KR910000542B1 - Inverter - Google Patents

Abstract

The inverter utilizes thyristers and one capacitor for four quadrant operation of large capacity motor. The circuit includes thyristers (T11-T16) for main inverter for dviving motor, thyristers (A21-A26) for auxiliary inverter, a capacitor (Cr) for energy reproducing when line commutation is executed, and thyrister (A33,A34) and diodes (D31,D32) for circulating current.

Description

Current source inverter circuit with energy regeneration circuit

1 is a circuit diagram of a conventional automatic sequential reflux current source inverter.

2 is a circuit diagram in which a spike voltage limiting circuit is added to the circuit of FIG.

3 is another circuit diagram that operates similarly to FIG.

4 is a circuit diagram of a simultaneous regenerative reflux method using a conventional gate torn-off thyristor as a main power device.

5 is a current source inverter circuit diagram having an energy regenerative circuit of the present invention.

6A to 6H are in-plane operation description circuit diagrams step by step through the line current exchange operation mode of FIG.

7 is a voltage and current waveform diagram of each part in the line current exchange operation mode of FIG.

8 is a first embodiment circuit diagram for solving the problem of FIG.

9 is a voltage and current waveform diagram of each part during the reflux operation of FIG.

10 and 11 are second and third embodiment circuit diagrams for solving the problems of FIG.

12 is a current source inverter circuit diagram having an energy regenerative circuit of the present invention.

13A to 13H are explanatory circuit diagrams showing the line current exchange operation mode of FIG. 12 step by step.

FIG. 14 is a voltage and current waveform diagram of each part in the line current exchange operation mode of FIG.

* Explanation of symbols for main parts of the drawings

DP, DN: DC power output terminal PB, NB: Main connection line of inverter

AP, AN: Main connection line of auxiliary inverter T ₁₁ -T ₁₆ : Host thyristor

A ₂₁ -A ₂₆ : Auxiliary inverter die lister A ₃₁ -A ₃₄ : Reflux die lister

D ₂₁ -D ₂₆ : Full-wave rectifier diode D ₃₁ , D ₃₂ , D _41- D ₄₄ : Diode

Rx: Reflux resistance M: AC motor

L, Lx: Reflux reactor Ld: DC reactor

Cr: Regenerative Capacitor C: Reflux Capacitor

C ₁ , C ₂ : Capacitor Tr: Single winding transformer

The present invention relates to an inverter circuit for driving a three-phase induction motor or a synchronous motor, and in particular, a wide quadruple quadrant operation is possible using a low breakdown voltage, low-speed phase control thyristor, and a large power of several horsepower to several hundred horsepower. The present invention relates to a current source inverter circuit having an energy regenerative circuit that can easily perform control.

There are three types of conventional current source inverter circuits as shown in FIGS. 1 to 4 [Ref. 1.w. Farre, "Quasi-sine wave fully regenerative inverter", Proc. IEE Vol. 120, No. 9, Sept., 1973 2. Rassapa G. Palaniappan, "Voltage clamping circuit for CSI / IM drives", IEEE Trans. Ind. Appl. Vol. IA-21, No. 2, March / April. 1985 3. Gyu-Hyeong Cho, Sun-Soon park, "A new current souce inverter with simultaneous recovery and commutation", IEEE-IAS Conference Record, Oct., 1987, pp 691-698].

FIG. 1 is a circuit diagram of the most commonly known auto-sequentially commutated inverter (hereinafter referred to as ASCI), and six thyristors (T ₁ -T ₆ ) function as main power switches. Diodes (D ₁ -D ₆ ) separate the capacitors (C ₁ -C ₆ ) from the motor (M) as the load, and the six capacitors (C ₁ -C ₆ ) are the thyristors (T _1- ). T ₆ ) is used to turn off (Turn-off) and serves to store the energy stored in the leakage inductance of the motor (M). The maximum operating frequency of this ASIC circuit increases with a smaller capacitance value, while the magnitude of the spike voltage generated at each reflux decreases with a larger capacitance value, so it is necessary to trade off between the maximum operating frequency and the maximum allowed spike voltage. .

Circuits for solving this problem are shown in FIGS. In the case of FIG. 2 and FIG. 3, the energy stored in the leakage inductance of the motor M is absorbed by the spike limiting circuit, and the reflux capacitors C ₁ -C ₆ are limited to blocking the thyristor. In addition, the maximum operating frequency can be increased even further while limiting the spike voltage. However, when the energy absorbed by the spike voltage limiting circuit is returned to the DC reactors Ld ₁ and Ld _{2 as} shown in FIG. ₂ , ripple occurs in the line current of the motor M. In the case of returning energy to the power supply side, the inverter circuit price increases.

