CN205283449U - AC motor drive arrangement - Google Patents

Abstract

The application discloses AC motor drive arrangement. AC motor drive arrangement includes: a rectification circuit, rectifier circuit includes a plurality of diodes for it presses to become rectified alternating current with the AC input voltage rectification, and a switch circuit, switch circuit includes a plurality of transistors for press rectified alternating current to be transformed into to exchange output voltage, wherein, at least one transistor in a plurality of transistors obtains control signal from rectifier circuit from rectifier circuit, switch on or turn -off in turn in the realization work frequency. The control signal that this AC motor drive arrangement can utilize rectifier circuit to provide at least one transistor exchanges output voltage with the acquisition to simplify drive circuit. In preferred embodiment, utilize switch or another transistor to carry out copped wave to realize stepless speed control.

Description

AC motor drives

Technical field

The utility model relates to electric machines control technology, more specifically, it relates to AC motor drives.

Background technology

Alternating current machine is the rotating electromagnetic machinery of running under voltage of alternating current drives, for the conversion realized between electric energy and mechanical energy. The structure of alternating current machine is simple, output rating big, reliable operation, is widely used in machinofacture and household electrical appliance. Such as, alternating current machine is the main power source of the electrical equipment such as fan, blower fan, water pump.

Existing AC motor drives not only provides the actuate signal needed for alternating current machine, and comprises speed governing and protection function. In the application such as fan, stepless speed regulation can obtain better Consumer's Experience. Existing speed regulating method comprises series connection inductance speed governing, the inner tap speed-regulating of machine winding, exchange thyristor speed governing and speed control by frequency variation. By the voltage of change actuate signal, electric current and frequency etc., it is possible to realize the speed governing of alternating current machine so that the rotating speed of alternating current machine and matching of load optimizing, thus realize high use properties.

But, above-mentioned speed regulating method uses additional circuit element (inductance of such as connecting), or change the structure (such as machine winding tap) of motor internal, or change the driving method (such as frequency conversion) of AC motor drives. In series connection inductance speed governing, the volume of inductance is relatively big and the power factor of motor is had bigger impact. In exchange thyristor regulates, exchange thyristor operationally produces bigger noise, and runs imbalance. The cost of machine winding tap speed-regulating is low, uses more in the application. Can not arranging a large amount of taps in machine winding, thus machine winding tap speed-regulating can not realize stepless speed regulation. Ac motor speed control by variable frequency can realize stepless speed regulation and efficient energy-saving, due to circuit complicated and the high cost of AC motor drives, limits the widespread use of speed control by frequency variation.

And reduce costs thus, it would be desirable to improve AC motor drives further to realize stepless speed regulation.

Practical novel content

In view of this, the purpose of this utility model is to provide a kind of AC motor drives, and this drive unit utilizes ac input signal to produce switch controlling signal, such that it is able to simplify circuit structure, it is achieved the chop control of motor, it is achieved stepless speed regulation.

According to one side of the present utility model, it is provided that a kind of AC motor drives, comprising: rectifying circuit, and described rectifying circuit comprises multiple diode, for AC-input voltage is rectified into pulsating dc voltage; And switch circuit, described switch circuit comprises multiple transistor, for pulsating dc voltage is transformed into ac output voltage, wherein, at least one transistor in described multiple transistor obtains control signal from rectifying circuit from rectifying circuit, it is achieved alternate conduction or shutoff in power frequency period.

Preferably, described multiple diode composition full bridge rectifier of described rectifying circuit, comprises the first input terminus being connected to external ac power source and the 2nd input terminus, and provides the first output terminal and the 2nd output terminal of pulsating dc voltage.

Preferably, described multiple transistor of described switch circuit forms the first branch road and the 2nd branch road, described first branch road and described 2nd branch circuit parallel connection are connected between the first output terminal of described rectifying circuit and the 2nd output terminal, described first branch road comprises type complimentary to one another and the first crystal pipe being connected in series and two-transistor, and the first node between described first crystal pipe and described two-transistor is connected to the first output terminal of described switch circuit, described 2nd branch road comprises type complimentary to one another and the third transistor being connected in series and the 4th transistor, and the Section Point between described third transistor and described 4th transistor is connected to the 2nd output terminal of described switch circuit.

Preferably, described first crystal pipe, described two-transistor, described third transistor and described 4th transistor comprise first end, the 2nd end and control end respectively, corresponding transistor is turned on or off, and electric current flows to the 2nd end from first end in the on-state according to the control signal of control end.

Preferably, the first end of described first crystal pipe is connected to the first output terminal of described rectifying circuit, 2nd end of described two-transistor is connected to the 2nd output terminal of described rectifying circuit, 2nd end of described first crystal pipe is connected to the first end of described two-transistor, the first end of described third transistor is connected to the first output terminal of described rectifying circuit, 2nd end of described 4th transistor is connected to the 2nd output terminal of described rectifying circuit, and the 2nd end of described third transistor is connected to the first end of described 4th transistor.

Preferably, described at least two transistors in described multiple transistor control end separately is connected to one of first input terminus and the 2nd input terminus of described rectifying circuit, forward bias during the semi-period of at least two transistors described in making in the positive half period or negative half-cycle of AC-input voltage and conducting, oppositely biased and disconnect during another semi-period.

Preferably, described AC motor drives also comprises at least two resistance, described at least two transistors control end separately is connected to one of first input terminus and the 2nd input terminus of described rectifying circuit respectively via resistance corresponding in described at least two resistance, to obtain described control signal.

Preferably, described AC motor drives also comprises at least two diodes, described at least two transistors control end separately respectively via corresponding resistance in described at least two resistance and in described at least two diodes corresponding diode be connected to one of first input terminus and the 2nd input terminus of described rectifying circuit, to obtain described control signal.

