Sine wave output frequency is up to the three phase electric machine frequency conversion speed-adjusting system of 20000Hz
technical field
The utility model relates to a kind of sine wave output frequency up to the three phase electric machine frequency conversion speed-adjusting system of 20000Hz.
background technology
At present, if want to do low power motor performance test, signal generator can produce enough high-frequency sinusoidal signals, but can not carry by band.Frequency converter can be exported high-power, but output frequency is too low, and wiring debugging is complicated.If 50 hertz of work of power frequency for known common three phase alternating current motor, can only be for fixed rotating speed as the occasion of the fixed rotating speeds such as 3000 revs/min, 1500 revs/min.Common variable frequency adjustment scope is also limited, and these have all limited the scope of application of threephase motor.And common frequency converter PWM frequency is generally on the low side, tens KHz hertz only, driver sine wave output frequency is low, generally only has hundreds of HZ, and waveform is also level and smooth not, particularly exports sinusoidal frequency higher time.While controlling motor operation, noise and vibration are all generally bigger than normal.Common Controller and the speed of service are slow, and I/O is limited, are also unfavorable for the expansion of driver allomeric function.In common driver circuit, generally only do high-low pressure isolation, not all signal is all made quarantine measures, and interference free performance is also good not.
utility model content
In order to overcome the problems referred to above, the utility model provides a kind of sine wave output frequency of motor when operation noise and vibration that can lower up to the three phase electric machine frequency conversion speed-adjusting system of 20000Hz to society.
The technical solution of the utility model is: the three phase electric machine frequency conversion speed-adjusting system of a kind of sine wave output frequency up to 20000Hz is provided, comprises:
Dsp processor, differs three groups of three-phase drive pwm signals of 120 degree for output phase;
Three-phase amplification channel, its structure is identical, and parallel arranging, receives respectively the corresponding described three-phase drive pwm signal being sent by dsp processor, and the frequency of three-phase drive pwm signal is brought up to and is more than or equal to 20000Hz, for controlling drive circuit, carry out drive motors.
As to improvement of the present utility model, every mutually described amplification channel comprises:
PWM photoelectric coupled circuit, for receiving from the pwm signal of dsp processor input, and optocoupler is to filter circuit;
Filter circuit, receives the pwm signal of coming from PWM photoelectric coupled circuit, and carries out filtering;
Dual output high-speed comparator, receives the pwm signal of coming from filter circuit, and the frequency of described pwm signal is brought up to and is more than or equal to 20000Hz;
Amplifying circuit, the pwm signal that frequency is more than or equal to 20000Hz amplifies, and flows to drive circuit;
Drive circuit, receives the pwm signal that amplifying circuit is come, and drive motors rotation.
As to improvement of the present utility model, between described filter circuit and dual output comparator, be also provided with selector switch, described selector switch for selecting between analog signal input and digital signal input.
As to improvement of the present utility model, between described filter circuit and dual output comparator, be also provided with the peak-clipping circuit being formed by RC circuit.
As to improvement of the present utility model, also comprise feedback circuit, described feedback circuit includes Hall current sensor, feedback photoelectric coupled circuit and the feedback signal amplifying circuit being connected with the output of drive circuit, Hall current sensor flows to feedback photoelectric coupled circuit by collected output end current, described feedback photoelectric coupled circuit flows to electric current feedback signal amplifying circuit again, after amplifying, feed back to dsp processor, control the operating state of dsp processor.
The utility model is more than or equal to 20000Hz owing to having improved the output frequency of pwm signal, having reached, and the waveform of its sine wave output is more level and smooth, and motor operation noise is little, smooth-going; And existing common frequency changer circuit can only be operated in the low-frequency range from tens hertz to hundreds of K hertz, sine wave output is level and smooth not, and while controlling motor, noise and vibration are all larger.
At output, be connected to LC low pass circuit, guaranteed that high-frequency PWM converts the output of level and smooth sine wave to.When sine wave freuqency, bring up to after 20 KHz, application is more extensive than existing homogeneous circuit.
