KR19980017964A - Circuit for zero voltage switching of switched reluctance motor drive circuit - Google Patents

Abstract

According to the present invention, a voltage applied to both ends of current interruption switching elements in a hard switching driving circuit is inserted into and connected to a hard switching driving circuit for driving a switched reluctance motor. A circuit for zero voltage switching of a switched reluctance motor driving circuit in which the switching elements in the motor driving circuit achieve zero voltage switching by switching to zero when a short-circuit is switched. A transistor having an open / close signal terminal connected in series Resonant coils, branch diodes and capacitors; A diode connected to the ground from the contact point of the transistor and the resonant coil; and the capacitor is connected in parallel with a reflux diode in the motor driving circuit to enable zero voltage switching of the current interrupt switch in the driving circuit, thereby switching noise. It is an invention that can stabilize the motor torque by significantly reducing the over-loss and enabling high-speed switching to improve the dynamic characteristics of the system and to reduce the ripple of the phase current.

Description

Circuit for zero voltage switching of switched reluctance motor drive circuit

The present invention relates to a circuit for zero voltage switching of a switched reluctance motor driving circuit, and more particularly to a hard switching driving circuit for driving a switched reluctance motor. The switching elements in the motor driving circuit perform zero voltage switching by inserting and connecting the voltages applied to both ends of the current interrupting switching elements in the hard switching driving circuit to 0 at the time of switching between the opening and short-circuit of the switching element. The present invention relates to a circuit for zero voltage switching of a switched reluctance motor driving circuit which can reduce the switching power loss and the switching noise.

The hard switching circuit for driving a conventional switched reluctance motor is configured as shown in FIG. 6, wherein each phase selection switch S1, for selecting the phase winding lines PL1, PL2, PL3, and PL4 of the motor to which current is supplied. S2, S3, S4); An intermittent switch (S13, S14) for supplying intermittent current to the phase winding selected by the phase selection switch; When the phase selection switches S1, S2, S3, and S4 are opened, diodes D1 and D2 which form a path for quickly removing energy stored in the phase windings PL1, PL2, PL3, and PL4 at the time of switching. , D3, D4); And a free wheeling diode (D13, D24) for creating an instantaneous path of the current flowing in the selected phase winding while the intermittent switch repeats the process of switching from short to open at high speed. The intermittent switches S13 and S24 and the flyback diodes D13 and D24 are commonly used in two phases of a motor.

The hard switching motor driving circuit configured as described above obtains a continuous rotational force by applying a voltage to each of the windings PL1, PL2, PL3, and PL4 sequentially to supply current, and firstly selecting the intermittent switch S13. When the input voltage is applied by shorting the switch S1, current flows through the intermittent switch S13, the phase winding PL1, and the selection switch S1, and the motor has a rotational force to rotate. Next, the shorted switches S1 and S13 are opened, and instead, the interruption switch S24 and the selector switch S2 are short-circuited to supply current to the motor winding line PL2, thereby providing continuous rotational force to the rotating motor. Will be added. In this way, when each phase winding (PL1, PL2, PL3, PL4) of the motor is excited in turn, the motor continues to rotate.

However, since the speed of the motor is proportional to the magnitude of the current flowing in the phase windings PL1, PL2, PL3, and PL4, the phase current must be constantly controlled in order to drive the motor at a constant speed. In order to control the magnitude of the phase current to the desired size, the interruption switches S13 and S24 should be interrupted at a necessary time ratio.

First, it is assumed that the selection switch S1 is short-circuited and the intermittent switch S13 is open. In this state, the current flowing in the phase winding PL1 flows through a loop through the reflux diode D13 and is reduced in braille by the counter electromotive force of the rotating motor. When the intermittent switch S13 is shorted by applying a voltage to the open / close signal terminal of the intermittent switch S13, the intermittent switch S13 is connected to the terminal through the intermittent switch S13 rather than a value of a current flowing in the forward direction through the reflux diode D13. After the supply and flow of the current flowing in the reverse direction through the reflux diode D13 increases, the reflux diode D13 is cut off and the current from the power source gradually increases through the motor winding PL1 of the motor. Will flow. After a limited time to prevent the current from flowing above a predetermined value, the interrupt switch S13 is opened again to cut off the current supplied from the power source, and the current flowing through the phase winding PL1 is the reflux diode S13 as described above. It gradually decreases through the loop formed by).

As described above, the excited winding winding PL1 is continuously supplied with a current within a certain fluctuation to maintain a constant rotational power, and this operation is performed by the other selection switches S2, S3, and S4. The same applies to the case of (PL3, PL4).

