JP2781562B2 - Variable speed generator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a variable-speed power generator having a power converter and generating electric power of a predetermined frequency regardless of the rotational speed of a hydraulic machine as a prime mover, and particularly to a hydraulic machine. The present invention relates to a variable-speed power generator suitable for improving the reliability and accuracy of the rotational speed control of a vehicle.

[Conventional technology]

Japanese Patent Application Laid-Open No. 61-170300 discloses a basic control method of a variable-speed power generator of a type in which rotation speed control is performed on a hydraulic machine, which is a prime mover, and power control is performed on a rotary electric machine.

However, there is no mention of how the hydraulic machine-side rotational speed control, which is the object of the present invention, responds to the case where the function is substantially lost.

[Problems to be solved by the invention]

Even if it is not an abnormal time, if the rotation speed control signal is slightly lost due to the dead band in which the flow control mechanism of the hydraulic machine is present, a continuous vibration phenomenon of the guide blade opening and the rotation speed appears.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method capable of taking over the rotation speed control on an emergency or temporary basis even when the rotation speed control function of the hydraulic machine is substantially lost. It is an object of the present invention to ensure reliability and to greatly improve the accuracy of rotation speed control.

[Means for solving the problem]

In order to achieve the above object, in the variable-speed power generator according to the present invention, when the turbine-side rotation speed control unit is in the disabled state, the detection unit that detects the disabled state, and when the detection unit detects the disabled state, Has a rotating electric machine-side rotation speed control means for controlling a rotation speed of the rotating electric machine by controlling a power converter.

[Action]

According to the variable speed power generator of the present invention, the rotation speed is generated by the deviation between the generated energy of the prime mover and the energy consumption of the rotating electric machine. By maintaining the rotation speed control, the rotation speed of the variable speed power generator can be constantly controlled.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

 FIG. 1 shows an embodiment of the present invention.

Reference numeral 1 denotes an induction machine which is rotationally driven by a water wheel 2 connected to its rotor and has a secondary winding 1b of the induction machine 1 which is driven by a secondary excitation control device 3 having a frequency converter. Variable speed operation is performed so that an AC exciting current adjusted to a predetermined phase according to the rotation speed is supplied, and AC power of the same frequency as that of the AC system 4 is output from the primary winding 1a of the induction machine 1. It is.

Reference numeral 5 denotes a turbine characteristic function generator, which is a power generation output command from outside.
It generates P _O and water level signal appropriate guide vane opening command from a H Y _a and Value rotational speed command N _a. When the water level fluctuation is small, the water level signal H can be omitted. 16 outputs a proper rotational speed command N _a and the rotational speed detector 6 compares the rotational speed signal N detected by the guide vane opening correction signal ΔY at a rotational speed control device, from the water turbine characteristic function generator 5 appropriate guide vane opening command Y _a is the guide vane opening correction signal ΔY to the adder 21 is adjusted in response to this opening of the input guide vanes 11 to guide the blade drive device 10 is biased by the hydraulic turbine output P _T is controlled.

7 detects the slips phase S _P equal to the difference of the induction machine secondary side rotational phase is expressed in voltage phase and the electric Minister angle of the AC system 4 by slips phase detector. A configuration example of the slip phase detector 7 will be described. The rotor of the slip phase detector is provided with a three-phase winding connected in parallel with the primary winding 1a of the induction machine 1. The stator side of the slip phase detector 7 differs by π / 2 in electrical angle from the stator. One Hall converter in each position
AC system 4 viewed from the secondary side of the provided induction machine 1
Signal voltage phase of match is detected from the Hall converter, it is converted into slips phase S _P.

Power output command P _O 'and the slips of the phase detector 7 slips phase signal S _P is secondary exciter output detection of the induction machine 1 detected by the active power detector 9 is input to the third signal P is power output command P _The AC exciting current supplied to the secondary winding 1b of the induction machine 1 is controlled so as to be equal to _O '. Specifically, Tokiko Sho 57
The control method proposed in −60645 can be applied.

