CN100499350C - A flying wheel electromotor control system with magnetic suspending counteraction - Google Patents

Abstract

A magnetic suspension counteraction flywheel motor control system adapts to control of three-phase permanent-magnet brushless DC motors for magnetic suspension counteraction flywheels, a new generation of high accuracy attitude control actuating mechanism for high-stability satellites. The invention mainly comprises a controller with a core of a Digital Signal Processor (DSP), a power amplifier, an upper bridge arm driving circuit in the power amplifier, a lower bridge arm driving circuit in the power amplifier, a resonance-type soft switch control circuit, a three-phase permanent-magnet brushless DC motor, a current detection circuit, a 28VDC steady power source, a +15VDC steady power source and a +5VDC steady power source. The invention can control On/Off of each power switch tubes on resonance-type soft switches through a non-demodulated isolation driving circuit, so as to fulfill high-reliability but low power-consumption running of control system driving circuits for magnetic suspension counteraction flywheel motors.

Description

A kind of flying wheel electromotor control system with magnetic suspending reaction

Technical field

The present invention relates to a kind of flying wheel electromotor control system with magnetic suspending reaction, be mainly used in the long-life, the high-precision attitude control executing mechanism that realize satellite of new generation---highly reliable, the low-power consumption of the power switch tube grid of flying wheel electromotor control system with magnetic suspending reaction drive.

Background technology

Magnetic suspension reaction fly-wheel is as the high accuracy of satellite platform of new generation, the actuator of high stability attitude control system, have angular momentum output accuracy height, control the linearity good, and have advantages such as very strong anti-interference and very fast-response speed, progressively be applied in the world, and will become the first-selected actuator of China a new generation high accuracy, high stability satellite platform.

The highly reliable driving of attitude of satellite control actuator of a new generation is the basic demand that use in the space.Improve the reaction fly-wheel motor drive system reliability, reducing driving power consumption is that the target of being pursued is used in the space all the time.

Magnetic suspension reaction fly-wheel motor generally adopts the three-phase permanent brshless DC motor, and the MOSFET drive circuit is adopted in the driving of three-phase permanent brushless DC motor control system mostly.Power MOSFET has that switching speed is fast, high frequency performance good, input impedance is high, driving power is little, the distinguishing feature of no second breakdown problem.Four kinds of MOSFET drive circuits commonly used are arranged at present: (1) grid source floating power supply drives, (2) transformer isolation drives, (3) bootstrapping drives, (4) integrated circuit drives.At first, grid source floating power supply drives (as Fig. 7 (a)) the indefinite time cycle is done complete grid control, each high-pressure side MOSFET needs an insulating power supply, insulating power supply will be that the signal of reference carries out complexity of level conversion with ground, and adopt optical isolator limited on bandwidth and noise susceptibility; Transformer isolation driving (as Fig. 7 (b)) mode will be added in the elementary high-frequency PWM signal of Isolated Pulse Transformer and isolate, obtain self-supporting power in secondary direct rectification, this rectifier system only keeps amplitude and is negative signal waveform for positive signal waveform has filtered amplitude, and need carry out demodulation to high-frequency modulation signal, the size of transformer significantly increases (volume of transformer and signal frequency square be inversely proportional to) when frequency modulating signal descends, its control is complicated, volume is big, and power consumption is bigger; The restriction that bootstrapping driving (as Fig. 7 (c)) duty ratio and service time are refreshed by bootstrap capacitor all, electric capacity charges from high-voltage line, and power consumption may be very big, needs level translator complicated; Drive for integrated circuit, it adopts integrated drive chips to drive, because space flight is restricted with chip, and common integrated drive chips can't satisfy the space application requirements aspect reliability, for example, integrated drive chips can produce the logic upset under the radiation effects of space particle, the high level upset causes the motor misoperation for low level.And integrated drive chips signal modulating frequency is low, has overcome the switching loss of power switch pipe at this control method of soft switch, can be with the frequency high frequencyization of drive signal.But the highest chip of integrated drive chips modulating frequency is IR21366 at present, and it opens the propagation delay time is 250ns, and the shutoff propagation delay time is 180ns, and the width of front end pwm signal is greater than 1us.Therefore, its maximum modulating frequency is 699khz, and the sort signal modulating frequency is unsuitable for the high frequency application.

In the drive circuit of three-phase permanent brushless DC motor control system, the gate driving of the power MOSFET that last brachium pontis drives must guarantee: gate voltage must be higher than its drain voltage 10～15V, gate voltage from must being controlled in logic.Thus, control signal must switching levels be the source potential of high-pressure side power device.Therefore the MOSFET pipe needs high pressure to float, and this just needs the input of mosfet driver and output to carry out electrical isolation.Driving the general dual mode that adopts isolates: the employing photoelectrical coupler is isolated or is utilized pulse transformer to carry out electrical isolation.The shortcoming that adopts photoelectrical coupler to isolate is that reaction is slow, has bigger time of delay the accessory power supply power supply that (high speed photo coupling is generally greater than 500ns) and photoelectrical coupler need be isolated.With pulse transformer isolation drive insulated-gate power device three kinds of methods are arranged: passive, active and self-supporting power drives.Passive way does not need independent driving power, be high-power signal but need the input signal of primary, otherwise the waveform between the grid source will have tangible distortion; Active method drive waveforms is better, but need provide the accessory power supply of isolation to supply with amplifier in addition; And existing self-supporting power method is that the PWM drive signal is carried out high frequency modulated, and the high-frequency modulation signal after transformer isolation and rectification need be demodulated into low frequency signal, and its volume is big and design, control is complicated, power consumption is higher.