On the other hand, in the case of FIG. 4, since the regenerative energy is supplied to the motor M side during the reflux section, the same problem as in the case of FIG. 2 and FIG. 3 does not occur. On the other hand, because the reflux and the regenerative process are performed at the same time, the maximum operating frequency is increased than in the case of FIG. 2 and FIG. However, in this circuit, since the main power switch is a gate turn-off thyristor, it is disadvantageous in terms of price and reliability when applied to large power, and this circuit is also abrupt during the reflux period. If a load change occurs, there is a possibility that the reflux operation does not work properly.

In order to solve this problem, the present invention uses a low breakdown voltage, low-speed phase-yester as a main power switching element, and can operate a wide range of quadrants using only one capacitor in a reflux circuit. It is also easy to control the large power up to 100 horsepower, was created to configure the inverter circuit at a lower price, it will be described in detail with reference to the accompanying drawings as follows.

5 is a circuit diagram of a current source inverter having an energy regenerative circuit of the present invention. As shown in FIG. 5, a phase controlled rectifier for converting a three-phase AC power source to a DC power source or a DC power output terminal DP or DN of a variable voltage source corresponding thereto is shown. It is connected to the main connection lines (PB, NB) of the inverter through the smooth DC reactor (Ld) to supply a constant current (Id) to the inverter, and the main butter dielister (TB) between the main connection lines (PB, NB) of the inverter. _11- T ₁₆ ) and the reflux die lister (A ₃₁ , A ₃₂ ), and each input terminal (U, V, M) of the AC motor (M) connected to the main butter die lister (T ₁₁ -T ₁₆ ). M) connects a full-wave rectifier diode (D ₂₁ -D ₂₆ ) and one side of the auxiliary inverter die lister (A ₂₁ -A ₂₆ ) and connects the other side thereof to the main connection line (AP, AN) of the auxiliary inverter. Connection of the auxiliary inverter main thyristor for (AP, AN) regeneration capacitor (Cr) for between, reflux (a _33, a _34), and Ryuyong diode reflux between connecting the (D _31, D _32), respectively, and the connection point (Q) of the freewheeling diode (D _31, D ₃₂₎ connecting point (P) and refluxing thyristors (A _31, A ₃₂₎ for for A reflux reactor (L) is connected between the melt resistance (Rx) and the connection point (Q) of the reflux die lister (A ₃₁ , A ₃₂ ) and the connection point (R) of the reflux die lister (A ₃₃ , A ₃₄ ). And the reflux capacitor C are configured in series, and the operation process of the present invention configured as described above will be described with reference to FIGS. 6 and 7. 6A to 6H are line current exchange operations (hereinafter referred to as reflux). Mode is shown step by step, and FIG. 7 shows the voltage and current waveforms of each part of the reflux section.

That is, 6a to turn illustrating a state of before the reflux is started, the thyristors _{(T 11), (T 12} ) is conducting direct current power output terminal (DP, DN) of the direct-current power supply is a DC reactor (Ld output to Is supplied to the U and W phases of the AC motor (M). At this time, assuming that the voltage Vco at both ends of the reflux capacitor C is charged to a potential higher than the connection point Q, as shown in FIG. 6A, the first mode is a sub-distorter for auxiliary inverters. It starts by turning on A ₂₃ ) and (A ₂₄ ) at the same time and starts to supply the energy stored in the energy regenerative capacitor (Cr) to the next phase (V phase) of the AC motor (M) during this period.

That is, at this time, as shown in FIG. 6B, the regenerative capacitor Cr → the auxiliary inverter dielister A ₂₃ → the V phase of the motor M → the U phase of the motor M → the auxiliary inverter dielister ( A closed circuit connected to A ₂₄ ) is formed so that the current of the current phase (U phase) of the AC motor M starts to decrease, and the current begins to flow in the next phase (V phase). Thereafter, when a certain time elapses, the second mode is started by turning on the reflux dielister (A ₃₁ ) and (A ₃₄ ) to cut off the main butter die Lister (T ₁₁ ). Reflux reactor (L) → reflux capacitor (C) → reflux die thruster (A ₃₄ ) → reflux diode (D ₃₂ ) → reflux resistance due to the initial charge charged in reflux capacitor (C) as follows. (R) and the resonance current to flow through, wherein the reflux resistance (Rx) the reverse bias to the thyristors (T ₁₁₎ for the main inverter, due to a voltage drop took on both ends for is applied to the main inverter bridge Easter (T ₁₁₎ Starts to turn off. In addition, during this period, the auxiliary inverter die Lister A ₂₄ turned on in the second mode is turned off due to the conduction of the diode D ₂₄ . That is, as shown in FIG. 7, as time passes, the auxiliary inverter die lister A ₂₄ and the main butter die lister T ₁₁ are turned off. Thus, the auxiliary inverter die lister A ₂₄ is turned off. When the main die dielister T ₁₁ is turned off, the third mode starts as shown in FIG. 6D.

