JP2012081813A - Marine electric propulsion system, motor drive system, power converter, and power conversion method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a marine electric propulsion system, along with a motor drive system, a power converter and a power conversion method, capable of maintaining an inboard system stability, even if a load fluctuation occurs in an inboard power system, irrespective of a ship space restricted.SOLUTION: In the marine electric propulsion system with a high power load, a power converter 5 for supplying an effective power to a propulsion electric motor 6 regulates power supplied to the propulsion electric motor 6 based on the effective power supplied to the high power load 9, thereby achieving the stabilization of the inboard power system upon the sudden change of the inboard load.

Description

  The present invention relates to a marine electric propulsion system, a motor drive system, a power conversion device, and a power conversion method.

  In general, in a system for propelling a ship with electric power, one or more generators are provided in the ship, and the power generated by the generator is linked to the power converter together with the ship load to convert the power. The ship is propelled by controlling the power supplied from the device to the propulsion motor.

  In addition to propulsion motors, there are various power loads in the ship, but it is equipped with a power storage device that stores power based on meteorological sea state data and ship operation data received by the weather sea state prediction electronic data receiver. By adjusting the output of the device and the output of the motor for driving the generator, it was possible to cope with fluctuations in the ship load as well as ship navigation. Such a technique is described in, for example, Japanese Patent Application Laid-Open No. 2008-24187.

JP 2008-24187 A

  However, ship loads have been diversified in recent years, and some of them require power comparable to the power generation capacity of generators, and there are large power loads with large load fluctuations. When load control is performed based on meteorological and oceanographic data received by the receiver and ship operation data, especially when a large power load consumes power in a short time, disturbance of the inboard power system due to a rapid increase in load may occur. End up. Therefore, there has been a problem that it is difficult to cope with a sudden change in load. In addition, if the power storage device tries to cope with this sudden change in load, the power storage device is inevitably increased in size and weight, and the mountability deteriorates in a situation where the space of the ship is limited. Has also occurred.

  An object of the present invention is to provide an electric propulsion system for a ship, a motor drive system, and a power conversion device capable of maintaining the system stability in the ship even if the load on the ship power system is fluctuated despite the restricted ship space. And providing a power conversion method.

  In order to achieve the above object, the present invention controls a power conversion device that converts power of a generator based on the active power of a power load, and propels a ship with the power from the power conversion device. Configured.

  According to the present invention, it is possible to effectively use a limited space in a ship, and maintain the in-board system stability even when the load of the in-board power system varies.

FIG. 3 is a power system diagram in the ship according to the first embodiment. 1 is a schematic configuration diagram of a power conversion device according to Embodiment 1. FIG. 1 is a configuration diagram of a converter 11 in Embodiment 1. FIG. 1 is a configuration diagram of an inverter 12 in Embodiment 1. FIG. 1 is a control block diagram of a central control device 1 in Embodiment 1. FIG. FIG. 3 is a control block diagram of the DC link capacitor constant control calculator 21 in the first embodiment. FIG. 3 is a control block diagram of a propulsion motor output control arithmetic unit according to the first embodiment. FIG. 3 is a control block diagram of the control device 15 in the first embodiment. FIG. 3 is a control block diagram of the control device 18 according to the first embodiment. The power system figure in a ship in Example 2. FIG. The power system figure in a ship in Example 3. FIG. The power system figure in a ship in Example 4. FIG. The block diagram of the electric power storage apparatus 42 in Example 3. FIG. FIG. 7 is a control block diagram of the central control device 1 in Embodiment 3. FIG. 6 is a control block diagram of an inverter 12 in a fourth embodiment. The block diagram of the power converter device 5 in Example 5. FIG. FIG. 10 is a configuration diagram of a converter 11 according to a fifth embodiment. The block diagram of the power converter device 5 in Example 6. FIG. FIG. 10 is a configuration diagram of a converter 11 according to a sixth embodiment. The block diagram of the inverter 12 in Example 6. FIG. FIG. 10 is a configuration diagram of a unit converter 54 according to a sixth embodiment. FIG. 10 is a control block diagram of a central control device 1 in a sixth embodiment. FIG. 12 is a control block diagram of a DC link voltage constant control computing unit 71 in the sixth embodiment. FIG. 10 is a control block diagram of a propulsion motor output control calculator 72 in a sixth embodiment. FIG. 10 is a control block diagram of a control device 15 according to a sixth embodiment. FIG. 10 is a control block diagram of a control device 18 according to a sixth embodiment. FIG. 10 is a configuration diagram of a unit converter 54 according to a seventh embodiment. FIG. 10 is a control block diagram of a control device 15 in a seventh embodiment. The block diagram of the converter 11 in Example 9. FIG. FIG. 10 is a configuration diagram of a harmonic filter 95 according to the ninth embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following examples show one form of the invention, and the present invention includes other forms unless departing from the gist.