Current, each brachium pontis power MOSFET of flying wheel electromotor control system with magnetic suspending reaction is generally operational in the hard switching mode, the high frequency development that big switching voltage stress, current stress and high voltage change ratio du/dt and current changing rate di/dt have limited it, make converter volume, weight be difficult to reduce and reduce, and produce very big electromagnetic interference.And soft switch technique then with its lower switch stress, the switching loss that goes to zero and less du/dt and di/dt, greatly improves the switching frequency of power electronic device.

Summary of the invention

The technical problem that the present invention solves is: overcome the discrete isolated drive circuit control complexity of motor driven systems employing that prior art exists, volume is big, power consumption is big, adopt the integrated drive electronics reliability, shortcoming that modulating frequency is low and three-phase permanent brshless DC motor inversion circuit adopt hard switching mode power consumption, harmonic content, the shortcoming that switch stress is bigger, the present invention proposes a kind of pulse transformer isolated drive circuit that need not demodulation that adopts discrete component to build, and is driven the magnetic suspension reaction fly-wheel motor drive system of soft each power switch pipe of switch of resonant mode by drive signal.

Technical solution of the present invention: a kind of flying wheel electromotor control system with magnetic suspending reaction comprises: isolated drive circuit, with DSP is the control core device, rotating speed detects link, the current detecting link, power amplification circuit, the soft ON-OFF control circuit of resonant mode, the three-phase permanent brshless DC motor, with DSP is that control core device and rotating speed detect link, the current detecting link, isolated drive circuit links to each other, isolated drive circuit links to each other with power amplification circuit, power amplification circuit links to each other with the soft ON-OFF control circuit of resonant mode, the soft ON-OFF control circuit of resonant mode links to each other with the three-phase permanent brshless DC motor, rotating speed detects link, the current detecting link links to each other with power amplification circuit with the three-phase permanent brshless DC motor respectively, be used for detecting the rotating speed of three-phase permanent brshless DC motor and the electric current of its winding, its characteristics are: described isolated drive circuit adopts discrete component to constitute, mainly comprise: former limit voltage doubling rectifing circuit, push-pull circuit, pulse transformer, the secondary voltage doubling rectifing circuit, high-pass filtering circuit, the discharge triode, the capturing unit module that with DSP is the control core device is caught the position that obtains current rotor to three-phase permanent brushless DC motor rotor position sensor signal, and producing nine road PWM drive signals by the PWM waveform generation module that with DSP is control core device inside, former limit voltage doubling rectifing circuit receives the PWM drive signal drive signal rectification is produced the single-polarity PWM drive signal; Push-pull circuit receives the PWM drive signal after the voltage doubling rectifing circuit rectification of former limit, and its driving power is increased; Pulse transformer receives the PWM drive signal after push-pull circuit increases power, becomes the secondary drive signal through the pulse transformer isolation; The secondary voltage doubling rectifing circuit receives the drive signal after isolating, with the drive signal rectification after isolating; High-pass filtering circuit receives the drive signal after the rectification, and filtering is attached to the low-frequency noise on the drive signal after the rectification; Through the opening and turn-offing of filtered drive signal in order to control discharge triode.

Described isolated drive circuit also comprises: diode and decoupling capacitor go to recoil, the described diode that goes to recoil links to each other with the secondary voltage doubling rectifing circuit, be used to eliminate of the interference of pulse transformer secondary to former limit, described decoupling capacitor one end links to each other with the diode that goes to recoil, the other end links to each other with the emitter of discharge triode, is used to eliminate the influence of high-frequency ac coupled signal.

The parameter of described isolated drive circuit can be chosen by following principle: former limit voltage doubling rectifing circuit and secondary voltage doubling rectifing circuit are made up of an electric capacity and a diode respectively.Discharging and recharging the time of the value size decision electric capacity of electric capacity generally chosen less capacitance, and optional scope is 10 ⁴PF～10 ⁵PF.Diode is chosen according to the collector electrode rated voltage of NPN type triode Q1 in the push-pull circuit, the reverse voltage that diode bears when the triode conducting of drive circuit is the collector electrode rated voltage 15V of NPN type triode Q1, and the reverse withstand voltage that diode can bear should be 1.8～2.5 times of rated voltage.Push-pull circuit is made up of NPN type triode Q1 and positive-negative-positive triode Q2, and the base stage of NPN type triode Q1 and emitter link together with base stage and the emitter of positive-negative-positive triode Q2 respectively.NPN type triode Q1 and positive-negative-positive triode Q2 choose according to the modulating frequency of signal, and modulating frequency is generally 1Hz to 1MHz, require the switching frequency of NPN type triode and positive-negative-positive triode will be higher than the modulating frequency of signal.Pulse transformer is made up of lc circuit, and its capacitor and inductor value is chosen according to modulating frequency, its modulating frequency $f=\frac{1}{2\mathrm{\π}\sqrt{\mathrm{LC}}},$ Transformer turn ratio is 1:1.High-pass filtering circuit is a cut-off frequency with the amplitude attenuation-3dB frequency of the drive signal that enters the secondary voltage doubling rectifing circuit, and the resistance of high-pass filtering circuit, capacitance are determined according to the restriction of cut-off frequency.

