AUTOMATIC METHOD OF POWER ECOLOGICAL MANAGEMENT FOR A CRANE

Abstract

An automatic method of power management for supplying power to a crane includes a main power source comprising a generating set having an optimum power range in which it delivers a main power and a rechargeable secondary power source configured to deliver a secondary power, has a charge level, and may be recharged by the main power source. The automatic method implements, depending on the power required for the operation of the crane and the charge level, one or more power management modes for which the crane receives power coming from the single main power source or from the two power sources, and such that the generating set operates for each of them in the optimum power range.

Claims

1-20. (canceled)

21. An automatic method of power management for supplying power to a crane configured to use, for operating and moving a load, an operating power (PF) operable to reach a maximum operating value (PFmax), the automatic method comprising: a main power source comprising a generating set provided with an endothermic engine configured to supply the crane with a main alternating current for a main power (P1) operable to reach a main maximum value (P1max); the generating set being sized according to a power ratio such that the main maximum value (P1max) is equal to the maximum operating value (PFmax) multiplied by the power ratio which is lower than 1.2, and the generating set has an optimum power range (P1opt) bounded by a minimum optimum value (P1opt_min) and a maximum optimum value (P1opt_max) which is lower than the main maximum value (P1max); and a secondary power source comprising at least one rechargeable electric battery having a charge level (C) comprised between zero and a maximum charge level (Cmax), and configured to provide a secondary alternating current to deliver a secondary power (P2) and to receive a charge power (Pload) to be electrically recharged; the automatic method implementing one or more power management modes, wherein the one or more power management modes includes a main mode (MM), in which: if the operating power (PF) has an operating value included in the optimum power range (P1opt) of the generating set, and if the charge level (C) is greater than a first charge threshold (C1), then the crane is electrically connected to the single generating set so that the crane receives from the generating set the main power (P1) which is equal to the operating value (PF), the generating set then operating in the optimum power range (P1opt).

22. The automatic method according to claim 21, wherein the one or more power management modes further include a mixed mode (XM), in which: if the operating power (PF) has an operating value non-zero and lower than the maximum optimum value (P1opt_max) and if the charge level (CL) is lower than the first charge threshold (C1), then: the crane is electrically connected to the single generating set to receive the operating power (PF) from the single generating set, the generating set delivering the main power (P1) which has a main value; and the secondary power source is electrically connected to the generating set to receive from the generating set the charge power (Pload) taking a given charge value, in order to recharge the secondary power source; and wherein the charge value is adjusted so that the main value, which corresponds to a sum of the operating value and the charge value, is included in the optimum power range (P1opt), the generating set then operating within the optimum power range (P1opt).

23. The automatic method according to claim 21, wherein the one or more power management modes further include a hybrid mode (HM), in which: if the operating power (PF) has an operating value which is greater than the maximum optimum value (P1opt_max), and if the charge level (C) is greater than a second charge threshold (C2), then: the crane is electrically connected both to the generating set and to the secondary power source so that the crane receives: the secondary power (P2) coming from the secondary power source, said secondary power (P2) taking a given secondary value; and the main power (P1) coming from the generating set, the main power (P1) taking a given main value; and wherein the secondary value is adjusted so that the main value, which corresponds to the difference between the operating value and the secondary value, is included in the optimum power range (P1opt), the generating set then operating within the optimum power range (P1opt).

24. The automatic method according to claim 21, wherein the one or more power management modes further include a charge mode (CM), in which: if the operating power (PF) has an operating value zero, and if the charge level (C) is lower than the maximum charge threshold (Cmax), then: the secondary power source is electrically connected to the generating set to receive from the generating set the charge power (Pload) taking a given charge value, in order to recharge the secondary power source; and wherein the charge value is adjusted so that the main value, which corresponds to the charge value, is included in the optimum power range (P1opt), the generating set then operating within the optimum power range (P1opt).