However, in the conventional hard switching motor driving circuit operating as described above, when the intermittent switch S13 is turned on (switched from the open state to the shorted state), the intermittent switch s13 The voltage applied to both ends decreases and the current flowing increases, resulting in power loss during the transition process where the voltage at both ends is completely zero (hatched portion in the lower figure of Fig. 7 (a)). When the interrupt switch S13 is cut off, a reverse current flows in the reflux diode D13 after a predetermined time, and the current component recovers to a power voltage after an instantaneous short circuit time. The voltage at both ends of the freewheeling diode D13 causes power loss in the freewheeling diode D13. (See the hatched portion in the upper figure of FIG. 7 (a).)

Further, the intermittent switch S13 is turned off (turned off from the shorted state to the open state) while the current is supplied to the upper winding line PL1 of the motor while the interrupted switch S13 is shorted. Then, a power supply voltage is instantaneously applied to both ends of the intermittent switch S13, and the current flowing through the intermittent switch S13 decreases, and power is consumed for a predetermined time by the voltage and the current component. Corresponds to the hatched area of (b) of)

Therefore, in the conventional hard switching motor driving circuit, since the intermittent switches S13 and S24 for driving the motor perform the opening / closing operation at a high speed in the state where the power supply voltage is applied, the above switching loss is greatly generated. There is a problem in that the residual peak value is generated at the time of switching switching and switching noise is generated, thereby greatly reducing the efficiency of the motor driving circuit as a whole.

Accordingly, the present invention has been made to solve the above problems, and the zero voltage switching of the switched reluctance motor driving circuit enabling the zero voltage switching of the current interrupted switching element in the switched reluctance motor driving circuit. The purpose is to provide a circuit for

Another object of the present invention is to reduce the cost increase by reducing the number of devices used in the circuit, and to reduce the zero voltage switching of the switched reluctance motor driving circuit which enables zero current switching of many current interrupted switching elements in the motor driving circuit. To provide circuitry for

It is still another object of the present invention to provide a circuit for zero voltage switching of a switched reluctance motor driving circuit which greatly reduces the resonance of unnecessary energy in a circuit and greatly improves efficiency.

1 is a motor driving circuit capable of zero voltage switching, in which an embodiment of a circuit for zero voltage switching according to the present invention is combined with a conventional hard switching motor driving circuit.

FIG. 2 is a waveform diagram of an essential part to show an operation of a motor driving circuit capable of switching zero voltage of FIG. 1,

3 is a waveform diagram showing the waveform of the main part to show the process of switching the excitation between the upper winding line of the motor,

4 is a motor driving circuit combined with an embodiment of a circuit for zero voltage switching using a junction capacitor of a diode,

5 is a motor driving circuit combined with another embodiment of a circuit for zero voltage switching of the motor driving circuit according to the present invention,

6 is a hard switching circuit diagram for driving a conventional switched reluctance motor,

FIG. 7 is a waveform diagram illustrating a power loss occurring in switching of a switch for controlling a current supplied to a motor from a reluctance motor according to the related art.

(a) is a waveform diagram at the time of turn-on of an interrupt switch,

(b) is a waveform diagram at the time of turn-off of an interrupt switch.

Explanation of symbols on the main parts of the drawings

100 embodiment of a circuit for zero voltage switching

200: Another embodiment of a circuit for zero voltage switching

C101, C102, C103, C104: Capacitor CD13, CD24: Junction capacitor of diode

D1, D2, ..., D4: Diode D100: Diode

D101, D102, D103, D104: Branch diode D13, D24: Free wheeling diode

D1 ', D2', D3 ', D4': Free-wheel diode DS13, DS24: Parasitic diode

L100: Resonant coils PL1, PL2, ..., PL4: Phase winding of motor

S1, S2, ..., S4: Phase winding selector switch S13, S24: Intermittent switch

S1 ', S2', S3 ', S4': Intermittent switch Vs: Motor drive power

A circuit for zero voltage switching of a switched reluctance motor driving circuit according to the present invention for achieving the above object, the first charging and discharging means having a capacitance; Inductive elements; First and second rectifying means for flowing a current in only one direction; And switching means having an open / close signal terminal, wherein the first charging / discharging means, the first rectifying means, the inductive element and the switching means are all connected in series, and the second rectifying means The first charging and discharging means connected in series is connected in parallel with the first rectifying means and the inductive element, and the first charging and discharging means is connected between the current output terminal and the ground of the current interrupt switching element in the motor driving circuit. And a non-connected end of the switching means is connected to a motor driving DC power supply, the first rectifying means is connected in a direction in which a current supplied from the power supply can flow, and the second rectifying means is connected to the power supply. It is characterized by being wired in a direction that cannot supply current.

