CN208337404U - A kind of circuit carrying out frequency converter braking using Switching Power Supply - Google Patents
A kind of circuit carrying out frequency converter braking using Switching Power Supply Download PDFInfo
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- CN208337404U CN208337404U CN201820953389.5U CN201820953389U CN208337404U CN 208337404 U CN208337404 U CN 208337404U CN 201820953389 U CN201820953389 U CN 201820953389U CN 208337404 U CN208337404 U CN 208337404U
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Abstract
The utility model discloses a kind of circuits that frequency converter braking is carried out using Switching Power Supply, including PWM driving chip, the input terminal that busbar voltage passes through protection circuit connection two-stage amplifying circuit, the base stage of the output end connecting triode Q2 of two-stage amplifying circuit, the compensation pin Comp of the base stage connection PWM driving chip of triode Q2, the Voltage Reference pin VREF and oscillation frequency pin Osc of oscillating circuit connection PWM driving chip, the output end vo ut pin of PWM driving chip connects the grid of IGBT pipe Q1 by driving circuit, the drain electrode of IGBT pipe Q1 connects protection circuit by braking circuit, the current input terminal of the source electrode connection current sensor F of IGBT pipe Q1, the output end of current sensor F is grounded.This programme is directly fed back busbar voltage as Voltage loop, while this programme generates PWM drive waveforms using power supply chip, and frequency is fixedly adjustable；Feedback control loop is simple and reliable, it is easy to accomplish.
Description
Technical field
The utility model belongs to field of circuit technology, and in particular to a kind of electricity that frequency converter braking is carried out using Switching Power Supply
Road.
Background technique
In frequency conversion speed-adjusting system, the basic skills of reduction of speed is exactly to be realized by gradually reducing given frequency.Work as dragging
The inertia of system is larger, and the lower general who has surrendered of the revolving speed of motor does not catch up with the decline of motor synchronous rotational speed, i.e. the actual speed ratio of motor
Its synchronizing speed is high, just phase when the direction of the rotating excitation field magnetic line of force of rotor winding cutting at this time and motor constant-speed operation
Instead, the induced electromotive force of rotor windings and sense of current also all on the contrary, generated electromagnetic torque also just and motor rotation side
To on the contrary, negative torque will occur in motor, practical motor at this time is generator, and system is in regenerative braking state, will drag
The kinetic energy of dynamic system is fed back on frequency changer direct current bus, constantly increase DC bus-bar voltage, even up to dangerous stage
(frequency converter damage etc.).
Summary of the invention:
The purpose of the utility model is to provide a kind of circuits that frequency converter braking is carried out using Switching Power Supply, solve background skill
The problem of art, and feedback control loop is simple and reliable, it is easy to accomplish.
To achieve the goals above, the technical solution of the utility model are as follows:
A kind of circuit carrying out frequency converter braking using Switching Power Supply, including PWM driving chip, busbar voltage pass through protection
The input terminal of circuit connection two-stage amplifying circuit, the base stage of the output end connecting triode Q2 of two-stage amplifying circuit, triode Q2
Base stage connection PWM driving chip compensation pin Comp, oscillating circuit connect PWM driving chip Voltage Reference pin VREF
The grid of IGBT pipe Q1 is connected by driving circuit with the output end vo ut pin of oscillation frequency pin Osc, PWM driving chip,
The drain electrode of IGBT pipe Q1 connects protection circuit by braking circuit, and the electric current of the source electrode connection current sensor F of IGBT pipe Q1 is defeated
Enter end, the output end ground connection of current sensor F, the voltage output end of current sensor connects resistance R21, one end of resistance R21
Ground connection, the other end connect the current sampling pin Sense of PWM driving chip.
Preferably, the feedback input pin Vfb of PWM driving chip is grounded by pull down resistor R13.
Preferably, protection circuit includes protective resistance R3 and filter capacitor C1, one end connection bus electricity of protective resistance R3
Positive pressure pole, the other end connect the input terminal of two-stage amplifying circuit, and the both ends of filter capacitor C1 are separately connected the positive and negative of busbar voltage
Pole.