  FIG. 1 shows a power system in a ship to which a power conversion apparatus according to an embodiment of the present invention is connected. The power system in the ship is a central controller 1 that controls the entire power system 1, a gas turbine 2 (2a, 2b) that drives the generator (a diesel engine or the like that generates power other than the gas turbine 2) ), Generator 3 (3a, 3b), switchboard 4, power conversion device 5, propulsion motor 6, propeller 7 for propulsion, inboard load 8 such as lighting, large power load 9, and large power load The active power detector 10 detects the active power.

  A schematic configuration diagram of the power converter 5 is shown in FIG. The power converter 5 includes a converter 11, an inverter 12, a DC link capacitor 13, and a DC link voltage detection sensor 14 that detects a voltage applied to the DC link capacitor (hereinafter referred to as a DC link capacitor voltage).

  Various systems can be applied to the circuit configurations of the converter 11 and the inverter 12. In this embodiment, a case where a two-level circuit method is applied will be described.

  FIG. 3 shows a configuration diagram of the converter 11. The converter 11 includes a control device 15, IGBT elements 16 (16 Ua, 16 Va, 16 Wa, 16 Ub, 16 Vb, and 16 Wb) installed on the positive side and the negative side of the UVW phase, a current sensor 17 that detects a current of each phase flowing on the AC side, The voltage sensor 98 detects the phase voltage on the AC side. FIG. 4 shows the configuration of the inverter 12. The inverter 12 includes a control device 18, an IGBT element 19 (19Ua, 19Va, 19Wa, 19Ub, 19Vb, 19Wb) installed on the positive and negative sides of the UVW phase, a current sensor 20 for detecting the current of each phase flowing on the AC side, AC It comprises a voltage sensor 100 that detects the side phase voltage. In this embodiment, the configuration is the same as that of the inverter 12, but other circuit methods may be used.

  The control performed by the power conversion apparatus according to the present invention adjusts the DC link capacitor voltage constant control for maintaining the voltage applied to the DC link capacitor 13 in the DC link at a predetermined value, and the effective power supplied to the propulsion motor 6. It is propulsion motor output control, and these controls will be described.

  First, a control block diagram of the central controller 1 is shown in FIG. The central controller 1 includes a DC link capacitor voltage constant control calculator 21 that calculates the UVW phase voltage command value of the converter 11 and a propulsion motor output control calculator 22 that calculates the UVW phase voltage command of the inverter 12. ing. Hereinafter, both arithmetic units will be described.

A control block diagram of the DC link capacitor voltage constant control calculator 21 is shown in FIG. The DC link capacitor voltage constant control calculator 21 includes currents Iu1, Iv1, Iw1 detected by the current sensor 17, voltages Vu1, Vv1, Vw1 detected by the voltage sensor 109, and a DC link voltage detection sensor 14. The DC link capacitor voltage Vdc and the system frequency f detected in the above are input. However, the system frequency f is not detected by a sensor or the like, but is a value held in the DC link capacitor voltage constant control calculator 21 in advance. The uvw-dq converter 23 converts the Iu1, Iv1, Iw1, Vu1, Vv1, and Vw1 into coordinate axes and converts them into dq-axis currents Id1, Iq1, Vd1, and Vq1. The d-axis current and voltage are invalid components, and the q-axis current and voltage are effective components. The q-axis voltage command calculator 24 receives the system frequency f, the DC link capacitor voltage Vdc, the preset DC link capacitor voltage command value Vdc ^* , the dq-axis currents Id1, Iq1, and the q-axis voltage Vq1, and receives the q-axis current command value. Iq1 ^* and q-axis voltage command value Vq1 ^* are calculated. Further, in the d-axis voltage command calculator 25, the outputs Id1, Iq1, and Vd1 of the uvw-dq converter 23, the system frequency f, and the q-axis current command value Iq1 ^* calculated by the q-axis voltage command calculator 24 are input. The d-axis voltage command value Vd1 ^* is calculated. The value obtained by adding the DC link capacitor voltage command value Vdc ^* set in advance to the value obtained by converting the coordinate axes of the Vq1 ^* and Vd1 ^* obtained in this way by the dq-uvw converter 26 is the UVW phase voltage command value Vu1 ^* , Vv1 of the converter 11. ^* , Vw1 ^* .