Preferably, described first crystal pipe and described third transistor be respectively in PNP triode and NPN triode one, described two-transistor and described 4th transistor be respectively in PNP triode and NPN triode another.

Preferably, described PNP triode and described NPN triode are respectively Darlington transistor.

Preferably, at least another transistor in described multiple transistor obtains pwm signal from outside, thus described ac output voltage is carried out copped wave.

Preferably, the semi-period period conducting of described at least another transistor in the positive half period or negative half-cycle of AC-input voltage, disconnects all the time during another semi-period.

Preferably, described at least another transistor in described multiple transistor is selected from MOS field by one of effect transistor and insulated gate bipolar transistor npn npn.

Preferably, described AC motor drives also comprises switch, and described switch is connected between one of first output terminal and the 2nd output terminal of described rectifying circuit and corresponding one end of described first branch road.

Preferably, described switch obtains pwm signal from outside, thus described ac output voltage is carried out copped wave.

According to another aspect of the present utility model, it is provided that a kind of AC machine driving method, comprising: adopt rectifying circuit that AC-input voltage is rectified into pulsating dc voltage; Adopting switch circuit that pulsating dc voltage is transformed into ac output voltage, wherein, described switch circuit comprises multiple transistor, and obtains control signal being turned on or off with at least two transistors controlling described multiple transistor from described rectifying circuit.

Preferably, described rectifying circuit comprises multiple diode, and at least one transistor described utilizes at least two diodes in described multiple diode at the pressure drop forward bias of conducting state and conducting.

Preferably, forward bias during the semi-period of described at least two transistors in the positive half period or negative half-cycle of AC-input voltage and conducting, oppositely biased and disconnect during another semi-period.

Preferably, at least another transistor in described multiple transistor obtains pwm signal from outside, thus described ac output voltage is carried out copped wave.

Preferably, the semi-period period conducting of described at least another transistor in the positive half period or negative half-cycle of AC-input voltage, disconnects all the time during another semi-period.

Preferably, described switch circuit comprises switch, and via switch, institute provides pulsating dc voltage to described multiple transistor, and described switch obtains pwm signal from outside, thus described ac output voltage is carried out copped wave.

This AC motor drives can utilize rectifying circuit to provide the control signal of at least one transistor to change current flow path, thus periodically changes the polarity of ac output voltage. Owing to utilizing the signal of rectifying circuit as control signal, the quantity of the external PWM signal of transistor therefore can be reduced. Four switching tubes in switch circuit only need 2 roads or less pwm signal, thus simplify driving circuit.

Further, the switch circuit of this AC motor drives directly using pulsating dc voltage as input voltage, such that it is able to save bus capacitor, the system cost of reduction, the reliability of the system more improved and life-span.

In a preferred embodiment, this AC motor drives utilizes switch or another transistor to carry out copped wave, thus realizes stepless speed regulation.

Compared with the tradition series connection inductance speed governing of load motor, the inner tap speed-regulating of electric motor winding, exchange thyristor speed governing etc., this scheme can realize adjustment continuous, electrodeless by the actuate signal of controlled switching tube, so the adjustment continuous, electrodeless of motor terminal voltage can be realized, motor is finally made to reach the effect of stepless time adjustment. In application scenarios such as fans, stepless time adjustment can bring better experience to user. In addition this scheme has more stable speed governing effect. And due to the switching frequency of controlled switch higher, do not produce the noise in people's ear audible range, there is better quiet operating performance.

Accompanying drawing explanation

By referring to accompanying drawing to the description of the utility model embodiment, above-mentioned and other objects of the present utility model, feature and advantage will be more clear, in the accompanying drawings:

Fig. 1 illustrates the schematic block diagram according to AC motor drives of the present utility model.

Fig. 2 illustrates the schematic circuit of the AC motor drives according to the first embodiment of the present utility model.

Fig. 3 illustrates the schematic circuit of the AC motor drives according to the 2nd embodiment of the present utility model.

Fig. 4 illustrates the schematic circuit of the AC motor drives according to the 3rd embodiment of the present utility model.

Fig. 5 illustrates the oscillogram of the AC motor drives according to the of the present utility model first to the 3rd embodiment.

Fig. 6 illustrates the schematic circuit of the AC motor drives according to the 4th embodiment of the present utility model.

Fig. 7 illustrates the schematic circuit of the AC motor drives according to the 5th embodiment of the present utility model.

Fig. 8 illustrates the oscillogram of the AC motor drives according to the of the present utility model 4th and the 5th embodiment.

Embodiment

Hereinafter with reference to accompanying drawing, the utility model is described more in detail. In various figures, identical element adopts similar Reference numeral to represent. For the sake of clarity, each part in accompanying drawing is not drawn in proportion. Furthermore, it may be possible to do not illustrate some known part.

Describe hereinafter many specific details of the present utility model, the structure of such as device, material, size, treatment process and technology, more clearly to understand the utility model. But as the technician of this area can understand, it is possible to realize the utility model not in accordance with these specific details.

The utility model can present in a variety of manners, below will describe some of them example.

Fig. 1 illustrates the schematic block diagram according to AC motor drives of the present utility model. This AC motor drives comprises rectifying circuit 200 and switch circuit 300. It is connected with zero line N via live wire L between outside AC power 100 and rectifying circuit 200. AC power 100 is such as the power supply grid of 220V. Rectifying circuit 200 receives AC-input voltage Vac from AC power 100, provides DC bus-bar voltage Vdc after rectification. Switch circuit 300 converts DC bus-bar voltage Vdc to AC drive voltage Vout further, thus drive-motor M runs.

As shown in Figure 1, this AC motor drives eliminates bus capacitor. Oscillogram shown in Figure 5, the ac output voltage Vac that power supply grid provides is normally sinusoidal wave, and the DC bus-bar voltage Vdc after overcommutation is pulsating dc voltage, as the input voltage of switch circuit 300. This AC motor drives carries out filtering to obtain straight volts DS without using bus capacitor.