Preferably, two-stage amplifying circuit includes operational amplifier X1 and operational amplifier X2, the anode of operational amplifier X1
Input terminal connects the anode of busbar voltage by resistance R4 with the protective resistance R3 of protection circuit, and the cathode of operational amplifier X1 is defeated
Enter the cathode that end passes through resistance R6 connection busbar voltage, feedback is equipped between the output end and negative input of operational amplifier X1
Circuit；
The negative input of operational amplifier X2 passes through the output end of resistance R15 connection operational amplifier X1, operation amplifier
The electrode input end of device X2 by resistance R16 connection reference voltage source, the output end and negative input of operational amplifier X2 it
Between be equipped with concatenated resistance R14 and capacitor C2；The output end of operational amplifier X2 is connect by concatenated resistance R12 and resistance R11
Base stage of the common point of ground, resistance R12 and resistance R11 as the output end connecting triode Q2 of two-stage amplifying circuit；Feedback electricity
Road includes resistance R10 and resistance R22 in parallel.
Preferably, the model UC3843 of PWM driving chip
Preferably, the electrode input end of operational amplifier is equipped with first feed forward circuit in parallel with resistance R4, operation amplifier
The negative input of device is respectively equipped with second feed forward circuit in parallel with resistance R6；First feed forward circuit includes concatenated capacitor C5
With resistance R17, the second feed forward circuit includes concatenated capacitor C7 and resistance R18.
Preferably, oscillating circuit includes resistance R7, capacitor C4 and capacitor C14, one end connection Voltage Reference of resistance R7 draws
One end of foot VREF and capacitor C14, one end of the other end connection oscillation frequency pin Osc and capacitor C4 of resistance R7, capacitor C4
The other end connection capacitor C14 the other end.
Preferably, braking circuit includes R2 and diode D1 in parallel.
Preferably, driving circuit includes resistance R1, triode Q3, triode Q4, resistance R9 and resistance R19；Resistance R1's
One end connection PWM driving chip output end vo ut pin, the base stage of the other end connecting triode Q3 and triode Q4 of resistance R1,
The emitter of triode Q3 and the emitter of triode Q4 pass through the grid that resistance R9 connects IGBT pipe Q1 with resistance R19 respectively；
The base stage of triode Q3 connects power supply, the base earth of triode Q4.
Preferably, resistance R21 connects the current sampling pin Sense of PWM driving chip, filter circuit by filter circuit
Including resistance R5 and capacitor C6.
The utility model has the beneficial effects that: this programme is directly fed back busbar voltage as Voltage loop, while we
Case generates PWM drive waveforms using power supply chip, and frequency is fixedly adjustable；Feedback control loop is simple and reliable, it is easy to accomplish.And the electricity
Line structure has electric current loop and external Voltage loop double -loop control inside PWM driving chip, and bus voltage value fluctuates small etc. excellent
Point.For the utility model for brake unit higher cost in practical application, circuit structure is complicated, a kind of at low cost, nothing of proposition
Software design is needed, circuit structure is simple, safe and reliable, the solution with practical application value.The utility model is current
Implementation be, it is a kind of using current mode PWM chip UC3843 carry out frequency converter control for brake circuit, work as busbar voltage
When not reaching pre-determined threshold voltage value, 1 foot of feedback output pin of UC3843 is pulled low, and PWM chip does not export PWM waveform,
IGBT is in an off state, on major loop without influence；When busbar voltage is more than pre-determined threshold voltage value, the feedback of UC3843 is defeated
1 foot of pin is raised out, open-minded, the major loop conducting of the 6 feet output PWM drive signal control IGBT of UC3843, busbar voltage
It is discharged by braking resistor, busbar voltage maintains setting voltage.The key of the utility model is by busbar voltage sampled signal
Result after amplifier processing is compared integral with reference voltage is outer loop control, which drops by diode and resistance
The benchmark being compared after pressure as electric current loop sampled signal, to realize the braking of double -loop control busbar voltage.