FIG. 2 shows an embodiment of the rotation speed control device 16. The actual deviation of the rotational speed N and the proper rotation speed command N _a comparator 16 is derived which is integral element 16A, is input to the proportional element 16B.

The speed deviation signal is also input to a differential element including the comparator 16C, the integrator 16D, and the gain adjuster 16E. Thus, the output signals from these three PID elements (three elements of proportional, integral, and differential) are combined by the adder 16E to become the guide blade opening correction signal ΔY. Power output command P _O is being combined with the output from the power correction controller 102 at one adder 101 is input to the hydraulic turbine characteristic function generator 5 final power output command from the outside
P _O ′.

First, assuming an ideal state where there is no output from the power correction controller 102, the operation of the present embodiment at this time will be described below with reference to the time chart of FIG. At time t0, for example, the power generation output command _{PO is set} to the third level in order to raise the power generation output P in a step-like manner.
Raising to the step shape as shown in FIG. (A), the power generation output P of the induction machine 1 is increased following the change of the power generation output command P _O as shown in FIG. 3 (g). On the other hand, the power generation output command P _O
, The response of the opening Y of the guide blade 11 is slower than the response of the power generation output P. For this reason, the turbine output PT is smaller than the power output P, and the rotation speed N is temporarily reduced after the sudden change in the power output command P _O , and thereafter, at time t1, the power output P and the turbine output PT become equal, and the rotation speed N Is minimal. Incidentally guide vane opening correction signal ΔY This At time t1 the speed deviation ΔN is positive is positive, the guide vane opening Y is properly guided valve opening command Y _a
It rises even more than. Accordingly, the turbine output PT becomes larger than the power generation output P, and the rotation speed N starts to increase as shown in FIG. 3 (f). The deviation between the proper rotational speed command N _a with increasing rotational speed N decreases, the guide vane opening correction signal Δ
As Y decreases, the turbine output PT decreases, and the acceleration of the rotation speed N decreases.

When the embodiment of FIG. 1 is used, the speed deviation ΔN in the steady state becomes zero due to the integral element 16A. On the other hand, the error of the proper guide vane opening command Y _a and deviation of the guide vane opening degree Y the real properties of the water wheel characteristics and waterwheel 2 stored in the waterwheel characteristic function generator 5 from water turbine characteristic function generator 5 It is possible to make it almost zero by increasing the accuracy of the water turbine characteristic function with the corresponding one. Accordance connexion, guide vane opening deviation in the steady state (Y _a -Y)
Only the integral element 16A needs to be generated.

The above will be described again using equations. Steady state in the secondary exciter 3 has integral element or the like is incorporated in order to adjust the P to P ₀ is the steady by integral element incorporated in P = P ₀ ... 16 rotation controller N = N _a ... Also, in the steady state, Y = Y _a + ΔY ... in the steady state, and the turbine output P _T and the generator output P should be the same in the steady state. P = P _T = f (H, Y, N) ... More appropriate guidance since the vane opening command Y _a should have given as originally corresponding to P _O under water level H and N = N _a at that _{time, P O = f (H,} Y a, N a) ... more comprehensive Then, a steady state will be Y = Y _a that is ΔY = 0.

The gain K1 of the proportional element 16B with a braking effect increased to by a gain K _I1 of the integral element 16A relatively small as fast as possible the response speed of the guide vane opening degree. On the other hand, as shown in FIGS. 3 (e) and 3 (f), the turbine output PT and the rotation speed N are set without vibration.

FIG. 4 shows an embodiment of the guide vane driving device 10 in the embodiment of FIG.

10A is a comparator, 10B is a pilot servo motor open,
Alpha ₁ is opening speed set value in a closed speed limiting section, alpha ₂ is a closing speed set value. 10C is amplification of the pilot servomotor, Y _x is the degree of opening of the pilot servo motor.

