CN1279685C - Converter and control method - Google Patents
Converter and control method Download PDFInfo
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- CN1279685C CN1279685C CNB031206204A CN03120620A CN1279685C CN 1279685 C CN1279685 C CN 1279685C CN B031206204 A CNB031206204 A CN B031206204A CN 03120620 A CN03120620 A CN 03120620A CN 1279685 C CN1279685 C CN 1279685C
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Abstract
The present invention relates to a converter. A DC link voltage detector 16 detects a voltage value of a DC link voltage. A U-shape current detector 13 detects a current value of a U-shape current. A controller 17 acquires a voltage value of the DC link voltage detected by the detector 16. The controller 17 compensates voltage drops in transistors Q1 to Q6 or the like of a voltage converter 12. If the DC link voltage exceeds a rated voltage, the controller 17 controls to reduce the output current of the inverter so that the output capacity of the inverter becomes constant. Since the output capacity of the inverter does not exceed the maximum output capacity, suitable output capacities of the inverter are used for the transistors Q1 to Q6. The invention can prevent an inverter device from being increased in size and cost due to an increase in an output capacity.
Description
Technical field
The present invention relates to the control method of converting means and converting means.
Background technology
Converting means is that a DC who adds a connection voltage transformation is the device of alternating voltage.Converting means is especially for the driving of induction motor.Relevant converting means is by carrying out pulse duration control etc., and it is alternating voltage that the DC that adds is connected voltage transformation.Its output voltage is connected magnitude of voltage, the pulse duration of voltage by the DC that adds the conducting load etc. of control decides.
In addition, in converting means, used and the corresponding output capacity of the rated value of induction motor.The output capacity of this converting means is by output voltage and output current decision.The rated value of the element that uses in the converting means is also decided by this output capacity.And, particularly driving in VVVF (output of the variable voltage variable frequency) converter of usefulness as induction motor, what have can carry out work with higher output capacity.
But when the output voltage of converting means was higher, if amount of exports definite value electric current intactly, then the output capacity of converting means will increase.If the output capacity of converting means increases,, just be necessary to use and the corresponding element of this output capacity then for the element that is built in the converting means.For this reason, must use rated value to this element is one more than the grade.In addition, fan also must use radiating effect big.Thereby caused the maximization of converting means, cost has been risen.
Summary of the invention
The existence of problem in view of the above the objective of the invention is to: provide a kind of and can prevent to maximize and converting means and control method thereof that cost rises.
To achieve these goals, the invention provides a kind of converting means, it comprises:
According to control signal is dc voltage conversion alternating voltage, and the alternating voltage of this conversion is applied to voltage transformating part in the load; With
Generate described control signal and provide it to the control part of described voltage transformating part,
Described control part,
For the output capacity that makes described voltage transformating part is below the predefined maximum output capacity,,, set the rated current of first value when described direct voltage is first threshold voltage when following for the output current of this voltage transformating part;
When described direct voltage surpasses described first threshold voltage and is second threshold voltage when following, set if this direct voltage increases the rated current that its value then reduces;
When described direct voltage surpasses described second threshold voltage, set the rated current that the discontinuous running of second value also lower than described first value is used;
The output current that generates described voltage transformating part is the following described control signal of described each rated current and provides it to this voltage transformating part.
In addition, the invention provides a kind of control method of converting means, this converting means comprises according to control signal and is alternating voltage and the alternating voltage of this conversion is applied to voltage transformating part in the load that this method may further comprise the steps to dc voltage conversion:
For the output capacity that makes described voltage transformating part is below the predefined maximum output capacity,,, set the rated current of first value when described direct voltage is first threshold voltage when following for the output current of this voltage transformating part;
When described direct voltage surpasses described first threshold voltage and is second threshold voltage when following, set if this direct voltage increases the rated current that its value then reduces;
When described direct voltage surpasses described second threshold voltage, set the rated current that the discontinuous running of second value also lower than described first value is used;
The output current that generates described voltage transformating part is the following described control signal of described each rated current and provides it to this voltage transformating part.
In addition, converting means of the present invention comprises: preestablishing maximum output capacity, is dc voltage conversion alternating voltage according to control signal, and the alternating voltage of conversion is applied to voltage transformating part in the load; Set the rated current of this voltage transformating part, the output capacity that makes described voltage transformating part is below the maximum output capacity, generates control signal, make to the output current of described load for this below rated current, and offer the control part of this voltage transformating part.