As shown in the waveform of FIG. 7, when the current Ic (t) of the reflux capacitor C becomes equal to the current Id value of the DC reactor Ld, the third mode is terminated. As shown in FIG. 6E, a fourth mode in which the reflux capacitor C is charged by the current of the direct current reactor Ld is started. On the other hand, by turning on the auxiliary inverter die Lister (A ₂₃ ), (A ₂₄ ) in the first mode, the current starts to flow in the next phase (V phase) of the AC motor (M). Regardless of the change occurring on the reflux circuit during the period from the 4th mode to the 4th mode, it is noted that the main butter thyristors (T ₁₁ ) during the 2nd and 3rd modes have a resistance for reflux ( Rx) It was in reverse bias due to the voltage drop across both ends, but with the termination of the third mode, the voltage between the both ends of the reflux capacitor C is directly caught by both ends of the main butter dielister (T ₁₁ ). Since the thyristor T ₁₁ is biased in the forward direction, the section lengths of the second mode and the third mode are longer than the time taken for the main butter die lister T ₁₁ to turn off. , Rx) set the values It should be.

On the other hand, if the fourth mode is continued, a forward bias is applied to the main butter thyristor T ₁₃ at the instant when the voltage Vc (t) of the reflux capacitor C becomes greater than the voltage of the energy regeneration capacitor Cr. The master butter die Lister T ₁₃ is turned on to start the fifth mode.

In addition, during this period, the auxiliary inverter die Lister A ₂₃ turned on in the first mode is turned off due to the conduction of the diode D ₂₃ . That is, as shown in FIG. 6F, the voltage between the connection point Q and the connection point R during this period becomes almost equal to the voltage between the main connection lines AP and AN of the auxiliary inverter, and the reflux capacitor ( Since the capacity of the energy regeneration capacitor Cr is much larger than that of C), it can be considered that a constant voltage source is connected between the connection point Q and the connection point R. Therefore, the current flowing through the reflux capacitor C and the reflux reactor L decreases rapidly and reaches zero, and the fifth mode is terminated. During this period, as shown in the waveform diagram of FIG. 7, the regenerative capacitor Cr changes the current Ir (t) polarity from a negative value to a positive value. ₂₃ ) is turned off due to the conduction of the diode D ₂₃ . On the other hand, when the current flowing through the reflux capacitor (C) is zero, the sixth mode starts as shown in Figure 6g, the energy regenerative capacitor (Cr) is recharged due to the energy remaining in the leakage inductance of the motor It is used for the next reflux operation. After that, when the current phase (U-phase) current of the AC motor (M) becomes 0, the entire reflux is completed, and as shown in FIG. 6h, the current flows from the DC power output terminal (DP) to the DC reactor (Ld) to the main inverter. The thyristor T ₁₃ flows through the V phase of the alternating current motor M, the W phase of the alternating current motor M, and the main inverter die lister T ₁₂ , the DC power output terminal DN.

Referring to the reflux operation and the waveform of FIG. 7, the current source inverter circuit described above has the following characteristics.

First, the reflux capacitor is only involved in the turn-off of the main butter die Lister.

Second, the energy stored in the leakage inductance of the motor is stored in the energy regenerative capacitor and discharged to the next phase of the motor during the next reflux period.

Third, unlike the case of FIGS. 1, 2, and 3, which are conventional current source inverters, the reflux operation and the regenerative discharge of energy occur simultaneously, so that the length of the reflux section is shorter than that of the conventional method. In addition, even if the main butter dielister is used for low-speed phase control, the inverter can operate up to almost half of the maximum operating frequency of the device used, and thus has a wider operating frequency range than that of any conventional thyristor type current source inverter.

Fourth, since the current capacity (effective value) of the device used in the reflux and auxiliary inverter circuit is much smaller than the current capacity of the main butter die Lister, the price increase of the inverter due to the added circuit is not very large.

Fifth, by controlling the length of the first mode, it is possible to control the magnitude of the spike voltage generated in the reflux section to a considerable range.

On the other hand, the current source inverter circuit of the present invention has the following disadvantages.

