JPS63171192A - Controller for elevator - Google Patents

Abstract

PURPOSE:To enhance a power factor and obtain a comfortable elevator system to ride in, by applying a converter system controlling phase and pulse width, for controlling the elevator. CONSTITUTION:Via a current type converter section 3 and a current type inverter section 5 through an AC power source 1, an induction motor 6 driving an elevator riding-cage and a balance weight is driven. From one-chip micro- computers 10, 11, pulse patterns (control signals) are respectively fed to transistors 31-36, 51-56. On the micro-computers 10, 11, a phase control system and a pulse width control system set in a variable state at the same time are worked to compensate for gain lowering due to the cos characteristic of the phase control system. As a result, an elevator system driven by a controller having the pulse width control system and the phase control system is to have almost constant responding capacity regardless of the change of the control systems, and so the elevator is released from unnecessary oscillation phenomena due to the change of the systems.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an elevator control device, and is particularly applicable to an elevator driven by an AC/DC power converter that uses both phase control and pulse width (time width) control. The present invention relates to an elevator control device suitable for always providing stable riding comfort.

[Conventional technology]

From the viewpoint of improving the power factor of AC/DC power converters, JP-A-56-16
No. 2976 proposes a method in which a controllable switching element having a current cutoff function is connected to an arm, and phase control and pulse width control are used together. By using this method, high power factor control is possible from low to high output ranges, whether directly controlling a DC motor or indirectly controlling an induction motor via an inverter. For applications that require extremely delicate control, it has been found that there is a problem in which resonance occurs with the mechanical system that acts as a load in a specific output range.

A more specific example is when the above method is applied to an elevator system using an induction motor. When the operating point of the control system remains exactly at the switching point between phase control and pulse width control, that is, when the number of passengers and driving direction are such that the operating point moves to this point during steady driving. In this case, the rope system (mechanical system) and control system (electrical system) of the elevator begin to resonate, and sustained vibrations that are inappropriate for an elevator occur. In some cases, a large value of 20 gal was recorded as a result of actual measurements using experimental equipment. However, this phenomenon is a serious problem unless the operating point of the control system exists for a certain period of time near the switching point between phase control and pulse width control as described above, and there is no mechanical system affected by this phenomenon. Therefore, there was a problem in that it was difficult to find the above-mentioned problem.

Problems at the switching point of both control systems can be found in "Thyristor Applied Engineering", Separate Excitation Converter Edition, Denki Shoin, page 44, No. 12-2
As shown in line 0 and Figures 2 and 13, the output characteristic of the converter is a cosine characteristic and the slope changes, and the control delay angle α becomes almost zero near σ, 180°. caused by. If the system performs only phase control, then c
Changes in response time due to changes in O8 characteristics are gradual, and in applications where the system itself does not require rapid changes (for example, elevator control), problems due to this cos characteristic do not occur. However, systems that use both phase control and pulse width control have the problem that even if the system does not require a sudden response, the response changes dramatically at the switching point between the two control systems. In the control of elevators, etc., which requires delicate matching between the motor and the electrical system, this problem becomes a decisive problem in that it deteriorates ride comfort.

[Problem that the invention seeks to solve]

The above conventional technology does not take into account response changes near the switching between phase control and pulse width control of the converter, and the control method is not applied to applications that require delicate control, such as elevator control. There was a problem.

An object of the present invention is to make it possible to apply a converter system that uses both phase control and pulse width control to elevator control, and to provide an elevator control system that provides a high power factor and a comfortable ride. Our goal is to provide the following.

[Means for solving problems]

The above object is achieved by making the pulse width control system variable in a region where the input/output characteristics (cos characteristics) of the phase control system are highly nonlinear and compensating the characteristics.

[Effect]

The pulse width control system is variable at the same time as the phase control system.
It operates to compensate for gain reduction due to cosine characteristics of the phase control system. Thereby, an elevator driven by a control device having a pulse width control system and a phase control system.
Since the system will have a nearly constant response capability regardless of changes in the control system, it will be free from unnecessary vibration phenomena caused by system switching.

〔Example〕

The present invention will be described below with reference to FIGS. 1, 2, and 4 to 7.

The embodiment shown in FIG. 9 and FIGS. 3, 8, 10,
This will be explained in detail using FIG. 11.

FIG. 1 is an overall configuration diagram showing an embodiment of an elevator control device of the present invention. In Figure 1, 1 is a three-phase AC power supply, 2 is a capacitor for overvoltage suppression, 3 is a current source converter section, 31 to 36 are transistors that constitute the main switching elements, 4 is a DC reactor, and 5 is a current source converter section. In the inverter section, 51 to 56 are transistors constituting the main switching elements, 6 is a capacitor for overvoltage suppression, 7 is an induction motor that drives the elevator car and counterweight (not shown), and 8 is a DC current detector. ,
9 is a comparator that compares the primary current command 1i11 and the feedback value i1, and 10.11 is a pulse pattern (
control signal) to transistors 31 to 36, 51 . This is a one-chip microcomputer for supplying signals to the microcomputers 10 and 56 (note that since these one-chip microcomputers 10 and 11 have the same hardware configuration, the detailed explanation will mainly be given for the control circuit 10).