  Subsequently, a control block diagram of the propulsion motor output control calculator 22 is shown in FIG. In the present embodiment, a case where the propulsion motor is a permanent magnet motor will be described. The propulsion motor output control arithmetic unit 22 includes an active power P supplied to a large power load detected by the active power detector 10, a rotational angular velocity ω of the propulsion motor, and a current sensor 20 installed at the AC side output of the inverter 12. The UVW phase currents Iu2, Iv2, and Iw2 detected by the above are input. However, the rotational angular velocity ω is a value held in advance in the propulsion motor output control calculator 22. The uvw-dq converter 27 converts the Iu2, Iv2, and Iw2 into coordinate axes and converts them into dq-axis currents Id2 and Iq2. The ΔP processor 28 calculates the amount of change ΔP in the active power supplied to the propulsion motor 6 using the active power P supplied to the large power load detected by the active power detector 10 as an input. Here, since it is necessary to ensure the stability of the inboard power system even when the change in the effective power amount supplied to the large power load 9 is steep, the effective power amount PM supplied to the propulsion motor 6 is quickly increased. It is required to calculate to. Therefore, as one of the methods for realizing a quick calculation, the effective power PM supplied to the propulsion motor 6 is determined based on the difference between the active power P_z1 supplied to the large power load one control cycle before and the current value P. A change amount ΔP is calculated. However, if the effective power PM supplied to the propulsion motor is changed even when ΔP is small, the stability of the entire system is impaired. Therefore, the active power P input to the ΔP processor 28 is subjected to a high-pass filter, the output value Phi is compared with a predetermined threshold value Pth, and ΔP is set to zero when Phi is lower than Pth. A dead zone may be provided. At this time, the constant of the high-pass filter or the threshold value Pth may be changed according to the value of the active power P.

Here, if the motor output is P ′ and the motor torque is τ, there is a relationship P ′ = τω. Therefore, the method of changing the motor output by ΔP is to change the motor torque by Δτ while keeping the motor rotation speed constant. Alternatively, there are three methods of changing the motor rotation speed by Δω while keeping the motor torque constant, or changing both the motor torque τ and the motor rotation speed ω. Here, a method of changing the motor output by ΔP by changing the motor torque by Δτ while keeping the motor rotation speed constant will be described as an example. Δτ is a torque coefficient k _E , a magnetic flux Φ, and a q-axis current change amount ΔIq 2.

Therefore, the q-axis current difference calculator 29 calculates ΔIq2 based on the equation (1).

The dq-axis voltage command calculator 30 calculates the dq-axis voltage command values Vd2 ^* and Vq2 ^* based on the following equation (2), using Id2, Iq2, and ΔIq2 calculated as described above as inputs.

Here, r, L _d , L _q , and k _E are the armature winding resistance, d-axis inductance, q-axis inductance, and torque constant of the propulsion motor 6, respectively.

The thus obtained Vd2 ^* and Vq2 ^* are coordinate-axis converted by the dq-uvw converter 31 to obtain the UVW phase voltage command values Vu2 ^* , Vv2 ^* and Vw2 ^* of the inverter 12.

The controller 15 of the converter 11 receives the phase voltage command values Vu1 ^* , Vv1 ^* , Vw1 ^* , the DC link capacitor voltage command Vdc ^* , and the DC link capacitor voltage Vdc calculated by the DC link capacitor constant control calculator 21 as input. Then, the ON / OFF signal of each IGBT element 16 is calculated. FIG. 8 shows a control block diagram of the control device 15. The modulation wave calculator (also referred to as modulation wave generator) 32 calculates the modulation wave of each IGBT element 16 based on the following equation (3).