Principle of the present invention is: the capturing unit module that with DSP is control core device 1 is caught the position that obtains current rotor to the motor rotor position sensor signal, and produce nine road PWM drive signals by PWM waveform generation module, this nine road PWM drive signal is through the break-make of isolated drive circuit 4 and power amplification circuit 5 each power MOSFET switch tube of control major loop, and wherein six road PWM drive signals are used for controlling the break-make of three-phase permanent brshless DC motor inversion circuit (as shown in Figure 2 10) each power switch pipe of upper and lower bridge arm.Other three road PWM drive signals are used for controlling the break-make of resonant tank 9 each power switch pipe, make each power switch pipe discharge and recharge the voltage U cr vanishing that makes the electric capacity two ends by resonant tank to capacitor C r (as Fig. 2) before opening and when turn-offing by controlling each power switch pipe, thereby the no-voltage that realizes power switch pipe turn on and off.The conducting in certain sequence of each power switch pipe of inversion circuit 10 upper and lower bridge arms, shutoff, thus the forward of realizing the three-phase permanent brshless DC motor moves and inverted running.The rotor-position that detects 2 pairs of three-phase permanent brshless DC motors of link by rotating speed detects, obtain the spinner velocity feedback, by being that control core device 1 is compared rotational speed setup with speed feedback with DSP, thereby carry out the der Geschwindigkeitkreis control of three-phase permanent brshless DC motor.Detect three-phase permanent brshless DC motor bus current by current detecting link 3, be that control core device 1 is converted to digital quantity by analog-to-digital conversion (A/D) module with the current value that detects with DSP, thereby carry out the current loop control of three-phase permanent brshless DC motor.

Isolated drive circuit 4 mainly is made up of former limit voltage doubling rectifing circuit 12, push-pull circuit 13, pulse transformer 14, secondary voltage doubling rectifing circuit 15, high-pass filtering circuit 16, the diode 17 that goes to recoil, decoupling capacitor 18 and discharge triode 19.Be the course of work that example illustrates drive system with one road PWM drive signal below.

Produce the PWM drive signal by the PWM waveform generation module that with DSP is control core device 1, former limit voltage doubling rectifing circuit 12 receives the PWM drive signal drive signal rectification is produced the single-polarity PWM drive signal; The PWM drive signal that push-pull circuit 13 receives after voltage doubling rectifing circuit 12 rectifications of former limit increases its driving power; Pulse transformer 14 receives the PWM drive signal after push-pull circuit 13 increases power, isolates through pulse transformer 14 to become the secondary drive signal; The drive signal that secondary voltage doubling rectifing circuit 15 receives after isolating is with the drive signal rectification after isolating; High-pass filtering circuit 16 receives the drive signal after the rectifications, and filtering is attached to the low-frequency noise on the drive signal after the rectification.Be used to control opening and turn-offing of discharge triode 19 through high-pass filtering circuit 16 filtered drive signals.When the level of drive signal when low, A point (as Fig. 3) be a low level, control main circuit switching power pipe turn-offs, discharge triode 19 is open-minded, this moment, the junction capacitance of power switch pipe was discharged by discharge triode 19; When drive signal was high level, the A point was a high level, controlled the open-minded of main circuit switching power pipe, and discharge triode 19 turn-offs.The diode 17 that goes to recoil links to each other with secondary voltage doubling rectifing circuit 15, reverse spike can occur when switching tube is opened or turn-off, and the diode 17 that goes to recoil is used to eliminate the interference of pulse transformer secondary to former limit.Decoupling capacitor 18 links to each other with the diode 17 that goes to recoil, and is used to eliminate the influence of high-frequency ac coupled signal.