25. The automatic method according to claim 22, wherein the one or more power management modes further include: a hybrid mode (HM), in which: if the operating power (PF) has an operating value which is greater than the maximum optimum value (P1opt_max), and if the charge level (C) is greater than a second charge threshold (C2), then: the crane is electrically connected both to the generating set and to the secondary power source so that the crane receives the secondary power (P2) coming from the secondary power source, the secondary power (P2) taking a given secondary value, and the main power (P1) coming from the generating set, the main power (P1) taking a given main value; and wherein the secondary value is adjusted so that the main value, which corresponds to the difference between the operating value and the secondary value, is included in the optimum power range (P1opt), the generating set then operating within its optimum power range (P1opt); and a charge mode (CM), in which: if the operating power (PF) has an operating value zero, and if the charge level (C) is lower than the maximum charge threshold (Cmax), then: the secondary power source is electrically connected to the generating set to receive from the generating set the charge power (Pload) taking a given charge value, in order to recharge the secondary power source; and wherein the charge value is adjusted so that the main value, which corresponds to the charge value, is included in the optimum power range (P1opt), said generating set then operating within the optimum power range (P1opt); the automatic method further comprising at least: a first comparison step (Q1) during which the operating value of the operating power (PF) is compared with the maximum optimum value (P1opt_max), a second comparison step (Q2; Q5; Q6) during which the charge level (C) is compared with the first charge threshold (C1) and/or the second charge threshold (C2) and/or the maximum charge level (Cmax), and a step of selecting (ES) the power management mode from among the main mode (MM), the mixed mode (XM), the hybrid mode (HM) and the charge mode (CM), depending on the comparison results of the comparison steps (Q1; Q2; Q5; Q6).

26. The automatic method according to claim 25, wherein the automatic method further comprises a comparison step (Q3) during which the operating value of the operating power (PF) is compared with the minimum optimum value (P1opt_min).

27. The automatic method according to claim 23, wherein, in the hybrid mode (HM), the secondary value is adjusted so that the main value is equivalent to the maximum optimum value (P1opt_max).

28. The automatic method according to claim 21, wherein the power ratio is comprised between 0.6 and 1.2.

29. The automatic method according to claim 28, wherein the power ratio is comprised between 0.6 and 0.8.

30. The automatic method according to claim 21, wherein the maximum optimum value (P1opt_max) is equal to kmax times the main maximum value (P1max), kmax being comprised between 0.8 and 0.95.

31. The automatic method according to claim 21, wherein the minimum optimum value (P1opt_min) is equal to kmin times the main maximum value (P1 max), km in being non-zero and depending on intrinsic properties of the generating set.

32. The automatic method according to claim 31, wherein kmin is comprised between 0.4 and 0.8.

33. The automatic method according to claim 21, wherein the first charge threshold (C1) is comprised between 50 and 90% of the maximum charge level (Cmax).

34. The automatic method according to claim 23, wherein the second charge threshold (C2) is comprised between 20% and 70% of the maximum charge level (Cmax).

35. The automatic method according to claim 23, wherein at least one of the first charge threshold (C1) and of the second charge threshold (C2) is fixed.

36. The automatic method according to claim 23, wherein at least one of the first charge threshold (C1) and of the second charge threshold (C2) varies depending on a measured temperature.

37. The automatic method according to claim 36, wherein the measured temperature is a temperature of the secondary power source, or an outside temperature.