According to such structure,, rise so can prevent the maximization of locking apparatus and cost because the output capacity of voltage transformating part is below the maximum output capacity.
And described control part can comprise: more described direct voltage and with described maximum output capacity corresponding threshold voltage, if this direct voltage surpasses this threshold voltage, reduce parts with regard to the rated current that reduces described rated current.
In addition, the structure of described control part can be: the conversion loss from direct voltage to described alternating voltage according to described voltage transformating part is set described threshold voltage.
In addition, described control part can be set current instruction value, and making the output current to described load is below the described rated current, and generates described control signal according to the current instruction value of this setting.
In addition, when described control part surpasses set-point at described direct voltage, described voltage transformating part is set the rated current that predefined discontinuous running is used, generate the control signal that discontinuous running is used, make below the rated current that described output current uses for this discontinuous running, and the output capacity that makes this voltage transformating part is below the described maximum output capacity, offers this voltage transformating part.
At this moment, the rated current used of described discontinuous running can be also lower than the rated current that described direct voltage sets when set-point is following.
In addition, the control method of converting means of the present invention is to have to preestablish maximum output capacity, is dc voltage conversion alternating voltage, the alternating voltage of this conversion is applied to the control method of the converting means of the voltage transformating part in the load, this method comprises: set this voltage transformation. and the rated current of portion, the output capacity that makes described voltage transformating part are the following step of maximum output capacity; Generate control signal, making the output current to described load is below the described rated current, and offers the step of described voltage transformating part.
Description of drawings
Following brief description accompanying drawing.
Fig. 1 is the block diagram of the converting means structure of the expression embodiment of the invention.
Fig. 2 is the flow chart of action of the control part of presentation graphs 1.
Fig. 3 is the key diagram of the content of the coefficient that uses in the computing of expression.
Fig. 4 is the key diagram of action of the converting means of presentation graphs 1.
Following brief description reference numeral.
The 12-voltage transformating part; 13-U phase current detector; 14-V phase current detector; 16-DC connects voltage detector; The 17-control part; The 19-induction motor.
Embodiment
Below, the converting means of the embodiment of the invention is described with reference to accompanying drawing.
Fig. 1 has represented the converting means structure of present embodiment.
The converting means of present embodiment is that output voltage is the voltage shape transformer of square wave, is made of direct current smmothing capacitor 11, voltage transformating part 12, U phase current detector 13V, phase current detector 14, rotor position detector 15, DC connection voltage detector 16 and control part 17.
Direct current smmothing capacitor 11 is used to make the direct voltage smoothing of DC power supply 18.
Voltage transformating part 12 is according to the voltage instruction value that is provided by control part 17, with 11 smoothings of direct current smmothing capacitor DC connection voltage transformation be alternating voltage.Voltage transformating part 12 has transistor Q1-Q6 and diode D1-D6.It should be noted that, in this transistor Q1-Q6, used IGBT (Injection Enhanced Gate Transistor) etc.
Transistor Q1-Q6 is the switch element that switch is provided according to the pulse signal that provides from control part 17.The collector electrode of transistor Q1, Q3, Q5 is connecting the positive pole of direct current smmothing capacitor 11.The collector electrode of transistor Q2, Q4, Q6 is connecting the emitter of transistor Q1, Q3, Q5 respectively, and emitter is connecting the negative pole of direct current smmothing capacitor 11 respectively.
The U phase coil that on the tie point of the emitter of transistor Q1 and the collector electrode of transistor Q2, is being connected induction motor 19.On the tie point of the emitter of transistor Q3 and the collector electrode of transistor Q4, be connected the V phase coil.On the tie point of the emitter of transistor Q5 and the collector electrode of transistor Q6, be connected the W phase coil.
Diode D1-D6 is when transistor Q1-Q6 disconnects, and is used for output current is carried out the diode of rectification.The negative electrode of diode D1-D6 is connected on the collector electrode of transistor Q1-Q6.The anode of diode D1-D6 is connected on the emitter of transistor Q1-Q6.
It is on the three phase induction motor (among the figure, being called " IM ") 19 that voltage transformating part 12 is applied to load to the alternating voltage of conversion.
U phase current detector 13, V phase current detector 14 detect current value I u, the Iw of electric current of the primary winding (stator coil) of the U phase that offers induction motor 19, V phase respectively.
