Abstract
The utility model discloses a kind of DC-DC switch power supply system based on three level DC bus, comprise three level DC bus, first order Switching Power Supply, second level Switching Power Supply, the first output and the second output; Described three level DC bus is connected with the input of first order Switching Power Supply, and the output of first order Switching Power Supply is connected with the input of the first output and second level Switching Power Supply, and the output of second level Switching Power Supply is connected with the second output.Power density of the present utility model is high, and busbar voltage is low.
Description
Technical field
The utility model belongs to field of power electronics, relates to a kind of switch power supply system, is specifically related to a kind of DC-DC switch power supply system based on three level DC bus.
Background technology
The investigation and application of multi-electrical level inverter is one of latest development direction of modern power electronics technology, also be the emerging Semiconductor Converting Technology of one that development in recent years is got up, three-level inverter is as the one of multi-electrical level inverter, it has more simple circuit topology and control algolithm, good output characteristic, now be widely used in the fields such as frequency converter, electric-power filter of having chance with (APF), solar photovoltaic inverter, become the most very powerful and exceedingly arrogant current inversion transformation technique.The controller of three-level inverter be unable to do without low-tension supply, and therefore Switching Power Supply is that three-level inverter is necessary efficiently.
Traditional switch power supply is based on two level DC bus technology, it inputs or is directly inverter DC bus positive and negative electrode, or the DC power supply that low-voltage alternating current power supply obtains after rectification, before these two kinds of patterns, a kind of pattern is by the impact of busbar voltage grade, in Switching Power Supply, the voltage withstand class of each element requires higher, and electric stress is large; Although rear a kind of pattern solves the too high adverse effect of busbar voltage, it causes its inconvenience in actual use to the requirement of input ac power, and power density is low.
Utility model content
The purpose of this utility model is the shortcoming overcoming above-mentioned prior art, and provide a kind of DC-DC switch power supply system based on three level DC bus, the power density of this system is high, and busbar voltage is low.
For achieving the above object, the DC-DC switch power supply system based on three level DC bus described in the utility model comprises three level DC bus, first order Switching Power Supply, second level Switching Power Supply, the first output and the second output;
Described three level DC bus is connected with the input of first order Switching Power Supply, and the output of first order Switching Power Supply is connected with the input of the first output and second level Switching Power Supply, and the output of second level Switching Power Supply is connected with the second output.
Described first order Switching Power Supply comprise the first power supply soft circuit, the first controller UC2845 circuit, metal-oxide-semiconductor drive circuit, pulse transformer T1 circuit, for detecting the first current detection circuit of current information on three level DC bus and the first output voltage feedback circuit for detecting the first output end voltage information;
Three level DC bus is connected with the input of pulse transformer T1 circuit, described first power supply soft circuit is connected with the first controller UC2845 circuit, the output of the first controller UC2845 circuit is connected by the control end of metal-oxide-semiconductor drive circuit with pulse transformer T1 circuit, and the output of pulse transformer T1 circuit is connected with the input of the first output and second level Switching Power Supply;
The output of described first current detection circuit and the output of the first output voltage feedback circuit are all connected with the control end of the first controller UC2845 circuit.
Described second level Switching Power Supply comprise second source soft circuit, second controller UC2845 circuit, pulse transformer T4 circuit, for detecting the second current detection circuit of the current information of second level Switching Power Supply input end and the second output voltage feedback circuit for the information of voltage that detects the second output;
First output is connected by the power input of divider resistance with second controller UC2845 circuit, second source soft circuit is connected with the reference voltage output terminal of second controller UC2845 circuit, the output of the second current detection circuit and the output of the second output voltage feedback circuit are all connected with the input of second controller UC2845 circuit, the output of second controller UC2845 circuit is connected with the control end of pulse transformer T4 circuit, and the output of pulse transformer T4 circuit is connected with the second output.
Described metal-oxide-semiconductor drive circuit comprises the first transformer, the first drive circuit and the second drive circuit;
The output of described controller UC2845 circuit is connected with the former limit winding of the first transformer, two vice-side winding of the first transformer are connected with the input of the first drive circuit and the input of the second drive circuit respectively, and the output of the first drive circuit and the output of the second drive circuit are connected with two former limit windings of the second transformer in pulse transformer T1 circuit respectively.
