JPH0724471B2 - 4 quadrant controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a control system for a four-quadrant chopper, and is particularly suitable for high-speed response, high-efficiency rotation and forward / reverse rotation control of a DC motor, and is easily applied to an inverter. Is something that can be done.

<Outline of the Invention> The present invention uses a DC chopper such as a transistor chopper to drive a load having a back electromotive force such as a DC separately excited motor, regardless of whether the load current is continuous or discontinuous, or whether the current is positive or negative. The average value of the terminal voltage of the load can be maintained at the set value, and even when the set value continuously changes from positive to negative, the average value of the terminal voltage of the load follows the so-called 4 automatically. It provides a quadrant chopper control method.

<Prior Art> FIGS. 12 to 19 show the circuit configurations and characteristics of four types of choppers that individually operate in the first quadrant to the fourth quadrant, respectively. The electric motor M that is the load here
Is the equivalent circuit shown in Fig. 20, that is, the inductance
It is represented by a series circuit of La, resistance Ra, and back electromotive force En. Load voltage is positive at A terminal, load current is A terminal → B
Make the terminal direction positive. The transistor turns on and off in a very fast cycle, and the ratio of the on period, that is, the duty factor is represented by α.

12 and 13 are examples of the first quadrant chopper. 12th
The figure shows the configuration of the chopper, and Fig. 13 shows the voltage-current characteristics when α is constant. The transistor Tr1 is driven on by α in one cycle and is turned off during the period of 1-α. The load voltage becomes 0 because the DC power supply voltage E _s is supplied during the ON period and the current flows through the diode D2 during the OFF period.
Therefore, the average voltage is αE _s . However, when the back electromotive force becomes large under a light load, the current becomes zero in the middle of the current discontinuity, that is, the current does not continue to flow in D2 during the off period, and the back electromotive force appears at the terminal. The average voltage becomes higher than αE _s , and the voltage control dynamics due to α are not linear. In the chopper of Fig. 12, no matter how α is changed,
No matter how the back electromotive force changes, the load voltage and load current are always positive, so the range of characteristics is limited to the first quadrant, as shown in FIG.

14 and 15 are examples of the second quadrant chopper. When the transistor Tr2 is on, La,
Current flowing through Ra-I _a increases and Tr2 is off-
i _a flows through D1 and regenerates power to the power supply E _s . Since the counter electromotive force E _n operates as a power source, the motor M moves as a generator, the regenerative braking. Instantaneous voltage v _a is becomes zero when Tr2 is on, Tr2 is D1 off period of ON E
_s . Therefore, the average voltage V _a becomes (1-α) E _s . When the current becomes discontinuous, the current does not continue to flow in D2 while Tr2 is off, so v _a cannot be kept at E _s during off, and V _a becomes smaller than when current is continuous. The average current −I _a is equal to (E _n −V _a ) / R _a , and can be controlled to any value by α. Second quadrant chopper is referred to as step-up chopper, current can be supplied to the high-pressure high equivalent load E _S than the equivalent power E _n.

16 and 17 are examples of the third quadrant chopper. Connect the A terminal of the motor M to the negative terminal of the power supply, and connect the B terminal to the B terminal of FIG.
Tr3 and D4 symmetrically arranged with Tr1 and D2 operate similarly. Both the average voltage and the average current have negative values, and the characteristics appear in the third quadrant as shown in Fig. 17. The higher the voltage of the B terminal, the more negative it is drawn on the graph. When the load is an electric motor, it is driven in the rotation direction opposite to the first quadrant.

18 and 19 are examples of the fourth quadrant chopper. The transistor Tr4 and the diode D3 are arranged symmetrically with Tr2 and D1 in FIG. The back electromotive force of the load is negative, and if it is a DC motor, it is rotating in the opposite direction, and the current is in the positive direction.Therefore, the torque generated by the motor is in the positive direction, and the motor operates as a generator and brakes. Has been done. The current of the power supply E _s flows through the diode D3 when the transistor Tr4 is off, regenerating power. That is, a step-up chopper of the reverse rotation regenerative braking characteristic V _a as Figure 19
Operates only in the fourth quadrant where is negative and _Ia is positive.

When it is necessary to control a single load, such as a DC separately excited motor, with a single DC power source over four quadrants, the switching element connects transistors Tr1 to Tr4 and diodes D1 to D4 to a single-phase bridge inverter and turns on a predetermined transistor. Or off or on with a predetermined duty factor
By turning off, four-quadrant chopper control can be performed.