In the case of the circuit system of the converter 11 according to the present embodiment, the voltage command of the IGBT element 16 on the upper side and the IGBT element 16 on the lower side is an ON / OFF signal using a phase voltage command value shifted by a half cycle. Since it is necessary to calculate, the modulation wave calculator 32 generates voltage command values whose phases are shifted by 180 ° from Vu1 ^* , Vv1 ^* , Vw1 ^*, and calculates the modulation wave of each IGBT element 16. Then, the comparator 34 compares the magnitude relationship between the carrier wave generated by the switching drive carrier wave generator 33 and the modulated wave calculated above. Using this magnitude relationship as an input, the gate driver 35 outputs an ON / OFF signal for each IGBT element 16. A control block diagram of the control device 18 of the inverter 12 is shown in FIG. In the modulation wave calculator 36, the phase voltage command values Vu2 ^* , Vv2 ^* , Vw2 ^* calculated by the propulsion motor output control calculator 22 and the DC link capacitor voltage Vdc are input and based on the following equation (4). The modulation wave of each IGBT element 19 is obtained.

  The control device 18 outputs the ON / OFF signal of each IGBT element 19 in the same manner as the control device 15 of the converter 11 using the modulated wave obtained by the equation (4).

  By controlling the power conversion device 5 in this way, even when the load of the large power load 9 suddenly increases in a very short time, the effective power supplied to the propulsion motor is adjusted according to the increase. be able to. As a result, it is possible to prevent the generator from being stopped and to ensure the stability of the inboard power system.

  In the first embodiment, the active power P supplied to the large power load 9 is directly detected by the active power detector 10, but the current sensor 40 and the voltage sensor 41 are installed at the positions shown in FIG. The active power may be detected based on the current flowing through the power load and the applied voltage. Here, it is assumed that the instantaneous value of the active power is obtained, the current of each phase flowing through the large power load is Iu3, Iv3, Iw3, and the voltage of each phase applied to the large power load is Vu3, Vv3, Vw3. (5).

  In the above embodiment, the active power PM supplied to the propulsion motor 6 is adjusted based on the fluctuation of the active power P supplied to the large power load 9, but the power storage device 42 is provided in the ship electric propulsion system. The active power PM may be adjusted in consideration of the active power supplied from the power storage device 42. The power storage device 42 is linked to the marine electric propulsion system via the converter 43. At this time, there are a method of connecting the converter 43 between the active power detector 10 and the large power load 9 as shown in FIG. 11 and a method of connecting the converter 43 to the switchboard 4 as shown in FIG. In the former case, the amount of change in active power detected by the active power detector 10 is reduced due to the effect of active power supplied by the power storage device 42 with respect to the change in active power required by the large power load 9. The adjustment amount of the active power supplied to the propulsion motor 6 can be reduced. On the other hand, in the latter case, when the amount of adjustment of the active power is insufficient due to a delay or the like generated when adjusting the amount of active power supplied to the propulsion motor 6, it is compensated by the effective power supplied from the power storage device 42. It will be.

FIG. 13 shows a schematic configuration diagram of the power storage device 42. The power storage device 42 includes a power storage device 44 such as an electrolytic capacitor, a lithium ion capacitor, or a lead storage battery, a voltage sensor 45 that detects the voltage of the power storage device 44, and a current sensor 46 that detects a current flowing through the power storage device 44. From storage device output voltage VB detected by voltage sensor 45 and current sensor 46, storage device output current IB, currents Iu4, Iv4, Iw4 detected by a current sensor installed at the AC output terminal of converter 43, and large power load 9 The required active power P ^* is sent to the central control device 1 and input to the power storage device output control calculator 47 shown in FIG. The control method of the converter 43 is the same as that in the above embodiment.

を入力としてトルク電流Ｉｑ２′を演算する。また、ΔＰ処理器４９では上記の実施例に記載の方法でΔＰを演算する。そして、Ｉｑ２′，Ｉｄ２^*，ΔＰを入力として滑り演算器５０では推進用電動機６の滑り周波数ω_sを演算する。ここで、電動機回転速度を一定として電動機トルクを変化させることでΔＰを発生させる場合について説明する。この場合には上記実施例に記載の通り、ΔＰよりΔＩｑ２を求める。この時、滑り周波数ω_sは以下の式（６）で求めることができる。 In the above embodiment, the propulsion motor 6 is a permanent magnet synchronous motor, but it may be an induction motor. A control block diagram of the inverter 12 in this case is shown in FIG. Based on the definition of the dq-axis current in the above embodiment, the d-axis current is defined as an excitation current and the q-axis current is defined as a torque current. In the rotation speed controller (or also referred to as a rotation speed calculator) 48, the rotation speed command value ω ^* and the estimated rotation speed value obtained by the dq axis voltage command calculator 52 are used.