Further, switch circuit 300 utilizes AC-input voltage Vac to control the switching of current flow path, thus produces AC drive voltage Vout synchronously with AC-input voltage Vac. When AC power 100 is power supply grid, AC-input voltage Vac and AC drive voltage Vout is power frequency period. In each power frequency period, switch circuit 300 carries out high frequency chopping, thus changes the virtual value of ac output voltage Vout. The stepless speed regulation of motor M is realized by high frequency chopping.

Fig. 2 illustrates the schematic circuit of the AC motor drives according to the first embodiment of the present utility model. This AC motor drives comprises rectifying circuit 200 and switch circuit 300.

Two input terminuss of rectifying circuit 200 are connected to outside AC power 100, two output terminals via live wire L and zero line N and are connected to switch circuit 300. In the example shown in figure 2, rectifying circuit 200 is the full bridge rectifier that first to fourth diode D1 to D4 forms. First diode D1 and the 2nd diode D2 and the 3rd diode D3 and the 4th diode D4 is connected in series between the first output terminal of rectifying circuit 200 and the 2nd output terminal respectively. First input terminus of rectifying circuit 200 is the first diode D1 and the middle node of the 2nd diode D2, and this first input terminus is connected to live wire L. 2nd input terminus of rectifying circuit 200 is the 3rd diode D3 and the middle node of the 4th diode D4, and the 2nd input terminus is connected to zero line N.

Between the under-stream period of rectifying circuit 200, in the positive half period of AC-input voltage Vin, first diode D1 and the 4th diode D4 conducting, in the negative half-cycle of AC-input voltage Vin, 2nd diode D2 and the 3rd diode D3 conducting, make electric current flow to the 2nd output terminal from the first output terminal of rectifying circuit 200 all the time, thus produce pulsating dc voltage, as DC bus-bar voltage Vdc.

First input terminus of switch circuit 300 and the 2nd input terminus connect the first output terminal and the 2nd output terminal of rectifying circuit 200 respectively, thus receive DC bus-bar voltage Vdc. 3rd input terminus of switch circuit 300 and four-input terminal connect the 2nd input terminus of rectifying circuit 200 respectively. It is connected with alternating current machine M between first output terminal of switch circuit 300 and the 2nd output terminal, thus latter provides AC drive voltage Vdc.

Switch circuit 300 comprises first to fourth transistor Q1 to Q4, the first and second resistance R1 and R2 and the 5th and the 6th diode D5 and D6. First crystal pipe Q1 and two-transistor Q2 is connected in series between the first input terminus of switch circuit 300 and the 2nd input terminus, thus forms the first branch road of switch circuit. Third transistor Q3 and the 4th transistor Q4 is connected in series between the first input terminus of switch circuit 300 and the 2nd input terminus, thus forms the 2nd branch road of switch circuit.

In this embodiment, first crystal pipe Q1 is PNP triode, and two-transistor Q2 is NPN triode. Such as, aforementioned triode can be Darlington transistor. The emtting electrode of first crystal pipe Q1 is connected to the first input terminus of switch circuit 300, and base stage is connected to the 2nd input terminus of rectifying circuit 200 via the first resistance R1. The emtting electrode of two-transistor Q2 is connected to the 2nd input terminus of switch circuit 300, and base stage is connected to the 2nd input terminus of rectifying circuit 200 via the 2nd resistance R2. The collector electrode of first crystal pipe Q1 and the collector electrode of two-transistor Q2 are connected to public first node, as the first output terminal of switch circuit 300.

In this embodiment, third transistor Q3 and the 4th transistor Q4 is the switching tube of any type. Such as, aforementioned switches pipe can be metal oxide semiconductor field effect transistor (MOSFET) (MOSFET) or insulated gate bipolar transistor npn npn (IGBT). The first end of third transistor Q3 is connected to the first input terminus of switch circuit 300, and control end receives pwm signal Vctrl1. The first end of the 4th transistor Q4 is connected to the 2nd input terminus of switch circuit 300, and control end receives pwm signal Vctrl2. 2nd end of third transistor Q2 and the 2nd end of the 4th transistor Q4 are connected to public Section Point, as the 2nd output terminal of switch circuit 300.

In this embodiment, the 5th diode D5 is connected in reverse parallel between the first end of third transistor Q3 and the 2nd end, and the 6th diode D6 is connected in reverse parallel in and between the first end of the 4th transistor Q4 and the 2nd end. 5th diode D5 and the 6th diode D6, as afterflow diode, for providing the path of releasing of reversible circulation when transistor disconnects, thus protects transistor. In alternate embodiments, the sustained diode 5 in switch circuit 300, D6 can be the parasitic diodes of transistor Q3, Q4.

Between the under-stream period of switch circuit 300, switch circuit 300 utilizes AC-input voltage Vac to control the switching of current flow path, thus convert DC bus-bar voltage Vdc to AC drive voltage Vout, and pwm signal Vctrl1 and Vctrl2 is utilized to carry out copped wave. As shown in Figure 5, third transistor Q3 is only in the negative half-cycle conducting of AC-input voltage Vin, and the 4th transistor Q4 is only in the positive half period conducting of AC-input voltage Vin, thus four transistor Collaborative Control current flow path.

In the positive half period of AC-input voltage Vin, the first diode D1 in rectifying circuit 200 and the 4th diode D4 conducting. Owing to the first diode D1 and the 4th diode D4 is in the pressure drop of conducting state, forward bias between the emtting electrode of first crystal pipe Q1 and base stage, thus conducting automatically. , oppositely it is biased between the base stage of two-transistor Q2 and emtting electrode meanwhile, thus automatically disconnects. Therefore, in the positive half period of AC-input voltage Vin, electric current in AC motor drives flows through the first diode D1, first crystal pipe Q1, outside alternating current machine M, the 4th transistor Q4 and the 4th diode D4 successively, thus forms the waveform of the positive half period of AC drive voltage Vout.