Described first drive circuit comprises the first resistance, the second resistance, the 3rd resistance and the 4th resistance, the first diode, the second diode, the first electric capacity, the first triode and the first metal-oxide-semiconductor;
One end of first vice-side winding and the collector electrode of the first triode in first transformer, one end of second resistance R106, one end of first electric capacity and the drain electrode of the first metal-oxide-semiconductor are connected, in first transformer, the other end of first vice-side winding is connected with one end of the anode of the first diode and the first resistance, the other end of the first resistance is connected with the base stage of the first triode, the negative electrode of the first diode is through the emitter of the 3rd resistance and the first triode, the anode of the second diode and one end of the 4th resistance are connected, the other end of the second resistance and the negative electrode of the second diode are connected with the grid of the first metal-oxide-semiconductor, the other end of the 4th resistance is connected with the other end of the first electric capacity, the other end of the first metal-oxide-semiconductor is connected with first former limit winding on the second transformer in pulse transformer circuit.
Described second drive circuit comprises the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance, the second triode, the 3rd diode, the 4th diode, the second electric capacity, the second metal-oxide-semiconductor;
One end of second vice-side winding and the collector electrode of the second triode in first transformer, one end of 8th resistance, one end of second electric capacity and the drain electrode of the second metal-oxide-semiconductor are connected, the other end of second vice-side winding and one end of the 5th resistance in first transformer, the anode of the 3rd diode is connected, the other end of the 5th resistance is connected with the base stage of the second triode, the negative electrode of the 3rd diode is through the emitter of the 6th resistance and the second triode, the anode of the 4th diode and one end of the 7th resistance are connected, the negative electrode of the 4th diode is connected with the other end of the 8th resistance and the grid of the second metal-oxide-semiconductor, the other end of the 7th resistance is connected with the other end of the second electric capacity, the source electrode of the second metal-oxide-semiconductor is connected with second former limit winding on the second transformer in pulse transformer T1 circuit.
The utility model has following beneficial effect:
DC-DC switch power supply system based on three level DC bus described in the utility model adopts three level DC bus to provide electric energy, the scope of application is wider, and the input of first order Switching Power Supply 1 is directly connected with three level DC bus, voltage transitions is carried out by first order Switching Power Supply 1 and second level Switching Power Supply 2, thus reduce the voltage of each element in first order Switching Power Supply and second level Switching Power Supply, and the power density of switch power supply system is significantly improved.First output and the second output all can be used as the power supply that user directly uses, and greatly reduce the volume of power supply, and are significantly reduced by out-put supply ripple, and power supply ripple only has ± 50mV.
Further, described first order Switching Power Supply comprises the first power supply soft circuit, first controller UC2845 circuit, metal-oxide-semiconductor drive circuit, pulse transformer T1 circuit, first current detection circuit and the first output voltage feedback circuit, the pwm control signal of the first controller UC2845 circuit is by metal-oxide-semiconductor drive circuit control impuls transformer T1 circuit, the three level DC busbar voltage that input is come in converts, the pwm control signal effectively avoiding the first controller UV2845 circuit to export by the first power supply soft circuit is excessive in the duty ratio of powered on moment, prevent from impacting,
Further, described second level Switching Power Supply comprises second source soft circuit and two controller UV2845 circuit, and the pwm control signal effectively avoiding second controller UV2845 circuit to export is excessive in the duty ratio of powered on moment, prevents from impacting.
Accompanying drawing explanation
Fig. 1 is structural representation of the present utility model;
Fig. 2 is the structural representation of first order Switching Power Supply 1 in the utility model;
Fig. 3 is the structural representation of second level Switching Power Supply 2 in the utility model;
Fig. 4 is the structural representation of the first power supply soft circuit 11 in the utility model;
Fig. 5 is the structural representation of the first controller UC2845 circuit 12 in the utility model;
Fig. 6 is the structural representation of metal-oxide-semiconductor drive circuit 13 in the utility model;
Fig. 7 is the structural representation of the first current detection circuit 14 in the utility model;
Fig. 8 is the structural representation of pulse transformer T1 circuit 15 in the utility model;
Fig. 9 is the structural representation of the first output voltage feedback circuit 16 in the utility model;
Figure 10 is the structural representation of second source soft circuit 21 in the utility model;
Figure 11 is the structural representation of second controller UC2845 circuit 22 in the utility model;
Figure 12 is the structural representation of the second current detection circuit 23 in the utility model;
Figure 13 is the structural representation of Pulse Electric depressor T4 circuit in the utility model;
Figure 14 is the structural representation of the second output voltage feedback circuit 25 in the utility model;
Figure 15 is the first Switching Power Supply 1 output voltage U in the utility model
o1 testing circuit schematic diagram.