Wherein, former limit voltage doubling rectifing circuit 12 respectively is made up of an electric capacity and a diode with secondary voltage doubling rectifing circuit 15, and its effect is equivalent to a charge pump, doubles with drive signal rectification generation single-polarity PWM drive signal and with voltage of signals.Push-pull circuit 13 is made up of NPN type triode Q1 and positive-negative-positive triode Q2, and the base stage and the emitter of two pipes interconnect.Q1 conducting when signal is in positive half period, Q2 conducting when signal is in negative half-cycle.Push-pull circuit 13 is used for increasing the driving power of drive signal.Isolated drive circuit 4 usefulness pulse transformers 14 isolation drive insulated-gate power device.The self-supporting power method that employing need not demodulation drives, pulse transformer 14 is made up of lc circuit, the former secondary coil of pulse transformer is than being 1:1, supply with the elementary PWM of pulse transformer through high frequency modulated, obtain the high frequency self-supporting power by direct rectification and need not demodulation secondary, and square being inversely proportional to of the volume of transformer and frequency modulating signal, the frequency of the modulation signal volume of high transformer more is more little, because each power switch pipe of major loop adopts soft switching control method to eliminate switching loss, its high-frequency modulation signal can directly be controlled the break-make of each power switch pipe of major loop, and does not have the HF switch loss.

The operation principle of the control circuit of the soft switch of resonant mode is: by resonant tank capacitor C r (as Fig. 2) is discharged and recharged the voltage U cr vanishing that makes the electric capacity two ends before switching tube is opened and when turn-offing, thereby the no-voltage that realizes power switch pipe turns on and off.Set forth the course of work and the principle of the soft switch of resonant mode below for example with one-period (pwm signal becomes 0 by 1, becomes 1 by 0 again).Because the phase current of inverter is that the frequency of square wave current and resonant tank is very high, can analyze inverter as a constant-current source.Circuit diagram after it is simplified as shown in Figure 4.

In a work period, the triggering signal of corresponding power switch pipe (Sa, Sb, Sl) and correspondent voltage current waveform are as shown in Figure 5.All corresponding a kind of operating state of each time period wherein, soft switch has six kinds of operating states during resonance as can be seen from Figure 5, as shown in Figure 6.State 1 corresponding diagram 6 (a) wherein is for pwm signal is 1 o'clock normal operating conditions; State 2 corresponding diagram 6 (b) will be for pwm signal will become the process of Cr being discharged at 0 o'clock from 1; State 3 corresponding diagram 6 (c) are for pwm signal is 0 o'clock normal diode continuousing flow process; State 4 corresponding diagram 6 (d) are for PWM becomes 1 o'clock process to Lr charging and while diode continuousing flow by 0; State 5 corresponding diagram 6 (e) are for pwm signal becomes the charging process of 1 back resonant circuit to Cr by 0; State 6 corresponding diagram 6 (f) are that 1 o'clock DC power supply and resonant circuit are simultaneously to the process of inverter power supply for pwm signal.

The present invention's advantage compared with prior art is: (1) drive circuit adopts transformer isolation to drive its insulating power supply or level conversion of need not simple in structure.(2) drive circuit adopts the driving method that need not the demodulation self-supporting power, obtain the high frequency self-supporting power at transformer secondary output by voltage multiplying rectifier and need not demodulation, square being inversely proportional to of the volume of transformer and frequency modulating signal, the frequency of the modulation signal volume of high transformer more is more little, because each power switch pipe of major loop adopts soft switching control method to eliminate switching loss, its high-frequency modulation signal can directly be controlled the break-make of each power switch pipe of major loop, and does not have the HF switch loss.The driving method pulse transformer volume that employing need not the demodulation self-supporting power is little, low in energy consumption, control, simplicity of design.(3) drive circuit adopts the driving method that need not the demodulation self-supporting power, its former limit and secondary adopt voltage doubling rectifing circuit, double with the drive signal rectification and with the voltage of drive signal, made full use of signal waveform like this and increased the power of original drive signal.And that its method for rectifying of existing pulse transformer Driving technique keeps amplitude is constant for negative its signal voltage amplitude of waveform for positive signal waveform has filtered amplitude, power reduction.(4) drive circuit adopts transformer isolation to drive the reliability height, can not appear at the abnormal overturn under the space particle radiation effect.(5) drive circuit adopts transformer isolation to drive its modulating frequency height, at the control method of this no switching loss of soft switch, can mention the switching frequency of power switch pipe very high and does not have switching loss.(6) drive circuit adopts transformer isolation to drive reaction soon, thereby the propagation delay time is short, and its output stage need not the accessory power supply power supply.(7) the present invention's isolation drive method that further will need not the demodulation self-supporting power merges mutually with soft switch technique, magnetic suspension reaction fly-wheel three-phase permanent brushless DC motor control system adopts the control method of soft switch, drives the break-make that the high-frequency driving signal that provides is controlled each power switch pipe by the transformer isolation that need not demodulation.Resonant circuit is used for realizing that the no-voltage of its switching tube turns on and off.Thereby greatly reduce the switching loss of power switch pipe, improved the operating efficiency of motor.And switching voltage stress current stress and high du/dt and di/dt have been reduced.

Description of drawings

Fig. 1 three-phase permanent brshless DC motor of the present invention control chart;

Fig. 2 is three-phase permanent brshless DC motor of the present invention and control circuit main circuit diagram;

Fig. 3 is power driving circuit figure of the present invention;

Fig. 4 is the main circuit diagram after the simplification of the present invention.