In the negative half-cycle of AC-input voltage Vin, the 3rd diode D3 in rectifying circuit 200 and the 2nd diode D2 conducting. Owing to the 3rd diode D3 and the 2nd diode D2 is in the pressure drop of conducting state, forward bias between the base stage of two-transistor Q2 and emtting electrode, thus conducting automatically. , oppositely it is biased between the emtting electrode of two-transistor Q1 and base stage meanwhile, thus automatically disconnects. Therefore, in the negative half-cycle of AC-input voltage Vin, electric current in AC motor drives flows through the 3rd diode D3, two-transistor Q2, outside alternating current machine M, third transistor Q3 and the 2nd diode D2 successively, thus forms the waveform of the negative half-cycle of AC drive voltage Vout.

Due to the automatic conducting of first crystal pipe Q1 and two-transistor Q2 in the power frequency period of AC-input voltage Vin and disconnection, for driving the AC drive voltage Vout of alternating current machine M and the AC-input voltage Vin that external ac power source 100 provides substantially synchronous.

Further, during half power frequency period of AC-input voltage Vin, third transistor Q3 and the 4th transistor Q4 is in the control periodical conducting of pwm signal Vctrl1 and Vctrl2 and disconnection, thus AC drive voltage Vout is carried out copped wave. Pwm signal Vctrl1 and Vctrl2 is such as the square wave signal with dutycycle, through the AC drive voltage Vout of copped wave and incomplete sine wave, but amplitude is the modified sine wave of zero between the low period of pwm signal Vctrl1 and Vctrl2, as shown in Figure 5.

In this embodiment, by changing the dutycycle of pwm signal Vctrl1 and Vctrl2, so that it may to change the virtual value of ac output voltage Vout, thus realize the stepless speed regulation of motor M.

Fig. 3 illustrates the schematic circuit of the AC motor drives according to the 2nd embodiment of the present utility model. This AC motor drives comprises rectifying circuit 200 and switch circuit 400. The rectifying circuit 200 used in a second embodiment is identical with the first embodiment, therefore no longer describes in detail.

First input terminus of switch circuit 400 and the 2nd input terminus connect the first output terminal and the 2nd output terminal of rectifying circuit 200 respectively, thus receive DC bus-bar voltage Vdc. 3rd input terminus of switch circuit 400 and four-input terminal connect the first input terminus and the 2nd input terminus of rectifying circuit 200 respectively. It is connected with alternating current machine M between first output terminal of switch circuit 400 and the 2nd output terminal, thus latter provides AC drive voltage Vdc.

Switch circuit 400 comprises first to fourth transistor Q1 to Q4, the first and second resistance R1 and R2 and the 5th and the 6th diode D5 and D6. First crystal pipe Q1 and third transistor Q3 is connected in series between the first input terminus of switch circuit 400 and the 2nd input terminus, thus forms the first branch road of switch circuit. Two-transistor Q2 and the 4th transistor Q4 is connected in series between the first input terminus of switch circuit 400 and the 2nd input terminus, thus forms the 2nd branch road of switch circuit.

In this embodiment, first crystal pipe Q1 is PNP triode, and two-transistor Q2 is PNP triode. Such as, aforementioned triode can be Darlington transistor. The emtting electrode of first crystal pipe Q1 is connected to the first input terminus of switch circuit 400, and base stage is connected to the 2nd input terminus of rectifying circuit 200 via the first resistance R1. The emtting electrode of two-transistor Q2 is connected to the first input terminus of switch circuit 400, and base stage is connected to the first input terminus of rectifying circuit 200 via the 2nd resistance R2.

In this embodiment, third transistor Q3 and the 4th transistor Q4 is the switching tube of any type. Such as, aforementioned switches pipe can be metal oxide semiconductor field effect transistor (MOSFET) (MOSFET) or insulated gate bipolar transistor npn npn (IGBT). The first end of third transistor Q3 and the collector electrode of first crystal pipe Q1 are connected to disclosed first node, as the first output terminal of switch circuit 400. 2nd end of third transistor Q3 is connected to the 2nd input terminus of switch circuit 400, and control end receives pwm signal Vctrl1. The first end of the 4th transistor Q4 and the collector electrode of two-transistor Q2 are connected to disclosed Section Point, as the 2nd output terminal of switch circuit 400. 2nd end of the 4th transistor Q4 is connected to the 2nd input terminus of switch circuit 400, and control end receives pwm signal Vctrl2.

In this embodiment, the 5th diode D5 is connected in reverse parallel between the first end of first crystal pipe Q1 and the 2nd end, and the 6th diode D6 is connected in reverse parallel in and between the first end of two-transistor Q2 and the 2nd end. 5th diode D5 and the 6th diode D6, as afterflow diode, for providing the path of releasing of reversible circulation when transistor disconnects, thus protects transistor. In alternate embodiments, the sustained diode 5 in switch circuit 400, D6 can be the parasitic diodes of transistor Q1, Q2.

Between the under-stream period of switch circuit 400, switch circuit 400 utilizes AC-input voltage Vac to control the switching of current flow path, thus convert DC bus-bar voltage Vdc to AC drive voltage Vout, and pwm signal Vctrl1 and Vctrl2 is utilized to carry out copped wave. As shown in Figure 5, third transistor Q3 is only in the negative half-cycle conducting of AC-input voltage Vin, and the 4th transistor Q4 is only in the positive half period conducting of AC-input voltage Vin, thus four transistor Collaborative Control current flow path.

