Series-parallel hybrid power ship power system

Abstract

The utility model discloses a series-parallel hybrid power ship power system which comprises two groups of main propulsion diesel engines and two groups of shaft-driven motors which are respectively connected with propellers through gear boxes, and further comprises shaft-driven frequency converters connected with the shaft-driven motors and a DC-BUS connected with the shaft-driven frequency converters, the DC / DC converter, the controllable rectifier and the daily inverter power supply are connected with the DC-BUS, and the controllable rectifier and the DC / DC converter are respectively connected with a diesel generating set and a power battery pack. According to different operation working conditions of the ship, the corresponding working modes of the hybrid power system are started, and related propulsion equipment and a power supply device are applied, so that the requirements of functions and navigational speed of the ship are met, the operation economy of ship power equipment is improved, and the life cycle of the ship power equipment is prolonged.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the ship electrical control technical field, specifically designs a kind of series-parallel hybrid power ship power system. BACKGROUND

[0002] At present, hybrid power ship type is more and more, among them, parallel type ship using main propulsion diesel engine and shaft motor combined driving and series-parallel hybrid power ship using diesel generator set and power battery pack mixed power supply are mostly.

[0003] The two types of ships have advantages and disadvantages, and the power of the parallel type ship is only borne by the battery pack when it is parked in seawater, which is difficult to meet the demand of long-time parking of the ship. The power propulsion of the series-parallel hybrid power ship is completely provided by the motor, and the power response of the ship is insufficient.

[0004] Combining the power types of parallel and series-parallel hybrid power ships to meet various use scenarios of the ship is a development direction of future hybrid power ships. INVENTION CONTENTS

[0005] The utility model aims at providing a kind of series-parallel hybrid power ship power system.

[0006] The utility model solves the technical scheme that the technical problem thereof adopts: a kind of series-parallel hybrid power ship power system, including two groups of main propulsion diesel engine and two groups of shaft motor respectively through gear box connection propeller, still including the shaft motor connection shaft generator frequency converter and the DC-BUS of connection shaft generator frequency converter, and the DC / DC converter, controllable rectifier and daily inverter power supply of connection DC-BUS of connection DC-BUS, the controllable rectifier and DC / DC converter are respectively connected with diesel generator set and power battery pack.

[0007] The two groups of shaft motor of the series-parallel hybrid power ship power system connect the AC bus of shaft generator frequency converter, the two groups of main propulsion diesel engine and the diesel generator set connect the AC bus of controllable rectifier, the power battery pack connects the AC bus of DC / DC converter, and the DC bus of shaft generator frequency converter and daily inverter power supply and the DC bus of DC / DC converter and controllable rectifier are respectively connected with DC-BUS.

[0008] The DC-BUS of the series-parallel hybrid power ship power system is composed of DC-BUS bus A and DC-BUS bus B connected by solid-state switch.

[0009] The utility model discloses a beneficial effect is: the utility model discloses to the different operation condition of ship, under the corresponding working mode of mixed power system, application relevant propulsion equipment and power device, in order to adapt to the function and the speed demand of ship, and promote the operation economy and the life cycle of ship power equipment. The utility model discloses can realize the distribution of ship propulsion power in main engine power and shaft motor power, and according to the power distribution of power battery and diesel generating set of shaft motor power and daily load size adjustment, be applicable to the main propulsion diesel engine and shaft motor combined drive, diesel generating set and power battery group mixed power supply's ship. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 It is the structural diagram of power system of the utility model;

[0011] Figure 2 It is the principle diagram of control method of the utility model;

[0012] Figure 3 It is the membership function of fuzzy rule input and output on respective interval.

[0013] Each reference sign is: 1 - diesel generating set, 2 - power battery group, 3 - DC / DC converter, 4 - controllable rectifier, 5 - daily inverter power supply, 6 - shaft frequency converter, 7 - shaft motor, 8 - main propulsion diesel engine. DETAILED DESCRIPTION

[0014] The utility model will be further explained in detail in combination with the drawings and examples, but the example should not be understood as the limitation of the utility model.

[0015] Referring to Figure 1 The utility model discloses mixed power system device by diesel generating set 1, power battery group 2, DC / DC converter 3, controllable rectifier 4, daily inverter power supply 5, shaft frequency converter 6, shaft motor 7, main propulsion diesel engine 8 and gear box 9 are formed. DC / DC converter 3 is used to control power battery group 2 charge and discharge and DC bus voltage, and controllable rectifier 4 is used to control the output power of diesel generating set 1, and daily inverter power supply 5 is used to supply power to daily load of whole ship, and shaft frequency converter 6 is used for the control of shaft motor 7, and main propulsion diesel engine 8 and shaft motor 7 are connected through gear box propeller.