Fig. 5 is the voltage and current waveform of resonant circuit of the present invention;

Fig. 6 is six kinds of working state figures of the soft switch of resonant mode of the present invention; Wherein: be 1 o'clock normal operating conditions figure (a) for pwm signal, (b) will become the working state figure that Cr is discharged at 0 o'clock from 1 for PWM, (c) for pwm signal be the working state figure of the normal afterflow of diode in 0 o'clock, (d) become 1 o'clock working state figure for pwm signal by 0 to Lr charging and diode continuousing flow, (e), be 1 o'clock DC power supply and resonant circuit working state figure (f) to inverter power supply for pwm signal for pwm signal becomes the working state figure of 1 back resonant circuit to Cr charging by 0.

Fig. 7 (a) is that grid of the present invention source floating power supply drives figure, (b) is that transformer isolation of the present invention drives figure, (c) is that bootstrapping of the present invention drives figure

Embodiment

As Fig. 1, the present invention mainly by isolated drive circuit 4, be that control core device 1, rotating speed detect link 2, current detecting link 3, power amplification circuit 5, the soft ON-OFF control circuit 6 of resonant mode, three-phase permanent brshless DC motor 7 and form with DSP.Isolated drive circuit 4 mainly is made up of former limit voltage doubling rectifing circuit 12, push-pull circuit 13, pulse transformer 14, secondary voltage doubling rectifing circuit 15, high-pass filtering circuit 16, the diode 17 that goes to recoil, decoupling capacitor 18 and discharge triode 19.

The capturing unit module that with DSP is control core device 1 is caught the position that obtains current rotor to the motor rotor position sensor signal, and produce nine road PWM drive signals by PWM waveform generation module, former limit voltage doubling rectifing circuit 12 is with this nine road PWM drive signal rectification, and push-pull circuit 13 is used for increasing the driving power of this nine road PWM drive signal.Pulse transformer 14 receives nine road PWM drive signals after push-pull circuit 13 increases power, nine road PWM drive signals after pulse transformer 14 is isolated, carry out rectification by secondary voltage doubling rectifing circuit 15, through high-pass filtering circuit 16 filtering low-frequency noises, control opening and turn-offing of discharge triode 19 again through filtered drive signal.Locate to produce the grid control signal of power switch pipe like this at the collector electrode (A as shown in Figure 3) of Q3, six tunnel in this nine road grid control signal is used for controlling the break-make of each power switch pipe of upper and lower bridge arm of three-phase permanent brshless DC motor inversion circuit.Other three road grid control signals are used for controlling the break-make of each power switch pipe of resonant tank, make each power switch pipe discharge and recharge the voltage U cr vanishing that makes the electric capacity two ends by resonant tank to capacitor C r before opening and when turn-offing by controlling each power switch pipe, thereby the no-voltage that realizes power switch pipe turn on and off.The conducting in certain sequence of each power switch pipe of inversion circuit upper and lower bridge arm, shutoff, thus the forward of realizing the three-phase permanent brshless DC motor moves and inverted running.Detect by rotor-position, obtain the spinner velocity feedback, thereby carry out the der Geschwindigkeitkreis control of three-phase permanent brshless DC motor the three-phase permanent brshless DC motor.Detect three-phase permanent brshless DC motor bus current by current sensing means, carry out the current loop control of three-phase permanent brshless DC motor.

Each parameter selection principle of isolated drive circuit: diode D1, the D2 of voltage doubling rectifing circuit choose according to rated voltage, the reverse voltage that diode bears when the triode of drive circuit is opened is rated voltage 15V, the reverse withstand voltage that diode can bear should be 1.8～2.5 times of rated voltage, therefore the reverse withstand voltage of diode D1, D2 is generally elected 30V as, if the reverse withstand voltage of condition permission diode is the bigger the better, the present embodiment selects for use its withstand voltage of IN4148 bigger, the reverse voltage that can bear is 75V, and the electric current that can bear is 150mA; Discharging and recharging the time of the value size decision electric capacity of electric capacity generally chosen less capacitance, and optional scope is 10 ⁴PF～10 ⁵PF, the present embodiment selects 10 for use ⁴PF; Push-pull circuit triode Q1, Q2 choose according to modulating frequency, modulating frequency is generally 1Hz to 1MHz, and the TIP9013 switching frequency is 100MHz, and its switching frequency of S9012 is that 30MHz can satisfy general modulating frequency demand, therefore the present embodiment Q1 selects TIP9013 for use, and Q2 selects S9012 for use; The lc circuit capacitor and inductor value of pulse transformer is chosen its modulating frequency according to modulating frequency $f=\frac{1}{2\mathrm{\π}\sqrt{\mathrm{LC}}},$ It is that to select capacitance for use be 10 to 160KHz that the present embodiment is set modulating frequency ³PF, inductance value is 1mH, transformer need not buck, so its turn ratio is 1:1; The cut-off frequency of high-pass filtering circuit is the pairing frequency of its signal amplitude decay-3dB point.The resistance of high-pass filtering circuit, capacitance are determined according to the restriction of cut-off frequency; Decoupling capacitor generally elects 10 as ⁴PF～10 ⁵PF; Switching tube Q3 selects S9012 for use; The reverse voltage that diode D3 bears also is a load voltage value, and therefore oppositely withstand voltage also should be more than or equal to 30V, and it is 40V that the present embodiment is selected its reverse voltage that can bear of IN5819 for use, and the electric current that can bear is 1A.