In the positive half period of AC-input voltage Vin, the first diode D1 in rectifying circuit 200 and the 4th diode D4 conducting. Owing to the first diode D1 and the 4th diode D4 is in the pressure drop of conducting state, forward bias between the emtting electrode of first crystal pipe Q1 and base stage, thus conducting automatically. , oppositely it is biased between the emtting electrode of two-transistor Q2 and base stage meanwhile, thus automatically disconnects. Therefore, in the positive half period of AC-input voltage Vin, electric current in AC motor drives flows through the first diode D1, first crystal pipe Q1, outside alternating current machine M, the 4th transistor Q4 and the 4th diode D4 successively, thus forms the waveform of the positive half period of AC drive voltage Vout.

In the negative half-cycle of AC-input voltage Vin, the 3rd diode D3 in rectifying circuit 200 and the 2nd diode D2 conducting. Owing to the 3rd diode D3 and the 2nd diode D2 is in the pressure drop of conducting state, forward bias between the emtting electrode of two-transistor Q2 and base stage, thus conducting automatically. Meanwhile, oppositely it is biased between the emtting electrode of first crystal pipe Q1 and base stage, thus automatically disconnects. Therefore, in the positive half period of AC-input voltage Vin, electric current in AC motor drives flows through the 3rd diode D3, two-transistor Q2, outside alternating current machine M, third transistor Q3 and the 2nd diode D2 successively, thus forms the waveform of the positive half period of AC drive voltage Vout.

Due to the automatic conducting of first crystal pipe Q1 and two-transistor Q2 in the power frequency period of AC-input voltage Vin and disconnection, for driving the AC drive voltage Vout of alternating current machine M and the AC-input voltage Vin that external ac power source 100 provides substantially synchronous.

Further, during half power frequency period of AC-input voltage Vin, third transistor Q3 and the 4th transistor Q4 is in the control periodical conducting of pwm signal Vctrl1 and Vctrl2 and disconnection, thus AC drive voltage Vout is carried out copped wave. Pwm signal Vctrl1 and Vctrl2 is such as the square wave signal with dutycycle, through the AC drive voltage Vout of copped wave and incomplete sine wave, but amplitude is the modified sine wave of zero between the low period of pwm signal Vctrl1 and Vctrl2, as shown in Figure 5.

In this embodiment, by changing the dutycycle of pwm signal Vctrl1 and Vctrl2, so that it may to change the virtual value of ac output voltage Vout, thus realize the stepless speed regulation of motor M.

Fig. 4 illustrates the schematic circuit of the AC motor drives according to the 3rd embodiment of the present utility model. This AC motor drives comprises rectifying circuit 200 and switch circuit 500. The rectifying circuit 200 used in the third embodiment is identical with the first embodiment, therefore no longer describes in detail.

First input terminus of switch circuit 500 and the 2nd input terminus connect the first output terminal and the 2nd output terminal of rectifying circuit 200 respectively, thus receive DC bus-bar voltage Vdc. 3rd input terminus of switch circuit 500 and four-input terminal connect the first input terminus and the 2nd input terminus of rectifying circuit 200 respectively. It is connected with alternating current machine M between first output terminal of switch circuit 500 and the 2nd output terminal, thus latter provides AC drive voltage Vdc.

Switch circuit 500 comprises first to fourth transistor Q1 to Q4, the first and second resistance R1 and R2 and the 5th and the 6th diode D5 and D6. Third transistor Q3 and first crystal pipe Q1 is connected in series between the first input terminus of switch circuit 500 and the 2nd input terminus, thus forms the first branch road of switch circuit. 4th transistor Q4 and two-transistor Q2 is connected in series between the first input terminus of switch circuit 500 and the 2nd input terminus, thus forms the 2nd branch road of switch circuit.

In this embodiment, first crystal pipe Q1 is NPN triode, and two-transistor Q2 is NPN triode. Such as, aforementioned triode can be Darlington transistor. The emtting electrode of first crystal pipe Q1 is connected to the 2nd input terminus of switch circuit 500, and base stage is connected to the 2nd input terminus of rectifying circuit 200 via the first resistance R1. The emtting electrode of two-transistor Q2 is connected to the 2nd input terminus of switch circuit 500, and base stage is connected to the first input terminus of rectifying circuit 200 via the 2nd resistance R2.

In this embodiment, third transistor Q3 and the 4th transistor Q4 is the switching tube of any type. Such as, aforementioned switches pipe can be metal oxide semiconductor field effect transistor (MOSFET) (MOSFET) or insulated gate bipolar transistor npn npn (IGBT). 2nd end of third transistor Q3 and the collector electrode of first crystal pipe Q1 are connected to disclosed first node, as the first output terminal of switch circuit 500. The first end of third transistor Q3 is connected to the 2nd input terminus of switch circuit 500, and control end receives pwm signal Vctrl2. 2nd end of the 4th transistor Q4 and the collector electrode of two-transistor Q2 are connected to disclosed Section Point, as the 2nd output terminal of switch circuit 500. The first end of the 4th transistor Q4 is connected to the 2nd input terminus of switch circuit 500, and control end receives pwm signal Vctrl1.

In this embodiment, the 5th diode D5 is connected in reverse parallel between the first end of first crystal pipe Q1 and the 2nd end, and the 6th diode D6 is connected in reverse parallel in and between the first end of two-transistor Q2 and the 2nd end. 5th diode D5 and the 6th diode D6, as afterflow diode, for providing the path of releasing of reversible circulation when transistor disconnects, thus protects transistor. In alternate embodiments, the sustained diode 5 in switch circuit 500, D6 can be the parasitic diodes of transistor Q1, Q2.