38. A load lifting assembly comprising: a crane comprising at least several electrical apparatuses and a control-command system in communication with the several electrical apparatuses, the crane configured to use, for operating and moving a load, an operating power (PF) operable to reach a maximum operating value (PFmax), the operating power (PF) being equal to a sum of powers demanded by the electrical apparatuses; a main power source comprising a generating set provided with an endothermic engine configured to supply the crane with a main alternating current for a main power (P1) operable to reach a main maximum value (P1max); the generating set being sized according to a power ratio such that the main maximum value (P1max) is equal to the maximum operating value (PFmax) multiplied by the power ratio which is lower than 1.2, and the generating set has an optimum power range (P1opt) bounded by a minimum optimum value (P1opt_min) and a maximum optimum value (P1opt_max) which is lower than the main maximum value (P1max); a secondary power source comprising at least one rechargeable electric battery having a charge level (C) comprised between zero and a maximum charge level (Cmax), and configured to provide a secondary alternating current to deliver a secondary power (P2) and to receive a charge power (Pload) to be electrically recharged; and an electrical coupling circuit between the crane, the generating set and the secondary power source, wherein the control-command system is in communication with: the secondary power source to receive the charge level (C) and to adjust a secondary value of the secondary power (P2) and a charge value of the charge power (Pload); and the electrical coupling circuit for driving couplings between the crane, the generating set and the secondary power source, and wherein the control-command system comprises a program for implementing the automatic method of power management according to claim 21.

39. The assembly according to claim 38, wherein the control-command system is configured to send a control order to the electrical coupling circuit, which is configured on receipt of the control order to link or not electrically link the main power source to the secondary power source, the main power source to the crane, and the secondary power source to the crane.

40. The assembly according to claim 39, wherein the control-command system is configured to send the control order depending on results of comparison between at least the operating value of the operating power (PF) and the maximum optimum value (P1opt_max), and also depending on the charge level (C).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0149] Other characteristics and advantages of the present disclosure will appear on reading the detailed description below, of a non-limiting example of implementation, made with reference to the appended figures in which:

[0150] FIG. 1 is an illustration of the operating principle of the main mode according to an embodiment of the present disclosure;

[0151] FIG. 2 is an illustration of the operating principle of the mixed mode according to an embodiment;

[0152] FIG. 3 is an illustration of the operating principle of the charge mode, according to an embodiment;

[0153] FIG. 4 is an illustration of the operating principle of the hybrid mode, according to an embodiment;

[0154] FIG. 5 is an illustration of the operating principle of a secondary mode for which only the secondary power source is electrically linked to the crane to supply it with power, this mode being implemented when the charge capacity of the at least one of the batteries constituting it is at its maximum charge level and the crane demands an operating power lower than the optimum minimum value, according to an embodiment; and

[0155] FIG. 6 is a flowchart of the automatic power management method according to an embodiment of the present disclosure, showing in particular how the different power management modes are selected according to the operating value of the operating power required for the power supply and the charge level of the secondary power source, according respectively to the optimum power range and the charge thresholds.

DESCRIPTION

[0156] As illustrated in FIGS. 1 to 4, the automatic power management method 100 is implemented within the framework of an application context of the assembly 101, for which are used a generating set provided with an endothermic engine and constituting a main power source 1, and a secondary rechargeable power source 2 comprising at least one rechargeable electric battery; this with the aim of supplying a crane 3 with an operating power PF necessary for its operation and for example necessary for moving a load such as lifting a load, or rotating the jib.

[0157] More specifically, the operating power PF is used to supply all of the electrical/electronic apparatuses of the crane 3 involved in its operation. Among these apparatuses: the actuators suitable for moving a load and/or moving an element of the crane (for example lifting winch, distribution winch, winch for lifting the jib, slewing motor; accessories such as lights; alarms; sensors; safety devices; temperature control devices; control station, etc.

[0158] The operating power PF required is variable and depends on the nature of the operating tasks and the electrical/electronic systems involved. The value of the operating power PF, or operating value, may reach a maximum operating value PFmax, which corresponds, among all the actions that the crane 3 can possibly perform, to that demanding the most supply power (that is to say for which the sum of the supply powers of the electrical/electronic systems is the highest) which generally corresponds to a simultaneous combination of several simple tasks, for example the implementation of several displacements such as a lifting of a load while the boom rotates.

[0159] The main power source 1 is used to deliver a main power P1 which can reach a main maximum value P1max. In the embodiment shown, the main power source 1 is a generating set with an endothermic engine. Also, in the remainder of the description, it is considered, for greater convenience, that the generating set refers to the main power source 1 and may therefore bear the same numerical reference 1.