Conventionally, in order to operate a DC separately excited motor in four quadrants by a chopper, it is judged whether or not it should be operated in the quadrant by measuring the rotation speed and the current, and switched to the operation circuit of FIG. 12 to FIG. A method of controlling the load voltage or the load current by the duty factor α has been used.

<Problems to be Solved by the Invention> However, this method has the following drawbacks.

The characteristics are not continuous in the first and second quadrants or the third and fourth quadrants. Even if α and (1-α) are associated in each quadrant, the characteristics do not match in the state of current discontinuity.

When switching the operation circuit by quadrant, to prevent the formation of a short circuit or abnormal current increase,
It is necessary to turn off all transistors for a certain period of time and have a current decay.

Due to such a drawback, when the operation is performed over a plurality of quadrants, it takes time to switch the operation circuit, a fast response operation cannot be expected, and since the characteristics are not continuous, there is an impact at the time of switching and smooth operation, for example, The forward and reverse operation of the electric motor was difficult, and the circuit was complicated.

As another method, a driving method for turning on / off a plurality of transistors in one cycle of the chopper, for example, Tr1 and T
Turn on r2 or Tr3 and Tr4 alternately. Tr1 and Tr4 or
The method of turning on and off Tr2 and Tr3 at the same time allows good linearity control because the current does not become discontinuous, but when switching the transistor that turns on, a short-circuit mode occurs for a short time, or a square wave applied to the load is generated. There is a drawback that power loss is large due to large voltage.

<Object of the Invention> The present invention relates to a method for driving a bridge type four-quadrant chopper, in which the load voltage is equal to the set value regardless of whether the quadrant or the current is continuous or discontinuous. However, the quadrant switching time is very short, and there is no danger of a power supply short circuit, and a driving method that can operate smoothly is provided.

The present invention develops a "chopper control system" for driving a two-quadrant chopper, which is disclosed in Japanese Patent Publication No. 56-2503, and enables operation over four quadrants.

<Embodiment> FIG. 1 shows the construction of a four-quadrant chopper and an embodiment of a drive circuit according to the control method of the invention.

The transistors Tr1 to Tr4 and the diodes D1 to D4 form a bridge, and the load motor is connected between the terminals A and B.

Table 1 shows the flow elements in the first to fourth quadrants. In the first quadrant, when both Tr1 and Tr4 are on, the chopper turns on, the instantaneous voltage v _a is equal to E _s , and the current i _a flows in the path of E _s -Tr1-M-Tr4-E _s . There are two possible chopper-off circuits, Tr1 is off,
i _a is when flowing to M-Tr4-D2-M and when Tr4 is off, i _a
In either case flowing through the M-D3-Tr1-M, both v _a
= 0. The circuit of FIG. 12 is formed by turning on Tr4 and turning on and off Tr1. Similar characteristics can be obtained by turning on Tr1 and turning off Tr4.

In the operation of the second quadrant, when Tr2 is turned on and off, current always flows in D4, and current flows alternately in Tr2 and D1.
The chopper circuit of FIG. 14 is formed. There is no problem if Tr4 is driven on. Similar characteristics can be obtained by turning on and off only Tr3. At this time, Tr1 may be driven on.

In the operation of the third quadrant, the circuit of FIG. 16 is formed by turning Tr2 on and turning Tr3 on and off. Turn on Tr3, Tr2
Similar characteristics can be obtained by turning on and off.

In the operation of the fourth quadrant, the circuit of FIG. 18 is formed by turning Tr4 on and off. You may leave Tr2 on, but
Since the current flows through D2, it does not flow through Tr2. Similar characteristics can be obtained by turning on and off only Tr1. At this time, Tr3 may be on or off.

The control circuit of the four-quadrant chopper of FIG. 1 time-integrates the load terminal voltage, that is, the difference between the voltage difference between the terminal A and terminal B and the voltage setting value by one adding integrator, and adds the integrated output to the four hysteresis comparators. . Comparator 1-4
Supplies an on / off signal to the transistors Tr1 to Tr4, respectively. The four comparators have different input moving point voltages depending on the voltages of Er1 to Er4.