The control circuit parameter selection principle of the soft switch of resonant mode:

State 1: the time period corresponding to Fig. 5 is 0＜t＜t0, SL conducting under this state, Sa, Sb by, the voltage swing at Cr two ends is that the Vs. DC power supply is directly to inverter power supply.

State 2: the time period corresponding to Fig. 5 is to＜t＜t1, and SL turn-offs under this state, the Sa triggering and conducting; Cr discharges simultaneously by resonant circuit and inverter circuit, is that zero moment pwm signal becomes 0 by 1 in the Cr discharge, has realized that the no-voltage of inverter power switching tube is turn-offed.Therefore, in order accurately to determine the triggering moment of Sa, the discharge time that must calculate Cr, promptly before pwm signal becomes 0 by 1, carry and trigger Sa previous discharge time.Definition t0 is zero constantly constantly, and the constant-current source electric current is Io, and the resistance of resonant inductance and lead is RL, because resonance frequency Wr is very high, WrLr〉〉 RL, so the pressure drop and the loss that cause because of RL can be ignored.Get the equivalent equation of circuit by Fig. 6 (b):

$\left\{\begin{array}{c}{u}_{\mathrm{Cr}}\left(t\right)=\frac{\mathrm{Vs}}{2}-\mathrm{Lr}\frac{{\mathrm{di}}_{\mathrm{Lr}}\left(t\right)}{\mathrm{dt}}\\ C_r\left(t\right)\frac{{\mathrm{du}}_{\mathrm{cr}}\left(t\right)}{\mathrm{dt}}=i_{\mathrm{Lr}}-I_0\\ u_{\mathrm{cr}}\left(0\right)=\mathrm{Vs},i_{\mathrm{Lr}}\left(0\right)=0\end{array}\right.---\left(1\right)$

Solve an equation and organize:

$\left\{\begin{array}{c}{u}_{\mathrm{cr}}\left(t\right)=\frac{\mathrm{<figure-callout\; id="2"\; label="Vs"\; filenames="C200710122406E00151.png,C200710122406E00161.png"\; state="\{\{state\}\}">Vs</figure-callout>}}{2}+K\cos (w_{r}t+a)\\ i_{\mathrm{Lr}}\left(t\right)=I_0-K\sqrt{\frac{\mathrm{Cr}}{\mathrm{Lr}}}\sin (w_{r}t+a)\end{array}\right.---\left(2\right)$

Wherein:

$K=\sqrt{\frac{{\mathrm{<figure-callout\; id="2"\; label="Vs"\; filenames="C200710122406E00151.png,C200710122406E00161.png"\; state="\{\{state\}\}">Vs</figure-callout>}}^2}{4}+\frac{I_0^2\mathrm{Lr}}{\mathrm{Cr}}},$ ? $\mathrm{Wr}=\sqrt{\frac{1}{\mathrm{LrCr}}},$ ? $a={\mathrm{tg}}^{-1}\left(\frac{I_0}{\mathrm{Vs}}\sqrt{\frac{\mathrm{Lr}}{\mathrm{Cr}}}\right)$

Solve discharge time:

$t_{\mathrm{sc}}=t1-t0=\frac{\mathrm{\&pi;}-2a}{w_r}---\left(3\right)$

At t1 constantly, u _Cr(t1)=0, substitution formula (2) gets i _Lr(t1)=0, therefore automatically shut down at t1 moment Sa.

State 3: the time period corresponding to Fig. 5 is t1＜t＜t2, and Sa, Sb, SL are in by state under this state, and phase current is by the normal afterflow of diode.

State 4: the time period corresponding to Fig. 5 is t2＜t＜t3, Sb triggering and conducting under this state, SL, Sa by, power supply charges to i to Lr _Lr=I ₀, pwm signal becomes 1 by 0 then.Therefore in order accurately to provide the triggering signal of Sb, must calculate the charging interval of resonant inductance Lr, served as zero moment with t2 constantly, got the equivalent equation of circuit by Fig. 6 (d):

$\mathrm{Lr}\frac{{\mathrm{di}}_{\mathrm{Lr}}\left(t\right)}{\mathrm{dt}}=\frac{\mathrm{Vs}}{2}---\left(4\right)$

Initial moment i _Lr(0)=0, gets the charging interval

${\mathrm{<figure-callout\; id="1"\; label="t\; c"\; filenames="C200710122406E00142.png,C200710122406E00143.png"\; state="\{\{state\}\}">t</figure-callout>}}_c=t3-\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="C200710122406E00151.png,C200710122406E00161.png"\; state="\{\{state\}\}">t</figure-callout>}2=\frac{{2I}_0\mathrm{Lr}}{\mathrm{Vs}}---\left(5\right)$

