CN217445278U

CN217445278U - Frequency-changing speed regulator for three-phase AC motor with mixed switch

Info

Publication number: CN217445278U
Application number: CN202122763843.5U
Authority: CN
Inventors: 龚秋声
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-11-06
Filing date: 2021-11-06
Publication date: 2022-09-16
Anticipated expiration: 2031-11-06

Abstract

A three-phase AC motor frequency-changing speed regulator with mixed switch is composed of DC power supply E, three-phase AC motor M, 3 reverse conducting thyristors CTR 1-CTR 3 and 3 reverse conducting switches S1-S3, which are connected to form a three-phase bridge and a control trigger circuit, and is characterized in that 3 reverse conducting thyristors are used to replace 3 reverse conducting switches in the existing three-phase AC motor frequency-changing speed regulator, compared with the existing three-phase AC motor frequency-changing speed regulator, the cost of 3 reverse conducting thyristors is far lower than that of 3 reverse conducting switches, therefore, the utility model discloses a three-phase AC motor frequency-changing speed regulator with mixed switch provides another type of three-phase AC motor frequency-changing speed regulator with lower cost and higher cost performance for the society, and has great economic and social benefits.

Description

Frequency-changing speed regulator for three-phase AC motor with mixed switch

Technical Field

The utility model relates to a mixed switch three-phase alternating current motor variable frequency speed regulator composed of a reverse conducting thyristor and a reverse conducting switch.

Background

The existing three-phase alternating current motor variable frequency speed regulator adopts three-phase full-bridge PWM inverter circuits on textbooks, so far, only one three-phase full-bridge PWM inverter circuit consisting of 6 reverse conducting switches is arranged on a three-phase bridge type chopping control inverter basic circuit in the world, and the variable frequency speed regulator is high in cost and not beneficial to popularization. The utility model discloses the designer designs and adopts 3 to lead the thyristor and replace 3 among the current three-phase AC motor frequency conversion speed regulator and lead the switch against the direction, makes three-phase AC motor frequency conversion speed regulator's cost reduce by a wide margin, and the price/performance ratio improves, and this type of three-phase AC motor frequency conversion speed regulator is named as hybrid switch three-phase AC motor speed regulator.

SUMMERY OF THE UTILITY MODEL

The utility model aims at designing a another kind of three-phase bridge type PWM inverter circuit that cost is lower than current three-phase full-bridge type PWM inverter for three-phase AC motor frequency conversion speed regulator becomes another kind of three-phase bridge type PWM inverter and three-phase AC motor frequency conversion speed regulator.

In order to realize the above-mentioned purpose, the utility model provides a hybrid switch three-phase AC motor variable frequency speed regulator, it is by DC power supply E, three-phase AC motor M, 3 reverse conducting thyristors CTR1 ~ CTR3, 3 reverse conducting switches S1 ~ S3 and control trigger circuit constitute, reverse conducting switch S1 comprises triode or IGBT pipe V1 and diode D1, reverse conducting switch S2 comprises triode or IGBT pipe V2 and diode D2, reverse conducting switch S3 comprises triode or IGBT pipe V3 and diode D3, its characterized in that: 3 reverse conducting thyristors CTR 1-CTR 3 and 3 reverse conducting switches S1-S3 are connected into a three-phase bridge type, a first direct current input end (1) is connected with the positive end of a direct current power supply E, the anode of the reverse conducting thyristor CTR1, the anode of the reverse conducting thyristor CTR2 and the anode of the reverse conducting thyristor CT3, a second direct current input end (2) is connected with the negative end of the direct current power supply E, one end of the reverse conducting switch S1, one end of the reverse conducting switch S2 and one end of the reverse conducting switch S3, a 1 st end (U) of a star-connected three-phase thyristor motor M is connected with the cathode of the reverse conducting thyristor CTR1 and the other end of the reverse conducting switch S2, a 2 nd end (V) of the star-connected three-phase motor M is connected with the cathode of the reverse conducting thyristor CTR2 and the other end of the reverse conducting switch S3, and a 3 rd end (W) of the star-connected three-phase motor M is connected with the cathode of the reverse conducting thyristor CTR3 and the reverse conducting switch S1.

Drawings

Figure 1 is the utility model discloses a main circuit of hybrid switch three-phase AC motor variable frequency speed regulator, wherein: and E is a direct current power supply. CTR 1-CTR 3 are reverse conducting thyristors. S1-S3 are reverse conducting switches. M is a star-connected three-phase alternating current motor. D1-D3 are diodes, V1-V3 are triodes or IGBTs. D1 and V1 form a reverse conducting switch S1. D2 and V2 form a reverse conducting switch S2. D3 and V3 form a reverse conducting switch S3.