DC connects the magnitude of voltage Vdc that voltage detector 16 detects the direct voltage of using 11 smoothings of direct current smmothing capacitor.
When carrying out vector control, 17 pairs of voltage in three phases command value of control part Vu
*, Vv
*, Vw
*Carry out computing.When being the VVVF converter, control part 17 is according to voltage instruction value Vu
*, Vv
*, Vw
*Come setpoint frequency, generate pulse signal based on this frequency.Then, control part 17 outputs to this pulse signal in the voltage transformating part 12.999
In addition, control part 17 makes the output power of converting means not exceed the control of maximum output capacity (maximum output power).As mentioned above, obtain the output capacity of converting means according to output voltage and output current.Because the detection of output voltage is difficult, so control part 17 is controlled according to the magnitude of voltage Vdc that DC connects voltage, make the output power of converting means not exceed maximum output capacity (maximum output power), and in the scope that can turn round continuously, it is certain making output capacity.
In order to carry out such control, connect in the magnitude of voltage of voltage Vdc setting threshold Vdc1, Vdc2 at DC.Threshold value Vdc1 is the maximum output capacity corresponding threshold with converting means, is to be used to switch to the certain threshold value of control capacity.Threshold value Vdc2 is the threshold value of the expression scope that can turn round continuously.Control part 17 has not shown memory, and threshold value Vdc1, Vdc2 are stored in this memory in advance.
Below, the action of the converting means of present embodiment is described.
Direct current smmothing capacitor 11 is the direct voltage smoothing of DC power supply 18.In the transistor Q1-Q6 of voltage transformating part 12, the DC that has added by 11 smoothings of direct current smmothing capacitor connects voltage.DC connects voltage detector 16 and detects the magnitude of voltage Vdc that this DC connects voltage.
By making transistor Q1-Q6 conducting, disconnection, generate alternating voltage, each coil of the U of current direction induction motor 19, V, W phase.U phase current detector 13, V phase current detector 14 detect current value I u, the Iv of electric current of each coil of the U that flows into induction motor 19, V phase respectively.
When carrying out vector control, control part 17 is obtained current value I u, Iv from U phase current detector 13, V phase current detector 14 respectively, obtains rotor-position from rotor position detector 15.It should be noted that,, can calculate the current value I w of W electric current mutually from current value I u and current value I v according to this condition of three-phase equilibrium.
In addition, if set the current instruction value Id of exciting curent
*Current instruction value Iq with torque current
*, control part 17 is just obtained the current instruction value Id of exciting curent
*With the deviation cd of exciting curent value Id, the current instruction value Iq of torque current
*Deviation eq with torque current value Iq.
If control part 17 is obtained deviation ed, eq, the deviation ed that just obtains, the PI of eq (proportional integral) computing etc., obtaining respectively and making deviation ed, eq is 0 voltage instruction value Vd
*, Vq
*
Then, control part 17 carries out voltage instruction value Vd according to rotor-position
*, Vq
*To the coordinate transform of rest frame, obtain three-phase voltage command value Vu
*, Vv
*, Vw
*
When carrying out PWM (Pulse Width Modulation) control, control part 17 is according to each the voltage instruction value Vu that obtains
*, Vv
*, Vw
*Generate pulse signal, of the grid output of this pulse signal to the transistor Q1-Q6 of voltage transformating part 12.
Transistor Q1-Q6 comes conducting, disconnection according to the pulse signal that provides from control part 17, and the alternating current that phase place is different flows to U, the V of induction motor 19, each coil of W phase each other.
In addition, the DC that control part 17 detects according to DC connection voltage detector 16 connects the magnitude of voltage of voltage Vdc, sets the current value of rated current Ir, makes the output capacity of converting means be no more than maximum output capacity.At this, so-called rated current is meant the limit in the design of output current of converting means.
The action of this control part 17 of the flowcharting of Fig. 2.
Vdrop＝kd×Iout+b (1)
In expression formula (1), kd is the device voltage decline coefficient that the loss of the switch element of IGBT etc. causes.As shown in Figure 3, this coefficient k d is obtained by the electric current of switch element and the relation of voltage.Iout is the value from the output current of voltage transformating part 12 outputs.This Iout obtains according to the current value that U phase current detector 13, V phase current detector 14 detect.B is a bias voltage.