[0160] The generating set 1 is characterized by an optimum power range P1opt bounded by a non-zero minimum optimum value P1opt_min and a maximum optimum value P1opt_max lower than P1max, in which it delivers a main power value P1, called main value, for a lower fuel consumption and a lower emission of carbon dioxide and regulated particles.

[0161] The secondary power source 2 is designed to deliver a secondary power P2 whose value, called secondary value, may reach a maximum secondary value P2max. It is also characterized by a charge level C (that is to say the capacity of the battery) which can be comprised between 0 and a maximum charge level Cmax (classically 100%).

[0162] As a reminder, as previously explained, conventionally, in order to absorb a maximum operating power peak PF, the generating sets are oversized with a capacity to deliver a main power P1 which can reach a main maximum value P1max greater than 1.5 times, or even 3 times the maximum operating value PFmax necessary for a nominal operation of the crane 3. This oversizing generally means that the generating sets rarely operate in their optimum power range P1opt.

[0163] The advantage of the automatic power management method 100 described herein is to avoid such overdimensioning and to enable the generating set 1 to be able, in the greatest number of possible situations, to operate in its optimum power range P1opt.

[0164] The secondary power source 2 is in particular provided to both make it possible to minimize the sizing of the generating set 1 but also, as already mentioned and re-indicated below, to deliver, if the operating value of the operating power PF should be greater than the maximum optimum value P1opt_max of the generating set 1, a secondary value equal to the operating value minus the maximum optimum value P1opt_max, the main power source 1 delivering to the crane 3 a main value equal to the maximum optimum value P1opt_max. In another variant, the main power source 1 may deliver a main value slightly lower than the maximum optimum value P1opt_max, so as to guarantee that the generating set 1 remains well within its optimum power range P1opt.

[0165] The present disclosure provides for several dimensions of the generating set 1 such that the power ratio of the main maximum value P1max to the maximum operating value PFmax is comprised between 0.6 and 1.2. Thus, in a first variant described by the present disclosure, the generating set 1 may be slightly oversized, for a power ratio greater than 1 and lower than 1.2; whereas in a second embodiment, it can on the contrary be slightly or significantly undersized, for a power ratio greater than or equal to 0.6 and lower than or equal to 1.

[0166] The sizing of the generating set 1 may, in part, be dictated by the performance of the references of the battery(ies) available and used as secondary power source 2.

[0167] An interest of the present disclosure is that it provides that the generating set 1 and the secondary power source 2 deliver to the crane 3 an alternating current. Thus, an embodiment of the present disclosure may be implemented by means of standard generating sets and batteries, that is to say commercially available at moderate prices.

[0168] As indicated previously, the generating set 1 and the secondary power source 2 are provided to be easily replaceable. Old generating sets 1 and secondary power sources 2 that would have been used to implement the automatic power management method 100 before may be replaced/changed with newer generating sets 1 and secondary power sources 2 responding favorably to the current safety and environmental requirements.

[0169] The optimum power range P1opt of the generating set 1 is defined such that: [0170] the maximum optimum value P1opt_max is equal to kmax times the main maximum value P1max, with kmax generally comprised between 0.8 and 0.95. [0171] the minimum optimum value P1opt_min is equal to kmin times the main maximum value P1max, the value of kmin depending on the characteristics/performance of the generating set 1 used and possibly comprised between 0.4 and 0.8, or even between 0.6 and 0.7.

[0172] According to the power management modes defining the automatic method 100, and which will be described later: [0173] the crane 3 is power supplied either by the main power source 1 only, or by the main power source 1 and the secondary power source 2, or by the secondary power source 2 only; [0174] in case of discharge, the secondary power source 2 is power supplied by the main power source 1 which provides it with a charge power Pload.