First, as can be seen from the reflux operation, with the end of the fourth mode, a sudden forward voltage stress (Reapplied dv / dt) is applied to the main butter die lister (T ₁₁ ), which causes the main butter die lister to be turned off. In order to prevent (T ₁₁ ) from being turned on again, the snubber circuit used at both ends of the main thyristor is increased.

Second, because the energy stored in the reflux reactor (L) during the fourth mode of the reflux period is transferred to the reflux capacitor in the fifth mode section, the voltage stress of the reflux capacitor is greater than the voltage stress of the energy regenerative capacitor The voltage stress of the device used in the circuit becomes large.

The first embodiment of the present invention, which eliminates these disadvantages, is shown in FIG. 8, and the voltage and current waveforms at each point in the reflux section of the circuit of FIG. 8 are shown in FIG. In FIG. 8, since the right part of the energy regenerative capacitor Cr is the same as FIG. 5, the illustration of the part is omitted, and the modified part different from FIG. 5 will be described below.

Diode D ₃₁ that separates the main circuit (PB, NB) and the reflux circuit, instead of directly connecting the reflux die Lister (A ₃₁ ), (A ₃₂ ) between the main connection line (PB), (NB) of the inverter. (D ₃₂ ) is connected in series with the reflux die lister (A ₃₁ ), (A ₃₂ ), and the main connection line of the connection point (X) of the diode (D ₃₁ ) and the reflux die lister (A ₃₁ ) and the auxiliary inverter (aN) a capacitor between the capacitor connected to the (C _1), and said diode (D ₃₂₎ and a reflux thyristor connection point (Y) to the main connecting line of the auxiliary inverter (AP) of the (a ₃₂₎ for between the (C ₂₎ And a reflux reactor (L) between the reflux die lister (A ₃₁ ) and (A ₃₂ ) between the connection point (Q) and the reflux die lister (A ₃₃ ) and (A ₃₄ ). Connect the reflux capacitor C in series, connect the primary terminal of the reflux energy regenerative single winding transformer (Tr) instead of the reflux resistor Rx of FIG. 5, and connect the secondary side terminal of the single winding transformer (Tr). Die for single-phase full-wave rectification Constitute the connection to the energy recovery capacitor (Cr) for through-de (D ₄₁ -D _44).

In the circuit configured as described above, the voltage polarity and the current direction of the capacitors are defined as shown in FIG. 8, and the winding ratio between the primary side and the secondary side of the single winding transformer Tr is referred to as N ₁ : N ₂ , and the reflux capacitor ( The initial voltage of C) is charged to the potential Vco at which the connection point R is higher than the connection point Q. The initial voltage of the capacitor C ₁ is also equal to the potential when the connection point X is higher than the auxiliary inverter main connection line AN. It is charged with (Vco), and the initial voltage of the regenerative capacitor (Cr) is also assumed to be charged to the potential (Vco) higher than the main connecting line (AP) side of the auxiliary inverter (AN) side, for reflux Operation of this inverter circuit with reference to the waveform diagram of FIG. 9 under the assumption that the capacitor C has a larger capacity than the capacitor C ₁ , and the regenerative capacitor Cr has a much larger capacity than the reflux capacitor C. Explain the process.

As shown in FIG. 6, when the reflux die Lister (A ₃₁ ) and (A ₃₄ ) are turned on when the first mode proceeds, the diode (D ₄₁ ), () by the initial charge charged in the reflux capacitor (C) D ₄₄ ) is in a reverse bias state, so the closed circuit through the capacitor (C ₁ ) → reflux die lister (A ₃₁ ) → reactor (L) → reflux capacitor (C) → reflux die lister (A ₃₄ ) As shown in FIG. 9, a resonant current flows as shown in FIG. 9, whereby the voltage Vc ₁ (t) of the capacitor C ₁ and the voltage Vc (t) of the reflux capacitor C also differ from those in FIG. as there is changed, it is reversed when the capacitor (C ₁₎ a capacitor (C ₁₎ is refluxed capacitor (C) for the voltage polarity of the capacitor because of the relatively small size than the reflux capacitors (C) than for the first. As such, when the voltage across the capacitor C ₁ has a negative value, reverse bias is applied to both ends of the main butter die Lister T ₁₁ , and the die Lister T ₁₁ enters a turn-off process. When the voltage across the capacitor C ₁ increases in the negative direction even more by the resonance current and reaches-(N ₁ / N ₂ ) Vco, which is the conduction condition of the diode D ₄₄ , the diode D ₄₁ , ( D ₄₄ ) is turned on to limit the voltage across the capacitor C ₁ to-(N ₁ / N ₂ ) Vco, while the energy supplied to the capacitor C ₁ by the resonant circuit is transferred to the secondary side of the single winding transformer Tr. It is transmitted to the regenerative capacitor Cr through the full-wave rectifier diodes D ₄₁ and D ₄₄ .