In addition, control part 17 is according to the drop-out voltage Vdrop that obtains, and the voltage that carries out threshold value Vdc1, Vdc2 descends and compensates, and according to following expression formula (2), (3), obtains threshold value Vdc1, Vdc2 respectively.
Vdc11＝Vdc1+Vdrop (2)
Vdc12＝Vdc2+Vdrop (3)
Then, control part 17 connects the magnitude of voltage (step S13) that voltage detector 16 is obtained DC connection voltage Vdc from DC.
Whether control part 17 decision voltage value Vdc surpass threshold value Vdc11 (step S15).
If magnitude of voltage Vdc does not surpass threshold value Vdc11 (Vdc≤Vdc11), even rated current flows through induction motor 19, yet can not surpass the maximum output capacity of converting means.Therefore, (in step S15, for denying) is set at certain value Iref (step S16) to rated current Ir when control part 17 is judged to be magnitude of voltage Vdc above threshold value Vdc11.
When decision voltage value Vdc has surpassed threshold value Vdc11 (in step S15, for being), whether control part 17 decision voltage value Vdc are below Vdc12 (step S17).
When magnitude of voltage Vdc (during Vdc11＜Vdc≤Vdc12), even the continuous running of converting means is possible, if the electric current of current value I ref flows through converting means, will surpass maximum output capacity below Vdc12.Therefore, control part 17 is threshold value Vdc12 when following (at step S17, for being) at decision voltage value Vdc, just according to magnitude of voltage Vdc, reduces rated current Ir from current value I ref, makes the output capacity of converting means become certain value (step S18).
In order to obtain this rated current Ir, control part 17 is at first obtained the current value I a that reduces from current value I ref according to following expression formula (4).
Ia＝Iref×(Pout/(Vdc11×k)) (4)
In expression formula (4), Pout represents maximum output capacity, and k represents the capacity coefficient (0≤k≤1) set according to output capacity.It should be noted that when being three phase times, the value that the square root of the electric power of each phase and 3 is multiplied each other becomes maximum output capacity Pout.
And control part 17 is obtained output capacity according to following expression formula (5) and is become certain rated current Ir.
Ir＝Iref-Ia (5)
Then, (Vdc12＜Vdc), even the current value of rated current Ir is reduced, if carry out the continuous running of converting means, then the output power of converting means also exceeds maximum output capacity when magnitude of voltage Vdc surpasses threshold value Vdc12.Therefore, control part 17 is (in step S17, for denying) when being judged to be magnitude of voltage Vdc above threshold value Vdc12, and rated current Ir is set at the certain value Idec that discontinuous running is used.(step S19)
When carrying out vector control, control part 17 is set the current instruction value Id of exciting curent
*Current instruction value Iq with torque current
*, make it to be no more than the rated current Ir that in step S16, S17, S18, S19, sets.
Carry out such control by control part 17, converting means has had characteristic shown in Figure 4.
When Vdc≤≤ 11 (among the figure, being called 1.), rated current Ir is set at current value I ref.Even the electric current of current value I ref flows into induction motor 19, the output capacity of converting means can not surpass maximum output capacity yet.
When Vdc11＜Vdc≤Vdc12 (among the figure, being called 2.),, reduce rated current Ir according to expression formula (5) according to magnitude of voltage Vdc.The output capacity of converting means can not surpass maximum output capacity.
When Vdc12＜Vdc (among the figure, being called 3.), because rated current Ir becomes Idec, so can not turn round continuously (promptly working), converting means carries out discontinuous running.
It should be noted that, if magnitude of voltage Vdc reaches charge threshold level Vsv, the converting means that then can only in the short time, turn round, even discontinuous running, but the operating range of converting means also is till the maximum voltage value Vov.
In sum, according to present embodiment, control part 17 connects voltage Vdc according to DC and sets rated current, makes the output power of converting means be no more than maximum output capacity.
Therefore, even the magnitude of voltage Vdc condition higher than rated voltage in the switch element of transistor Q1-Q6 etc., also used the following element of output capacity of converting means, and the protection converting means, and can obtain and identical in the past characteristic.In addition, its radiator, fan etc. needn't use the above main equipment of output capacity of converting means.In view of the above, can prevent that the maximization of locking apparatus and cost rise.In addition, can also reduce the thermal loss of device, suppress the rising of temperature, improve reliability.
In addition, because as long as the software that change has existed so do not need the change of hardware, just can be implemented such control.