FIG. 2 shows an operation circuit in the first quadrant. In the figure, the outputs of the comparators 2 to 4 are constant, and Tr2 and Tr3 are driven off and Tr4 is driven on. FIG. 3 shows the operation waveforms of FIG. The upper limit of the comparator 1 is V _c 11, and the lower limit is V _c 11.
It is represented by _c 10. Comparator 1 is turned ON when the input _{v c} is equal to or higher than _{V c} 11, _{v c} is turned off when the _{V c} 10 below. Comparator 1 does not change when the input v _c is between V _c 11 and V _c 10. The output of the summing integrator is the current of R ₁
The sum of the currents of R ₂ is stored in the capacitor C. When expressed by a formula, formula (1) is obtained.

If equation (1) is transformed into equation (2), However, V _a ^* is the voltage setting value v _c is the time integral of the error between the instantaneous value v _a of the load voltage and the set value V _a ^* . v inclination of _c is proportional to the _{V ^a} * -v ^a. While Tr1 is on, v _a is + E _s , and since v _a is larger than V _a ^* , v _c has a negative slope and the initial value is V _c 11.

Since the period during which Tr1 is on continues until v _c = V _c 10, the equation (3) Becomes (4) the right side of the equation is equal to the area (A) on FIG. 3 v _a waveform. When v _c reaches the lower limit V _c 10 of the comparator 1, Tr1 is driven off, the chopper turns off, and the current i _a flows through the diode D2, so v _a
= 0. Since the error voltage v _a −V _a ^* becomes negative, v _c
Has a positive slope. v _c The initial value is V _c 10. When v _c = V _c 11, the comparator 1 turns on and the off period ends, so from equation (5) Becomes (6) the right side of the equation is equal to the area (a) on FIG. 3 v _a waveform. When the average current I _a is as small as I _a2 as shown in FIG. 3B, i _a is midway during the off period.
_{Interrupted, i} a = 0 when it comes to appear on the back electromotive force _{E n} is _{v a waveform,} v a = _{E n} becomes, _v gradient of _c is - _{(v a} -
V _a ^* ) becomes gentler, but in the first quadrant E _n
Since <V _a ^* , the polarity of the slope does not change. Although the off time extends, the area (a) expressed by the equation (6) is the same as that when the current is continuous.

As can be seen by comparing equations (4) and (6), the positive area (a) and the negative area (a) created by the error voltage are always equal because v is the same as the upper and lower potential differences of the comparator. mean value V _a of _a is always equal controlled to the set value V _a ^*, also very fast response when changing the V _a ^* by E _1. The same can be said for operations in other quadrants. In addition, 0 <V _a ^* <
As long as E _s and E _n <V _a ^* , v _c reciprocates between the upper and lower limits of comparator 1 and the chopper operation remains in the first quadrant. FIG. 9 illustrates the characteristics of V _a vs. I _a in the operating circuit of FIG. 7. Compared with FIG. 1 (b), the output voltage V _a is not controlled by α but is directly controlled. Is controlled by V _a ^* , and α and chopper cycle are such that V _a is V
_The characteristic that automatically changes to be equal to _a ^* is independent of the continuity / discontinuity of the current.

FIG. 5 shows an example of the arrangement of the upper and lower limit voltages of the comparators 1 to 4 in FIG. Flip-flop 1,2
The input signal is output as it is. The input voltage v _c is on the vertical axis. The upper and lower limits of the comparators are arranged so that they do not overlap, and the comparators 1, 2, 4, and 3 are arranged in this order. For example v if _c is changed from positive to negative direction, the first v _c> V in _c 11 Tr1 and T
r4 is on. As v _c changes negatively, Tr1 → off, Tr2 → on, Tr4 → off, Tr3 → on are sequentially changed, and Tr2 and Tr3 are turned on when v _c <V _c 31. Because Tr1 and Tr2 and Tr3 and Tr4 rather than v _c together turned on or instantaneously on-state nor interchanged, and no power short circuit mode. The characteristics of V _a vs. I _a are shown in FIG. In the figure, the constant V _a is the chopper output characteristic when V _a ^* is constant, and the slope is E.
The load characteristic when _{n is} constant is V _a = E _n + R _a I _a (7). The operating point is the intersection of the output characteristic and the load characteristic. An example of quadrant movement will be described below.

The operating point ^{_{E n = E n1, V a}} * = operating point and a V _a1 is as first quadrant. The error integral v _c is V _c 11 and V _c as shown in FIG.
After going back and forth between 10, Tr2 and Tr3 are off, Tr4 is on, and Tr1 is on and off.