[0175] To this end, the assembly 101 comprises an electrical coupling circuit 4 serving to link electrically or not, depending on the power management mode implemented by the automatic method 100: the main power source 1 and the secondary power source 2 to the crane 3; and the main power source 1 to the secondary power source 2. These couplings are made according to control orders that the electrical coupling circuit 4 receives from the crane 3, more precisely from a control-command system 30 of the latter.

[0176] The automatic method 100 is contained and executed by a program implemented inside the control-command system 30 of the crane 3. In one embodiment, the automatic method 100 may be started at the beginning of the day, when the crane operator starts the control-command system 30.

[0177] A flowchart of one of several possible embodiments of the automatic method 100 is illustrated in FIG. 5.

[0178] The power management modes that can be implemented by the automatic method 100 are activated according to the results of several comparisons. Among these comparisons: [0179] a comparison of the maximum operating value PFmax with the maximum optimum value P1opt_max and eventually also with the minimum optimum value P1opt_min, in particular to determine if the maximum operating value PFmax is included in the optimum power range P1opt, and [0180] comparisons between the charge level C of the secondary power source 2 with a first charge threshold C1, a second charge threshold C2 and the maximum charge level Cmax.

[0181] The first charge threshold C1 corresponds to a charge threshold below which it is estimated that the secondary power source 2 must be recharged, in other words if its charge level C is below this first charge threshold C1 then the secondary power source 2 is insufficiently charged. The first charge threshold C1 is comprised between 50% and 90% of the maximum charge level Cmax.

[0182] The second charge threshold C2 is representative of a state of charge of the secondary power source such that it is precisely capable of delivering a secondary value of secondary power P2 to the crane 3 without the risk of presenting a state close to discharge or to be completely discharged. According to different embodiments described by the present disclosure, depending on the characteristics and performance of the secondary power source 2, the second charge threshold C2 may be lower than the first charge threshold C1, or else be substantially equal to the latter. The second charge threshold C2 is comprised between 20% and 70% of the maximum charge level Cmax.

[0183] The realization of the different comparisons implemented by the automatic method 100 require that the program/the control command system 30 know the following information: [0184] the operating value of the operating power PF demanded by the crane 3; [0185] the minimum optimum value P1opt_min and the optimum value P1_optmax of the generating set 1; [0186] the charge level C, the first charge threshold C1, and the second charge threshold C2 of the secondary power source 2.

[0187] The characteristics of the generating set 1 being information known by the operators when it is purchased, they can be, in one embodiment, entered by the latter in the program executing the automatic method, for example during a parameterization step taking place before the actual execution step. The charge thresholds C1 and C2 may for their part be defined by the user, in particular by taking into account the characteristics of the battery.

[0188] Finally, the operating power PF is known to the control-command system given that it communicates with the electrical/electronic apparatuses of the crane 3; knowing their power supply needs.

[0189] Knowing the operating power PF and the optimum power range P1opt of the generating set 1, the control-command system 30 does not need to know the main power P1, therefore to communicate with it for activating the power management modes and driving the electrical coupling circuit 4.

[0190] On the other hand, the control-command system must be aware of the charge level C of the secondary power source 2.

[0191] This is why it is only necessary for the secondary power source 2 among the two power sources to communicate with the control-command system 30 of the crane 3, for example by means of a communication bus or of a wireless communication protocol, in order to transmit the charge level(s) C to it.

[0192] Optionally, and so that the impact of the temperature of the environment on the performance of the at least one battery included in the secondary power source 2 is taken into account, the program executing the automatic method may modify the values of the first charge threshold C1 and of the second charge threshold C2 according to the temperature of the secondary power source 2 (in a first variant described by the present disclosure), or the outside temperature (in a second variant described by the present disclosure), more precisely according to a measurement of said temperature of the secondary power source 2 or said outside temperature which is transmitted to the control-command system 30.

[0193] Depending on the temperature of the secondary supply source 2 or the outside temperature, the program: [0194] leaves as it is/does not modify the values of the first charge threshold C1 and of the second charge threshold C2, or [0195] increases at least one of the two values, or [0196] decreases at least one of the two values.