It should be noted that considered various forms when enforcement is of the present invention, the present invention is not limited to described embodiment.
For example, converting means is not limited to the voltage shape transformer, and also can be applied to output current is the electric current shape transformer of square wave.
In the present embodiment, having carried out making capacity according to current value Vdc is certain control.But,, just can carry out the certain control of capacity according to this output voltage if can detect output voltage.In addition, capacity is also nonessential certain, and to be no more than maximum output capacity just passable as long as be controlled to be.
In addition, for the transistor Q1-Q6 of voltage transformating part 12,, can use transistor, FET (field-effect transistor), thyratron transistor etc. according to power capacity.
In addition, induction motor 19 not only can be a three-phase, also can be two-phase or surpass three-phase.Can not induction motor also, and use synchronous motor.
In addition, the speed control of induction motor is not limited to vector control, also can use FREQUENCY CONTROL, voltage/frequency control etc.
In sum, according to the present invention, just can prevent to maximize and the cost rising.
Claims (2)
1. converting means is characterized in that: comprising:
According to control signal is dc voltage conversion alternating voltage, and the alternating voltage of this conversion is applied to voltage transformating part in the load; With
Generate described control signal and provide it to the control part of described voltage transformating part,
Described control part,
For the output capacity that makes described voltage transformating part is below the predefined maximum output capacity,,, set the rated current of first value when described direct voltage is first threshold voltage when following for the output current of this voltage transformating part;
When described direct voltage surpasses described first threshold voltage and is second threshold voltage when following, set if this direct voltage increases the rated current that its value then reduces;
When described direct voltage surpasses described second threshold voltage, set the rated current that the discontinuous running of second value also lower than described first value is used;
The output current that generates described voltage transformating part is the following described control signal of described each rated current and provides it to this voltage transformating part.
2. the control method of a converting means, this converting means comprise according to control signal and are dc voltage conversion alternating voltage and the alternating voltage of this conversion is applied to voltage transformating part in the load, it is characterized in that, may further comprise the steps:
For the output capacity that makes described voltage transformating part is below the predefined maximum output capacity,,, set the rated current of first value when described direct voltage is first threshold voltage when following for the output current of this voltage transformating part;
When described direct voltage surpasses described first threshold voltage and is second threshold voltage when following, set if this direct voltage increases the rated current that its value then reduces;
When described direct voltage surpasses described second threshold voltage, set the rated current that the discontinuous running of second value also lower than described first value is used;
The output current that generates described voltage transformating part is the following described control signal of described each rated current and provides it to this voltage transformating part.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002070976A JP3951759B2 (en) | 2002-03-14 | 2002-03-14 | Inverter device and control method thereof |
| JP070976/2002 | 2002-03-14 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1450716A CN1450716A (en) | 2003-10-22 |
| CN1279685C true CN1279685C (en) | 2006-10-11 |
Family
ID=28786119
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB031206204A Expired - Fee Related CN1279685C (en) | 2002-03-14 | 2003-03-14 | Converter and control method |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP3951759B2 (en) |
| CN (1) | CN1279685C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105706355B (en) * | 2013-11-07 | 2018-01-19 | 三菱电机株式会社 | The protection device of vehicle inverter |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2518886B1 (en) * | 2009-12-24 | 2021-11-03 | Mitsubishi Electric Corporation | Power conversion apparatus and driving method for power conversion apparatus |
| CN103580463A (en) * | 2013-10-11 | 2014-02-12 | 友达光电股份有限公司 | Current transforming device and control method thereof |
| JP6530306B2 (en) * | 2015-11-27 | 2019-06-12 | 日立ジョンソンコントロールズ空調株式会社 | Two-phase induction motor, air conditioner having two-phase induction motor and program |
| JP6638746B2 (en) * | 2018-01-31 | 2020-01-29 | ダイキン工業株式会社 | Inverter control method, AC load drive system, refrigeration circuit |
-
2002
- 2002-03-14 JP JP2002070976A patent/JP3951759B2/en not_active Expired - Fee Related
-
2003
- 2003-03-14 CN CNB031206204A patent/CN1279685C/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105706355B (en) * | 2013-11-07 | 2018-01-19 | 三菱电机株式会社 | The protection device of vehicle inverter |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2003274666A (en) | 2003-09-26 |
| CN1450716A (en) | 2003-10-22 |
| JP3951759B2 (en) | 2007-08-01 |
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