[0016] The DC-BUS consists of DC-BUS bus A and DC-BUS bus B connected by a solid-state switch; a diesel generator set 1 and a controllable rectifier 4 are connected in series to DC-BUS bus A; a shaft-driven motor 7 and a shaft-driven inverter 6 are connected in series to DC-BUS bus A; a power battery pack 2 and a DC / DC converter 3 are connected in series to DC-BUS bus A; a daytime inverter 5 is connected to DC-BUS bus A; another diesel generator set 1 and a controllable rectifier 4 are connected in series to DC-BUS bus B; another shaft-driven motor 7 and a shaft-driven inverter 6 are connected in series to DC-BUS bus B; another power battery pack 2 and a DC / DC converter 3 are connected in series to DC-BUS bus B; and another daytime inverter 5 is connected to DC-BUS bus B, thus forming a series-parallel hybrid power ship propulsion system. The two sets of shaft-driven motors 7 are connected to the AC bus of the shaft-driven inverter 6, the two sets of main propulsion diesel engines 8 and diesel generator set 1 are connected to the AC bus of the controllable rectifier 4, the power battery pack 2 is connected to the AC bus of the DC / DC converter 3, and the DC bus of the shaft-driven inverter 6 and the daily inverter power supply 5, as well as the DC bus of the DC / DC converter 3 and the controllable rectifier 4, are respectively connected to the DC-BUS.

[0017] Reference Figure 2 As shown, this utility model discloses a mode switching control method for a series-parallel hybrid power ship propulsion system, with the following steps.

[0018] a) Determine the propulsion mode for the hybrid vessel: Based on the position information of the propulsion handle in the wheelhouse, determine the required propeller speed and the propulsion mode: single-motor drive, propulsion diesel engine drive, or a combination of propulsion diesel engine and motor drive. The relationship between the required speed and the propulsion mode is shown in the table below.

[0019] .

[0020] In single-motor propulsion mode, the motor end of gearbox 9 is coupled together, while the main propulsion diesel engine end is not coupled together. In diesel engine propulsion mode, both the motor and diesel engine ends are coupled together, and the motor rotates with the diesel engine. The motor power is controlled by adjusting the forward and reverse torque of the battery.

[0021] b) In the diesel engine drive mode, determine the power output of the shaft-driven motor 7.

[0022] The following factors need to be considered when determining the power of the shaft-driven motor: the surplus power at the current speed that propels the diesel engine to operate at its highest efficiency point. P sur Current daily load power P load Power battery pack capacity SOC batTherefore, a fuzzy logic method can be used to control the power of the shaft-driven motor, based on the current daily load power. P load With power battery pack capacity SOC bat The input is the power of the shaft-driven frequency converter, and the output is the power of the output. P motor .

[0023] Among them, load power P load The definition of fuzzy intervals should refer to P sur A new variable can be introduced. ;because P load >0 Here we only consider P 0 Within the range of -2 to 2, when P load >2× P sur When the daily load is too high, the shaft generator can directly operate at its spare power. P sur Points, no judgment required.

[0024] To ensure the ship's overall power is not affected, the power output of the shaft generator needs to be limited to no more than [a certain value]. P sur The units and ranges of the input and output quantities of fuzzy rules are different. Therefore, it is first necessary to... P 0 , SOC bat , P motor Perform a quantification level conversion, transforming its range to an interval symmetric about 0:

[0025] ,

[0026] In the formula P 0 , SOC bat , P motor The fuzzy sets include five types: VL, L, M, H, and VH, representing very low, low, medium, high, and very high, respectively. The membership function is in the interval [0, 1], with a value closer to 1 indicating a higher degree of membership to the fuzzy set, and a membership function of 0 indicating non-membership. The membership functions of the fuzzy rule input and output in their respective intervals are as follows: Figure 3 .

[0027] It can be found from the membership function that, except for the point with membership of 1, the input and output of the system have membership relationship with two fuzzy sets in the respective interval. Figure 3 The membership function in the formula of function equation can be expressed as:

[0028] .

[0029] The fuzzy rules are designed according to the actual situation of the hybrid system. P sur The rules of the fuzzy logic control are shown in the following table.

[0030] .

[0031] According to the membership function curve, P 0 , SOC bat There are values in only two fuzzy sets at most, corresponding to the four cases in the above rule table. The 25 rules are expressed in the form of function as follows:

[0032] .