Is used as an input to calculate the torque current Iq2 '. Also, the ΔP processor 49 calculates ΔP by the method described in the above embodiment. The slip calculator 50 calculates the slip frequency ω _s of the propulsion motor 6 by using Iq2 ′, Id2 ^* , and ΔP as inputs. Here, the case where ΔP is generated by changing the motor torque while keeping the motor rotation speed constant will be described. In this case, ΔIq2 is obtained from ΔP as described in the above embodiment. At this time, the slip frequency ω _s can be obtained by the following equation (6).

However, L ₂ is the secondary winding inductance, R ₂ represents a secondary winding resistance. Thus, the slip calculator 50 outputs ω _s and Iq2 ^* (= Iq2′−ΔIq2).

The ω _s and Iq2 ^* output from the slip calculator 50, Iq2 and Id2 output from the uvw-dq converter 51, and the d-axis current command value Id2 ^* are input, and the dq-axis voltage command calculator 52 receives the dq-axis voltage command. Vq2 ^* , Vd2 ^* , and frequency command ω1 are calculated. Note that the frequency command ω1 is obtained by Expression (7).

は式（８）に示す様に、式（９）の第１項，第２項の部分に相当する。 Here, k _P1 and k _I1 are the proportional gain and integral gain of PI control. In addition, the above estimated rotational speed

Corresponds to the first and second terms of equation (9) as shown in equation (8).

Accordingly, the dq voltage commands Vq2 ^* and Vd2 ^* are obtained by the equation (9).

  In the above embodiment, the circuit configuration of the converter 11, the inverter 12, and the converter 43 is a two-level circuit method, but may be a three-level circuit method. FIG. 16 shows a schematic configuration diagram of the power converter at this time. In this case, two DC link capacitors 13 are connected in parallel with the converter 11 and the inverter 12, and the converter 11 and the inverter 12 are connected at three locations including a neutral point.

  As an example, FIG. 17 shows a configuration diagram when the converter 11 is a three-level circuit system. The IGBT element 16 and the diode 53 are arranged as shown in FIG. The calculation method of the UVW-phase voltage command of the converter 11, the inverter 12, and the converter 43 in this circuit configuration is the same as that in the above embodiment, and will be omitted.

  As a circuit configuration of the converter 11, the inverter 12, and the converter 43, there is a cascade system in which unit converters configured by IGBT elements, DC capacitors, and the like are connected in series in addition to the above-described embodiments. FIG. 18 shows a configuration diagram of the power conversion device 5 in the cascade system. The power conversion device 5 includes a converter 11, an inverter 12, and a DC link voltage detection sensor 14 that detects a voltage applied to the DC link. FIG. 19 shows a configuration diagram when the converter 11 is a cascade system. The converter 11 includes a control device 15, a unit converter 54, and a buffer reactor 55. Further, as shown in FIG. 19, the control device 15 and the unit converter 54 are connected in a daisy chain by a signal line 57. Here, as shown in FIG. 19, a plurality of unit converters connected in cascade are collectively referred to as an arm. The upper three arms are referred to as U-phase arm 54_U, V-phase arm 54_V, and W-phase arm 54_W, respectively, and the lower three arms are referred to as U-phase arm 54_u, V-phase arm 54_v, and W-phase arm 54_w, respectively. Here, the current sensor 56 for detecting the current flowing through the six arms is installed at the position shown in FIG. Similarly, a configuration diagram of the inverter 12 is shown in FIG. Similarly, the inverter 12 includes a control device 18, a unit converter 58, and a buffer reactor 59. The control device 18 and the unit converter 58 are connected in a daisy chain by a signal line 61. The upper three arms are referred to as U-phase arm 58_U, V-phase arm 58_V, and W-phase arm 58_W, respectively, and the lower three arms are referred to as U-phase arm 58_u, V-phase arm 58_v, and W-phase arm 58_w, respectively. Here, the current sensor 60 for detecting the current flowing through the six arms is installed at the position shown in FIG.