Wherein, 1 be first order Switching Power Supply, 2 be second level Switching Power Supply, 11 to be the first power supply soft circuit, 12 be the first controller UC2845 circuit, 13 be second source soft circuit for metal-oxide-semiconductor drive circuit, 14 is the first current detection circuit, 15 for pulse transformer T1 circuit, 16 is the first output voltage feedback circuit, 21,22 for second controller UC2845 circuit, 23 be the second current detection circuit, 24 for pulse transformer T4 circuit, 25 be the second output voltage feedback circuit.
Embodiment
Below in conjunction with accompanying drawing, the utility model is described in further detail:
With reference to figure 1, Fig. 2 and Fig. 3, the DC-DC switch power supply system based on three level DC bus described in the utility model comprises three level DC bus, first order Switching Power Supply 1, second level Switching Power Supply 2, first output and the second output; Described three level DC bus is connected with the input of first order Switching Power Supply 1, the output of first order Switching Power Supply 1 is connected with the input of the first output and second level Switching Power Supply 2, and the output of second level Switching Power Supply 2 is connected with the second output.
Described first order Switching Power Supply 1 comprise the first power supply soft circuit 11, first controller UC2845 circuit 12, metal-oxide-semiconductor drive circuit 13, pulse transformer T1 circuit 15, for detecting the first current detection circuit 14 of current information on three level DC bus and the first output voltage feedback circuit 16 for detecting the first output end voltage information; Three level DC bus is connected with the input of pulse transformer T1 circuit (15), first power supply soft circuit 11 is connected with the first controller UC2845 circuit 12 middle controller reference voltage output terminal, the output of the first controller UC2845 circuit 12 is connected by the control end of metal-oxide-semiconductor drive circuit 13 with pulse transformer T1 circuit 15, and the output of pulse transformer T1 circuit 15 is connected with the input of the first output and second level Switching Power Supply 2; The output of the first current detection circuit 14 and the output of the first output voltage feedback circuit 16 are all connected with the control end of the first controller UC2845 circuit 12.
Described second level Switching Power Supply 2 comprise second source soft circuit 21, second controller UC2845 circuit 22, pulse transformer T4 circuit 24, for detecting the second current detection circuit 23 of the current information of second level Switching Power Supply 2 input and the second output voltage feedback circuit 25 for the information of voltage that detects the second output; First output is connected by the power input of divider resistance with second controller UC2845 circuit 22, second source soft circuit 21 is connected with the reference voltage output terminal of second controller UC2845 circuit 22, the output of the second current detection circuit 23 and the output of the second output voltage feedback circuit 25 are all connected with the input of second controller UC2845 circuit 22, the output of second controller UC2845 circuit 22 is connected with the control end of pulse transformer T4 circuit 24, and the output of pulse transformer T4 circuit 24 is connected with the second output.
Described metal-oxide-semiconductor drive circuit 13 comprises the first transformer T2, the first drive circuit and the second drive circuit; The output of controller UC2845 circuit is connected with the former limit winding of the first transformer T2, two vice-side winding of the first transformer T2 are connected with the input of the first drive circuit and the input of the second drive circuit respectively, and the output of the first drive circuit and the output of the second drive circuit are connected with two former limit windings of the second transformer in pulse transformer T1 circuit 15 respectively.Described first drive circuit comprises the first resistance, the second resistance R106, the 3rd resistance R104 and the 4th resistance RF1, the first diode D2, the second diode D6, the first electric capacity C82, the first triode Qt1 and the first metal-oxide-semiconductor Q2, one end of first vice-side winding and the collector electrode of the first triode Qt1 in first transformer T2, one end of second resistance R106, one end of first electric capacity C82 and the drain electrode of the first metal-oxide-semiconductor Q2 are connected, in first transformer T2, the other end of first vice-side winding is connected with the anode of the first diode D2 and one end of the first resistance, the other end of the first resistance is connected with the base stage of the first triode Qt1, the negative electrode of the first diode D2 is through the emitter of the 3rd resistance R104 and the first triode Qt1, the anode of the second diode D6 and one end of the 4th resistance RF1 are connected, the other end of the second resistance R106 and the negative electrode of the second diode D6 are connected with the grid of the first metal-oxide-semiconductor Q2, the other end of the 4th resistance RF1 is connected with the other end of the first electric capacity C82, the other end of the first metal-oxide-semiconductor Q2 is connected with first former limit winding on the second transformer in pulse transformer T1 circuit 15.Described second drive circuit comprises the 5th resistance, the 6th resistance R103, the 7th resistance RF2, the 8th resistance R107, the second triode Qt2, the 3rd diode D3, the 4th diode D7, the second electric capacity C83, the second metal-oxide-semiconductor Q3, one end of second vice-side winding and the collector electrode of the second triode Qt2 in first transformer T2, one end of 8th resistance R107, one end of second electric capacity C83 and the drain electrode of the second metal-oxide-semiconductor Q3 are connected, the other end of second vice-side winding and one end of the 5th resistance in first transformer T2, the anode of the 3rd diode D3 is connected, the other end of the 5th resistance is connected with the base stage of the second triode Qt2, the negative electrode of the 3rd diode D3 is through the emitter of the 6th resistance R103 and the second triode Qt2, the anode of the 4th diode D7 and one end of the 7th resistance RF2 are connected, the negative electrode of the 4th diode D7 is connected with the grid of the other end of the 8th resistance R107 and the second metal-oxide-semiconductor Q3, the other end of the 7th resistance RF2 is connected with the other end of the second electric capacity C83, the source electrode of the second metal-oxide-semiconductor Q3 is connected with second former limit winding on the second transformer in pulse transformer T1 circuit 15.