The utility model frequency response is wide, and signal to noise ratio is high, and distorted signals is little.Owing to rationally having used high-frequency amplifier circuit and high speed components and parts, dual output high-speed comparator U5(LT1016) conduction delay time representative value was 10 nanoseconds, high-speed driving integrated circuit U6(IR2011S) the switch conduction time is respectively 80 nanoseconds and 60 nanoseconds, for being operated in, also leaves sufficient allowance on 2 megahertzes.Q1 and Q2 are connected into common base and amplify form in high frequency uses, and make circuit more stable.Add after loop negative feedback, whole circuit can steady operation on 2 megahertzes, even higher, and can also guarantee performance good under high-frequency.
The utility model wide dynamic range, circuit stability are good.Because circuit working is in high-frequency, high-frequency circuit work is to the stability requirement of the power supply particular importance that just seems.Common frequency converter or driver, circuit only does simple filtering or only to the voltage stabilizing of fraction circuit, the stability of integrated circuit work is obviously not as whole circuit voltage stabilizing.So native system, except the power supply of final stage power tube, all adopts linear circuit of three-terminal voltage-stabilizing integrated to power, and has strengthened decoupling, has guaranteed the stability of circuit working.Negative and positive dual power power supply, has guaranteed wider dynamic range and frequency response.Every group of stabilized voltage power supply all has perfect filtering and decoupling capacitance.
The utility model antijamming capability is strong.Feedback optocoupler U4 and PWM photoelectric coupled circuit U1, by the power supply of dsp processor one end, are all to be inputted by dsp processor power supply VDSP, and PWN IN signal and I-SENSOR signal share a signal ground loop, the power supply earth-return of other partial commons V+, V-.Like this, no matter be input or feedback, signal is all thoroughly to isolate, and has greatly strengthened antijamming capability.
The utility model can be inputted numeral or analog signal, uses flexibly.Because high frequency performance is good, native system not only can be applied to Industry Control, can also be for motor performance test.General driver can only be inputted digital PWM signal, has limited the scope of application.
Current foldback circuit is stable, reliable.Use linear optical coupling and track to track amplifier to amplify faint sampled signal, not only isolated unnecessary interference, and the band-pass circuit of amplifier carries out a filtering again to signal, guaranteed the pure of signal.
Accompanying drawing explanation
Fig. 1 is the structural representation of a kind of embodiment of the present utility model.
Fig. 2 is the wherein block diagram of a phase amplification channel of the utility model.
Fig. 3 is the circuit theory schematic diagram of Fig. 2.
Embodiment
Refer to Fig. 1 to Fig. 3, Fig. 1 to Fig. 3 discloses be a kind of sine wave output frequency up to the three phase electric machine frequency conversion speed-adjusting system of 20000Hz, comprising:
Dsp processor, differs three groups of three-phase drive pwm signals of 120 degree for output phase;
Three-phase amplification channel, its structure is identical, and parallel arranging, receives respectively the corresponding described three-phase drive pwm signal being sent by dsp processor, and the frequency of three-phase drive pwm signal is brought up to and is more than or equal to 20000Hz, for controlling drive circuit, carry out drive motors.
As to improvement of the present utility model, every mutually described amplification channel comprises:
PWM photoelectric coupled circuit, for receiving from the pwm signal of dsp processor input, and optocoupler is to filter circuit;
Filter circuit, receives the pwm signal of coming from PWM photoelectric coupled circuit, and carries out filtering;
Dual output high-speed comparator, receives the pwm signal of coming from filter circuit, and the frequency of described pwm signal is brought up to and is more than or equal to 20000Hz;
Amplifying circuit, the pwm signal that frequency is more than or equal to 20000Hz amplifies, and flows to drive circuit;
Drive circuit, receives the pwm signal that amplifying circuit is come, and drive motors rotation.
Between described filter circuit and dual output comparator, be also provided with selector switch, described selector switch for selecting between analog signal input and digital signal input.
Between described filter circuit and dual output comparator, be also provided with the peak-clipping circuit being formed by RC circuit.
The utility model also comprises feedback circuit, described feedback circuit includes Hall current sensor, feedback photoelectric coupled circuit and the feedback signal amplifying circuit being connected with the output of drive circuit, Hall current sensor flows to feedback photoelectric coupled circuit by collected output end current, described feedback photoelectric coupled circuit flows to electric current feedback signal amplifying circuit again, after amplifying, feed back to dsp processor, control the operating state of dsp processor.