Between the under-stream period of switch circuit 500, switch circuit 500 utilizes AC-input voltage Vac to control the switching of current flow path, thus convert DC bus-bar voltage Vdc to AC drive voltage Vout, and pwm signal Vctrl1 and Vctrl2 is utilized to carry out copped wave. As shown in Figure 5, third transistor Q3 is only in the positive half period conducting of AC-input voltage Vin, and the 4th transistor Q4 is only in the negative half-cycle conducting of AC-input voltage Vin, thus four transistor Collaborative Control current flow path.

In the positive half period of AC-input voltage Vin, the first diode D1 in rectifying circuit 200 and the 4th diode D4 conducting. Owing to the first diode D1 and the 4th diode D4 is in the pressure drop of conducting state, forward bias between the base stage of two-transistor Q2 and emtting electrode, thus conducting automatically. Meanwhile, oppositely it is biased between the base stage of first crystal pipe Q1 and emtting electrode, thus automatically disconnects. Therefore, in the positive half period of AC-input voltage Vin, electric current in AC motor drives flows through the first diode D1, third transistor Q3, outside alternating current machine M, two-transistor Q2 and the 4th diode D4 successively, thus forms the waveform of the positive half period of AC drive voltage Vout.

In the negative half-cycle of AC-input voltage Vin, the 3rd diode D3 in rectifying circuit 200 and the 2nd diode D2 conducting. Owing to the 3rd diode D3 and the 2nd diode D2 is in the pressure drop of conducting state, forward bias between the base stage of first crystal pipe Q1 and emtting electrode, thus conducting automatically. , oppositely it is biased between the base stage of two-transistor Q2 and emtting electrode meanwhile, thus automatically disconnects. Therefore, in the positive half period of AC-input voltage Vin, electric current in AC motor drives flows through the 3rd diode D3, the 4th transistor Q4, outside alternating current machine M, first crystal pipe Q1 and the 2nd diode D2 successively, thus forms the waveform of the positive half period of AC drive voltage Vout.

Due to the automatic conducting of first crystal pipe Q1 and two-transistor Q2 in the power frequency period of AC-input voltage Vin and disconnection, for driving the AC drive voltage Vout of alternating current machine M and the AC-input voltage Vin that external ac power source 100 provides substantially synchronous.

Further, during half power frequency period of AC-input voltage Vin, third transistor Q3 and the 4th transistor Q4 is in the control periodical conducting of pwm signal Vctrl1 and Vctrl2 and disconnection, thus AC drive voltage Vout is carried out copped wave. Pwm signal Vctrl1 and Vctrl2 is such as the square wave signal with dutycycle, through the AC drive voltage Vout of copped wave and incomplete sine wave, but amplitude is the modified sine wave of zero between the low period of pwm signal Vctrl1 and Vctrl2, as shown in Figure 5.

In this embodiment, by changing the dutycycle of pwm signal Vctrl1 and Vctrl2, so that it may to change the virtual value of ac output voltage Vout, thus realize the stepless speed regulation of motor M.

Fig. 6 illustrates the schematic circuit of the AC motor drives according to the 4th embodiment of the present utility model. This AC motor drives comprises rectifying circuit 200 and switch circuit 600.

Two input terminuss of rectifying circuit 200 are connected to outside AC power 100, two output terminals via live wire L and zero line N and are connected to switch circuit 600. In the example shown in Fig. 6, rectifying circuit 200 is the full bridge rectifier that first to fourth diode D1 to D4 forms. First diode D1 and the 2nd diode D2 and the 3rd diode D3 and the 4th diode D4 is connected in series between the first output terminal of rectifying circuit 200 and the 2nd output terminal respectively. First input terminus of rectifying circuit 200 is the first diode D1 and the middle node of the 2nd diode D2, and this first input terminus is connected to live wire L. 2nd input terminus of rectifying circuit 200 is the 3rd diode D3 and the middle node of the 4th diode D4, and the 2nd input terminus is connected to zero line N.

Between the under-stream period of rectifying circuit 200, in the positive half period of AC-input voltage Vin, first diode D1 and the 4th diode D4 conducting, in the negative half-cycle of AC-input voltage Vin, 2nd diode D2 and the 3rd diode D3 conducting, make electric current flow to the 2nd output terminal from the first output terminal of rectifying circuit 200 all the time, thus produce pulsating dc voltage, as DC bus-bar voltage Vdc.

First input terminus of switch circuit 600 and the 2nd input terminus connect the first output terminal and the 2nd output terminal of rectifying circuit 200 respectively, thus receive DC bus-bar voltage Vdc. 3rd input terminus of switch circuit 600 and four-input terminal connect the 2nd input terminus of rectifying circuit 200 respectively. It is connected with alternating current machine M between first output terminal of switch circuit 600 and the 2nd output terminal, thus latter provides AC drive voltage Vdc.

Switch circuit 600 comprises K switch 1, first to fourth transistor Q1 to Q4, first to fourth resistance R1 to R4. The first end of K switch 1 is connected to the first input terminus of switch circuit 600. First crystal pipe Q1 and two-transistor Q2 is connected in series between the 2nd end of K switch 1 and the 2nd input terminus of switch circuit 600, thus forms the first branch road of switch circuit. Third transistor Q3 and the 4th transistor Q4 is connected in series between the 2nd end of K switch 1 and the 2nd input terminus of switch circuit 600, thus forms the 2nd branch road of switch circuit.

In this embodiment, first crystal pipe Q1 and third transistor Q3 is PNP triode, and two-transistor Q2 and the 4th transistor Q4 is NPN triode. Such as, aforementioned triode can be Darlington transistor. The emtting electrode of first crystal pipe Q1 is connected to the 2nd end of K switch 1, and base stage is connected to the 2nd input terminus of rectifying circuit 200 via the first resistance R1. The emtting electrode of two-transistor Q2 is connected to the 2nd input terminus of switch circuit 600, and base stage is connected to the 2nd input terminus of rectifying circuit 200 via the 2nd resistance R2. The emtting electrode of third transistor Q3 is connected to the 2nd end of K switch 1, and base stage is connected to the first input terminus of rectifying circuit 200 via the 3rd resistance R3. The emtting electrode of the 4th transistor Q4 is connected to the 2nd input terminus of switch circuit 600, and base stage is connected to the first input terminus of rectifying circuit 200 via the 4th resistance R4. The collector electrode of first crystal pipe Q1 and the collector electrode of two-transistor Q2 are connected to public first node, as the first output terminal of switch circuit 600. The collector electrode of third transistor Q3 and the collector electrode of the 4th transistor Q4 are connected to public Section Point, as the 2nd output terminal of switch circuit 600.