  Then, the block diagram of the above-mentioned unit converter 54 is shown in FIG. A unit converter (or unit cell) 54 includes two IGBT elements 62, one DC capacitor 63, a cell 65 composed of a fuse 64, a gate driver 66, a gate power supply 67, a unit converter control circuit 68, and a self-supplied power supply. 69 and a voltage sensor 70. The gate driver 66 and the unit converter control circuit 68 supply the power charged in the DC capacitor 63 through the self-supply power source 69 and the gate power source 67. The DC capacitor voltage detected by the voltage sensor 70 is sent to the central controller 1. Hereinafter, a voltage applied to the DC capacitor 63 of the unit converter 54 is referred to as a DC capacitor voltage. The configuration of unit converter 58 in converter 12 is the same as the configuration shown in FIG.

  A control block diagram of the central controller 1 in this embodiment is shown in FIG. Since the power conversion device 5 in this embodiment performs control to make the DC link voltage constant and control the output of the propulsion motor, the central control device 1 includes a DC link voltage constant control computing unit 71, a propulsion motor output. A control calculator 72 is provided. In addition, when the power storage device is mounted in the electric propulsion system for ships, the power storage device output control arithmetic unit is also provided as in the above-described embodiment, but here, the case where there is no power storage device will be described. To do.

A control block diagram of the DC link voltage constant control calculator 71 is shown in FIG. The DC link voltage constant control computing unit 71 is located under the converters detected by the UVW phase current values Iu1a, Iv1a, Iw1a of the upper arms of the converter detected by the current sensors 56a, 56c, 56e, and the current sensors 56b, 56d, 56f. The UVW phase current values Iu1b, Iv1b, Iw1b of the side arm, the generator frequency f, and the DC capacitor voltage Vc detected by the voltage sensor 70 are input. The uvw-dq converter 73 converts the above Iu1a, Iv1a, Iw1a, Iu1b, Iv1b, and Iw1b into coordinate axes and converts them into dq-axis currents Id1a and Iq1a of the upper arm and dq-axis currents Id1b and Iq1b of the lower arm. The q-axis voltage command calculator 74 receives Id1a, Iq1a, Id1b, Iq1b, ω, Vc, a preset DC capacitor voltage command value Vc ^*, and inputs the q-axis voltage command value Vq1a ^* of the upper arm and the q-axis of the lower arm. The voltage command value Vq1b ^* is calculated. Further, the d-axis voltage command calculator 75 receives Id1a, Iq1a, Id1b, Iq1b, ω, a preset q-axis current command value Id1 ^*, and inputs the d-axis voltage command value Vd1a ^* of the upper arm and the d-axis of the lower arm. The voltage command value Vd1b ^* is calculated. UVW of the upper arm of the converter 11 is obtained by adding Vd1a ^* , Vq1a ^* , Vd1b ^* , and Vq1b ^* thus obtained to the coordinate axis converted by the dq-uvw converter 76 and a preset DC link voltage command value Vdc ^*. The phase voltage command values Vu1a ^* , Vv1a ^* , Vw1a ^* and the lower arm UVW phase voltage command values Vu1b ^* , Vv1b ^* , Vw1b ^* .

Subsequently, a control block diagram of the propulsion motor output control calculator 72 is shown in FIG. The propulsion motor output control calculator 72 is the lower side of the inverter detected by the UVW phase current values Iu2a, Iv2a, Iw2a of the inverter upper arm detected by the current sensors 60a, 60c, 60e, and the current sensors 60b, 60d, 60f. The arm UVW phase current values Iu2b, Iv2b, Iw2b, the number of revolutions ω of the propulsion motor, and the effective power P supplied to the large power load detected by the active power detector are input. The uvw-dq converter 77 converts the inverter UVW phase current values Iu2a, Iv2a, Iw2a, Iu2b, Iv2b, Iw2b into coordinate axes and converts them into dq-axis currents Id2a, Iq2a, Id2b, Iq2b. In the ΔP processor 78, ΔP is calculated from the active power P supplied to the large power load by the same method as in the above embodiment, and is input to the q-axis current difference calculator 79 together with ω. The q-axis current difference calculator 79 calculates the change amount ΔIq2a of the q-axis current of the upper arm and the change amount ΔIq2b of the q-axis current of the lower arm, and inputs these and the aforementioned Id2a, Iq2a, Id2b, Iq2b, dq-axis voltage command value of the upper arm of the inverter dq-axis voltage command calculator 80 Vd2a ^*, Vd2b ^*, dq-axis voltage command value of the lower arm of inverter Vq2a ^*, calculates the Vq2b ^*. Finally dq-uvw converter 81 UVW phase voltage command value of the upper arm of the inverter and the coordinate axis conversion ^{Vu2a *, Vv2a *, Vw2a *} , UVW phase voltage command value of the lower arm of inverter Vu2b ^*, Vv2b ^*, Vw2b ^* is obtained.