In the utility model, A, B, the C three-phase drive pwm signal of the phase phasic difference of being exported by dsp processor 120 degree, enter respectively the differential input end of A, B, C, three amplification channels.In the present embodiment, the A phase amplification channel of only take is illustrated as example, and all the other B phase amplification channels are identical with C phase amplification channel structure, and operation principle too; In A phase amplification channel, signal, at circuit input end PWM IN+ and PWM IN-, arrives photoelectric coupled circuit U1 through the first resistance R 1, the second resistance R 2.The power pack of photoelectric coupled circuit U1 is divided into two groups: transmitting terminal power supply is provided by DSP part power supply, and incoming level mates with DSP; Receiving terminal power supply is provided by drive part, isolates completely with DSP.Pwm signal after isolation exports by 6,7 pin of photoelectric coupled circuit U1 the filter circuit forming through the 27 resistance R 27, the 6th diode D6, the 37 capacitor C 37 and the 26 resistance R 26, the 5th diode D5 and the 36 capacitor C 36, export respectively after selector switch S1, again through the 8th resistance R 8, the 7th resistance R 7 to dual output high-speed comparator U5(LT1016) 2,3 pin, the positive inverting input of dual output high-speed comparator U5 namely, dual output high-speed comparator U5(LT1016) 7,8 pin are respectively positive and negative output.Selector switch S1 is input selector switch, and what in the present embodiment, adopt is single-pole double-throw switch (SPDT); In Fig. 3, the position of selector switch S1 is digital PWM input state, if need analog signal input, selector switch S1 is placed in to another one position, and analog signal is from the common port input of S1A.The 24 resistance R 24 is to establish in order to mate the output impedance of input signal source, and the 34 capacitor C 34 can elimination interference noise, guarantees the pure of signal.Because 3 pin of dual output high-speed comparator U5 are received ground by the 8th resistance R 8, the analog signal of input, if frequency continually varying is compared with ground (low level) so, can produce a pwm signal.Dual output high-speed comparator U5 (LT1016) is a positive and negative dual output high-speed comparator, switch periods representative value reached for 10 nanoseconds, can export a positive negative two-way high speed signal, enter respectively by the 9th resistance R 9, the first triode Q1, the 11 resistance R 11 and the tenth resistance R 10, the second triode Q2, the elementary amplifying circuit of the 12 resistance R 12 two-way common base and amplify rear output drive signal.Drive signal to enter high-speed driving integrated circuit U6(IR2011S here), high-speed driving integrated circuit U6(IR2011S) be the high-speed driving integrated circuit of height output, can export positive and negative two-way pwm signal.High-speed driving integrated circuit U6(IR2011S) driving voltage of output, is enough to make the high-power FET conducting of output stage, produces enough current drives motors.The 3rd diode D3, the 17 capacitor C 17 form boostrap circuit, the further high-speed driving integrated circuit U6(IR2011S that increases) driving force, the 15 resistance R the 15, the 16 resistance R 16 is respectively the resistance of first power field effect pipe T1, second largest power field effect pipe T2, and the second diode D2, the 4th diode D4 prevent that disturbing pulse from passing through first power field effect pipe T1 and second largest power field effect pipe T2.When the positive pulse of pwm signal arrives, first power field effect pipe T1 conducting, second largest power field effect pipe T2 cut-off, electric current outputs to motor by first power field effect pipe T1 to the first inductance L 1 through V+, when the negative pulse of pwm signal arrives, second largest power field effect pipe T2 conducting, first power field effect pipe T1 cut-off, electric current outputs to motor by second largest power field effect pipe T2 to the first inductance L 1 through V-, so just completes conducting work in the PWM cycle.