Detailed description of the invention
Fig. 1 is the utility model embodiment electrical block diagram；
Fig. 2 is the internal structure chart of the PWM driving chip for the model UC3843 that the utility model embodiment uses；
Fig. 3 is the utility model embodiment busbar voltage waveform diagram；
Fig. 4 is the utility model embodiment PWM drive signal waveform diagram.
Specific embodiment
The utility model is described further with reference to the accompanying drawings and examples.
A kind of circuit carrying out frequency converter braking using Switching Power Supply, including PWM driving chip, busbar voltage pass through protection
The input terminal of circuit connection two-stage amplifying circuit, the base stage of the output end connecting triode Q2 of two-stage amplifying circuit, triode Q2
Base stage connection PWM driving chip compensation pin Comp, oscillating circuit connect PWM driving chip Voltage Reference pin VREF
The grid of IGBT pipe Q1 is connected by driving circuit with the output end vo ut pin of oscillation frequency pin Osc, PWM driving chip,
The drain electrode of IGBT pipe Q1 connects protection circuit by braking circuit, and the electric current of the source electrode connection current sensor F of IGBT pipe Q1 is defeated
Enter end, the output end ground connection of current sensor F, the voltage output end of current sensor connects resistance R21, one end of resistance R21
Ground connection, the other end connect the current sampling pin Sense of PWM driving chip.
The feedback input pin Vfb of PWM driving chip is grounded by pull down resistor R13.
Protection circuit includes protective resistance R3 and filter capacitor C1, and one end connection busbar voltage of protective resistance R3 is positive,
The other end connects the input terminal of two-stage amplifying circuit, and the both ends of filter capacitor C1 are separately connected the positive and negative anodes of busbar voltage.
Two-stage amplifying circuit includes operational amplifier X1 and operational amplifier X2, and the electrode input end of operational amplifier X1 is logical
The anode that resistance R4 connects busbar voltage with the protective resistance R3 of protection circuit is crossed, the negative input of operational amplifier X1 passes through
The cathode of resistance R6 connection busbar voltage is equipped with feed circuit between the output end and negative input of operational amplifier X1；
The negative input of operational amplifier X2 passes through the output end of resistance R15 connection operational amplifier X1, operation amplifier
The electrode input end of device X2 by resistance R16 connection reference voltage source, the output end and negative input of operational amplifier X2 it
Between be equipped with concatenated resistance R14 and capacitor C2；The output end of operational amplifier X2 is connect by concatenated resistance R12 and resistance R11
Base stage of the common point of ground, resistance R12 and resistance R11 as the output end connecting triode Q2 of two-stage amplifying circuit.Feedback electricity
Road includes resistance R10 and resistance R22 in parallel.
The model UC3843 of PWM driving chip.
The electrode input end of operational amplifier is equipped with first feed forward circuit in parallel with resistance R4, the cathode of operational amplifier
Input terminal is respectively equipped with second feed forward circuit in parallel with resistance R6；First feed forward circuit includes concatenated capacitor C5 and resistance
R17, the second feed forward circuit include concatenated capacitor C7 and resistance R18.
Oscillating circuit includes resistance R7, capacitor C4 and capacitor C14, one end connection Voltage Reference pin VREF of resistance R7 and
One end of capacitor C14, one end of the other end connection oscillation frequency pin Osc and capacitor C4 of resistance R7, the other end of capacitor C4
Connect the other end of capacitor C14.
Braking circuit includes R2 and diode D1 in parallel.
Driving circuit includes resistance R1, triode Q3, triode Q4, resistance R9 and resistance R19；One end of resistance R1 connects
PWM driving chip output end vo ut pin, the base stage of the other end connecting triode Q3 and triode Q4 of resistance R1, triode Q3
Emitter and the emitter of triode Q4 pass through the grid that resistance R9 connects IGBT pipe Q1 with resistance R19 respectively；Triode Q3
Base stage connect power supply, the base earth of triode Q4.