FIG. 25 shows a control block diagram of the control device 15 of the converter 11. Modulation wave calculation using the phase voltage commands Vu1a ^* , Vv1a ^* , Vw1a ^* , Vu1b ^* , Vv1b ^* , Vw1b ^* , and the DC link voltage command Vdc ^* , DC link voltage Vdc obtained by the DC link voltage constant control calculator 71 as inputs. In the device 82, the modulated wave is calculated based on the equation (10).

N is the number of unit converters in the arm. The comparator 84 compares the modulation wave with the switching driving carrier wave generated by the switching driving carrier wave generator 83, and the comparator 84 calculates the ON / OFF signal of the IGBT element 62 as input. FIG. 26 shows a control block diagram of the control device 18 of the inverter 12. In the modulation wave calculator 86, the phase voltage commands Vu1a ^* , Vv1a ^* , Vw1a ^* , Vu1b ^* , Vv1b ^* , Vw1b ^* and the DC link voltage Vdc obtained by the propulsion motor output control calculator 72 are input in the equation (11 ) To calculate a modulated wave.

  N is the number of unit converters in the arm. Thereafter, the ON / OFF signal of the IGBT element 62 is calculated in the same manner as the control device 15 of the converter 11.

The unit converters 54 and 58 described above have a so-called chopper circuit configuration, but may have a full bridge circuit configuration as shown in FIG. At this time, the unit cell 65 includes four IGBT elements 62 and a DC capacitor 63. The components other than the unit cell 65 are the same as those in the chopper circuit of the above embodiment. In the figure, 62A indicates IGBT elements 62a and 62b, 62B indicates IGBT elements 62c and 62d, and 62A and 62B are defined as leg A and leg B, respectively. FIG. 28 shows a control block diagram of the control device 15 of the converter 11 in this embodiment. The flow in the control device 15 is the same as in the above embodiment. However, since the voltage command for leg A and the voltage command for leg B are shifted from each other by a half cycle, the phase voltage commands Vu1a ^* , Vv1a ^* , Vw1a ^* , Vu1b ^* inputted in the modulation wave calculator 90 are used ^. , Vv1b ^* , Vw1b ^* are generated by generating a phase voltage command that is shifted by a half period, and these are converted to leg A voltage command values Vu1aA ^* , Vv1aA ^* , Vw1aA ^* , Vu1bA ^* , Vv1bA ^* , Vw1bA ^* , leg B voltage. Modulated waves are calculated based on the above equation (12) as command values Vu1aB ^* , Vv1aB ^* , Vw1aB ^* , Vu1bB ^* , Vv1bB ^* , and Vw1bB ^* . The comparator 92 compares the modulation wave obtained here with the switching drive carrier wave generated by the switching drive carrier generator 91, and the gate driver 93 calculates the ON / OFF signal of the IGBT element 62. Note that the ON / OFF signals of the two IGBT elements in the leg A and the leg B are not both ON or OFF. In the gate driver 93, the ON / OFF signal calculated based on the input of the comparator 103 is used. Another ON / OFF signal inverted from the / OFF signal is generated and output to the IGBT element 62.

  In the above embodiment, the switching element in the unit converter is an IGBT, but a MOSFET may be used instead.

  The circuit configuration of the converter 11 may be a rectifier circuit system using a diode as shown in FIG. 29 in addition to the above embodiment. In this case, a harmonic filter 95 is installed on the AC output side. As a circuit configuration of the harmonic filter 95, a system including a reactor 96 and a capacitor 97 as shown in FIG. In the present embodiment, a total of six diodes 94 are provided, two for each phase, but the number of diodes may be determined according to the input AC voltage and the rated voltage of the diode to be used.