State 5: the time period corresponding to Fig. 5 is t3＜t＜t4, Sb conducting under this state, SL, Sa still by, diode stops afterflow, resonant circuit charges to Cr, simultaneously to inverter power supply, i under this operating state _LrAbsolute value compare I _oGreatly, the Cr charging is until u _Cr=Vs was zero moment with t3, was got the equivalent equation of circuit by Fig. 6 (e):

$\left\{\begin{array}{c}{u}_{\mathrm{Cr}}\left(t\right)=\frac{\mathrm{Vs}}{2}-\mathrm{Lr}\frac{{\mathrm{di}}_{\mathrm{Lr}}\left(t\right)}{\mathrm{dt}}\\ C_r\left(t\right)\frac{{\mathrm{du}}_{\mathrm{cr}}\left(t\right)}{\mathrm{dt}}=i_{\mathrm{Lr}}-I_0\\ u_{\mathrm{cr}}\left(0\right)=\mathrm{Vs},i_{\mathrm{Lr}}\left(0\right)=0\end{array}\right.---\left(6\right)$

Solve:

$\left\{\begin{array}{c}{u}_{\mathrm{cr}}\left(t\right)=\frac{\mathrm{Vs}}{2}[1-\cos \left(w_{r}t\right)]\\ i_{\mathrm{Lr}}\left(\max \right)=I_0+\frac{\mathrm{<figure-callout\; id="2"\; label="Vs"\; filenames="C200710122406E00151.png,C200710122406E00161.png"\; state="\{\{state\}\}">Vs</figure-callout>}}{2}\sqrt{\frac{\mathrm{Cr}}{\mathrm{Lr}}}\sin \left(w_{r}t\right)\end{array}\right.---\left(7\right)$

Calculate the charging interval of Lr:

$t_{\mathrm{cc}}=t4-t3=\frac{\mathrm{\&pi;}}{w_r}---\left(8\right)$

Open SI. and enter next operating state when Cr is charged to Vs, SI both end voltage before opening is zero, has realized that no-voltage is open-minded.

State 6: the time period corresponding to Fig. 5 is t4＜t＜t5, and SL is open-minded under this state, Sa by, the Sb conducting, the resonant inductance discharge is zero until electric current, Sb automatically shuts down, and enters next operating state, and the discharge time of Lr is identical with the charging interval of 4 times Lr of state.

What inverter circulated when carrying out the PWM modulation is operated under 6 kinds of operating states, wherein to be operated in pwm signal be under 1 the situation to state 1,2,5,6, it is under 0 the situation that state 3,4 is operated in pwm signal, for guaranteeing system's operate as normal, pwm signal is that shortest time of 1 is state 2,5,6 operating time sums, PWM is shortest time of 0 to be operating time of 4, when the design resonant circuit, should reduce the operating time of these several operating states as far as possible, make inverter have bigger PWM modulation range.

The parameter of resonant circuit is selected: the main task of resonant circuit design is exactly to determine the parameter value of resonant inductance Lr and resonant capacitance Cr, when determining its parameter, should remain on as far as possible that resonance current impacts is not the operating time that reduces state 2,4,5,6 under the very big situation, for guaranteeing that phase current has good square wave characteristic, the PWM carrier frequency of inverter is selected 5kHz, resonance frequency f should be chosen as 100kHz far above carrier frequency.

By $f=\frac{1}{2\mathrm{\&pi;}\sqrt{\mathrm{LrCr}}}={10}^5$

: LrCr=2.536 * 10 ^-12(9)

The increase of the operating time that can be got state 4,6 by formula (5) with Lr reduces.Resonance current peak value by formula (7):

$i_{\mathrm{Lr}}\left(\max \right)=I_0+\frac{\mathrm{<figure-callout\; id="2"\; label="Vs"\; filenames="C200710122406E00151.png,C200710122406E00161.png"\; state="\{\{state\}\}">Vs</figure-callout>}}{2}\sqrt{\frac{\mathrm{Cr}}{\mathrm{Lr}}}---\left(10\right)$

i _Lr(max) increase with Lr reduces.Rated voltage, rated current, rated speed, phase resistance, phase inductance according to permanent-magnet brushless DC electric machine can solve best resonant inductance, resonant capacitance value.

Software is realized: the three-phase permanent brshless DC motor generally adopts the control mode of rotating speed and current double closed-loop adjusting, and the control of resonant circuit is belonged to the interior ring control of electric current loop.It is TMS320LF2407A that control chip is selected the dsp chip model, and the minimum clock cycle of this chip is 0.25us, can control the operating time of resonant circuit under each working method more accurately.Current closed-loop adopts the control mode of interrupting, i.e. its size of current is controlled in modulus (AD) conversion of phase current being carried out by the startup that does not stop.The duty ratio of in AD conversion interrupt service routine, regulating PWM by the phase current values that detects, and the triggering and conducting that calculates Sa, Sb, SL according to Fig. 5 is constantly, the power switch pipe of selecting for use is IRF3710 for the power MOSFET model.