[0197] In one embodiment, when defining the first charge threshold C1 and the second charge threshold C2 during the parameterization step, the operator may enter different temperature ranges in which the first charge threshold C1 and the second charge threshold C2 take a given first charge threshold value and a given second charge threshold value. During the execution of the automatic method, when a temperature measurement of the temperature of the secondary power source 2 is transmitted to the control command system 30, the program determines to which temperature range corresponds the measured temperature, and adapts the first charge threshold value C1 and the second charge threshold value C2 accordingly.

[0198] In the embodiment where the temperature measured and transmitted to the control-command system 30 corresponds to the temperature of the secondary power source 2, the temperature of the secondary power source 2 is either: [0199] if the technology of the at least one battery included in the secondary power source 2 allows it, transmitted by the secondary power source 2 itself (at the same time as the charge level), [0200] measured and then transmitted by an external temperature measurement device in communication with both the secondary power source 2 and the control-command system 30.

[0201] In the embodiment where the measured temperature corresponds to the outside temperature, the outside temperature is either: [0202] measured and then transmitted by an external temperature measurement device in communication with the control-command system 30 of the crane 3, [0203] or an apparatus integrated into the crane 3 in communication with the control-command system 30, for example a temperature measurement sensor.

[0204] In one embodiment, the stopping of the automatic method 100 may occur at the end of the day, with the crane operator turning off the control-command system 30 (note that the stop step STOP of the automatic method is not shown in FIG. 5). In a second embodiment, it is conceivable that the stopping of the automatic method 100 takes place automatically if the crane 3 is put to rest (and therefore its operating power is zero), and if the charge level C of the source secondary power supply 2 is at its maximum charge level Cmax after an automated recharging of the battery.

[0205] Between its start and its stop, the automatic method 100 is executed continuously, and switches from one power management mode to another power management mode among the several power management modes that it comprises according to the comparison results of the comparison steps.

[0206] The order in which these comparison steps are carried out does not matter since only their result counts. In the embodiment illustrated in FIG. 5, the selection of the power management modes during selection steps ES is firstly based on power comparisons (in particular to determine whether the operating power PF is included in the optimum power range P1opt) then on comparisons between the charge level C and the charge thresholds C1, C2. In another embodiment, it is conceivable that the comparisons between the charge level C and the charge thresholds C1, C2 could be carried out before the power comparisons.

[0207] In the remainder of the description, the power management modes implemented in the present examples and their activation conditions are now presented.

[0208] Referring to FIG. 5, during a comparison step Q1, the automatic method 100 determines if the operating value of the operating power PF is greater than the maximum optimum value P1opt_max. If this is not the case, it then compares the operating value during a comparison step Q3 with the minimum optimum value P1opt_min, with the aim of determining if it is included in the optimum power range P1opt.

[0209] If the operating value is included in the optimum power range P1opt, then the automatic method 100 compares the charge level C of the secondary power source 2 with the first charge threshold C1 during a comparison step Q5. If the charge level C is greater than the first charge threshold C1, then a first power management mode called main mode MM is selected. If not, a second power management mode called mixed mode XM is selected.

[0210] In the main mode MM, illustrated in FIG. 1, the electrical coupling circuit 4 electrically links only the generating set 1 to the crane 3, with the generating set 1 delivering a main power P1 which is constantly included in the optimum power range P1opt (because the operating power PF is included in this optimum power range P1opt), eliminating any risk of overconsumption of fuel, excessive emission of regulated exhaust constituents, and damage to the generating set 1. In this main mode MM, the secondary power source 2 has its charge level C greater than the first charge threshold C1, and it therefore does not need to be recharged, and therefore it is not connected to the generating set 1.