Resistance R21 connects the current sampling pin Sense of PWM driving chip by filter circuit, and filter circuit includes electricity
Hinder R5 and capacitor C6.
The specific working mode of circuit described in the present embodiment are as follows:
DC Source V1 is PWM driving chip power supply, and Pulse Source V2 is as emulation busbar voltage, DC
Source V3 is reference voltage source；Main devices include that bus filter capacitor C1 through protective resistance R3 is connected in parallel on bus both ends.System
Dynamic resistance R2 and anti-paralleled diode D1 is connected on bus both ends with Q1 (Q1 is IGBT pipe) and current sensor F1, works as mother
When line voltage is more than limit value, Q1 conducting is discharged.The output signal series connection divider resistance R21 of current sensor F1 is drawn to ground,
Current signal is converted into the voltage signal on resistance R21, the RC filter circuit that this signal is formed by resistance R5 and capacitor C6
It is transported to the ISENSE pin of PWM driving chip U1.U1 is the VCC foot and DC Source V1 of PWM driving chip UC3843, U1
It is connected and powers for chip, R1 is the driving resistance of pwm signal, the VOUT pin of a termination U1, the other end and divider resistance
R30, the base stage of NPN type triode Q3, the base stage of PNP type triode Q4 are connected, and the other end of R30 is drawn to ground, the collector of Q3
Be connected with DC Source V1, emitter is connected with one end driving resistance R9 of IGBT, the collector of Q4 draw to ground, emitter with
One end of discharge resistance R19 is connected, and the other end of R9 and R19 all access the grid of IGBT (Q1)；The access of the one end filter capacitor C14
The VREF foot of U1, the other end access the GND foot of U1, and resistance R7 is in parallel with C14 after connecting with capacitor C4, form oscillating circuit,
Frequency triangular wave is determined in the OSC foot of the common point access U1 of R7 and C4, input one, and R13 is pull down resistor, and the VFB of U1 is accessed in one end
Foot, it is another to terminate to GND；The anode of busbar voltage, the other end and resistance R8 are accessed in the one end resistance R4, and R20 is connected, R8 and R20
Bleeder circuit, the forward direction of the voltage signal input X1 operational amplifier of common point, resistance R17 series capacitance are formed after parallel connection with R4
It is parallel to the both ends of X1 forward direction input resistance R4 after C5, is parallel to X1 negative sense input resistance R6's after resistance R18 series capacitance C7
Both ends, as the feed forward circuit of X1, resistance R10 and R22 is the feedback resistance of X1；Resistance R15 is the negative sense of operational amplifier X2
Input resistance, the other end are connected with the output end of X1, and R16 is the positive input resistance of X2, the other end and reference voltage source DC
Source V3 is connected, and capacitor C2 series resistance R14 forms integrating circuit, and the negative input of a termination X2 is another to terminate X2's
Output end；Resistance R12 and R11 forms bleeder circuit, and the other end of R11 accesses ground, the other end of R12 and the output end phase of X2
Even, Q2 is NPN type triode, and collector accesses the COMP foot of U1, and emitter is drawn to ground, the common end phase of base stage and R12 and R11
Even.
The utility model is generally used for frequency converter brake portion, and common PWM driving chip is the pulsewidth modulation core of TI
The structure of piece UC3843, the chip are as shown in Figure 2.Wherein Osc foot is frequency pin, by setting the value of chip exterior R/C, frequency
Rate is fixedly adjustable；Vfb foot is the inverting input terminal of error amplifier, and this programme realizes outer loop control using external amplifier,
So directly Vfb foot is drawn by resistance R13 to GND；Comp foot is the output end of built-in chip type error amplifier；Sense foot
Pin is detected for main circuit current, the output of Comp foot is adopted after two built-in diodes and divider resistance decompression with Sense foot
The voltage value of sample is compared, and the duty cycle of the PWM waveform of the output of Vout foot is determined with this.