Consider the case where the voltage setting value is changed and set to V _a ^* = V _a2 from the case of operating from the operating point → operating point.

Since V _a2 is smaller than the back electromotive force E _n1 , the current decreases and Tr1
I _a = 0 during the off period. When i _a = 0, the counter electromotive force E _n1 appears at the load terminal and v _a = E _n1 . v _a -V
_{Since a} ^* is positive, v _c has a negative slope, v _c decreases without reaching V _c 11 again, and Tr1 remains off. When time elapses and v _c reaches the lower limit V _c 21 of the comparator, Tr2 is turned on, the chopper is turned on, and the current i
_a will to flow to _{E n -Tr2-D4-E n} , a _v a = 0. Since v _a -V _a ^* is negative, v _c rises with a positive slope. When v _c reaches _{V c} 20, Tr2 is driven off, the chopper off at current _{E n -D1-E s -D4-} E n
Flow to the power source to regenerate power. At that time, since v _a = E _s , v _a −V _a ^* is positive, and v _c changes toward V _c 21 with a negative slope. Since the current is discontinuous, i _a = 0 during the chopper-off period, and even if _a counter electromotive force appears at the terminal and v _a = E _n1 , v _a −V _a ^* is positive, v _c
Goes to V _c 21 with a negative slope. Thus, v _c is V _c 20
And V _c 21 are reciprocated and only Tr2 is turned on / off by the comparator 2, and the average load voltage value V _a is V _a ^* (= V _a2 ).
Is controlled equal to, and the operating point is. The load motor is regeneratively braked by forward rotation. This is the operation of the second quadrant.

Counter electromotive force _{E n} of the operating point → load remains E _n1, the voltage setting value _V ^{a *}
_Is changed to V _a3 (where -E _s <V _a3 <0). At this time, even if Tr2 is off, that is, v _a = E _s , Tr2
Is on, that is, when v _a = 0, the error voltage V _a -V
_a ^* becomes positive and the slope of v _c becomes negative, moving to V _c 31. The lower limit V _c 40 of the comparator 4 is crossed on the way, and Tr4 is driven off, but the current is flowing through D4, so it is not related to the operation of the chopper. v _c is V _c
When it reaches 31, Tr3 is turned on and Tr2 is already turned on, so the current i _a flows to E _s -Tr3-M-Tr2-E _s v _a
= -E _s . v _a −V _a ^* becomes negative and v _c becomes a positive slope. When v _c reaches V _c 30, Tr3 turns off, i _a flows to M-D4-Tr2-M, and v _a = 0. v _a-
V _a ^* becomes positive and v _c becomes a negative slope and changes toward V _c 31. The operating point is. V _a <0, I _a
Since it is <0, it is driven in reverse in the third quadrant. Turning on and off the chopper is the same as turning on and off Tr3. Terminal voltage V _a
Is controlled to V _a ^* (= V _a3 ).

Remains of the operating point → V _a ^* = V _a3, consider a counter-electromotive force _{E n} of the load is changed to E _n2.

At the operating point of E _n1 > V _a ^* , the current i _a was flowing in the negative direction. However, at E _n2 <V _a ^* , the counter electromotive force is smaller than the terminal voltage of M, so the current flows in the positive direction. Trying to change,
The period of i _a = 0 always occurs while Tr3 is off. i _a = 0
Since v _a = E _n , v _a −V _a ^* is negative and v _c changes with a positive slope. v _c is changed to V _c 41 without reaching V _c 31 again, Tr4 are turned on.
Current i _a flows in the positive direction E _n as a power supply circuit of M-Tr4-D2-M. At this time, since v _a = 0, v _a −V _a ^*
Is positive and v _c turns into a negative slope. When v _c reaches V _c 40, Tr4 is turned off and the current flows to M-D3-E _s -D2-M, and the electric power is E
regenerate to _s . v _a = -E _s and v _a -V _a ^* is negative, v _c
Is positive, and the following operating point is v _c is V _c 41 and V
_{Make a} round trip between _c 40. Since V _a is negative and I _a is positive, reverse regenerative braking and operation in the fourth quadrant are performed.

At the operating point → operating point, the counter electromotive force E _n3 remains unchanged and the voltage setting value V _a ^* is changed from V _a3 to V _a2 (where 0 <V _a2 <
E _s ).

