CN1217476C - Brushless DC motor starting control device - Google Patents

Abstract

The present invention relates to a brushless DC motor starting control device which comprises a first capacitor, a rectifying and filtering part, a rectangular wave phase converter, a half-wave charge and discharge power source part and a Hall sensor part, wherein the first capacitor uses an input AC power supply to charge and discharge; the rectifying and filtering part rectify and filter the first capacitor and an input power source; the rectangular wave phase converter is used for turning on and off the output voltage of the rectifying and filtering part and outputting the voltage to drive the motor; the half-wave charge and discharge power source part uses an input AC power supply to charge and discharge to carry out half-wave rectification for serving as a power supply for controlling the motor; the Hall sensor part is used for measuring the rotation speed of the motor and controlling a phase converter. The power supply from an input power supply end to a loading end is realized by the charge and the discharge of the capacitor. Meanwhile, a starting resistance is also arranged for the favoring charge and discharge of the capacitor, and thus, power supply is fluently carried out to a control power source and a drive power supply circuit.

Description

Brushless DC motor starting control device

One, technical field

The present invention relates to a kind of start-up control device of Brushless DC motor, particularly relate to and a kind ofly utilize discharging and recharging of capacitor and control the brushless DC motor starting control device that powers to the load of input power supply.

Two, background technology

Fig. 1 is the block diagram of existing brushless DC motor starting control device.As shown in Figure 1, existing motor starting control device mainly is made up of switch mode power portion 11, filtering capacitor C2, phase changer 12 and Hall element portion 13.11 pairs of AC power of switch mode power portion are carried out switching and rectifying and outputting standard direct voltage, with as the driving power of motor and the power supply of control circuit; Filtering capacitor C2 carries out filtering to the direct voltage of switching regulator power supply unit 11 outputs; 12 of phase changers carry out switch to direct voltage, with the output square wave.Hall element portion 13 is used to measure the rotating speed of motor and turns on and off phase changer 12.

AC power is a direct voltage by 11 rectifications of switch mode power portion, and this mode can be carried out precision adjustment to DC voltage level, and the fluctuation of direct voltage is little, voltage level does not change with the variation of load.But,, make the whole efficiency of motor reduce because the efficient of switch mode power portion 11 itself is lower.The whole efficiency η of motor can be represented by the formula:

[mathematical expression 1]

η＝η _SMPSSη _motor

η wherein _SMPSThe efficient of expression switch mode power portion, η _MotorExpression comprises the moyor of control circuit.Therefore, the whole delivery efficiency of motor will reduce 15-25% because of the efficient of switch mode power portion.

Three, summary of the invention

Purpose of the present invention promptly is to provide a kind of brushless DC motor starting control device, imports the power supply of power supply to load in order to controlling with discharging and recharging of capacitor, thereby improves the whole efficiency of motor.

The technical solution adopted for the present invention to solve the technical problems is:

A kind of brushless DC motor starting control device of the present invention, it is characterized in that, comprise: first capacitor that relies on alternating current input power supplying to discharge and recharge, to first capacitor and the input power supply rectification filtering part that carries out rectification and filtering, the rectification filtering part output voltage is carried out the phase changer of the square wave of switch control and output CD-ROM drive motor, discharge and recharge and the half-wave that carries out halfwave rectifier discharges and recharges power supply unit and measures motor rotary speed and control the hall sensing portion of phase changer by the input power supply, half-wave discharges and recharges power supply unit and is connected to phase changer as motor control power supply, so that phase changer is powered.

Aforesaid brushless DC motor starting control device, wherein half-wave discharges and recharges power supply unit and is made up of first diode, second diode, Zener diode, resistance and filter capacitor; The positive pole of first diode is connected in series with the negative pole of second diode, and an end of resistance is connected with the negative pole of Zener diode, and the other end of resistance is connected with the negative pole of first diode, and the positive pole of Zener diode is connected with the positive pole of second diode; Filter capacitor and resistance and Zener diode also connect.

In the present invention, be to realize by input supply terminal to the power supply of motor load end by discharging and recharging of capacitor, the whole efficiency of motor is improved.

Be described in further detail below in conjunction with the technical characterictic of specific embodiment brushless DC motor starting control device of the present invention.

Four, description of drawings

Fig. 1 is the circuit diagram of existing brushless DC motor starting control device.

Fig. 2 is the circuit diagram of brushless DC motor starting control device of the present invention.

Fig. 3 is the schematic diagram that the motor driven power supply unit among the present invention discharges and recharges route.

Fig. 4 is the schematic diagram that the motor control power supply unit among the present invention discharges and recharges route.