In this embodiment, K switch 1 can be the switching tube of any type. Such as, aforementioned switches pipe can be metal oxide semiconductor field effect transistor (MOSFET) (MOSFET) or insulated gate bipolar transistor npn npn (IGBT). The control end of K switch 1 receives pwm signal Vctrl0.

In this embodiment, the 5th diode D5 is connected in reverse parallel between the first end of first crystal pipe Q1 and the 2nd end, and the 6th diode D6 is connected in reverse parallel in and between the first end of third transistor Q3 and the 2nd end. 5th diode D5 and the 6th diode D6, as afterflow diode, for providing the path of releasing of reversible circulation when transistor disconnects, thus protects transistor. In alternate embodiments, the sustained diode 5 in switch circuit 600, D6 can be the parasitic diodes of transistor Q1, Q3.

Between the under-stream period of switch circuit 600, switch circuit 600 utilizes AC-input voltage Vac to control the switching of current flow path, thus four transistor Collaborative Control current flow path, convert DC bus-bar voltage Vdc to AC drive voltage Vout, and utilize pwm signal Vctrl0 to carry out copped wave. As shown in Figure 8, K switch 1 all carries out copped wave at positive half period and the negative half-cycle of AC-input voltage Vin.

In the positive half period of AC-input voltage Vin, the first diode D1 in rectifying circuit 200 and the 4th diode D4 conducting. Owing to the first diode D1 and the 4th diode D4 is in the pressure drop of conducting state, forward bias between the emtting electrode of first crystal pipe Q1 and base stage, forward bias between the base stage of the 4th transistor Q4 and emtting electrode, thus conducting automatically. , oppositely it is biased between the base stage of two-transistor Q2 and emtting electrode meanwhile, oppositely it is biased between the emtting electrode of third transistor Q3 and base stage, thus automatically disconnects. Therefore, in the positive half period of AC-input voltage Vin, electric current in AC motor drives flows through the first diode D1, first crystal pipe Q1, outside alternating current machine M, the 4th transistor Q4 and the 4th diode D4 successively, thus forms the waveform of the positive half period of AC drive voltage Vout.

In the negative half-cycle of AC-input voltage Vin, the 3rd diode D3 in rectifying circuit 200 and the 2nd diode D2 conducting. Owing to the 3rd diode D3 and the 2nd diode D2 is in the pressure drop of conducting state, forward bias between the emtting electrode of third transistor Q3 and base stage, forward bias between the base stage of two-transistor Q2 and emtting electrode, thus conducting automatically. , oppositely it is biased between the base stage of the 4th transistor Q4 and emtting electrode meanwhile, oppositely it is biased between the emtting electrode of first crystal pipe Q1 and base stage, thus automatically disconnects. Therefore, in the negative half-cycle of AC-input voltage Vin, electric current in AC motor drives flows through the 3rd diode D3, two-transistor Q2, outside alternating current machine M, third transistor Q3 and the 2nd diode D2 successively, thus forms the waveform of the negative half-cycle of AC drive voltage Vout.

Due to the first to two-transistor Q1 to Q4 automatic conducting in the power frequency period of AC-input voltage Vin and disconnection, for driving the AC drive voltage Vout of alternating current machine M and the AC-input voltage Vin that external ac power source 100 provides substantially synchronous.

Further, during half power frequency period of AC-input voltage Vin, K switch 1 is in the control periodical conducting of pwm signal Vctrl0 and disconnection, thus AC drive voltage Vout is carried out copped wave. Pwm signal Vctrl0 is such as the square wave signal with dutycycle, through the AC drive voltage Vout of copped wave and incomplete sine wave, but amplitude is the modified sine wave of zero between the low period of pwm signal Vctrl0, as shown in Figure 8.

In this embodiment, by changing the dutycycle of pwm signal Vctrl0, so that it may to change the virtual value of ac output voltage Vout, thus realize the stepless speed regulation of motor M.

Fig. 7 illustrates the schematic circuit of the AC motor drives according to the 5th embodiment of the present utility model. AC motor drives according to the 5th embodiment is substantially identical with work wave with the circuit structure of the AC motor drives according to the 4th embodiment, difference is only that the first end of K switch 1 is connected to the 2nd input terminus of switch circuit 600, is not described in detail in this.

In each embodiment of above-mentioned ac electrode drive unit, describe switch circuit and comprise the first branch road being connected in parallel and the 2nd branch road, each branch road comprises the transistor of two complementary types being connected in series, its emtting electrode connects hot end and low potential end respectively, its collector electrode is connected to each other, it is PNP transistor npn npn for connecting the transistor of hot end, it is NPN type transistor for connecting the transistor of low potential end. In alternate embodiments, in each branch road, the position of two transistors can be exchanged, the transistor for connecting hot end is made to be NPN type transistor, it is PNP transistor npn npn for connecting the transistor of low potential end, its collector electrode connects hot end and low potential end respectively, and its emtting electrode is connected to each other.