The circuit for zero voltage switching of the switched reluctance motor driving circuit according to the present invention includes a rectifying means and a capacitance which are the minimum components necessary for zero voltage switching of a plurality of switching elements in the hard switching switched reluctance motor driving circuit. It is configured by adding only the charging and discharging means having a different and the other components are configured so as not to change, the charging and discharging means having the capacitance is another diode that has a junction capacitance That is,

The circuit for zero voltage switching of the switched reluctance motor driving circuit according to the present invention has another feature, including a saturation reactor inserted to be connected in series with the inductive element,

In the circuit for zero voltage switching of the switched reluctance motor driving circuit configured as described above, the current interruption switching element in the switched reluctance motor driving circuit is in an open state (in this case, the supply power is cut off, and the current flowing in the upper winding line of the motor is gradually Power is applied to the inductive element by short-circuiting the switching means by inputting a signal to the open / close end of the switching means immediately before switching to the short-circuit state. When power is applied to the inductive element, a current flows in a reverse direction through a reflux diode which is turned on, and when the current component gradually increases and becomes larger than the current component of the reflux diode, the reflux diode is immediately blocked, and The inductive element and the first charging and discharging means resonate, and the current component is rapidly charged in the first charging and discharging means.

Since the voltage applied to the first charging and discharging means is connected to one terminal of the current interrupt switching element in the motor driving circuit, when the voltage applied to the first charging and discharging means is equal to the power supply voltage, one terminal is disconnected. Since the voltage between both ends of the current interruption switching element connected to the power supply is zero, the current interruption switching element is zero voltage switching from the open state to the short circuit state. Since the current flowing in the upper winding of the motor gradually increases in the short circuit state of the current interrupted switching element, the current interrupted switching element must be opened again after a certain time, and the charging / discharging means is still charged with the power supply voltage. In this state, zero voltage switching is performed even when switching from short circuit to open circuit. Since the voltage charged in the charging / discharging means is discharged instantaneously through the phase winding of the motor when the current interruption switching element is opened, the opening and shorting of the current interruption switching element described above may be repeated in a zero voltage state. Will be.

The second rectifying means is a component for creating a path of the current flowing in the inductive element when the switching means switches from short circuit to open to cut off the current supplied to the inductive element.

Hereinafter, the configuration and operation of a preferred embodiment of a circuit for zero voltage switching of a switched reluctance motor driving circuit according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a motor driving circuit capable of zero voltage switching in which an embodiment of a circuit for zero voltage switching according to the present invention is combined with a conventional hard switching motor driving circuit.

FIG. 2 is a waveform diagram of an essential part of the operation of the motor driving circuit capable of switching the zero voltage of FIG. 1.

1 is a diagram of the present invention for zero voltage switching in a conventional motor drive circuit in which one interrupt switch S13, S24 interrupts a current supplied to two phase windings PL1, PL3 or PL2, PL4 of a motor, respectively. As a driving circuit to which an embodiment 100 is added, capacitors C101 and C102 are connected between the current output terminal of the intermittent switches S13 and S24 in the conventional driving circuit and ground, respectively, and the feedback diode ( Two branch diodes D101 and D102 are connected in series from the contacts of D13 and D24 and the capacitors C101 and C102, and resonate with the resonant coil L100 from the contacts of the branch diodes D101 and D102. Transistor S100 is connected in series to the power supply terminal. In addition, the resonant diode D100 is connected from the contact point of the resonant transistor S100 and the resonant coil L100 to the ground of the power supply, and its direction is connected in a direction in which current from the power supply does not flow. D101 and D102 are connected in a direction in which current from a power source can flow.

In the circuit configured as described above, the operation in the state in which the selection switch S1 is short-circuited, that is, the current is supplied to and shut off in the motor winding line PL1 will be described step by step with reference to the waveform of FIG. In FIG. 2, V _GS13 , V _GS1, and V _GS100 represent voltages applied to an intermittent switch S13, a selection switch S1, and a gate of the resonant transistor S100, respectively, and V _D13 represents a free-flow diode D13. ), And Ir and Ia ₁ represent currents flowing through the resonant coil L100 and the phase winding PL1, respectively.

In addition, M1, M2, ..., M7 in Fig. 2 is a step-by-step classification of the state of the waveform according to the operation of the circuit for ease of explanation, and the operation of the circuit will be described sequentially based on the above-described steps do.