Fig. 5 is the circuit diagram that inserts the motor starting control device of starting resistance in the phase changer.

Five, embodiment

As shown in Figure 2, brushless DC motor starting control device of the present invention discharges and recharges power supply unit 23 by the first capacitor C9, rectification filtering part 21, phase changer 22, half-wave and Hall element portion 24 forms.The first capacitor C9 is discharged and recharged by AC power AC; 21 couples first capacitor C9 of rectification filtering part and AC power AC carry out rectification and filtering and output dc voltage; The direct voltage of 22 pairs of rectification filtering part outputs of phase changer carries out switch, with the square wave of output CD-ROM drive motor; Half-wave discharges and recharges power supply unit 23 and is discharged and recharged and halfwave rectifier by AC power AC, with as the motor control circuit power supply; Hall element portion 24 is used to measure the rotating speed of motor and controls phase changer 22.

In above-mentioned brushless DC motor starting control device, be provided with starting resistance between described phase changer 22 direct-current coupling terminal voltages and the switching transistor.

When motor has certain load, if utilize controlling organization control input power supply to power to load side, so, the level of direct-current coupling voltage will depend on load size and the size of electric weight of confession.Based on this point, the present invention has set up one and has discharged and recharged power supply unit, and this discharges and recharges power supply unit and comprises the rectification filtering part 21 be made up of diode D2-D5 and filter capacitor C2, the first capacitor C9 and discharge and recharge power supply unit 23, the second capacitor C1 by the half-wave that the first diode D1, the second diode D6, Zener diode DZ1 and capacitor C3 form; Input supply terminal is realized by the second capacitor C1 to the power supply of load side, therefore, can realize the power supply power supply of control.The all-wave that discharges and recharges power supply unit discharges and recharges route as shown in Figure 3.

Described half-wave discharges and recharges power supply unit 23 and is made up of the first diode D1, the second diode D6, Zener diode DZ1, resistance R 14 and filter capacitor C3; The positive pole of the first diode D1 is connected in series with the negative pole of the second diode D6, resistance R 14 be connected between the first diode D1 negative pole and the second diode D6 positive pole after Zener diode DZ1 negative pole is connected in series; Filter capacitor C3 and resistance R 14 and Zener diode DZ1 also connect.

Because filtering capacitor C2 is more much bigger than the first capacitor C9, so filtering capacitor C2 both end voltage is direct-current coupling voltage V _{Dc, link}Fluctuation can ignore, direct-current coupling voltage can be considered definite value.In this case, be shown below to average current (or the average current that the consumes) Iavg that the motor power circuit provides owing to discharging and recharging of the first capacitor C9:

[mathematical expression 2]

$I_{\mathrm{avg}}=C9\frac{{\mathrm{dV}}_{c9}}{\mathrm{dt}}=C9\frac{2(\sqrt{2}V-V_{\mathrm{dc},\mathrm{link}})}{1/2f}$

$=4\·f\·C9\·(\sqrt{2}V-V_{\mathrm{dc},\mathrm{link}})$

In the formula, C9 is first condenser capacitance, V _{Dc, link}The average current that provides to the motor power circuit is provided for expression direct-current coupling voltage, Iavg.In other words, when load during for the total load of average current Iavg decision, for the above-mentioned power circuit that discharges and recharges, as long as the capacitance of the adjustment first capacitor C9 can obtain required direct voltage.

Fig. 4 be motor control power supply unit discharge and recharge the route schematic diagram.As shown in Figure 4, control the discharge route of power circuit because filtering capacitor C2 is charged, thereby unexpected times of voltage function occurred.Because this characteristic, when utilizing transistor as the switching device of motor, just the startup problem may take place.In other words, before the motor starting, filtering capacitor C2 goes up the not discharge route of charging voltage, promptly is equivalent to the voltage charging by the input voltage twice.After the motor starting, because the electric weight that the first capacitor C9 supplies with is very little with respect to the electric weight that motor consumed, so direct-current coupling voltage can not be raised to more than the peak value of input voltage.But before motor starting, promptly the control supply voltage rise to can driving transistors Q1, Q2 before, problem then may take place in the direct-current coupling overtension.This moment, the first capacitor C9 can not discharge and recharge swimmingly, and control circuit and drive circuit all can not get power supply, and motor can not start.

Determining the factor that can above-mentioned Brushless DC motor start, is the voltage level V of control power circuit ₂Whether can be elevated to and to drive above-mentioned transistor Q ₁, Q ₂Voltage level.