[0033] The output obtained through the fuzzy rules P motor is a fuzzy quantity, which cannot be directly used.

[0034] Therefore, a certain method is needed to defuzzify, and the algebraic level-addition-center of gravity method is adopted in the utility model. The input X and Y of the system are substituted into the above formula to obtain the function about z:

[0035] ,

[0036] The obtained Z is P motor the value after conversion of the quantization level. P motor The value can be obtained through reverse calculation.

[0037] The fuzzy control and the logic threshold control strategy calculation amount mentioned in the utility model are not large, and the strategy is easy to realize in the ship PMS system, and the ship oil saving economy and the power battery pack charging and discharging rationality are fully considered.

[0038] c), determine the number and power of the diesel generator set.

[0039] When the power battery pack cannot meet the current DC bus load power (including shaft generator power and daily load power), the diesel generator set needs to be started to assist power supply. The diesel generator set is mainly applied in the electric working condition of the ship and the offshore mooring mode; the number of diesel generator sets started can adopt a logical threshold management mode, taking the bus load power as the state condition, and taking the number of diesel generator sets started as the control output. The logical rule makes the diesel generator set work at the highest efficiency point as much as possible, while ensuring that the power battery pack is not overcharged or overdischarged; when P DC and the power battery pack power SOC bat is the state condition, the control output is the number of diesel generator sets started. The logical rule makes the diesel generator set work at the highest efficiency point as much as possible, while ensuring that the power battery pack is not overcharged or overdischarged; when P DC <0, that is, the shaft generator is in the power generation mode and the power generation power is greater than the daily load power, at this time, the diesel generator set does not need to be started, and the power battery pack is charged to absorb the bus power. Therefore, the logical rule only needs to consider the case where P DC > 0, and the specific control rule is shown in Table 3, wherein P η is the power of the diesel generator set at the highest efficiency point.

[0040] .

[0041] Under the state condition judgment in the above table, there are 25 state combinations.

[0042] In order to prevent the bus power from being too high or too low, the bus load power P DC and the power battery pack power SOC bat The rule point setting dead zone state for the number of diesel generator sets started to prevent the diesel generator set from being frequently started and stopped due to the jitter of the rule interval edge. The state point of the number of diesel generator sets started is represented in the form of (a, b) to represent the dead zone state and the default value. The meaning of (a, b) is as follows: when the hybrid power system enters the state, the number of diesel generator sets running is a or b, then the number of diesel generator sets running is maintained unchanged; otherwise, after entering the state, the number of diesel generator sets started is controlled to a. If the dead zone mode only maintains the state of the last moment unchanged, then the bus load power P DC The sudden increase and decrease across the interval may cause the number of diesel generator sets running to be seriously inconsistent with the actual demand, so when the number of diesel generator sets running does not meet the two conditions of the dead zone, the number of diesel generator sets running needs to be controlled to the default value.

[0043] The control method can adapt to various use conditions of the ship, and can realize distribution of the ship propulsion power between the main engine power and the shaft motor power, and simultaneously adjust power distribution of the power battery and the diesel generator set according to the shaft motor power and the daily load size.

[0044] The above examples only exemplarily illustrate the principles and effects of the utility model, and part of the applied examples, and for the ordinary skilled in the art, without departing from the creative concept of the utility model, a number of modifications and improvements can be made, which all belong to the protection scope of the utility model.

Claims

1. A series-parallel hybrid marine power system, characterized by: Two groups of main propulsion diesel engines (8) and shaft generator (7) connected by gear box respectively, also including shaft generator (7) connected with shaft generator (6) and DC-BUS connected with shaft generator (6), and DC / DC converter (3), controllable rectifier (4) and daily inverter power supply (5) connected with DC-BUS, diesel generator set (1) and power battery group (2) connected with controllable rectifier (4) and DC / DC converter (3) respectively.

2. A series-parallel hybrid marine power system according to claim 1, characterized in that The DC-BUS is composed of DC-BUS bus A and DC-BUS bus B connected by solid-state switch.

3. A series-parallel hybrid marine power system according to claim 1 or 2, characterized in that Two groups of shaft generator (7) connect AC bus of shaft generator (6), two groups of main propulsion diesel engine (8) and diesel generator set (1) connect AC bus of controllable rectifier (4), power battery group (2) connect AC bus of DC / DC converter (3), DC bus of shaft generator (6) and daily inverter power supply (5) and DC bus of DC / DC converter (3) and controllable rectifier (4) connect DC-BUS respectively.

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