[0211] In the mixed mode XM, illustrated in FIG. 2, the electrical coupling circuit 4 electrically links the generating set 1 to both the secondary power source 2 and the crane 3. Being in communication with the secondary power source 2, the crane 3 is configured to drive it by sending it an adjustment order. The adjustment order is that the secondary power source 2 adjusts the charge power Pload that it demands and receives from the generating set 1, so that the main power P1 that it delivers, and which is equal to the sum of the operating power PF and the charge power Pload, is included in the optimum power range P1opt. In this mixed mode XM, the secondary power source 2 has its charge level C lower than the first charge threshold C1, and it therefore needs to be recharged, and therefore it is connected to the generating set 1 to receive the charge power Pload adjusted.

[0212] In the case, for example, where the operating power PF demanded by the crane 3 remains included in the optimum power range P1opt, and the charge level C of the secondary power source 2 again becomes greater than the first charge threshold C1, the automatic method 100 switches from the mixed mode XM to the main mode MM.

[0213] If at the end of the comparison step Q3, it is determined that the operating power PF is lower than the minimum optimum value P1opt_min, a new comparison step Q4 is implemented to determine if the operating power PF is equal to zero or not.

[0214] If in step Q4 the operating power PF is non-zero (and therefore is comprised between 0 and the minimum optimum value P1opt_min), the automatic method 100 then determines during a comparison step Q7 if the charge level C of the secondary power source 2 is at its maximum charge level Cmax.

[0215] If the charge level C is lower than the maximum charge level Cmax, the automatic method 100 implements the mixed mode XM described above.

[0216] Otherwise, if the charge level C is equal to the maximum charge level Cmax (in other words if the secondary power source 2 is fully charged), the automatic method 100 implements a secondary mode SM during which only the secondary power source 2 is electrically linked to the crane 3, and supplies the latter with a secondary power P2 corresponding to the operating power PF demanded. In this secondary mode SM, the main power source 1 is linked neither to the crane 3 nor to the secondary power source 2, and may therefore be put on standby. According to one option, this secondary mode SM may be implemented as long as the charge level C is greater than the first charge threshold C1, and of course as long as also the operating power PF is non-zero and lower than the minimum optimum value P1opt_min. If in step Q4 the operating power PF is zero, meaning that the crane 3 is not in demand for power, the automatic method 100 checks during a comparison step Q6 if the secondary power source 2 is fully charged or not (so if the charge level C is equal to the maximum charge level Cmax).

[0217] If in step Q6 the charge level C is lower than the maximum charge level Cmax (in other words the secondary power source 2 is not fully charged), the automatic method 100 implements a charge mode CM, illustrated in FIG. 3, in which the electrical coupling circuit 4 electrically links the generating set 1 to the secondary power source 2 so that it provides a main power P1 corresponding to a charge power Pload to recharge the secondary power source 2. The crane 3 does not receive any power from the two power sources 1, 2. In this charge mode CM, the control-command system 30 of the crane 3 is also configured to drive the secondary power source 2 by sending it an adjustment order so that it adjusts the charge power Pload that it demands from the generating set 1, so that it is included in the optimum power range P1opt. In this way, the main power P1 is included in the optimum power range P1opt.

[0218] If in step Q6 the charge level C is equal to the maximum charge level Cmax (in other words the secondary power source 2 is fully charged), the generating set 1, insofar as it does not have to deliver main power P1 goes into standby or goes out while waiting for the automatic method 100 to implement another power management mode. If the crane 3 remains inactive for a very long time, the charge level C of the at least one battery may eventually decrease. In this case, if it is active, the automatic method 100 then implements the charge mode CM.

[0219] Following the comparison step Q1, in the case where the operating power PF is greater than the maximum optimum value P1opt_max, the automatic method 100 proceeds to a comparison step Q2 during which it is checked if the charge level C of the secondary power source 2 is or is not greater than the second charge threshold C2. It should be noted that this scenario, where the operating power PF demanded by the crane 3 is greater than the maximum optimum value P1opt_max, corresponds to a case of peak power associated with a peak in activity of the crane 3 with a large number of electrical apparatuses requiring a power supply and which can reach PFmax.