When the sine wave input of input voltage the n time occurring, above-mentioned the 2nd capacitor C ₁Do not discharge between the two ends, remaining voltage level is V _{C1, n}, at this moment, through the 2nd capacitor C ₁The electric current of supply control circuit is i _{C1, n}, so, available following mathematical expression 3 is represented.

[mathematical expression 3]

V _c1，n＝0 (n＝0)

$V{=}_{c1,n}=\sqrt{2}\·\mathrm{Vs}\frac{C1}{C1+C2}+V_{c1,n-1}s\frac{C2}{C1+C2}(n@0)$

$v_{\mathrm{<figure-callout\; id="1"\; label="c"\; filenames="C0114436700081.png,C0114436700091.png"\; state="\{\{state\}\}">c</figure-callout>}1,n}=\sqrt{2}\&CenterDot;\mathrm{Vs}\frac{C1}{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C0114436700081.png,C0114436700091.png"\; state="\{\{state\}\}">C</figure-callout>}1+C2}s\frac{1-r^n}{1-r},(r=\frac{C2}{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C0114436700081.png,C0114436700091.png"\; state="\{\{state\}\}">C</figure-callout>}1+C2})$

${\mathrm{<figure-callout\; id="1"\; label="i\; c"\; filenames="C0114436700081.png,C0114436700091.png"\; state="\{\{state\}\}">i</figure-callout>}}_c(\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C0114436700081.png,C0114436700091.png"\; state="\{\{state\}\}">C</figure-callout>}1\&times;(\sqrt{2}\&CenterDot;V-{\mathrm{<figure-callout\; id="1"\; label="V\; c"\; filenames="C0114436700081.png,C0114436700091.png"\; state="\{\{state\}\}">V</figure-callout>}}_c)$

$(\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C0114436700081.png,C0114436700091.png"\; state="\{\{state\}\}">C</figure-callout>}1\&times;\sqrt{2}\&CenterDot;{\mathrm{Vsr}}^n$

In the formula, above-mentioned C ₁, C ₂The capability value of representing the 2nd, the 1st smoothing capacitor.If by above-mentioned the 2nd capacitor C ₁Charging current i _{C1, n}Change with function, then can represent with following mathematical expression to the time.

[mathematical expression 4]

$i_{\mathrm{<figure-callout\; id="1"\; label="c"\; filenames="C0114436700081.png,C0114436700091.png"\; state="\{\{state\}\}">c</figure-callout>}1,n}\left(t\right)(\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C0114436700081.png,C0114436700091.png"\; state="\{\{state\}\}">C</figure-callout>}1\&times;\sqrt{2}\&CenterDot;V{\mathrm{sr}}^{\left(2\mathrm{sf}{s}^{t-1}\right)/2}$

$(\frac{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C0114436700081.png,C0114436700091.png"\; state="\{\{state\}\}">C</figure-callout>}1\&times;\sqrt{2}\&CenterDot;V}{\sqrt{r}}s{e}^{g^t}$ (g＝fslnr)

The voltage level V of above-mentioned the 2nd filtering capacitor charging ₂If represent, then can change following mathematical expression 5 expressions into Laplce (LAPLACE) equation.

[mathematical expression 5]

$V_2\left(S\right)=\frac{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C0114436700081.png,C0114436700091.png"\; state="\{\{state\}\}">C</figure-callout>}1\&times;\sqrt{2}\&CenterDot;V}{\sqrt{r}}s\frac{1}{S-g}s\frac{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="C0114436700081.png,C0114436700091.png"\; state="\{\{state\}\}">R</figure-callout>}}{1+S\&CenterDot;R\&CenterDot;C3}$

In the formula, R represents the equivalent resistance of control circuit.Above-mentioned 5 usefulness time of mathematical expression is following mathematical expression 6 during function representation.

[mathematical expression 6]

$V_2\left(t\right)=\frac{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C0114436700081.png,C0114436700091.png"\; state="\{\{state\}\}">C</figure-callout>}1\&times;\sqrt{2}\&CenterDot;\mathrm{Vs}\frac{\mathrm{RsC}3}{1+\mathrm{RsC}3\&times;\ln r}}{\sqrt{r}\mathrm{sC}3}s(e^{g^t}-e^{h^t})$

$(h=\frac{1}{\mathrm{RsC}3})$

As a result, discharge and recharge in the motor control and drive circuit of power circuit,,, should select the 2nd capacitor C for smooth and easy starting if the input voltage permissible error is lower in use ₁Capability value, perhaps, increase starting resistance R ₂, R ₄, to substitute above-mentioned the 2nd capacitor C that designs by normal running conditions ₁Capability value, to satisfy the starting conditions requirement.