As such, the reason for limiting the voltage across the capacitor C ₁ is that the voltage across the main butter die Lister T ₁₃ during the reflux period is the voltage between both ends of the capacitor C ₁ and both ends of the regenerative capacitor Cr. This is because the voltage sum appears. On the other hand, while the voltage of the capacitor (C ₁ ) is limited by the single winding transformer (Tr), since the initially formed resonance circuit is deformed and the resonance frequency is lowered, the voltage and current of the reflux capacitor (C) are slower than the initial change. At the moment when the current polarity of the reflux capacitor C is about to change, the reflux dielisters A ₃₁ and A ₃₄ are turned off, and at this time, the main butter dielister T ₁₁ is turned off. The current Id flowing in the direct current reactor Ld flows through the capacitor C ₁ as shown in FIG. 9, and the voltage of the capacitor C ₁ increases linearly in a positive direction. The increase rate (Reapplied dv / dt) is determined by the capacitor (C ₁ ) and the direct current (Id), so that it can be arbitrarily selected within the dv / dt range allowed by the main butter die lister (T ₁₁ -T ₁₆ ). do.

In addition, the voltage across the capacitor C ₁ continues to increase, and is limited to the voltage across the regenerative capacitor Cr, and the voltage stress of the reflux capacitor C, which is a problem in FIG. 5, of the single winding transformer Tr. By appropriately selecting the turns ratio and the relative sizes of the reflux capacitor C and the capacitor C ₁ , it is possible to limit the voltage of the regenerative capacitor Cr. Therefore, in the circuit shown in FIG. 8, the problem of the basic circuit shown in FIG. 5 can be eliminated.

10 and 11 are modified circuits of FIG. 8 to eliminate the disadvantages of FIG. 5. The circuit configuration is further modified by changing the positions of the two capacitors C ₁ and C ₂ used in FIG. Keep it simple That is, FIG. 10 is different from FIG. 5, which is the first type of the current source inverter circuit of the present invention, in which the capacitors C ₁ and C ₂ are connected to the connection points Q of the reflux dielister A ₃₁ and A ₃₂ . Is an additional connection. Accordingly, the current source inverter circuit operates similar to that of the current source inverter circuit of FIG. 5, but the problem occurring in the current source inverter circuit of FIG. 5 is solved, and it becomes simpler and more practical than the current source inverter circuit of FIG. 8. The operation of FIG. 7 will be described with reference to FIG. 7 only for the portions which are not overlapped with the operation of the inverter of FIG. 5.

The initial voltage of the capacitor C ₁ is zero, the initial voltage of the capacitor C ₂ is the initial voltage Vro of the regenerative capacitor Cr, and the capacity of the reflux capacitor C is the capacitor C ₁ (C). ₂ ), the capacitor of the reflux capacitor C and the reflux resistor Rx are connected in parallel due to the conduction of the diode D ₃₂ during the second mode and the third mode as shown in FIG. 6C. The voltage at both ends of (C ₁ ) is limited to the voltage drop at both ends of the resistance (Rx) when the value of the resistance (Rx) is very small, and the reflux capacitor (C) with the progress of the third mode. When the current flowing in the current becomes smaller than the current Id of the DC reactor Ld, the diode D32 is turned off. At this time, unlike in the case of FIG. 6D, the current Id of the DC reactor Ld is the capacitor C _1. ) And the reflux capacitor (C) flows in both directions, and the capacity of the reflux capacitor (C) Since much larger than the sheeter C ₁ , most of the energy remaining in the reflux reactor L is transferred to the capacitor C ₁ so that the voltage rise across both ends of the reflux capacitor C is extremely small. Therefore, the voltage stress of the reflux capacitor (C) is limited unlike in the case of FIG. 5, rather it must be re-supplied the energy consumed through the reflux resistor (Rx). On the other hand, when the current value flowing through the reflux capacitor C becomes zero, the current Id of the DC reactor Ld flows through the capacitor C ₁ (C ₂ ), and the voltage at both ends of the capacitor C ₁ becomes the reflux capacitor. When the voltage exceeds both ends of (C), the reflux die thruster (A ₃₄ ) is turned on again to receive the energy consumed through the reflux resistor (Rx) during the second mode and the third mode, and the capacitor (C) _{When the} voltage at both ends of ₁ ) becomes greater than the voltage at both ends of the regenerative capacitor Cr, the main butter die Lister T13 is turned on and the energy remaining in the leakage inductance of the AC motor M is transferred to the regenerative capacitor Cr. The regenerative operation starts, and the reflux ends when the current (U phase) current of the AC motor (M) becomes zero.