[0220] If in step Q2 the charge level C is greater than the second charge threshold C2, the automatic method 100 implements a power management mode called hybrid mode HM, illustrated in FIG. 4, in which the electrical coupling circuit 4 electrically links the generating set 1 and the secondary power source P2 to the crane 3 so that it delivers to it respectively a main power P1 and a secondary power P2. In this hybrid mode HM, the control-command system 30 is designed to send to the secondary power source 2 an adjustment order so that the secondary power P2 that it sends to the crane 3 is at least equal to the difference between the operating power PF and the maximum optimum value P1opt_max, and at maximum equal to the difference between the operating power PF and the maximum optimum value P1opt_min, the generating set 1 then delivering a main power P1 still included in the optimum power range P1opt.

[0221] If in step Q2 the charge level C is lower than the second charge threshold C2, the automatic method 100 implements a power management mode called critical mode OM, in which the electrical coupling circuit 4 electrically connects the generating set 1 to the crane 3 so that it delivers a main power P1 to it, such that the main power P1 is greater than the maximum optimum value P1opt_max, in other words the generating set 1 is out of its optimum range Popt. In this critical mode OM the main power P1 may even be equal to the main maximum value P1max.

[0222] In this critical mode OM, the electrical coupling circuit 4 may also electrically link the secondary power source 2 to the crane 3 (depending on how the second charge threshold C2 has been fixed) so that the secondary power source 2 may provide for a given period of time (until it is completely discharged) a secondary power P2 making it possible to supplement, if necessary, the main power P1 provided by the generating set 1 in order to reach together the operating power PF in the exceptional case where the operating power PF is greater than the main maximum value P1max.

[0223] In another variant of the present disclosure, during the critical mode OM, the control-command system 30 is configured to determine at what rate the secondary power source 2 discharges when it must provide the secondary power P2, an excessive discharge presenting a high risk of completely discharging the secondary power source 2. In the event that this eventuality occurs: [0224] the secondary power source 2 no longer provides secondary power P2 to the crane 3, [0225] certain actions of the crane 3 which consume too much power are interrupted, such as the lifting operations, [0226] the generating set 1 provides a main power P1 to the crane 3 with a view to it continuing to carry out actions that are lower costly in energy, as well as to the secondary power source 2 to recharge it until it reaches at least the second charge threshold C2. This configuration is different from the mixed mode XM because the generating set 1 may or may not operate in its optimum power range P1opt (in other words this configuration may be considered as a degraded mode of the mixed mode XM).

[0227] Advantageously, the automatic method 100 implements several power management modes (main mode, mixed mode, hybrid mode, charge mode) such that for each of them, the generating set 1 operates constantly in its optimum power range Popt; except in the exceptional case of the critical mode OM. In secondary mode SM, the generating set 1 is put on standby.

[0228] It should be noted that the probability of occurrence of the critical mode OM remains very low. Its occurrence presupposes very frequent intense peaks in activity of the crane 3 over a long period without there being any possibility of recharging the secondary power source 2. Furthermore, the generating set 1 and the secondary power source 2 are chosen so as to be in line with the power requirements of the crane 3, thus having to prevent this critical mode OM from occurring.

[0229] Since the control-command system 30 indirectly manages the main power P1 delivered by the generating set 1 in the mixed mode XM, the hybrid mode HM, and the charge mode CM from a driving of the secondary power source 2 so that it remains in its optimum power range P1opt (the generating set 1 being whatever happens in this optimum power range P1opt in the main mode MM), the examples of the present disclosure have the advantage of not requiring the design and/or installation of a means of communication between the generating set 1 and the crane 3 to exchange information or order.

[0230] Also, the generating set 1 does not exchange information with the secondary power source 2 since it is content to deliver a charge power Pload only when it is electrically linked to it, in the mixed mode XM and the charge mode CM, and according to the power demand coming from it.

[0231] Consequently, the implementation of the automatic method is therefore more practical and less costly, with fewer hardware, software or protocol means to design and/or install.