10D comparators, 10E is dead band inherent in the main servo amplification mechanism (e.g. lap of Shuhai valve), 10F is the main servo motor to open, beta ₁ in the closed speed limiting portion opening speed set value,
β ₂ is a closing speed for the set value. 10G is an opening of the main servomotor which Y operates the guide blade 11 in the main servomotor amplifying unit.

x _x is the displacement or the like of the main servo motor-distribution valve in deviation of the opening degree Y _x and main servomotor opening Y of the pilot servo motor corresponds to this.

103 x _x is built contacts 103 of FIG. 1 in this in switch determines that there was entering a port in the range of deadband -γ~ + γ.

When nuclear and 103 switch the works, i.e. x _x rotational speed control by the active power control of the signal x _x is input is detected in the power correction controller 102 inductive generator side is started upon entering the dead band .

The reason that the control of the rotational speed of the other (generator side) is utilized only when the control of the rotational speed of one (turbine side) becomes substantially impossible is that the two controls operate simultaneously. This is because interference between controls becomes a problem.

In Figure 5 the modification of Figure 4, attempt to derive the same signal x _x 'and the fourth instead of the sensor for detecting the x _x of Figure Y _x and with the two sensors for detecting the Y x _x This is used when it is difficult to ensure the accuracy of the sensor that detects _xx .

A switch 104 corresponds to 103 in FIG. 4 and determines indirectly from x _x ′ that the arrowhead _xx has entered the dead zone, and its contact point 104a is used in place of 103a.

According to the calculation by the present inventor (in this case, 102 is a mere proportional operation), the steady oscillation of the rotation speed N can be almost completely eliminated without any side effect.

The above is an example of improving the accuracy of rotation speed control under normal conditions.However, this type of switching is performed to deal with abnormalities when the 10E, 10F, 10G parts, that is, the last stage part of the turbine speed control, fail for some reason. The rotation speed control can be maintained by the generator side, that is, by load control.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to the variable speed generator of this invention, even if rotation speed control by a water turbine becomes impossible, it becomes possible to provide the always stable and reliable variable speed generator.

[Brief description of the drawings]

1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a partial detailed view of the embodiment of FIG. 1, FIG. 3 is a time chart for explaining the operation of the embodiment of FIG. The figure is a partial detailed example of the embodiment of FIG. 5 ... function generator, 102 ... power correction controller.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F03B 15/08 F03B 15/16

Claims (3)

(57) [Claims] 1. A hydraulic machine acting as a prime mover, a rotating electric machine driven by the hydraulic machine, and electric power having the same frequency as that of the electric power system being supplied to the electric power system irrespective of the rotational speed of the electric rotating machine. A power converter that performs frequency conversion of electric power applied to the rotating electric machine so that it can be supplied, and a water turbine-side rotation speed control unit that controls rotation speed control of the rotating electric machine by adjusting an amount of water flowing through the hydraulic machine. In the variable speed power generator provided with, when the turbine-side rotation speed control means is disabled, detection means for detecting the disabled state, and when the detection means detects the disabled state, the power conversion A rotating electric machine-side rotating speed control means for controlling a rotating speed of the rotating electric machine by controlling a rotating machine. 2. The variable-speed power generator according to claim 1, wherein said turbine-side rotational speed control means includes a fixed band element in a control system, and said detection means includes a stationary band element provided by said rotary electric machine. Detecting that the rotation speed control of the rotary electric machine is disabled, and when the detection unit detects the disabled state, the rotary electric machine-side rotation speed control unit controls the power converter to control the rotation of the rotary electric machine. A variable-speed power generator that controls the speed. 3. The variable-speed power generator according to claim 1, wherein said turbine-side rotation speed control means includes an immovable zone element in a control system, and said detection means uses said immovable zone element to control said turbine side rotation. A state in which the control signal of the speed control means can be lost on the way is detected, and the rotating electric machine-side rotation speed control means, when the detecting means detects a state in which the control signal can be lost, switches the power converter. A variable-speed power generation device, comprising controlling the rotation speed of the rotating electric machine.