In Fig. 1, X1 is operational amplifier, constitutes difference scaling circuit in circuit, and busbar voltage is put by ratio
Value after big device is input to the cathode of amplifier X2 by R15.The positive input of amplifier X2 is the voltage reference of setting, and the two passes through
After comparing integrating circuit, output control triode Q2's opens ratio, and then controls the level of Comp foot.Work as frequency converter
In energy feedback state, busbar voltage is increased, and X1 output increases, and X2 output reduces, and COMP foot voltage increases, and PWM output accounts for
Reciprocal of duty cycle improves, and bus is discharged by R2, so that busbar voltage can reduce.When frequency converter is in normal motoring condition, busbar voltage
It reduces, X1 output reduces, and X2 output is high level, and COMP foot voltage is that 0, PWM output duty cycle is 0, and busbar voltage will not become
Change.Resistance R17, C5, C7, R18 are the feed forward circuit of amplifier, and effect is to play the role of feeding back in advance to the variation of bus, with
Reduce the voltage fluctuation of bus.R12, C2 are integrating circuit, guarantee that the duty cycle of PWM waveform is uniform, the voltage fluctuation ratio of bus
It is smoother.
Fig. 4 is bus simulation result diagram, and as can be seen from Figure, the fluctuation of 610V busbar voltage only has 0.5V, about
0.1%, and can achieve 20V, about 4% using the busbar voltage fluctuation of comparator, it is seen that using after the utility model can be with
The fluctuation of busbar voltage is greatly reduced, there is very high practicability.
It should be understood that for those of ordinary skills, it can be modified or changed according to the above description,
And all these modifications and variations all should belong to the protection scope of the appended claims for the utility model.Do not make in this specification in detail
What is carefully described partly belongs to the prior art well known to professional and technical personnel in the field.
Claims (10)
1. a kind of circuit for carrying out frequency converter braking using Switching Power Supply, it is characterised in that: including PWM driving chip, bus electricity
Pressure passes through the input terminal of protection circuit connection two-stage amplifying circuit, the output end connecting triode Q2's of the two-stage amplifying circuit
Base stage, the base stage of the triode Q2 connect the compensation pin Comp of the PWM driving chip, and oscillating circuit connects the PWM
The output end vo ut pin of the Voltage Reference pin VREF and oscillation frequency pin Osc of driving chip, the PWM driving chip are logical
Overdrive circuit connects the grid of IGBT pipe Q1, and the drain electrode of the IGBT pipe Q1 connects the protection circuit by braking circuit,
The current input terminal of the source electrode connection current sensor F of the IGBT pipe Q1, the output end ground connection of the current sensor F, institute
One end ground connection of voltage output end connection the resistance R21, the resistance R21 of current sensor are stated, the other end connects the PWM and drives
The current sampling pin Sense of dynamic chip.
2. a kind of circuit for carrying out frequency converter braking using Switching Power Supply according to claim 1, it is characterised in that: described
The feedback input pin Vfb of PWM driving chip is grounded by pull down resistor R13.
3. a kind of circuit for carrying out frequency converter braking using Switching Power Supply according to claim 1, it is characterised in that: described
Protection circuit includes one end connection busbar voltage anode of protective resistance R3 and filter capacitor C1, the protective resistance R3,
The other end connects the input terminal of the two-stage amplifying circuit, and the both ends of the filter capacitor C1 are separately connected the busbar voltage
Positive and negative anodes.