The 18 resistance R 18 is negative feedback resistor, for adjusting the gain of whole circuit, also guarantees the stable of high-frequency work simultaneously, and in order to eliminate, waveform shake adds the 25 resistance R the 25, the 35 capacitor C 35.The first inductance L the 1, the 23 capacitor C 23 forms LC low-pass filtering, makes the PWM square wave after amplifying become level and smooth sine wave, and output OUT connects motor.The 22 capacitor C the 22, the 17 resistance R 17 forms the spike circuit that disappears, and prevents that the spike of the coil inductance generation of the first inductance L 1 and motor from damaging high-power FET.The second integrated regulator U2, the 3rd integrated regulator U3, the 7th integrated regulator U7, tetra-integrated regulators of the 8th integrated regulator U8 are respectively corresponding circuit that burning voltage is provided.Wherein the 3rd integrated regulator U3 and the 8th integrated regulator U8 provide positive and negative stabilized power supply to respectively dual output high-speed comparator U5, the 7th integrated regulator U7 provides stabilized power supply to high-speed driving integrated circuit U6, the second integrated regulator U2 exports 3.3V to photoelectric coupled circuit U1 after voltage stabilizing again through the 3rd integrated regulator U3, and the 9th capacitor C the 9, the 27 C27 is respectively the decoupling capacitance of photoelectric coupled circuit U1 two-way power supply.Each organize stabilized voltage power supply not only input and output side be throughout connected to big capacity electrolyte capacitor filtering, the ceramic condenser that is also connected to low capacity simultaneously carries out high frequency decoupling.The first power field effect pipe T1 of final stage, the power supply of second largest power field effect pipe T2, by the 19 capacitor C the 19, the 20 capacitor C the 20, the 21 capacitor C 21 and the 24 capacitor C the 24, the 25 capacitor C the 25, the 26 capacitor C 26, carry out filtering and high frequency decoupling respectively, wherein the 19 capacitor C 19 and the 24 capacitor C 24 increase for improving frequency specially.At first power field effect pipe T1 and second largest power field effect pipe T2, be connected to the output of the first inductance L 1, be connected in series a Hall current sensor H, when cause specific makes output current surpass set point, Hall current sensor H exports a direct current signal, the optical coupling isolation circuit forming through the 3rd resistance R 3, the 4th resistance R 4, the first diode D1, feedback optocoupler U4 produces feedback signal I-SENSOR and sends dsp processor back to, dsp processor stops output, to avoid electric current excessive and cause component wear.Feedback optocoupler U4 input termination the first diode D1 prevents that input signal is excessive, the 19 resistance R 19 is signal current-limiting resistance, after the 31 31 pairs of capacitor C current sampling signal filtering, enter feedback light coupling U4, the model of feeding back optocoupler employing described in the present embodiment is HCPL-7840 chip, HCPL-7840 chip belongs to Low Drift Temperature linear optical coupling, bias voltage is only 0.3mV, is just in time applicable to the sampling of direct current.Feedback optocoupler U4 is also powered by two-way insulating power supply, and the 32 capacitor C the 32, the 33 capacitor C 33 is respectively the decoupling capacitance of two groups of power supplys.The signal of feedback optocoupler U4 output amplifies to feedback signal amplifying circuit U9A through the 20 resistance R the 20, the 21 resistance R 21, after deliver to again dsp processor.Feedback signal amplifying circuit U9A model is TLV2372, belongs to " rail-to-rail " amplifier, and amplifier output area can reach supply voltage, for the amplifier of low voltage operating, is even more important.The 22 resistance R 22 is negative feedback resistors of amplifier, it is logical that it and the 30 capacitor C 30 form RC band, prevent that non-useful signal from passing through, the 23 resistance R 23 is amplifier output resistances, the 28 capacitor C 28 is carried out filtering to the signal of sampling again, obtains pure current sampling signal to dsp processor.The 7th diode DA1 is double diode, and inside is connected to the diode of two a positive and a negative, is respectively the 7th A diode DA1A, the 7th B diode DA1B, and restricting signal voltage can beyond supply voltage.
In like manner, the structure of B phase amplification channel and C phase amplification channel is also like this.Like this, when three pwm signals that every phase 120 is spent that dsp processor is sent, in one-period, output just can make motor complete an action turning, and any one occurs when electric current is excessive protecting reliably mutually.
In the utility model, power supply V+, V-voltage range be+50V~+ 200V ,-50~-200V, and dsp processor can be selected model: the TMS320F2810 of Texas Instrument or TMS320F2811.