Tr4 is even on _(v a = 0) off _(v a = -
Even if E _s ), v _a −V _a ^* becomes negative, the slope of v _c is positive, and v _c changes toward V _c 11. Tr4 is turned on _(v a = 0) becomes, Tr2 are turned off, _{v c} is Tr1 reaches the 11 is turned _on, it is v ^a _-V a ^* is positive, v
The slope of _c changes to negative. v _c reciprocates between V _c 11 and V _c 10, the operation of the first quadrant.

In this way, the comparator that performs on / off operation is automatically switched depending on the relationship between the voltage setting value and the load, and the required transistors are automatically turned on / off. Since the error integration between the set value and the load voltage is performed, the average value of the load voltage is specifically controlled to the set value. The characteristics are completely continuous and there is no impact due to the characteristics change when the quadrant changes.

The operation of the chopper will be described by changing the order of the upper limit voltage and the lower limit voltage of the comparators 1 to 4 in the configuration of FIG.

FIG. 7 shows a configuration in which the upper and lower limit voltages of the comparators 1 to 4 are different from the order of FIG. 5, and the respective upper limit voltages are made closer and the lower limit voltages are also made closer. The operating points ~ correspond to the operating points ~ in Figs. 5 and 6. At the operating point, first, v _c reaches V _c 11, and Tr1
When is turned on, the comparator 2 is always turned off and Tr2 is always turned off. Tr1 is v _c decreases when turned on, v _c is Tr1 and reaches V _c 10 turned off. Tr1 is v _c is increased when turned off. By repeating this, v _c reciprocates between V _c 11 and V _c 10. The v _c in the first quadrant, never reach the V _c 21 which Tr2 is turned on. This is exactly the same as the operating point in FIG. When the operating point moves to another quadrant, it operates in the same order as in FIG. Since the operating voltages of the comparators are close to each other, the time required for the operating point to move in the quadrant is much shorter than that in the case of FIG.

However, there is a drawback that the reliability is slightly smaller than that in the case of FIG. For example, at the operating point, normally both Tr1 and Tr2 are not driven on, but Tr1 is on and v _c is V _c 10
<When in between v c _{<V 2} 0, since the comparator 2 is in the hysteresis region, if the changes on malfunction due to noise, so that the Tr1 and Tr2 are driven simultaneously. The power supply short circuit due to Tr1 and Tr2 is prevented by the flip-flop 1. Flip-flop 1 constitutes an RS flip-flop, the truth value of which is shown in Table 2.

In the normal operation, the operation is in the states 1 and 2 (first quadrant) or the states 2 and 3 (second quadrant), so that the output of the flip-flop 1 follows the outputs of the comparators 1 and 2. When the state is changed to 4 by a malfunction, the flip-flop output does not change, that is, the state 1 or 3 output is provided, so that the Tr1 and Tr2 short circuits are prevented. Flip-flop 2 is also Tr3 and T
Prevents r4 short circuit and improves reliability.

FIG. 8 shows another configuration in which the upper and lower limit voltages of the comparators 1 to 4 are different from the order shown in FIG.
The upper and lower limits of the comparator 1 are included in the upper and lower limits of 1, and the upper and lower limits of the comparator 2 are included in the upper and lower limits of the comparator 3. The operating points shown in the figure are the sixth
It corresponds to the operating points ~ in the figure.

Operating point At the operating point, if Tr4 is on, v _c is V _c 1
Reciprocating between 1 and V _c 10 turns Tr1 on and off. If Tr
If 4 is off, next v _{a =} E _n1 appearing in E _n the terminal because Tr1 is no current flows through the load be turned on, v
_{Since a-} V _a ^* is negative, v _c rises further beyond V _c 11 with a positive slope, reaching V _c 41 and turning on Tr4. T
When r4 is turned on, it operates normally in the first quadrant. Since v _c does not become more negative than V _c 10 at the operating point, it never reaches V _c 40 and Tr4 remains driven on.

Operating point → When the counter electromotive force remains E _n1 , and the voltage setting value V _a ^* is changed to V _a2 , the operating point becomes and the operation in the second quadrant occurs in the same manner as in FIG. Tr1, Tr4, Tr3 are off and only Tr2 is on / off.