First order Switching Power Supply 1 is mounted on three level DC bus, in order to not affect three level DC character, prevent due to the introducing of first order Switching Power Supply 1 and cause three level DC bus mid point N to offset, therefore in the present embodiment first order Switching Power Supply 1 use transformer to be that former limit devises two groups of identical windings, they are respectively by the control of the first metal-oxide-semiconductor Q2 and the second metal-oxide-semiconductor Q3, during work, the winding two ends pressure drop of two-way former limit is substantially equal, and simultaneously work done provides energy for rear end vice-side winding, in addition two former limit winding characteristics are identical, circuit impedance is equal, therefore the electric current flowing through two-way former limit winding is also substantially equal, avoid two-way former limit winding flow through the difference of electric current and cause three level DC bus mid point N to offset.
The voltage U that second level Switching Power Supply 2 exports with first order Switching Power Supply 1
o1 as power supply, the conducting under the pwm control signal that controller exports controls of transformer primary side winding, shutoff, for vice-side winding provides energy, exports user's required voltage U
o2.Transformer can be designed to multichannel vice-side winding when designing, and such user just can obtain multiple power supplies and export, and design must observe U
o1>U
othe principle of 2.
With reference to figure 4, first power supply soft circuit 11 is connected with the 5V reference voltage output pin of the controller UC2845 in the first controller UC2845 circuit 12, after controller UC2845 powers on, 5V reference voltage output pin and output reference voltage, through resistance R92, the carrying out of electric capacity C85 is charged, make reference voltage slowly rise to 5V, thus the pwm control signal duty ratio suppressing powered on moment controller UC2845 to export is excessive, prevents from impacting.
With reference to figure 5, first controller UC2845 circuit 12 adopts three level DC bus positive pole P and mid point N as power supply, first the positive pole P of three level DC bus obtains 15V voltage after electric resistance partial pressure, it meets the starting of oscillation voltage of controller UC2845, thus first order Switching Power Supply 1 is started working, owing to power supply can be caused to fall instantaneously when controller UC2845 exports pwm control signal, and cause controller UC2845 to quit work, therefore in rear class design of transformer, auxiliary power supply winding is added, the continuation that collateral security controller UC2845 powers, prevent pwm control signal from interrupting, cause system works unstable.
The outside frequency of oscillation of controller UC2845 is determined by resistance R112 and electric capacity C31, and the pwm frequency signal F that controller UC2845 exports is then the half of outside frequency of oscillation, i.e. F=f/2.
Provide enough low low level when the diode D5 of (three level DC bus mid point N) reversal connection is controller UC2845 output low level control signal to relatively, prevent metal-oxide-semiconductor q9 from occurring the phenomenon misleaded.
With reference to figure 8, in order to make three level DC bus mid point do not drawn partially when Switching Power Supply works in pulse transformer T1 circuit 15, the former limit Winding Design of transformer T1 is the half that the number of turn of two groups of winding T1-1 and T1-2 with identical parameters, winding T1-1 and T1-2 is former limit umber of turn NP.