DESCRIPTION OF SYMBOLS 1 Central control apparatus 2 Gas turbine 3 Generator 4 Distribution board 5 Power converter 6 Propulsion motor 7 Propulsion propeller 8 Inboard load 9 Large power load 10 Active power detector 11, 43 Converter 12 Inverter 13 DC link capacitor 14 DC link voltage Detection sensor 15, 18 Control device 16, 19, 62 IGBT element 17, 20, 40, 46, 56, 60 Current sensor 21 DC link capacitor voltage constant control calculator 22, 72 Propulsion motor output control calculator 23, 27, 51, 73, 77 uvw-dq converter 24, 74 q-axis voltage command calculator 25, 75 d-axis voltage command calculator 26, 31, 76, 81 dq-uvw converter 28, 49, 78 ΔP processor 29, 79 q-axis current difference calculator 30, 52, 80 dq-axis voltage command calculator 32, 36, 82, 86, 90 Modulated wave Calculator 33, 37 Switching drive carrier generator 34, 38, 84, 88, 92 Comparator 35, 39, 66, 85, 89, 93 Gate driver 41, 45, 70, 98, 99, 100, 101 Voltage sensor 42 Power storage device 44 Power storage device 47 Power storage device output control calculator 48 Rotational speed controller 50 Slip calculator 53 Diode 54, 58 Unit converter 55, 59 Buffer reactor 57, 61 Signal line 63 DC capacitor 64 Fuse 65 Cell 67 Gate power supply 68 Unit converter control circuit 69 Self-supplied power supply 71 DC link voltage constant control calculator 83, 87, 91 Switching drive carrier generator 94 Diode 95 Harmonic filter 96 Reactor 97 Capacitor

Claims (15)

  One or two or more generators, power distribution means for distributing power generated by the power generator, a power load linked to the power distribution means, a power converter linked to the power distribution means, A propulsion motor linked to a power converter, a ship propulsion unit connected to the propulsion motor, and a control unit for controlling the power converter, wherein the control unit is configured to increase the effective power of the power load. The electric propulsion system for ships which controls the power converter based on the above.   2. The marine electric propulsion system according to claim 1, wherein the control unit controls the power conversion device based on a fluctuation amount of an active power of the power load.   3. The marine electric propulsion system according to claim 2, wherein when the effective power of the electric power load increases, the control unit controls the electric power supplied to the propulsion motor to decrease.   3. The marine electric propulsion system according to claim 2, wherein the fluctuation amount is obtained by comparison with a previous value every predetermined period.   4. The change amount of a q-axis current command is determined so as to reduce the power supplied to the propulsion motor from the fluctuation amount and the magnetic flux, and the power is determined based on the change amount of the q-axis current command. A marine electric propulsion system characterized by controlling a conversion device.   The power conversion apparatus according to claim 1, further comprising a power load active power detection unit configured to detect active power supplied to the power load, and controlling the power converter based on the detected active power of the power load. Electric propulsion system for ships.   3. The marine electric propulsion system according to claim 2, wherein the torque of the propulsion motor is changed based on the active power.   2. The marine electric propulsion system according to claim 1, wherein the power conversion device includes a rectifier that converts AC power into substantially DC power, and a converter that converts the substantially DC power into power having a predetermined frequency. .   9. The marine electric propulsion system according to claim 8, wherein at least one of the rectifier and the converter is a circuit having a two-level conversion function using a switching element.   9. The marine electric propulsion system according to claim 8, wherein at least one of the rectifier and the converter has a diode clamp type three-level conversion function using a switching element and a diode.   9. The rectifier or the converter according to claim 8, wherein at least one of the rectifier and the converter includes a buffer reactor, an arm configured by cascading a plurality of unit converters, and current detection means for detecting a current flowing through the arm. A control device that controls the plurality of unit converters, and a signal line that transmits a control signal from the control device to the unit converter, and the arms are respectively connected to the positive side and the negative side of each of the three phases. A marine electric propulsion system characterized by being arranged.   2. The marine electric propulsion system according to claim 1, wherein the electric power storage means for storing electric power and the electric power stored in the electric power storage means are supplied to the electric power load.   Power distribution means for distributing power generated by the generator, a power load linked to the power distribution means, a power conversion device linked to the power distribution means, and a propulsion for propelling the ship linked to the power conversion device The motor drive system which has an electric motor for controlling the said power converter device based on the active electric power of the said electric power load, The motor drive system characterized by the above-mentioned.   In a power converter for supplying electric power generated by a generator to a propulsion motor for propelling a ship, the power converter is controlled based on the active power of a power load that operates with the power of the generator The power converter characterized by this.   A command value is obtained based on the active power of the power load that operates with the power of the generator, and the power supplied from the generator is converted into power based on the command value and supplied to a propulsion motor that propels the ship. Power conversion method.

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