4. a kind of circuit for carrying out frequency converter braking using Switching Power Supply according to claim 1, it is characterised in that: described
Two-stage amplifying circuit includes operational amplifier X1 and operational amplifier X2, and the electrode input end of the operational amplifier X1 passes through electricity
Resistance R4 connects the anode of busbar voltage with the protective resistance R3 of protection circuit, and the negative input of the operational amplifier X1 passes through
The cathode of resistance R6 connection busbar voltage is equipped with feedback electricity between the output end and negative input of the operational amplifier X1
Road；
The negative input of the operational amplifier X2 connects the output end of the operational amplifier X1 by resistance R15, described
The electrode input end of operational amplifier X2 by resistance R16 connection reference voltage source, the output end of the operational amplifier X2 with
Concatenated resistance R14 and capacitor C2 is equipped between negative input；The output end of the operational amplifier X2 passes through concatenated electricity
It hinders R12 and resistance R11 to be grounded, output of the common point of the resistance R12 and the resistance R11 as the two-stage amplifying circuit
End connects the base stage of the triode Q2.
5. a kind of circuit for carrying out frequency converter braking using Switching Power Supply according to claim 4, it is characterised in that: described
Feed circuit includes resistance R10 and resistance R22 in parallel.
6. a kind of circuit for carrying out frequency converter braking using Switching Power Supply according to claim 4, it is characterised in that: described
The electrode input end of operational amplifier is equipped with first feed forward circuit in parallel with the resistance R4, the cathode of the operational amplifier
Input terminal is respectively equipped with second feed forward circuit in parallel with the resistance R6；First feed forward circuit includes concatenated capacitor C5
With resistance R17, second feed forward circuit includes concatenated capacitor C7 and resistance R18.
7. a kind of circuit for carrying out frequency converter braking using Switching Power Supply according to claim 1, it is characterised in that: described
Oscillating circuit includes one end connection Voltage Reference pin VREF and capacitor of resistance R7, capacitor C4 and capacitor C14, the resistance R7
One end of C14, one end of the other end connection oscillation frequency pin Osc and capacitor C4 of the resistance R7, the capacitor C4's is another
The other end of one end connection capacitor C14；The braking circuit includes R2 and diode D1 in parallel.
8. a kind of circuit for carrying out frequency converter braking using Switching Power Supply according to claim 1, it is characterised in that: described
The model UC3843 of PWM driving chip.
9. a kind of circuit for carrying out frequency converter braking using Switching Power Supply according to claim 1, it is characterised in that: described
Driving circuit includes resistance R1, triode Q3, triode Q4, resistance R9 and resistance R19；Described in one end connection of the resistance R1
PWM driving chip output end vo ut pin, the other end of the resistance R1 connect the triode Q3's and triode Q4
Base stage, the emitter of the triode Q3 pass through resistance R9 with the emitter of the triode Q4 respectively and connect institute with resistance R19
State the grid of IGBT pipe Q1；The base stage of the triode Q3 connects power supply, the base earth of the triode Q4.
10. a kind of circuit for carrying out frequency converter braking using Switching Power Supply according to claim 1, it is characterised in that: institute
The current sampling pin Sense that resistance R21 connects the PWM driving chip by filter circuit is stated, the filter circuit includes
Resistance R5 and capacitor C6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820953389.5U CN208337404U (en) | 2018-06-21 | 2018-06-21 | A kind of circuit carrying out frequency converter braking using Switching Power Supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820953389.5U CN208337404U (en) | 2018-06-21 | 2018-06-21 | A kind of circuit carrying out frequency converter braking using Switching Power Supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN208337404U true CN208337404U (en) | 2019-01-04 |
Family
ID=64768092
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201820953389.5U Active CN208337404U (en) | 2018-06-21 | 2018-06-21 | A kind of circuit carrying out frequency converter braking using Switching Power Supply |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN208337404U (en) |
-
2018
- 2018-06-21 CN CN201820953389.5U patent/CN208337404U/en active Active
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Address after: 430040 workshop D, no.6, ligongyuan Road, Science Park, Wuhan University of technology, Donghu Development Zone, Wuhan City, Hubei Province Patentee after: Wuhan Gangdi Technology Co.,Ltd. Address before: 430223 No. 6, Ligong Road, science and Technology Park, Donghu New Technology Development Zone, Wuhan City, Hubei Province Patentee before: WUHAN GUIDE ELECTRIC DRIVE TECHNOLOGY Co.,Ltd. |