Winding T1-1 one end, former limit of transformer T1 is connected with the positive pole P of three level DC bus, and the other end is connected with the drain D of the first metal-oxide-semiconductor Q2, and the source S of the first metal-oxide-semiconductor Q2 is by the current sampling resistor R in the first current detection circuit 14
t1 is electrically connected with three level DC bus mid point N, thus forms the upper brachium pontis of first order Switching Power Supply 1; Winding T1-2 one end, former limit of transformer T1 is electrically connected with the mid point N of three level DC bus, the other end is electrically connected with the drain D of the second metal-oxide-semiconductor Q3 by the first side winding of current transformer T3 in the first current detection circuit 14, the source S of the second metal-oxide-semiconductor Q3 is electrically connected with the negative pole G of three level DC bus, thus forms the lower brachium pontis of first order Switching Power Supply 1.The upper brachium pontis of first order Switching Power Supply 1 and lower brachium pontis are connected by the mid point N of three level DC bus, the three level brachium pontis that common formation is complete, because transformer primary side winding T1-1 is identical with the T1-2 number of turn, be installed on same transformation skeleton, and two groups of windings use same magnetic core, its characteristic is substantially identical, and the identical two groups of former limit winding conductings simultaneously of duty ratio in the course of work, turn off simultaneously, and the upper brachium pontis of first order Switching Power Supply 1 and lower brachium pontis impedance identical, therefore the electric current flowing through the upper brachium pontis of first order Switching Power Supply 1 and lower brachium pontis is equal, thus effectively ensure that three level DC bus mid point can not offset, make three level DC bus can steady operation.
The vice-side winding Same Name of Ends of transformer T1 exports exports to user and second level Switching Power Supply 2 after diode D4 rectification.The AC power that transformer T1 vice-side winding exports is through diode D4 rectification, diode D4 constantly opens and turns off, thus produce switch time ripple voltage, in order to improve the quality of out-put supply, therefore rectifier diode D4 resistance capaciting absorpting circuit in parallel is given, open with absorption diode D4, turn off process formed impact, reduce ripple export.
With reference to figure 9, the output voltage U of first order Switching Power Supply 1 in the first output voltage feedback circuit 16
o1 obtains voltage U after electric resistance partial pressure
fb1, this voltage U
fb1 compares with the inner 2.5V reference voltage of AZ431, works as U
fbduring 1>=2.5V, AZ431 conducting, makes optocoupler U6 conducting, and controller UC2845 voltage detecting feed back input pin drags down, then the duty cycle adjustment of the pwm control signal of controller UC2845 output is 0%, works as U
fbduring 1<2.5V, AZ431 ends, then the voltage of controller voltage detecting feed back input pin is constant, and controller UC2845 normally exports pwm control signal.
With reference to figure 6, in the Switching Power Supply course of work, the phenomenon that mid point N offsets is there is in metal-oxide-semiconductor drive circuit 13 in order to prevent three level DC bus, ensure that the operating characteristic of three level DC bus does not change, first order Switching Power Supply 1 must ensure that the positive pole P alignment N of three level DC bus is identical with the load of mid point N anticathode G in the course of the work, and flow through the electric current of formed objects, therefore transformer T1 just devises two groups of characteristic identical former limit windings when designing, and the first metal-oxide-semiconductor Q2 using two specifications and models identical and the second metal-oxide-semiconductor Q3 controls.In order to ensure that two groups of former limit windings have identical load, therefore the first metal-oxide-semiconductor Q2 and the second metal-oxide-semiconductor Q3 opens simultaneously or turns off, and the first metal-oxide-semiconductor Q2 and the second metal-oxide-semiconductor Q3 has identical control signal.
In order to realize the first metal-oxide-semiconductor Q2 and the second metal-oxide-semiconductor Q3 has identical pwm control signal, the pwm control signal control transformer T2 using No. 1 controller UC2845 to export in design former limit work.Transformer T2 secondary is then two groups of identical windings, and two-way vice-side winding adopts isolation design, exports the pwm control signal of two-way isolation.This pwm control signal can export enough large current spike, to the joint capacitor fast charging of the first metal-oxide-semiconductor Q2 and the second metal-oxide-semiconductor Q3, thus makes the first metal-oxide-semiconductor Q2 and the second metal-oxide-semiconductor Q3 fast conducting.
Controller UC2845 exports pwm control signal driven MOS pipe q9 work, electric current is made to flow through transformer T2 former limit winding, and on the vice-side winding of transformer T2, form the identical control signal of pwm control signal exported with controller UC2845, when this pwm control signal is high level, electric current flows through the first diode D2, the 3rd resistance R104 and the second diode D6, charge to the junction capacitance of the first metal-oxide-semiconductor Q2 fast, after the grid voltage of the first metal-oxide-semiconductor Q2 rises to 5V, the complete conducting of the first metal-oxide-semiconductor Q2.When this control signal is low level, first diode D2 ends, second diode D6 both end voltage is reverse simultaneously, and the second diode D6 ends, and the grid voltage of the first metal-oxide-semiconductor Q2 puts on emitter and the collector electrode two ends of the first triode by the 4th resistance RF1.Low level control signal makes the first triode Qt1 base stage flow through base current I
b, the first triode Qt1 conducting, is made the grid of the first metal-oxide-semiconductor Q2 be discharged to transformer T2 vice-side winding different name end by the 4th resistance RF1, the first metal-oxide-semiconductor Q2 is turned off fast.