Operating point → It is assumed that the voltage setting value V _a ^* is changed from V _a2 to V _a3 at time t ₂₃ in FIG. In the second quadrant is _{0 ≦ v a ≦ E s,} -
Since E _s <V _a3 <0, v _a −V _a ^* is positive and v _c
Changes with a negative slope and reaches V _c 31. Since Tr3 is driven on, v _a is −E _s when Tr2 is on and 0 when Tr2 is off, so v _a −V _a ^* changes to negative and positive, and v _c is V
The _c 21, V _c 20 reciprocates, Tr2 are turned on and off. It differs from the operating point only in that Tr3 is turned off.

Operating point → If the voltage setting value is returned to V _a2 again at t ₃₂ , v _c
Moves to V _c 30 once, drives Tr3 off, and
Continue turning on and off r2. Go back to the second quadrant.

Operating point → When operating point (Tr2 to Tr4 off, Tr1 on / off)
When the voltage setting value V _a2 is set to a positive value at t ₄₅ , v _c once reaches V _c 41 to turn Tr 4 on, and then Tr 1 is turned on and off to operate in the first quadrant.

As described above, when the upper and lower limits of the comparator are arranged as shown in FIG. 8, Tr3 and Tr4 turn on or off only when the quadrant changes, and do not turn on or off during the operation in the same quadrant. Tr1 or Tr2 turns on / off in any quadrant to operate as a chopper. In such operation, Tr1,
If a fast switching element is used for Tr2, a slow element can be used for Tr3 and Tr4.

In addition, by setting the upper and lower limit voltages of the comparators 1 to 4 variously, a four-quadrant chopper having various operation modes can be configured. At this time, the necessary condition between the upper and lower limits of comparators 1 to 4 is to prevent short circuit. To satisfy at the same time.

FIG. 9 shows another embodiment of the invention in which four-quadrant speed control of a DC motor is performed. FIG. 9 shows only the portion changed from FIG. 1 (four quadrant voltage control circuit). A capacitor C is inserted in series with the voltage feedback resistor R, and the AC component (square wave) between the terminals A and B is supplied to the addition point of the OP amplifier.
Regarding the DC component, the output voltage V of the speed generator TG mounted on the shaft of the electric motor M is supplied to the addition point of the OP amplifier through the resistor R.

The speed of the electric motor is V _t = V _t ^* Chopper alters the V _a such that the capacitor C ₂
Is charged to V _a and enters _a steady state. Depending on the voltage V _a and the direction of the current required to keep V _t at V _t ^* , _a predetermined comparator operates as in the case of voltage control, and the quadrant moves automatically.

FIG. 10 shows a current limiting circuit added to the four-quadrant chopper control circuit shown in FIG. 1 (the additional portion is shown). The detected value (converted to voltage) of the current i _a is compared with the current set values I ₁ ^{* to} I ₄ ^* by the comparators 1I to 4I having hysteresis, and the outputs are voltage-controlled comparators 1 to 4 (see FIG. 1). Stuff) and AND circuit AND 1
Are combined by ~ 4. FIG. 11 is a diagram showing the characteristics. The comparators 1I to 4I have a hysteresis width corresponding to ± ΔI. For example, the comparator 1I sets an upper limit −I ₁ ^* + ΔI and a lower limit −I ₁ ^* −ΔI.

An operation example will be described. First, assuming that the voltage V _a ^* is set to V _a1 and I _a is positive and operates in the first quadrant of the characteristic, at this time, the operations of the comparators 2 to 4 turn off Tr2 and Tr3 and turn on Tr4. , Comparator 1 operates and T
r1 is on and off. While I _a is smaller than I ₁ , −
i _a does not reach the lower limit of the comparator 1I, the comparator 1I is always “1”, and the output of the AND 1 follows the output of the comparator 1. Voltage control is working.