A. M1 stage

This step is a state in which all the select switches S2, S3, S4 and the intermittent switch S13 are opened except for the selector switch S1, which flows to the upper winding line PL1 just before the intermittent switch S13 is opened. The current Ia ₁ flows through the loops D13-PL1-S1-D13 formed through the reflux diode D13, and the current Ia ₁ gradually decreases due to the counter electromotive force of the switched reluctance motor.

N. M2 stage

The transistor S100 is short-circuited by applying a voltage to the gate of the resonant transistor S100. In this case, since the flyback diode D13 is in a conductive state, the current from the power supply is looped for a while (Vs-S100-L100-). D101-D13-Vs).

At this time, in the flyback diode D13, the phase current I a ₁ flowing in the step M1 flows in the forward direction of the diode, and the power current Ir through the resonant coil L100 flows simultaneously in the reverse direction of the diode. The current flowing through the resonant coil L100 increases linearly with the slope of Vs / L100. While the value of the current is smaller than the phase current Ia flowing through the freewheel diode D13, the freewheel diode D13 is It will still be in a conductive state.

C. M3 step

The current Ir flowing through the resonant coil L100 by the power supply becomes larger than the phase current Ia ₁ , and at the moment when the magnitude of the current is reversed, the reflux diode D13 is cut off and the resonant coil L100 and the capacitor are blocked. C101 resonates with each other. At this time, the power supply voltage starts to be charged to the capacitor C101 through the loop Vs-S100-L100-D101-C101-Vs. This process is continued until all the voltages applied through the resonant transistor S100 are charged from the power source to the capacitor C101. Unlike the conventional motor driving circuit, in this step, after the current flowing through the freewheeling diode D13 is cut off, the voltage is charged at both ends of the freezing diode D13 while the voltage is charged in the capacitor C101 connected in parallel. Since it starts to be charged, even if switching occurs in the intermittent switch turn-on step (M4 step) described below, power loss as shown in the upper figure of FIG. 7A does not occur.

D. M4 step

After the capacitor C101 is charged to the voltage applied from the power source, the current component flowing through the resonant coil L100 passes through the loop S100-L100-D101-DS13-S100 through the internal diode DS13 of the interrupt switch S13. During this period, since the voltage across the capacitor C101 is charged to the power supply voltage through the power supply, the voltage applied to both ends of the control switch S13 becomes zero. Accordingly, the intermittent switch S13 is switched from the open state to the shorted state within this section, and the resonant transistor S100 is also cut off again after the intermittent switch S13 is switched.

M. M5 step

When the resonant transistor S100 is blocked, the current Ir flowing through the resonant coil L100 flows along the loop Vs-D100-L100-D101-DS13-Vs formed through the resonant diode D100. The energy stored in the coil L100 is returned to the power source. The resonance current Ir decreases linearly as energy returns to the power source.

Iii. M6 step

The current Ir flowing through the resonant coil L100 decreases and is no longer flowing. The motor operates in a power supply mode, and the phase current Ia ₁ at this time is a loop Vs-S13-PL1-S1-Vs. Gradually increasing through).

G. M7 step

The intermittent switch S13 is opened again according to the intermittent frequency determined so that the phase current Ia flowing above does not increase by a predetermined value or more. At this time, the voltage charged in the capacitor (C101) is rapidly discharged along the loop (C101-PL1-S1-C101), the moment the reflux diode (D13) is turned on when the voltage across the capacitor (C101) is all discharged, the phase current (Ia ₁ ) flows through the loops D13-PL1-S1-D13. Even when the interrupt switch S13 is switched from short to open, the capacitor C101 is charged to a power supply voltage, so the voltage between both ends of the interrupt switch S13 is still 0, and in this state, the interrupt switch ( Even though S13 is turned off, the voltage between the both ends of the control switch S13 does not increase rapidly but gradually increases, so that almost no power loss occurs while the current component that decreases from the time of opening the control switch S13 remains. Do not.

The seven steps described above are generated when energizing all the phases according to a predetermined frequency to supply rotational force, and when interrupting the phase winding lines PL2 and PL4, an intermittent switch S24 is used instead of the small and small switches S13. According to the circuit for zero voltage switching according to the branch diode (D101), instead of the branch diode (D102), capacitor (C101) capacitor (C102) is used and the zero voltage of the intermittent switch (S24) according to the same operation described above Switching takes place.