With reference to figure 7, the operation principle of the first current detection circuit 14 is: from the electric current I of the positive pole P inflow transformer T3 former limit winding of three level DC bus
o1, directly do not flow back to three level DC bus mid point N, but flow through the very little sampling resistor RT1 of resistance value, and form sampled voltage U at sampling resistor RT1 two ends
cT1, the electric current I flowed out by three level DC bus mid point N
o2 first flow through transformer T1 another organize former limit winding, then flow back to the negative pole G of three level DC bus after the first side winding and the second metal-oxide-semiconductor Q3 of current transformer T3.Electric current I
o2 flow through instrument transformer T3 first side winding, and in secondary side winding, form detection electric current I
cT2.Detect electric current I
cT2 entered diode D1 rectification after, form sampled voltage U at sampling resistor RT2 two ends
cT2.The result that above-mentioned two-way current detecting sampled voltage passes through superposition is current sample voltage U three level DC bus flowing through whole first order Switching Power Supply 1
cT, this voltage inputs to controller UC2845 after current-limiting resistance R97, and controller UC2845 is by detecting U
cTamplitude just can judge whether to be short-circuited or electric current excessive, wherein, when electric current is excessive or be short-circuited, the first current detection circuit 14 output voltage U
cT>1V, then controller UC2845 cuts off pwm control signal output; When electric current is normal, the first current detection circuit 14 output voltage U
cT<1V, then controller UC2845 normally exports pwm control signal.
With reference to Figure 10, second source soft circuit 21 is connected with the 5V reference voltage output pin of controller UC2845, after controller UC2845 powers on, 5V reference voltage output pin and output reference voltage charge to electric capacity C86 through resistance R91, reference voltage is made slowly to rise to 5V, thus the pwm control signal duty ratio suppressing powered on moment controller UC2845 to export is excessive, prevent from impacting.
With reference to Figure 11, the output voltage U of first order Switching Power Supply 1
o1 obtains the controller UC2845 starting of oscillation voltage U that is greater than 10V after resistance R178 and resistance R179 dividing potential drop
z2, controller UC2845 starts to export pwm control signal, supply voltage can be dragged down when controller UC2845 starts to export, and cause controller UC2845 to stop exporting pwm control signal, make system cannot steady operation, therefore need design the accessory power supply that a road is greater than 10V when Design of Transformer and export.
The outside frequency of oscillation f of controller UC2845 is determined by resistance R113 and electric capacity C32, and the pwm frequency signal F that controller UC2845 exports is then the half of outside frequency of oscillation.
Controller UC2845 delivery outlet can export the electric current being greater than 1A, and controller UC2845 can directly control metal-oxide-semiconductor q10.The diode D14 of reversal connection is at pwm control signal for providing enough low low level during low level over the ground, makes metal-oxide-semiconductor q10 be in stable off state, prevents metal-oxide-semiconductor q10 misoperation.
With reference to Figure 12, flow through transformer T4 and sample with the little valued resistor that the electric current of metal-oxide-semiconductor q10 passes through to connect, when electric current is excessive or short circuit time, this sampled voltage U
cT3>=1V, controller UC2845 cut off pwm control signal and export, and prevent from damaging metal-oxide-semiconductor q10.When electric current is normal, this sampled voltage U
cT3<1V, controller UC2845 normally exports pwm control signal.
With reference to Figure 13, winding one end, former limit of transformer T4 is connected with the output voltage positive pole of first order Switching Power Supply 1, the other end is connected with the drain electrode of metal-oxide-semiconductor q10, because metal-oxide-semiconductor is when turning off, transformer T4 former limit winding both end voltage polarity is reversed, the former limit of transformer T4 becomes power supply and continues outside output current, then form reverse spike voltage in the drain electrode of metal-oxide-semiconductor q10;
The vice-side winding output voltage of transformer T4 is less than original edge voltage U
othe rectifier diode of the vice-side winding output of 1, transformer T4 can produce larger ripple voltage in conducting and turn off process, by increasing RC absorbing circuit to the rectifier diode of each road vice-side winding, effectively reduces the output ripple of first order Switching Power Supply 1.