Counter electromotive force E _n of the load is reduced, increasing the load current I _a is,
Upon reaching the set value I _1, it becomes in Tr1 ON period (the output of the comparator 1 is "1" among a) to the output of the comparator 1I is "0", off of Tr1 is controlled by the output of the comparator 1I Like The output point of the chopper has an operating point on top of the constant current characteristic of. The load voltage V _a is V _a ^* (=
Since it is smaller than V _a1 ), the error integral value v _c of the integrator is
It rises until the OP amplifier is saturated, and comparators 1 and 4 always output "1" as shown in FIG. According off of Tr1 comparator 1I, i _a the back and forth between I ₁ + [Delta] I and I ₁ -.DELTA.I, the average value I _a of i _a is controlled to I _1. This is a so-called current instantaneous value control operation. Furthermore V _a of intersection or operating point of the load characteristics E _n is smaller decreases, Tr
The on time becomes shorter. When counter electromotive force E _n becomes V _a is 0 the operating point becomes negative, E is no longer on-period of the Tr1
_n is short-circuited by D2 and Tr4. Furthermore _{I a} the _{E n} is _{I a} is increased is negative reached I _4, comparator 4I
Therefore, Tr4 is turned on and off, and the characteristic becomes. At this time, T
It is necessary to make sure that r1 is off, which is why
I ₁ ^* <I ₄ ^* should be set. When En becomes even more negative, Tr
4 on-time gradually shortened, thus V _a becomes more negative, when V _a becomes -E _s, it is also Tr4 all periods off. Due to D2 and D3, V _a never becomes more negative than −E _s , and the function of current limiting is also lost. If the back electromotive force increases in the positive direction, the operating point moves on the characteristic of →→ and automatically returns to voltage control. When in E _n> V _a1 is the operating point on the characteristic (the comparator 2 is operating), E _n is increased, current increases in the negative direction I ₂
Is reached, since the ON time of the signal obtained from the comparator 2I is shorter than the ON time of the signal obtained from the comparator 2, as in the case of the characteristics, the AND circuit has the OFF priority and the output of the AND 2 is output. Is comparator 2I
Follow the output of. That limits the current I _a to I ₂ is an output characteristic of the chopper and.

As described above, when a current limiting circuit is added as shown in Fig. 15, when the voltage setting value is positive, the characteristic becomes -----, the current is limited by positive and negative values, and the back electromotive force of the load is increased. The operation of the first, second, and fourth quadrants is automatically performed according to the amount of electric power. When the voltage setting value is negative like V _a2 , the characteristic becomes ----------, positive and negative current limitation is performed, and the second, third, and fourth quadrants are automatically operated. At this time, Tr3 must be surely turned off at the operating point of H, which is why I ₂ ^* >
I ₃ ^*

That is, in the four quadrant current limit, the current limit value in the same current direction (first and fourth quadrants, second and third quadrants) is higher than that in the drive quadrant (first quadrant, third quadrant). It may be set to a large value in the four quadrants and the second quadrant.

In this way, by combining the voltage control circuit and the current control circuit with the logic circuit at the stage of the ON / OFF signal of each transistor, the two control circuits can automatically and smoothly operate according to the set value and the load state. Can be switched to.

<Effects of the Invention> As described above, according to the present invention, the voltage control of the 4-quadrant chopper can be accurately performed, and the operation switching of the 4-quadrant can be automatically and smoothly performed.
Also, since the response is very fast, if the voltage setting value is a sine wave, it becomes a sine wave inverter, which can be easily applied to the speed of the electric motor, and the current can be effectively limited.

[Brief description of drawings]

FIG. 1 is a circuit diagram of one embodiment of the present invention, FIG. 2 is an operation circuit diagram of the first quadrant in the same embodiment, FIG. 3 is a waveform diagram of the circuit shown in FIG. 2, and FIG. 5 is a characteristic diagram of the circuit shown in FIG. 5, FIG. 5 is an example of the upper and lower limit voltage arrangement of the comparator in the embodiment shown in FIG. 1, and an error voltage integrated waveform diagram at the time of quadrant switching. FIG. 6 is a characteristic diagram of the same embodiment. FIG. 7 is an explanatory view of the operating point, FIG. 7 is an example of another arrangement of the upper and lower limit voltages of the comparator in the same embodiment, and an error voltage integrated waveform diagram at the time of quadrant switching. FIG. 8 is an upper and lower limit voltage of the comparator in the same embodiment. FIG. 9 is a circuit diagram of four quadrant speed control of a DC motor to which the present invention is applied, FIG. 10 is a second invention, and FIG. 1 is a second invention. Connection of the current control hysteresis comparator and logic circuit to be added to the circuit And a circuit configuration diagram, FIG. 11 is an output voltage / current characteristic diagram of a four-quadrant chopper by the control method of the second invention, and FIGS. 12 and 13 are circuit diagrams and characteristic diagrams of a conventional general first quadrant chopper. FIGS. 14 and 15 are circuit diagrams and characteristic diagrams of the second quadrant chopper, FIGS. 16 and 17 are circuit diagrams and characteristic diagrams of the third quadrant chopper, and FIGS. 18 and 19 are the same fourth diagram. A quadrant chopper circuit diagram and characteristic diagram, and FIG. 20 is an equivalent circuit diagram of the load of the chopper.