12 is a primary current command 11 given to the converter control system.
Terminals 13 and 14 are supplied with the frequency command ω1m and phase command θ given to the inverter control system, and 15 is a signal line for inputting power synchronization signals.

The one-chip microcomputer 10 has an input port 101, an internal bus 102, a ROMIO 3 for storing programs, pulse width data tables, etc., a RAM 104 used for temporary storage and registers, an ALU 105 for performing calculations, etc., and a predetermined pulse pattern ( an event setting register 107 that sets the event necessary to output a control signal consisting of an event); a time setting register 108 that sets the time to enable this event; and the contents of both setting registers 107 and 108. a holding register 109 that connects and holds the data, an associative memory 110 that sequentially and cyclically stores several sets of setting data set in this holding register 109, and a timer 1 that outputs the actual time.
11. Time based on this timer 111 and associative memory 110
A comparison unit 112 that compares the contents of the set time and generates an output when they match, and an execution controller 113 that receives a trigger from the comparison unit 112 and controls the output of the set event to the output port 106. Consists of.

Next, using a flowchart, we will explain how this embodiment operates to output pulses, and how the new device works in the process.

In this embodiment, as shown in FIG. 2 and FIG. 4, it is composed of two large processing systems. First, FIG. It is a flowchart j- showing an example of the outline of the program F100O.

When processing of Flooo starts, first, preparations are made to obtain the total phase 0 in FIloo. In the frequency command ω1 umbrella, the frequency value of the AC power source is written in advance as data. The phase command Ph is a value determined based on the current deviation Δ11, as shown in the characteristics shown in FIG. The characteristics shown in FIG. 3 are closely related to the present invention and will be described in detail later.

Next, this frequency command ω1 umbrella is integrated every fixed time Δt1, and the phase command ph- is subtracted to process the total phase 0.
Calculate by 1200.

Next, among the six modes in which electrical angle 360' is divided into 606 units, which mode of pulse pattern should be output for the total phase 0 that we have found? Obtained using F1300 processing. Note that the relationship between the total phase 0 and the six modes will be explained in detail later. Finally, the pulse pattern is changed during the interrupt interval Δtx, but the time tEn until the change is determined is determined by referring to the data table with the phase fllT and by taking into account the value of the conduction rate command rI, which will be described later. Processing is performed using F1400. Through this processing, two items, event content and event change time, to be set in the two registers 107 and 108 are obtained.

Next, processing F200 sets the two items obtained in this way in the associative memory 110 for output boat control.
0 is shown in FIG.

First, the F2100 determines whether the event settings and time settings required for the six transistors have been completed. If no, the F2200 sets the corresponding event, and the F2300 sets the event change time and ends the process. .

Next, how are the phase command Ph* used in the process FI100 in FIG. How this is done will be specifically explained using FIG.

FIG. 5 shows the phase 9 conduction rate command creation process F3000.

The two commands obtained by this are used when calculating the pulse train.

As for the processing here, first, F
3200. Phase command Phi, conduction rate command γ with F8300
ask for advice. Of course, you can create these commands Phi and γ fist using external analog circuits, convert them into A/D and import them, or you can create a table for Δ11 in advance and search it using software. good.

As shown in FIG. 3, the relationship between the phase command Ph and the conduction rate command γ is such that both commands are variable with respect to the current deviation Δ11 in the intervals a1 to ax and ax to a4. This increases the conductivity command γ umbrella in the region where the gain decreases due to the influence of bending due to the COS characteristic of the phase control system, and operates the pulse width control system to compensate for the decrease in gain, and the phase command itself Also the limit value O° and 180°
This is an attempt to achieve a high power factor by opening the phase to the vicinity.

Furthermore, here a2. ~a8 and 81 ~a2 and a8
The slope of Ph* is changed at ~a4, but in this case, although there is a drawback that the region operating at the highest power factor is slightly narrower, the effect is that the gain reduction compensation is dispersed over a wide range and performed slowly. There is.

If the inclination of the Ph skewer is not changed, opposite advantages and disadvantages arise, but there is a compensating effect by using phase control and pulse width control together.

As shown in Table 1, the phase command and duty ratio command are determined in advance for the current deviation, and this is made into a table, which is used for searching.

This method has the advantage that there is no variation in the time it takes to obtain data and can be done in a short time, but it is necessary to secure a ROM area for the table.