With reference to Figure 14, using any output of transformer T4 as feedback, the effective stability ensureing second level Switching Power Supply 2 output voltage, and realize the closed-loop control of second level Switching Power Supply 2, the feedback voltage be removed obtains a reference voltage U after electric resistance partial pressure
fb, this voltage and the inner 2.5V reference voltage of controller UC2845 compare, and work as U
fbduring >2.5V, then switch power source output voltage is too high, and controller UC2845 will reduce pwm control signal duty ratio, work as U
fbduring <2.5V, then switch power source output voltage is too low, and controller UC2845 will increase pwm control signal duty ratio, realizes the control to second level Switching Power Supply 2 output voltage.
With reference to Figure 15, the output voltage U of first order Switching Power Supply 1
o1 not only can as user's power supply but also as the power supply of Switching Power Supply 2, U in circuit
o1 dividing potential drop entering resistance R134, resistance R136 and resistance R132, resistance R133 respectively, two kinds of bleeder circuits adopt different dividing ratios, make U
o1 reach respectively the upper limit and lower in limited time, dividing potential drop gained voltage is all 2.5V.Wherein, lower voltage limit U is obtained after resistance R134, resistance R136 dividing potential drop
oD, resistance R132, resistance R133 obtain upper voltage limit U after dividing potential drop
oT.
Work as U
o1<U
oDtime, gained voltage U after resistance R134, resistance R136 dividing potential drop
fY1<2.5V, detector U5 is by U
fY1 2.5V reference voltage inner with it compares, detector U5 not conducting, and power supply indicator D25 cathode terminal voltage is U
o1, the two ends of power supply indicator D25 are without pressure drop, and indicator light can not be lighted, and voltage-stabiliser tube D19 conducting simultaneously, makes NPN triode q5 base voltage raise, triode q5 conducting, and testing circuit exports high level fault signal.
Work as U
oT≤ U
o1≤U
oDtime, gained voltage U after resistance R134, resistance R136 dividing potential drop
fY1>=2.5V, now detector U5 is by U
fY1 2.5V reference voltage inner with it compares, detector U5 conducting, enters gained voltage U after resistance R132, resistance R133 dividing potential drop simultaneously
fY2<2.5V, detector U4 is by U
fY2 compare with inner 2.5V reference voltage, detector U4 not conducting.The cathode terminal of power supply indicator D25 drags down by detector U5, and indicator light D25 is lighted.Voltage-stabiliser tube D19 cut-off simultaneously, the base voltage of triode q5 is dragged down, and triode q5 ends, and fault-free signal exports.
Work as U
o1>U
oTtime, gained voltage U after resistance R132, resistance R133 dividing potential drop
fY2>2.5V, detector U4 is by U
fY2 compare with inner 2.5V reference voltage, and detector U4 conducting, by gained voltage U after resistance R134, resistance R136 dividing potential drop
fY1 is pulled to ground, due to U
fY1<2.5V, then detector U5 ends, and the cathode terminal voltage rise of power supply indicator D25 is U
o1, power supply indicator D25 two ends are without pressure drop, and indicator light extinguishes, and voltage-stabiliser tube D19 conducting simultaneously, makes the base voltage of NPN triode q5 raise, triode q5 conducting, and the first Switching Power Supply exports U
o1 voltage detecting circuit 31 exports high level fault signal.
Claims (6)
1. based on a DC-DC switch power supply system for three level DC bus, it is characterized in that, comprise three level DC bus, first order Switching Power Supply (1), second level Switching Power Supply (2), the first output and the second output;
Described three level DC bus is connected with the input of first order Switching Power Supply (1), the output of first order Switching Power Supply (1) is connected with the input of the first output and second level Switching Power Supply (2), and the output of second level Switching Power Supply (2) is connected with the second output.
2. the DC-DC switch power supply system based on three level DC bus according to claim 1, it is characterized in that, described first order Switching Power Supply (1) comprise the first power supply soft circuit (11), the first controller UC2845 circuit (12), metal-oxide-semiconductor drive circuit (13), pulse transformer T1 circuit (15), for detecting first current detection circuit (14) of current information on three level DC bus and the first output voltage feedback circuit (16) for detecting the first output end voltage information;
Described first power supply soft circuit (11) is connected with the control end of the first controller UC2845 circuit (12), the output of the first controller UC2845 circuit (12) is connected by the control end of metal-oxide-semiconductor drive circuit (13) with pulse transformer T1 circuit (15), three level DC bus is connected with the input of pulse transformer T1 circuit (15), and the output of pulse transformer T1 circuit (15) is connected with the input of the first output and second level Switching Power Supply (2);
The output of described first current detection circuit (14) and the output of the first output voltage feedback circuit (16) are all connected with the control end of the first controller UC2845 circuit (12).