As can be seen from the above operation description, the problem occurring in the current source inverter circuit of FIG. 5 is all solved in the current source inverter circuit of FIG.

11 is operated in the same manner as in FIG. 10, and the difference between the reflux energy during the second mode and the third mode is to use the single winding transformer Tr instead of the reflux resistance Rx of FIG. Instead of being dissipated through the reflux resistor (Rx), the efficiency of the inverter can be further increased by converting it into a regenerative capacitor (Cr) through its single winding transformer (Tr) and full-wave rectifier diodes (D ₄₁ -D ₄₄ ). It becomes possible.

FIG. 12 is a circuit diagram of a current source inverter having another energy regenerative circuit according to the present invention. As shown in FIG. 12, the difference in construction compared to the current source inverter circuit of FIG. 5 described above is on the left side of the regenerative capacitor Cr. Since only the reflux circuit shown is described, only the reflux circuit will be described.

The reflux circuit of FIG. 12 connects the reflux dielister A ₃₁ and A ₃₂ in series between the main connection lines PB and NB of the inverter, and the main connection lines AP and AN of the auxiliary inverter. A reflux die lister (A ₃₃ ) and (A ₃₄ ) are connected in series, and the connection point Q of the reflux die lister (A ₃₁ ) and (A ₃₂ ) and the reflux die lister (A ₃₃ ), A reflux capacitor C is connected between the connection points R of (A ₃₄ ), and a reflux reactor Lx and a switching element Sx are connected in series between the connection points Q and R. In the above configuration, the switching element Sx means that a triac is used or two diistors are de-parallelized.

The operation process of the present invention configured as described above will be described with reference to FIG. 13 showing the reflux mode step by step and FIG. 14 showing the voltage and current waveforms of each part of the reflux section.

First, as shown in FIG. 13A, the current of the DC power output to the DC power output terminal DP is changed from the DC reactor Ld to the main inverter dielister T _{11 to} the U phase of the AC motor. → It is assumed that the W phase of the alternating current motor (M) flows through the main inverter die lister (T ₁₂ ) to the path of the DC power output terminal (DP), and the initial voltage of the reflux capacitor (C) is the connection point (R). Assuming that the side is charged to a potential Vco higher than the connection point Q side, by turning on the reflux die lister A ₃₁ and A ₃₄ to turn off the main die die lister T ₁₁ . The first mode begins.

That is, as shown in FIG. 13B, the current supplied from the DC power output terminal DP is a DC reactor Ld → reflux die lister A ₃₁ → reflux capacitor C → reflux die lister A ₃₄ ) → Diode (D ₂₄ ) → U phase of AC motor (M) → W phase of AC motor (M) → DC power output terminal (DN) flows through the path of the main butter dielister (T ₁₁ ) The reverse bias is applied to the voltage at both ends of (C) to turn off the master butter die Lister (T ₁₁ ).

After the predetermined time has elapsed and the switching element Sx is turned on, the reflux capacitor C is formed by the resonance circuit formed by the reflux capacitor C and the reflux reactor Lx, as shown in FIG. 13C. When the voltage across both ends of the voltage starts to change rapidly, and the voltage polarity of the reflux capacitor C is about to be changed, the auxiliary inverter die lister A ₂₃ is turned on so that the AC motor M is shown in FIG. 13d. Start supplying current to the next phase (V phase).

As described above, unlike the current source inverter circuit of FIG. 5, the reason for delaying the current flowing in the next phase of the AC motor M until the voltage between the both ends of the reflux capacitor C reaches near zero is the reason. This is to reduce voltage stress of the main butter die Lister (T ₁₃ ). That is, the voltage across the If causing a conductive path between the main connecting line (AN) and the main inverter thyristors (T ₁₃₎ for the auxiliary drive for the main inverter thyristors (T _13), as mentioned in the description of the fifth degree is Since the voltage of the reflux capacitor (C) and the voltage of the regenerative capacitor (Cr) are combined to reduce the voltage stress of the main butter die Lister (T ₁₃ ).

In addition, the reason for controlling the length of the first mode using the reflux reactor Lx is that, when there is no reflux reactor Lx, the length of the reflux section in the no-load state as in the case of the ASCI of FIG. This is to maximize the inverter's maximum operating frequency, so that the length of the reflux section is independent of the load.