Claims (8)

1, a kind of flying wheel electromotor control system with magnetic suspending reaction comprises: isolated drive circuit (4), with DSP is control core device (1), rotating speed detects link (2), current detecting link (3), power amplification circuit (5), the soft ON-OFF control circuit of resonant mode (6), three-phase permanent brshless DC motor (7), with DSP is that control core device (1) detects link (2) with rotating speed, current detecting link (3), isolated drive circuit (4) links to each other, isolated drive circuit (4) links to each other with power amplification circuit (5), power amplification circuit (5) links to each other with the soft ON-OFF control circuit of resonant mode (6), the soft ON-OFF control circuit of resonant mode (6) links to each other with three-phase permanent brshless DC motor (7), rotating speed detects link (2), current detecting link (3) links to each other with power amplification circuit (5) with three-phase permanent brshless DC motor (7) respectively, be used for detecting the rotating speed of three-phase permanent brshless DC motor (7) and the electric current of its winding, it is characterized in that: described isolated drive circuit (4) adopts discrete component to constitute, mainly comprise: former limit voltage doubling rectifing circuit (12), push-pull circuit (13), pulse transformer (14), secondary voltage doubling rectifing circuit (15), high-pass filtering circuit (16), discharge triode (19), the capturing unit module that with DSP is control core device (1) is caught the position that obtains current rotor to three-phase permanent brushless DC motor rotor position sensor signal, and by being that the inner PWM waveform generation module of control core device (1) produces nine road PWM drive signals with DSP, former limit voltage doubling rectifing circuit (12) receives the PWM drive signal drive signal rectification is produced the single-polarity PWM drive signal; Push-pull circuit (13) receives the PWM drive signal after former limit voltage doubling rectifing circuit (12) rectification, and its driving power is increased; Pulse transformer (14) receives the PWM drive signal after push-pull circuit (13) increases power, isolates through pulse transformer (14) to become the secondary drive signal; Secondary voltage doubling rectifing circuit (15) receives the drive signal after isolating, with the drive signal rectification after isolating; High-pass filtering circuit (16) receives the drive signal after the rectification, and filtering is attached to the low-frequency noise on the drive signal after the rectification; Through the opening and turn-offing of filtered drive signal in order to control discharge triode (19).

2, a kind of flying wheel electromotor control system with magnetic suspending reaction according to claim 1, it is characterized in that: described isolated drive circuit (4) also comprises: diode (17) and decoupling capacitor (18) go to recoil, the described diode (17) that goes to recoil links to each other with secondary voltage doubling rectifing circuit (15), be used to eliminate of the interference of pulse transformer secondary to former limit, described decoupling capacitor (18) one ends link to each other with the diode (17) that goes to recoil, the other end links to each other with the emitter of discharge triode (19), is used to eliminate the influence of high-frequency ac coupled signal.

3, a kind of flying wheel electromotor control system with magnetic suspending reaction according to claim 1 is characterized in that: described former limit voltage doubling rectifing circuit (12) and secondary voltage doubling rectifing circuit (15) are made up of an electric capacity and a diode respectively.

4, a kind of flying wheel electromotor control system with magnetic suspending reaction according to claim 3 is characterized in that: the value size of described electric capacity determines discharging and recharging the time of electric capacity, and scope is 10 ⁴PF～10 ⁵PF; Described diode is chosen according to the collector electrode rated voltage of NPN type triode (Q1) in the push-pull circuit (13), the reverse voltage that diode bears when the triode conducting of drive circuit is the collector electrode rated voltage 15V of NPN type triode (Q1), and the reverse withstand voltage that described diode can bear should be 1.8～2.5 times of rated voltage.

5, a kind of flying wheel electromotor control system with magnetic suspending reaction according to claim 1 and 2, it is characterized in that: described push-pull circuit (13) is made up of NPN type triode (Q1) and positive-negative-positive triode (Q2), and the base stage of NPN type triode (Q1) and emitter link together with the base stage and the emitter of positive-negative-positive triode (Q2) respectively.

6, a kind of flying wheel electromotor control system with magnetic suspending reaction according to claim 5, it is characterized in that: described NPN type triode (Q1) or positive-negative-positive triode (Q2) are chosen according to the modulating frequency of signal, modulating frequency is 1Hz～1MHz, requires the switching frequency of NPN type triode (Q1) and positive-negative-positive triode (Q2) will be higher than the modulating frequency of signal.

7, a kind of flying wheel electromotor control system with magnetic suspending reaction according to claim 1 and 2 is characterized in that: the lc circuit capacitor and inductor value of described pulse transformer (14) is chosen its modulating frequency according to modulating frequency $f=\frac{1}{2\mathrm{\&pi;}\sqrt{\mathrm{LC}}},$ Transformer turn ratio is 1:1.

8, a kind of flying wheel electromotor control system with magnetic suspending reaction according to claim 1 and 2, it is characterized in that: described high-pass filtering circuit (16) is a cut-off frequency with the amplitude attenuation-3dB frequency of the drive signal that enters secondary voltage doubling rectifing circuit (15), and the resistance of high-pass filtering circuit, capacitance are determined according to the restriction of cut-off frequency.

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