3. the DC-DC switch power supply system based on three level DC bus according to claim 1, it is characterized in that, described second level Switching Power Supply (2) comprising second source soft circuit (21), second controller UC2845 circuit (22), pulse transformer T4 circuit (24), flowing through second current detection circuit (23) of the current information of second switch power supply (2) and the second output voltage feedback circuit (25) for the information of voltage that detects the second output for detecting first order Switching Power Supply (1) output;
First output is connected by the power input of divider resistance with second controller UC2845 circuit (22), second source soft circuit (21) is connected with the reference voltage output terminal of second controller UC2845 circuit (22), the output of the second current detection circuit (23) and the output of the second output voltage feedback circuit (25) are all connected with the input of second controller UC2845 circuit (22), the output of second controller UC2845 circuit (22) is connected with the control end of pulse transformer T4 circuit (24), the output of pulse transformer T4 circuit (24) is connected with the second output.
4. the DC-DC switch power supply system based on three level DC bus according to claim 2, is characterized in that, described metal-oxide-semiconductor drive circuit (13) comprises the first transformer (T2), the first drive circuit and the second drive circuit;
The output of described controller UC2845 circuit is connected with the former limit winding of the first transformer (T2), two vice-side winding of the first transformer (T2) are connected with the input of the first drive circuit and the input of the second drive circuit respectively, and the output of the first drive circuit and the output of the second drive circuit are connected with two former limit windings of the second transformer in pulse transformer T1 circuit (15) respectively.
5. the DC-DC switch power supply system based on three level DC bus according to claim 4, it is characterized in that, described first drive circuit comprises the first resistance, the second resistance (R106), the 3rd resistance (R104) and the 4th resistance (RF1), the first diode (D2), the second diode (D6), the first electric capacity (C82), the first triode (Qt1) and the first metal-oxide-semiconductor (Q2);
One end of first vice-side winding and the collector electrode of the first triode (Qt1) in first transformer (T2), one end of second resistance (R106), one end of first electric capacity (C82) and the drain electrode of the first metal-oxide-semiconductor (Q2) are connected, in first transformer (T2), the other end of first vice-side winding is connected with the anode of the first diode (D2) and one end of the first resistance, the other end of the first resistance is connected with the base stage of the first triode (Qt1), the negative electrode of the first diode (D2) is through the emitter of the 3rd resistance (R104) with the first triode (Qt1), the anode of the second diode (D6) and one end of the 4th resistance (RF1) are connected, the other end of the second resistance (R106) and the negative electrode of the second diode (D6) are connected with the grid of the first metal-oxide-semiconductor (Q2), the other end of the 4th resistance (RF1) is connected with the other end of the first electric capacity (C82), the other end of the first metal-oxide-semiconductor (Q2) is connected with first former limit winding on the second transformer in pulse transformer T1 circuit (15).
6. the DC-DC switch power supply system based on three level DC bus according to claim 5, it is characterized in that, described second drive circuit comprises the 5th resistance, the 6th resistance (R103), the 7th resistance (RF2), the 8th resistance (R107), the second triode (Qt2), the 3rd diode (D3), the 4th diode (D7), the second electric capacity (C83), the second metal-oxide-semiconductor (Q3);
One end of second vice-side winding and the collector electrode of the second triode (Qt2) in first transformer (T2), one end of 8th resistance (R107), one end of second electric capacity (C83) and the drain electrode of the second metal-oxide-semiconductor (Q3) are connected, the other end of second vice-side winding and one end of the 5th resistance in first transformer (T2), the anode of the 3rd diode (D3) is connected, the other end of the 5th resistance is connected with the base stage of the second triode (Qt2), the negative electrode of the 3rd diode (D3) is through the emitter of the 6th resistance (R103) with the second triode (Qt2), the anode of the 4th diode (D7) and one end of the 7th resistance (RF2) are connected, the negative electrode of the 4th diode (D7) is connected with the other end of the 8th resistance (R107) and the grid of the second metal-oxide-semiconductor (Q3), the other end of the 7th resistance (RF2) is connected with the other end of the second electric capacity (C83), the source electrode of the second metal-oxide-semiconductor (Q3) is connected with second former limit winding on the second transformer in pulse transformer T1 circuit (15).
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104868739A (en) * | 2015-05-13 | 2015-08-26 | 西安西驰电能技术有限公司 | DC-DC switching power system based on three-level DC bus |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104868739A (en) * | 2015-05-13 | 2015-08-26 | 西安西驰电能技术有限公司 | DC-DC switching power system based on three-level DC bus |
| CN104868739B (en) * | 2015-05-13 | 2017-03-15 | 西安西驰电能技术有限公司 | A kind of DC DC switch power supply systems based on three level DC bus |
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