On the other hand, as shown in the waveform diagram of FIG. 14, with the start of the third mode, the reflux capacitor (Cr) → the auxiliary inverter dielister (A ₂₃ ) → the V phase of the AC motor (M) → the AC motor (M). The closed phase of the diode (D ₂₄ ) is formed so that the energy regenerated in the previous reflux operation starts to discharge to the next phase of the AC motor (M), so that the current phase (U) of the AC motor (M) The current begins to decrease and current begins to flow in the next phase (V phase) of the AC motor (M).

Thereafter, with the passage of time, the switching element Sx is turned off at the moment when the polarity of the current flowing through the reflux reactor Lx is changed in the resonant circuit formed by the reflux capacitor C and the reflux reactor Lx. At the same time, the third mode is terminated. As shown in FIG. 13E, the reflux capacitor C is continuously charged with the DC current Id through the DC reactor Ld, and the voltage at both ends of the reflux capacitor C is regenerated. When the voltage of both ends of the capacitor capacitor Cr becomes equal, the main butter dielister T12 is turned on so that the reflux capacitor C and the regenerative capacitor Cr appear to be connected in parallel, and the regenerative capacitor Cr If the capacity of is much greater than the reflux capacitor (C), most of the current flowing through the reflux capacitor (C) flows to the regenerative capacitor (Cr), so as shown in Figure 14 to the regenerative capacitor (Cr) The polarity of the flowing current is sharply negative This is converted to a positive value. The diode D23 conducts by this operation to turn off the auxiliary inverter die lister A ₂₃ , and the energy remaining in the leakage inductance of the AC motor M is restored to the regenerative capacitor Cr. The sixth mode, which is regenerated by), starts as shown in FIG. 13G, and the voltage at both ends of the reflux capacitor C continues to be limited to the voltage at both ends of the regenerative capacitor Cr, followed by the AC motor M. When the phase (V phase) current reaches the DC current Id, reflux is terminated, and as shown in FIG. 13H, the current supplied from the DC power output terminal DP is changed from the DC reactor Ld to the main inverter. Dyster (T13) → V phase of the alternating current motor (M) → W phase of the alternating current motor (M) → flows through the DC power output terminal (NN), and this state is continued until the next reflux occurs.

On the other hand, the fifth mode shown in FIG. 13f does not occur in the normal state but occurs only in a transition state in which the load changes rapidly, and passes through the fifth mode to the sixth mode without passing through the fourth mode after the third mode. In the case of thin, it does not have much meaning.

Referring to the reflux operation and the waveform diagram of FIG. 14, another current source inverter circuit of the present invention described above has the following characteristics.

First, since the length of the entire reflux section is determined by the reflux capacitor and the reflux reactor, it is always possible to obtain a constant reflux time regardless of the load state by controlling the length of the first mode appropriately.

Second, as in the current source inverter circuit of FIG. 5, the regenerated energy is discharged to the motor side during reflux, thereby increasing efficiency.

Thirdly, the fourth and fifth terms of the current source inverter circuit of FIG. 5 have the same characteristics.

Fourth, since two problems in the inverter circuit of FIG. 5 do not occur, the structure is simpler than that of the inverter circuit of FIG.

On the other hand, another current source inverter circuit of the present invention has the following two disadvantages.

First, as shown in FIG. 14, the reflux time is about 1.5 times higher than that of the current source inverter circuit of FIG. 5 because the process of turning off the main butter die Lister and the energy regenerative discharge section are separated. long. However, since the absolute reflux section is very short, there is no problem in practical use.

Second, the capacity of the reflux capacitor should be larger than the reflux capacitor of the FIG. 5 current source inverter circuit. However, since only one reflux capacitor is used, the effect on the price increase is not large.

Claims (5)