Detailed Description

Fig. 1 is a main circuit of a variable frequency speed regulator of a hybrid switch three-phase alternating current motor, which can be known from fig. 1: the three-phase bridge type PWM inverter is formed by connecting 3 reverse conducting thyristors (CTR 1-CTR 3) and 3 reverse conducting switches (S1-S3). The inversion principle is similar to that of a three-phase bridge PWM inverter, the difference between the inversion principle and the three-phase bridge PWM inverter is only that an inductance follow current loop is different, and the blocking recovery capability of the reverse conducting thyristor after conduction depends on that the passing current is smaller than the maintaining current. For the convenience of analysis, we first see that the thyristor CTR3 and the switch S1 in fig. 1 are removed to form a hybrid switch single-phase bridge PWM inverter, the V2 and V3 control poles are controlled by PWM pulses, and the CTR1 and CTR2 trigger poles are triggered by dc voltage in the period from the 1 st PWM pulse to the last 1 PWM pulse:

a) when the control electrode of the triode switch V3 has PWM pulse and the CTR1 has the DC trigger voltage, when the V3 is switched on, the two output ends obtain the pulse voltage of the power supply voltage E with the U end being positive and the V end being negative, and the output current flows from the U end to the V end. When V3 is cut off, the freewheeling circuit of 2 series winding inductances of the star-connected three-phase alternating current motor M reversely conducts the switches CRE1 and CTR2, and when the last 1 PWM pulse is reached, the freewheeling current of the freewheeling circuit is rapidly reduced to be below the maintaining current of CTR1, so that the CTR1 recovers the blocking capability.

b) When the control electrode of the triode switch V2 has PWM pulse and the CTR2 has the DC trigger voltage, when the V2 is switched on, the two output ends obtain the pulse voltage of the power supply voltage E with the positive V end and the negative U end, and the output current flows from the V end to the U end. When the voltage V2 is cut off, the freewheeling circuits of 2 series winding inductances of the star-connected three-phase alternating current motor M are the reverse conducting switches CRE2 and CTR1, and when the last 1 PWM pulse is reached, the freewheeling current of the freewheeling circuits is rapidly reduced to be below the maintaining current of the CTR1, so that the CTR1 recovers the blocking capability.

From the above, it can be seen that: the single-phase bridge type PWM inverter formed by the single-phase hybrid switch is different from a single-phase full-bridge PWM inverter only in that an inductive energy storage follow current loop and a reverse thyristor are different in recovery blocking.

Present single-phase full-bridge PWM inverter adds 2 reverse-conducting switches, just constitutes present three-phase full-bridge PWM inverter, same principle, the utility model relates to a three-phase AC motor frequency conversion speed regulator difference that figure 1 blend switch three-phase AC motor frequency conversion speed regulator and present 6 reverse-conducting switches constitute also only lies in inductance energy storage afterflow return circuit and reverse-conducting thyristor resume to block differently.

The utility model discloses a characteristic is that replace 3 among the current three-phase alternating current motor variable frequency speed regulator with 3 contrary thyristors and lead the switch, it compares with current three-phase alternating current motor variable frequency speed regulator, because 3 cost of leading the thyristor is far less than 3 contrary switches that lead, consequently, the utility model discloses a mixed switch three-phase alternating current motor variable frequency speed regulator provides another type of cost for the society and lower the higher three-phase alternating current motor variable frequency speed regulator of high performance price ratio has great economic benefits and social.

Claims

1. A mixed switch three-phase AC motor frequency conversion speed regulator is composed of a DC power supply E, a three-phase AC motor M, 3 reverse conducting thyristors CTR 1-CTR 3, 3 reverse conducting switches S1-S3 and a control trigger circuit thereof, wherein the reverse conducting switch S1 is composed of 1 triode or IGBT tube V1 and 1 diode D1, the reverse conducting switch S2 is composed of 1 triode or IGBT tube V2 and 1 diode D2, the reverse conducting switch S3 is composed of 1 triode or IGBT tube V3 and 1 diode D3, and the mixed switch three-phase AC motor frequency conversion speed regulator is characterized in that: 3 reverse conducting thyristors CTR 1-CTR 3 and 3 reverse conducting switches S1-S3 are connected into a three-phase bridge type, a first direct current input end (1) is connected with the positive end of a direct current power supply E, the anode of the reverse conducting thyristor CTR1, the anode of the reverse conducting thyristor CTR2 and the anode of the reverse conducting thyristor CT3, a second direct current input end (2) is connected with the negative end of the direct current power supply E, one end of the reverse conducting switch S1, one end of the reverse conducting switch S2 and one end of the reverse conducting switch S3, a 1 st end (U) of the star-connected three-phase alternating current motor M is connected with the cathode of the reverse conducting thyristor CTR1 and the other end of the reverse different switch S2, a 2 nd end (V) of the star-connected three-phase alternating current motor M is connected with the cathode of the reverse conducting thyristor CTR2 and the other end of the reverse different switch S3, and a 3 rd end (W) of the star-connected three-phase alternating current motor M is connected with the cathode of the reverse conducting thyristor CTR3 and the reverse conducting switch S1.

2. The hybrid switching three-phase ac motor variable frequency governor of claim 1, wherein: the thyristor flyback trigger signal is a dc voltage from the 1 st to the last 1 PWM pulse.