Claims (2)

[Claims] 1. A first to a first antiparallel diode (D1 to D4)
Single-phase bridge inverter connection of the fourth switching element (Tr1 to Tr4), means for integrating the difference between the load terminal voltage (va) and voltage setting value (Va), and its integrated output (vc) as input The first to fourth switching elements (comparators 1 to 4) having the first to fourth hysteresis, and the first to fourth switching elements (comparators 1 to 4) corresponding to the output logics of the first to fourth comparators (comparators 1 to 4), respectively. The upper limit voltage (Vc ₁₁ , Vc ₂₀ , Vc ₃₀ , V) of the comparator (comparators 1 to 4) having the first to fourth hysteresis (Tr1 to Tr4) is turned on / off.
c ₄₁ ), the lower limit voltage (Vc ₁₀ ,, Vc ₂₁ ,, Vc ₃₁ ,, Vc ₄₀ ) to Vc ₂₁ <Vc ₂₀ <Vc ₁₁ Vc ₂₁ <Vc ₁₀ <Vc ₁₁ Vc ₃₁ <Vc ₃₀ <Vc ₄₁ Vc ₃₁ <Vc ₄₀ <Vc ₄₁ , and the load current (I
1st to 4th which can be positive / negative of a) and positive / negative of load voltage (Va)
In each of the quadrants, one comparator (comparators 1 to 4) that outputs one repetitive on / off logic is automatically selected, and the other three comparators (comparators 1 to 4) are turned on or off. The first to fourth switching elements (Tr1 to Tr4) compose a corresponding quadrant chopper to control the load voltage (Va), and the load voltage (Va) is applied to the load current (Ia) in both positive and negative directions.
A controller for a four-quadrant chopper, characterized in that the average value of is controlled to be equal to positive and negative set values. 2. A first to a first diode having antiparallel diodes (D1 to D4).
Single-phase bridge inverter connection of fourth switching element (Tr1 to Tr4) and means for detecting load current (ia), first
The have a means for providing to fourth current setting value (I ₁ ~I _4), with the connected hysteresis as detected load current (ia) compared with the first to fourth current setpoint 1 to 4
The current control comparators (comparators 1I to 4I) are equipped with the respective current control comparators (comparators 1I to 4I).
4I) outputs a logic signal that turns off the chopper when the detected value of the load current (ia) increases above the current setting value, and turns on the chopper when the detected value decreases, and the first to fourth switching elements (Tr1 to A current control circuit is configured in the first to fourth quadrants together with a means for driving Tr4) on / off, and the outputs of these first to fourth current control comparators (comparators 1I to 4I) are separately prepared voltages. Logic circuits (AND 1 to 4) are provided for the first to fourth voltage control outputs of the control circuit.
The voltage control circuit and the current control circuit share the means for connecting the switching elements (Tr1 to Tr4) with a single-phase bridge inverter and driving the switching elements (Tr1 to Tr4) on / off. 1 to 4) are means for preferentially outputting the OFF logic of the driven switching elements (Tr1 to Tr4), and the first to fourth current set values are set to the switching elements (Tr1).
Current limit value of the current flowing through Tr4), and when the load increases and the load current increases positively or negatively and tries to exceed the current setting value of each quadrant, the current control comparator (comparators 1I to 4I ) The output ON output time is shorter than the voltage control signal output ON time, and the current control comparator (comparator 1I to 4I) output OFF output time is longer than the voltage control signal output OFF time. (AND 1 to 4) has priority, and the switching elements (Tr1 to Tr4) in the corresponding quadrant are automatically turned on / off by the output of the current control comparator (comparators 1I to 4I), and the current control circuit is It operates to control the load current to the current setting value and operates as a current limiter.The load decreases, the load voltage increases positively or negatively, and the voltage exceeds the voltage setting value of each quadrant. When an attempt is made, the ON output time of the voltage control signal output becomes longer than the OFF time of the current control comparator (comparator 1I to 4I) output, and the logic circuit (AND 1 to 4) has priority, and the switching element in the corresponding quadrant. (Tr1 to Tr4) are automatically turned on / off by the voltage control signal output, and the voltage control circuit operates to perform voltage control, increasing or decreasing the load without using the circuit switching signal. A control device for a four-quadrant chopper, which automatically shifts from voltage control to current control by means of, and automatically returns from current control to voltage control.