In addition, in the above-described embodiment, describe one of the first input terminus and the 2nd input terminus that the respective control end of at least two transistors in described multiple transistor is connected to described rectifying circuit, forward bias during the semi-period of at least two transistors described in making in the positive half period or negative half-cycle of AC-input voltage and conducting, oppositely biased and disconnect during another semi-period. The resistance that described at least two transistors connect via respective control end obtains control signal from rectifier power source. In alternate embodiments, described at least two transistors connect via respective control end resistance and additional diode obtain control signal from rectifier power source.

Should be noted that, herein, the such as relational terms of first and second grades and so on is only used for separating an entity or operation with another entity or operational zone, and not necessarily requires or imply to there is any this kind of actual relation or sequentially between these entities or operation. And, term " comprises ", " comprising " or its any other variant are intended to contain comprising of nonexcludability, so that comprise the process of a series of key element, method, article or equipment not only comprise those key elements, but also comprise other key elements clearly do not listed, or also comprise the key element intrinsic for this kind of process, method, article or equipment. When not more restrictions, the key element limited by statement " comprising ... ", and be not precluded within process, method, article or the equipment comprising described key element and also there is other identical element.

According to embodiment of the present utility model as described above, these embodiments details that not detailed descriptionthe is not all, does not limit that this practicality is novel is only described specific embodiment yet. Obviously, according to above description, can make many modifications and variations. This specification sheets is chosen and is specifically described these embodiments, is to explain principle of the present utility model and practical application better, thus makes art technician that the utility model and the amendment on the utility model basis can be utilized well to use. The utility model is only by the restriction of right claim and whole scope and equivalent.

Claims (15)

1. an AC motor drives, it is characterised in that, comprising:

Rectifying circuit, described rectifying circuit comprises multiple diode, for AC-input voltage is rectified into pulsating dc voltage; And

Switch circuit, described switch circuit comprises multiple transistor, for pulsating dc voltage is transformed into ac output voltage,

Wherein, at least two transistors in described multiple transistor obtain control signal from rectifying circuit from rectifying circuit, it is achieved alternate conduction or shutoff in power frequency period.

2. AC motor drives according to claim 1, it is characterized in that, described multiple diode composition full bridge rectifier of described rectifying circuit, comprise the first input terminus being connected to external ac power source and the 2nd input terminus, and the first output terminal and the 2nd output terminal of pulsating dc voltage are provided.

3. AC motor drives according to claim 2, it is characterized in that, described multiple transistor of described switch circuit forms the first branch road and the 2nd branch road, and described first branch road and described 2nd branch circuit parallel connection are connected between the first output terminal of described rectifying circuit and the 2nd output terminal

Described first branch road comprises type complimentary to one another and the first crystal pipe being connected in series and two-transistor, and the first node between described first crystal pipe and described two-transistor is connected to the first output terminal of described switch circuit,

Described 2nd branch road comprises type complimentary to one another and the third transistor being connected in series and the 4th transistor, and the Section Point between described third transistor and described 4th transistor is connected to the 2nd output terminal of described switch circuit.

4. AC motor drives according to claim 3, it is characterized in that, described first crystal pipe, described two-transistor, described third transistor and described 4th transistor comprise first end, the 2nd end and control end respectively, corresponding transistor is turned on or off, and electric current flows to the 2nd end from first end in the on-state according to the control signal of control end.

5. AC motor drives according to claim 4, it is characterized in that, the first end of described first crystal pipe is connected to the first output terminal of described rectifying circuit, 2nd end of described two-transistor is connected to the 2nd output terminal of described rectifying circuit, 2nd end of described first crystal pipe is connected to the first end of described two-transistor

The first end of described third transistor is connected to the first output terminal of described rectifying circuit, and the 2nd end of described 4th transistor is connected to the 2nd output terminal of described rectifying circuit, and the 2nd end of described third transistor is connected to the first end of described 4th transistor.

6. AC motor drives according to claim 4, it is characterized in that, described at least two transistors in described multiple transistor control end separately is connected to one of first input terminus and the 2nd input terminus of described rectifying circuit, forward bias during the semi-period of at least two transistors described in making in the positive half period or negative half-cycle of AC-input voltage and conducting, oppositely biased and disconnect during another semi-period.

7. AC motor drives according to claim 6, it is characterized in that, also comprise at least two resistance, described at least two transistors control end separately is connected to one of first input terminus and the 2nd input terminus of described rectifying circuit respectively via resistance corresponding in described at least two resistance, to obtain described control signal.

8. AC motor drives according to claim 7, it is characterized in that, also comprise at least two diodes, described at least two transistors control end separately respectively via corresponding resistance in described at least two resistance and in described at least two diodes corresponding diode be connected to one of first input terminus and the 2nd input terminus of described rectifying circuit, to obtain described control signal.

9. AC motor drives according to any one of claim 3 to 8, it is characterized in that, described first crystal pipe and described third transistor be respectively in PNP triode and NPN triode one, described two-transistor and described 4th transistor be respectively in PNP triode and NPN triode another.

10. AC motor drives according to claim 9, it is characterised in that, described PNP triode and described NPN triode are respectively Darlington transistor.

11. AC motor drives according to claim 3, it is characterised in that, at least another transistor in described multiple transistor obtains pwm signal from outside, thus described ac output voltage is carried out copped wave.

12. AC motor drives according to claim 11, it is characterized in that, the semi-period period conducting of described at least another transistor in the positive half period or negative half-cycle of AC-input voltage, disconnects all the time during another semi-period.

13. AC motor drives according to any one of claim 11 and 12, it is characterized in that, described at least another transistor in described multiple transistor is selected from MOS field by one of effect transistor and insulated gate bipolar transistor npn npn.

14. AC motor drives according to claim 3, it is characterised in that, also comprise switch, described switch is connected between one of first output terminal and the 2nd output terminal of described rectifying circuit and corresponding one end of described first branch road.

15. AC motor drives according to claim 14, it is characterised in that, described switch obtains pwm signal from outside, thus described ac output voltage is carried out copped wave.