Table 1, Figure 6 is a flowchart of the method of direct calculation using software. Here, conduction rate command γ* and phase command Ph*
The part that requires the calculation is extracted and shown. Since both γ* and ph* are composed of simple linear functions, it does not take much time to obtain them directly using software as shown in FIG. Furthermore, compared to the method of referring to the table in Table 1, this method does not require a ROM area for the table, and is effective when configuring a system using a one-chip microcomputer or the like.

By providing such a function generator, it is expected that problems with riding comfort near the switching between the converter's phase control system and pulse width control system can be solved, but the specific experimental results will be discussed in the overall operation explanation. Do it after.

Next, the determination of the pulse pattern in process F1300 will be explained using FIG.

In this embodiment, the pulse pattern is changed every 60' of electrical angle, and six sets of modes that complete one cycle at 360' are repeated. Therefore, six sets of modes M1 to M6 having an interval of 60° are selected based on the overall phase θT. The flowchart is shown in FIG. In addition, phase 0 is 0
If you go to an area other than 6 to 360°, perform an area check that adds or subtracts 360° and returns 0 to within the area.F1
Go at the beginning of 300.

Next, Table 2 shows the specific period Δt1 in modes M1 to M6.
The combinations of transistors that are always turned on during the event, transistors that are turned on until an event occurs and then turned off, and transistors that are turned off until an event occurs and then turned on are shown below. Therefore, if we know the phase 0, we can know the mode and identify the transistor that should be turned on and off.What we do not yet know at this point (when the F1300 processing is finished) is when to turn on and off. Only. Regarding ignition,
For example, this means specifying the output to each transistor by setting "1" in the register when setting an event and setting "O" in the register when extinguishing the arc.

The process (F1400 in FIG. 2) for determining the time for changing an event using Table 3 will be explained.

In conclusion, it is sufficient to obtain a waveform close to a sine wave output, so in this embodiment, sunθT is adjusted according to the phase θT.
and sin with a 120° phase shift (θT-1206)
, 5un (θT-2400), multiplied by the current conductivity γ-ko, Δtx is distributed. In other words, the first
．． Second event occurrence (changing pulse pattern)
The time tElnyt Exn is made a function of 0-gun and γ-punch as shown in the equation below.

tHln::Δt1・(sin(θT-240
))-1"...(1)tE'2n=ΔtIN(S
inθT) Misery (2) Therefore, as an example of the pulse pattern is shown in Table 2, as the value of the conduction rate γ becomes smaller, both the values of tElnyt and Exn become smaller, and (Δts jElntEzn) becomes This increases the period during which the elements of the upper and lower arms are short-circuited, thereby realizing a decrease in the conduction rate γ.

This second table shows an example of the operation mode and the boat output signals 831 to S36 given to the transistors 31 to 36. This occurs because the interval Δt1 is asynchronous, and to eliminate this, ω1
It is only necessary to set Δt1 to a value so that it can just interrupt *.

Next, FIG. 9 shows a flowchart of a concrete event setting process taking the first part of mode 1 of this table as an example. Note that, as described above, although the loop configuration is described in FIG. 4 for the sake of general explanation, the process actually flows in series as shown in FIG. 9.

The flowchart in FIG. 9 is from time to to t in FIG.
This shows the event setting process for one timer interrupt period up to Δtx. First, when an interrupt occurs at time to, the transistor 35 (see Table 2), which always fires in mode 1, is set at F2410. Two sets of event sets 1 to 1 and time sets are performed for each transistor so that a firing signal is immediately generated in the transistor 33 that is fired until the first event occurs. That is, an event is set so that 1'1'' is generated at ports 3 and 5 corresponding to transistors 35 and 33, and then a predetermined time td is added to the current time to and set in a predetermined register as a time set. At this time, since the ignition will occur immediately, it is necessary to select a value as small as possible for this time td.By this, the event and time are set in the associative memory 110, and from then on, according to the schedule, after td elapses, A 1'1'' signal is output to transistors 35 and 33.

Note that the reason why the predetermined time td is added here is as follows. That is, some time necessarily elapses between the time an event is set in the associative memory 110 and the time it is read out. Therefore, the current time t is obtained without adding this time td.

This is because, if .

In F2420, assuming that the operating mode has changed from the previous one due to a sudden change in the phase command θ, etc., a process is performed to confirm the extinction of the transistor that should be in the extinction state in this mode. Processing uses the associative memory 110 as in the F2410, but here the event is arc extinction, so 110 is used for ports 1, 2, 4, and 6.
Events are set to generate 1+.

Next, a schedule process is performed in F2430 such that the transistor 33 is turned off at time to+tEtn.

The event is "0" output to port 3, and the time is t.

Set +tEtn. If td is a relatively large value, at this point, multiple events will have been scheduled at different times for one output port within the same timer interrupt.

Furthermore, in F2440, instead of turning off the transistor 33, a schedule for turning on the transistor 31 is set.