A phase controller for converting three-phase AC power into DC power or a DC power output terminal (DP, DN) of a variable voltage source corresponding thereto is connected to the main connection lines (PB, NB) of the inverter through a smooth DC reactor (Ld) to connect to the inverter. In the current source inverter circuit to which the constant current is supplied, the main butter die Lister (T ₁₁ -T ₁₆ ) and the reflux die Lister (A ₃₁ , A ₃₂ ) is connected between the main connection line (PB, NB) of the inverter, Auxiliary inverter die Lister (A ₂₁ -A ₂₆ ) and full-wave rectifier diode (D) at each input terminal (U, V, M) of the AC motor (M) connected to the master butter die lister (T ₁₁ -T ₁₆ ). ₂₁ -D ₂₆ ) is connected to the main connection line (AP, AN) of the auxiliary inverter, and between the main connection line (AP, AN) of the sub-inverter, the regenerative capacitor (Cr), the reflux thyristors (A ₃₃ , A) ₃₄ ) and the reflux diodes D ₃₁ and D ₃₂ , respectively, and the connection point P and the reflux dies of the reflux diodes D ₃₁ and D _32, respectively. A reflux resistor Rx is connected between the connection points Q of the terminals A ₃₁ and A ₃₂ , and between the connection point Q and the connection point R of the reflux thyristors A ₃₃ and A ₃₄ . By connecting the reflux reactor (L) and the reflux capacitor (C) in series, the energy stored in the regenerative capacitor (Cr) before the main rotor die Lister (T ₁₃ ) is turned on during reflux the AC motor A current source inverter circuit having an energy regeneration circuit, which is configured to flow through the next phase (M) of (M) to limit the magnitude of the spike voltage. The method of claim 1, wherein the main connection line (PB, NB) of the inverter to the reflux circuit to separate the main connection line (PB), (NB) of the inverter through the diode (D ₃₁ ), (D ₃₂ ) respectively It is connected in series to the thyristors (A ₃₁ ), (A ₃₂ ), and the capacitor (C) between the connection point (X) of the diode (D ₃₁ ) and the reflux die lister (A ₃₁ ) and the main connection line (AN) of the inverter ₁ ) and a capacitor (C ₂ ) between the connection point (Y) of the reflux die Lister (A ₃₂ ) and the diode (D ₃₂ ) and the main connection line (AP) of the auxiliary inverter, and for the reflux Instead of connecting the reflux resistor Rx to the connection point Q of the thyristors A ₃₁ and A ₃₂ , the primary terminal of the single winding transformer Tr is connected, and the secondary terminal of the single winding transformer Tr is voltage coming from the full-wave rectification diode (D ₄₁ -D ₄₄₎ to the main connecting line of the drive (AP, aN), and connected to, a reflux capacitor (C) regenerating the capacitor (Cr) for a voltage stress for a via for Current source inverter circuit having an energy recovery circuit, characterized in that the limit to the configuration. The method of claim 1, wherein the capacitor (C ₂ ) is connected between the main connection line (AP) of the auxiliary inverter and the connection point (Q) of the reflux die Lister (A ₃₁ ) (A ₃₂ ) and the connection point (Q) and A current source inverter circuit having an energy regenerative circuit, characterized in that the capacitor (C ₁ ) is connected between the main connection line (AN) of the auxiliary inverter to limit the voltage stress of the reflux capacitor (C). The method of claim 3 wherein the reflux thyristors (A _31, A ₃₂₎ and a capacitor (C _1, C ₂₎ connected to a primary side terminal of the autotransformer (Tr) instead of the connecting point reflux resistance (Rx) for the (Q) for And the secondary terminal of the single winding transformer (Tr) is connected to the main connection lines (AP, AN) of the auxiliary inverter through the single-phase full-wave rectifying diodes (D ₄₁ -D ₄₄ ). Current source inverter circuit. A phase controller for converting three-phase AC power into DC power, or a DC power output terminal (DP, DN) of a variable voltage source, is connected to the inverter's main connection lines (PB, NB) through a smooth DC reactor (Ld). In a current source inverter circuit to which a constant current is supplied, a main butter die Lister (T ₁₁ -T ₁₆ ) and a reflux die Lister (A ₃₁ , A ₃₂ ) are connected between the main connection lines (PB) and (NB) of the inverter. Each input terminal (U, V, W) of the AC motor (M) connected to the main butter die Lister (T ₁₁ -T ₁₆ ) and the auxiliary inverter die lister (A ₂₁ -A ₂₆ ) and full-wave rectifier diode Connect to the main connection line (AP, AN) of the auxiliary inverter through (D ₂₁ -D ₂₆ ), and between the main connection line (AP) and (AN) of the auxiliary inverter, the regenerative capacitor (Cr) and the reflux thyristor ( A ₃₃ , A ₃₄ ) and the connection point Q of the reflux die lister (A ₃₁ ) and (A ₃₂ ) and the connection point (R) of the reflux die lister (A ₃₃ ) and (A ₃₄ ). The reflux capacitor (C) is connected between the reflux reactor (Lx) and the switching element (Sx) in series between the connection points (Q) and (R), and the master butter thyristors (T) are connected. ₁₁ ) After turning off, when the voltage of the reflux capacitor C becomes near zero, the energy stored in the regenerative capacitor Cr flows through the next phase (V phase) of the AC motor M. It is configured to limit the voltage stress applied to both ends of the main butter die Lister (T ₁₃ ) to the voltage at both ends of the regenerative capacitor (Cr), and to limit the magnitude of the spike voltage generated during reflux. A current source inverter circuit having an energy regenerative circuit.

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