The selection switches S1, S2, S3, and S4 other than the intermittent switches S13 and S24 in which the zero voltage switching is performed are shorted only as long as the time to excite the phase windings PL1, PL2, PL3, and PL4. The switching frequency of S2, S3, S4 is very low, so the switching losses generated by the phase selection switches S1, S2, S3, S4 are very small and can be ignored.

FIG. 3 is a waveform diagram showing waveforms of a main part appearing in the excitation switching process between the phase windings of the motor, in a state for interrupting the current in the phase winding PL2 in a state for interrupting the current in the phase winding PL1. It shows the gate signal (V _GS13 , V _GS1, V _GS24 , V _GS2 , V _GS100 ) and the change of the current flowing through the _phase winding for switching. In FIG. 3, Ia ₁ is a current flowing in the phase winding PL1, Ia ₂ is a current flowing in the phase winding PL2, and V _D13 and V _D24 represent voltages across the reflux diodes D13 and D14, respectively. .

FIG. 4 is another embodiment of a circuit for zero voltage switching implemented using the junction capacitance in the flyback diodes D13 and D24 instead of the capacitors C101 and C102 of FIG. 1, in which the flyback diode D13 In addition to the function that the junction capacitors CD13 and CD24 in D14 create instantaneous paths of current, the charge and discharge functions of the capacitors C101 and C102 described in the operation of FIG. 1 are also performed. Zero voltage switching of the intermittent switches S13 and S14 in the furnace is enabled.

FIG. 5 is a motor driving circuit in which another embodiment 200 of the circuit for zero voltage switching of the motor driving circuit according to the present invention is coupled, and an intermittent switch S1 ', S2', S3 ', S4 ') and branch diodes D101, D102, D103, and D104 connected in series for each phase and capacitors C101, C102, and C103 for the driving circuits independently provided with the reflux diodes D1, D2, D3, and D4. C104 is coupled and the resonant transistor S100, the resonant coil L100, and the resonant diode D100 are commonly used circuits. The operation of the drive circuit is made the same as the operation in the preferred embodiment described above.

Preferably, an unnecessary resonance phenomenon between the parasitic capacitor component of the resonant transistor S100 and the junction capacitor of the diode D100 and the resonant coil L100 appearing when the resonant transistor S100 is switched. The silver saturation reactor is inserted and connected in series with the resonant coil L100 to remove the resonant transistor S100. Since the resonant transistor S100 needs to be small and have a high switching speed, the saturation reactor is composed of an insulating gate field effect transistor (MOSFET) suitable for this characteristic.

The circuit for zero voltage switching of the switched reluctance motor driving circuit according to the present invention configured and acting as described above enables zero voltage switching of an intermittent switch in a motor driving circuit for switching switching at high speed to reduce switching loss. And high speed switching operation, which not only improves the dynamic characteristics of the system but also reduces the ripple of the current flowing through the windings, resulting in a stable torque, thus reducing noise within a wide speed operating range. It is a very useful invention that can achieve.

Claims (6)

First charging and discharging means having a capacitance; Inductive elements; First and second rectifying means for flowing current in only one direction; And Switching means having an open and close signal terminal; is configured to include, The first charging and discharging means, the first rectifying means, the inductive element and the switching means are all connected in series, The second rectifying means is connected in parallel to the first charging and discharging means, the first rectifying means and the inductive element connected in series, The first charging / discharging means and the current output terminal of the current interruption switching element in the motor driving circuit are connected between the ground and the unconnected end of the switching means are connected to the motor driving DC power supply. For the zero voltage switching of the switched reluctance motor driving circuit, wherein the current supplied from the power source is connected in a direction that can flow, and the second rectifying means is connected in a direction that the current supplied from the power source cannot flow. Circuit. The method of claim 1, And the first charging and discharging means having the capacitance is a diode having a junction capacitance. The circuit for zero voltage switching of the switched reluctance motor driving circuit. The method according to claim 1 or 2, And at least one path configured as a third rectifying means for flowing a current in only one direction and a second charging / discharging means having capacitance connected in series with the third rectifying means. The branch is all connected in parallel to the first charging and discharging means and the first rectifying means connected in series, wherein the at least one second charging and discharging means is connected between the current output terminal and the ground of the current interruption switching elements in the motor driving circuit. And at least one third rectifier means are connected in a direction in which a current supplied from the power supply can flow. The method of claim 3, wherein And at least one second charging / discharging means having the capacitance is a diode having a junction capacitance, the circuit for zero voltage switching of the switched reluctance motor driving circuit. The method of claim 3, wherein And a saturation reactor connected in series with said inductive element. The method according to claim 1, 2 or 4, And a saturation reactor connected in series with said inductive element.