Note that here, the turning off of the transistor 33 and the turning on of the transistor 31 are set at the same time; however, in order to prevent overvoltage, the "1" period is wrapped in the current source converter, and the time tEn is set to create a non-lap period in the voltage source converter. F2430 and F
2440 is also possible.

Next, at the second event occurrence point to+tpzn, transistor 3
The schedule for extinguishing the transistor 32 (F2450) and the schedule for igniting the transistor 32 (F246(1)) are subsequently performed.

In this way, in the above embodiment, the phase θ1 is calculated, the transistor to be turned off is determined based on the zero value, the time for turning off is determined based on the zero value, and finally the transistor to be turned off is determined based on the zero value. The process of creating a schedule by pairing transistors and their times is performed every predetermined time Δt1. Therefore, this series of processes makes it possible to compare the conventional method of comparing carrier waves and modulated waves with microprocessors (
This is an example of a method that not only eliminates the problem of the ALU being forced to constantly perform comparisons, but also has the great industrial advantage of converting the power supply current waveform into a sine wave and preventing harmonic components from flowing into the power supply. I have explained the operation using the following steps.

Next, the effects of the present invention as an elevator system will be explained using actual measurement results as an example using FIGS. 10 and 11.

Figure 10 shows the elevator when the load is changed in 20 kg increments and the operating point of the elevator control system is near the switching point between the phase M control system and the pulse width control system during steady running. speed.

This is the actual measurement result of car acceleration. Figure 10 (,) shows a conventional method that simply combines phase control and pulse width control.
The torque shock and the mechanical system resonate, and the acceleration waveform shows a large value of 0.7 m/s at its maximum, indicating that coordination of the surface control system is a very big issue for elevators.On the other hand, (b ) is the actual measurement result when the embodiment of the present invention is applied and the phase control system and pulse width control system are coordinated, and it is clear from the actual machine test that it is effective in significantly improving the car acceleration vibration. was made into

FIG. 11 shows the results of measuring the relationship between the current deviation Δiz, the output voltage Ed of the comparator, and the response time T of the current control system using the motor generator as the load of the converter.

In the conventional method, the response of the current control system changes by a factor of 2.5 or more near the switching between the phase control system and the pulse width control system, and this change in response becomes a torque shock, and this shock further affects the mechanical system of the elevator. , it can be inferred from the experimental results that the problem was particularly exacerbated by resonance with the rope system.

Note that although the case where the system is constructed using a special one-chip microcomputer having an associative memory has been described as an example, it is clear that the essence of the invention is not limited to this.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to smooth the output characteristics of a converter system that uses both phase control and pulse width control. This has the great industrial effect of making it possible to apply a converter.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram showing an embodiment of an elevator control device of the present invention, Fig. 2 is a flowchart showing an outline of an embodiment of an event calculation processing program, and Fig. 3 is a phase 2 conduction rate characteristic. An explanatory diagram showing an example, FIG. 4 is a flowchart showing an example of an event setting processing program, FIG. 5 is a flowchart showing an example of a program for phase and conduction rate command work processing, and FIG. FIG. 7 is a flowchart showing an example of a specific realization program by the generator, FIG. 7 is a flowchart showing an example of a mode selection processing program, FIG. 8 is a time chart showing an example of PWM control pulses, and FIG. 9 is an event diagram. Flowchart showing an example of setting processing, No.: tOII. FIG. 11 is a diagram showing experimental results for explaining the present invention in detail. 2.6... Capacitor, 3... Current source converter section, 4... DC reactor, 5... Current source inverter section, 7... Induction motor, 9... Comparator, 10.11
...One-chip microcomputer, 101...Input port,
103...ROM, 1104-RA, 105.=AL
M, 106...Output port, 107...Event setting register, 109...Holding register, 110...Associative memory, 111...Timer, 112...Comparator, 1
13... Execution controller.

Claims (1)

[Scope of Claims] 1. An AC/DC power converter having a controllable opening/closing procedure having a current cutting function connected to at least one arm, a first means for controlling a phase angle of the switching means, and a first means for controlling the phase angle of the switching means; and a second means for controlling the time width for opening and closing the means, the elevator control device being driven directly or indirectly according to the output of the AC/DC power converter, wherein the first means and the second means A control device for an elevator, characterized in that it comprises a function generator having a region operable to simultaneously put the means into an operating state. 2. The function generator is configured to keep the time width constant and vary the phase angle in a region where the absolute value of the output current deviation of the AC/DC power converter is smaller than the first set value. In a region where the absolute value is larger than the first set value and smaller than the second set value, the time width and the phase angle are made variable at the same time, and the absolute value of the output current deviation is set to the second set value.
The phase angle is kept constant in a region larger than the set value of
The elevator control device according to claim 1, further comprising a region in which the time width is variable.