For this reason, further embodiment of this invention picture 5 shows the built-up circuit figure that inserts the Brushless DC motor start-control device of resistance in phase changer of the present invention portion.As shown in the figure, detect the excessive rising of direct-current coupling voltage VdcLink, when the electrical level rising of this direct-current coupling voltage is above to certain fiducial value, at direct-current coupling terminal voltage and above-mentioned transistor Q ₁, Q ₂Between the end, inserted starting resistance R ₂, R ₄, can force starting.

At this moment, after the power connection, if prestarting time delay is designed to t ₁, so, when the n time sinusoidal wave input of input voltage occurring,, calculate starting resistance R by the mathematical expression 7 of asking above-mentioned direct-current coupling terminal voltage ₂, R ₄The design load of value.

[mathematical expression 7]

$V_{\mathrm{dc},\mathrm{link}}=\sqrt{2}\&CenterDot;V+{\mathrm{<figure-callout\; id="1"\; label="V\; c"\; filenames="C0114436700081.png,C0114436700091.png"\; state="\{\{state\}\}">V</figure-callout>}}_c$

$=\sqrt{2}\&CenterDot;V+\sqrt{2}\&CenterDot;\mathrm{Vs}\frac{1-r^n}{1-r}$

$V_{\mathrm{dc},\mathrm{link}}\left(t\right)(\sqrt{2}\&CenterDot;V+\sqrt{2}\&CenterDot;\mathrm{Vs}\frac{1-r^{\mathrm{ft}}}{1-r})$

At this moment, make above-mentioned transistor Q ₁, Q ₂If the voltage level of conducting is V _{BB, turn-on}, so,, calculate following starting resistance R with following mathematical expression 8 ₂The design load of value.And, use the same method and obtain above-mentioned starting resistance R ₄Value.

[mathematical expression 8]

$\frac{R12}{R2+R12}\mathrm{<figure-callout\; id="1"\; label="s\; V"\; filenames="C0114436700081.png,C0114436700091.png"\; state="\{\{state\}\}">s</figure-callout>}{V}_{}{}_{1,s}=V_{\mathrm{BE},\mathrm{turn}-\mathrm{on}}$ $({\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="C0114436700081.png,C0114436700091.png"\; state="\{\{state\}\}">V</figure-callout>}}_{1,s}=\sqrt{2}\&CenterDot;V_i+\sqrt{2}\&CenterDot;V_{i}s\frac{{1-\mathrm{<figure-callout\; id="1"\; label="r\; ft"\; filenames="C0114436700081.png,C0114436700091.png"\; state="\{\{state\}\}">r</figure-callout>}}^{\mathrm{ft}}}{1-r})$

$R2=\frac{R12s(V_{1,s}-V_{\mathrm{BE},\mathrm{turn}-\mathrm{on}})}{V_{\mathrm{BE},\mathrm{turn}-\mathrm{on}}}$

In the formula, V _{1, S}The rated voltage of expression control circuit, R ₁₂The resistance that expression is maximum.

Adopt and insert above-mentioned starting resistance, this motor control circuit can start under any initial conditions.Be above-mentioned starting resistance R ₂, R ₄In operate as normal, cause power consumption, therefore, preferably consider the starting time, select big as far as possible value.

Claims (2)

1, a kind of brushless DC motor starting control device, it is characterized in that, comprise: first capacitor that relies on alternating current input power supplying to discharge and recharge, to first capacitor and the input power supply rectification filtering part that carries out rectification and filtering, the rectification filtering part output voltage is carried out the phase changer of the square wave of switch control and output CD-ROM drive motor, discharge and recharge and the half-wave that carries out halfwave rectifier discharges and recharges power supply unit and measures motor rotary speed and control the hall sensing portion of phase changer by the input power supply, half-wave discharges and recharges power supply unit and is connected to phase changer as motor control power supply, so that phase changer is powered.

2, brushless DC motor starting control device according to claim 1 is characterized in that described half-wave discharges and recharges power supply unit and is made up of first diode (D1), second diode (D6), Zener diode (DZ1), resistance (R14) and filter capacitor (C3); The positive pole of first diode (D1) is connected in series with the negative pole of second diode (D6), one end of resistance (R14) is connected with the negative pole of Zener diode (DZ1), the other end of resistance (R14) is connected with the negative pole of first diode (D1), and the positive pole of Zener diode (DZ1) is connected with the positive pole of second diode (D6); Filter capacitor (C3) and resistance (R14) and Zener diode (DZ1) also connect.

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