JP2007191973A - Power control system for hybrid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power control system for hybrid capable of totally and efficiently controlling a plurality of power sources and motor generator devices. <P>SOLUTION: Motor generators 17, 17a, 17b driving hydraulic devices/actuators 16, 16a and a load 16b which are operation objects, are controlled by inverters 18, 18a, 18b. The first power source 11 is an engine for driving the operation object by engine output automatically decreased or increased by governor control at the excess or shortage of power. The second power source 14 has an electric storage device 12 capable of storing electric energy generated by the motor generators 17, 17a, 17b, and a converter 13 controlling the charge/discharge to/from the electric storage device 12. A control circuit 21 computes a demand power command of the second power source 14 from the discharge demand of the second power source 14 determined from the total of demand power of the operation objects and the charged/discharged state of the electric storage device 12, to control the charge/discharge current of the second power source 14, and controls command currents to the respective inverters 18, 18a, 18b in a total control manner. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hybrid power control system having a first power source and a second power source.

In a hydraulic excavator, power is generated by interposing a regenerative generator in the oil discharge circuit of a hydraulic cylinder such as a boom cylinder, thereby effectively utilizing the normally wasted hydraulic energy and turning the upper part There is a hybrid excavator in which braking energy that is wasted during braking of a body turning operation is effectively extracted as regenerative power by a turning motor generator (see, for example, Patent Document 1).
JP 2002-242234 A (first page, FIG. 1)

  However, in a hybrid power control system having a plurality of power sources, a method for comprehensively controlling the power source and the motor generator has not been found in the present situation, and is not an efficient hybrid power control system as a whole.

  The present invention has been made in view of these points, and an object of the present invention is to provide a hybrid power control system capable of comprehensively and efficiently controlling a plurality of power sources and a motor generator.

  According to the first aspect of the present invention, there is provided a motor generator that is controlled by a first controller and drives an operation target, and a first power that drives the operation target by an engine output that automatically increases and decreases by governor control when the power is excessive or insufficient. And a second power source having an electric storage device capable of storing electric energy generated from the motor generator and having a second controller for controlling charging / discharging of the electric storage device, and a total required power to be operated And a control circuit for controlling a charge / discharge current of the second power source by calculating a required power command of the second power source from a discharge request of the second power source determined from a charge / discharge state of the electric storage device. This is a hybrid power control system.

  According to a second aspect of the present invention, a plurality of motor generators and a plurality of first controllers are provided in the hybrid power control system according to the first aspect, and the control circuit is connected to the power running side motor generator from the regeneration side motor generator. Power is supplied to the machine.

  According to a third aspect of the present invention, the control circuit in the hybrid power control system according to the second aspect of the present invention does not have sufficient power by allowing power to be interchanged between a plurality of motor generators and only discharging from the second power source. In some cases, a motor generator that is connected in parallel with the first power source is used as a generator that uses the first power source as a power source, so that power can be accommodated from the first power source.

  According to a fourth aspect of the present invention, the control circuit in the hybrid power control system according to any one of the first to third aspects includes a total required power calculation circuit for calculating a total required power from each required power to be operated, The charge / discharge required value calculation circuit for calculating the charge / discharge required power from the charge / discharge state of the electric storage device of the two power sources, and the total required power from the operation target and the charge / discharge required power from the second power source A priority determination circuit for determining whether to give priority as a command to the two power sources and calculating a power command to the first controller that is totally controlled so that the power balance in the bus is balanced; and a priority determination circuit The first controller control command calculation circuit for calculating the first controller control command supplied to the first controller for controlling the motor generator from the calculated power command, and the charge / discharge request behavior calculated by the priority determination circuit It is obtained by including a charge and discharge control command calculation circuit for calculating the charge and discharge control instruction supplied to the second controller of the second power source from the command.

  According to a fifth aspect of the present invention, in the hybrid power control system according to the fourth aspect, a bus voltage deviation correction is performed by calculating a correction amount so as to maintain the bus voltage within an allowable range and supplying the correction amount to the charge / discharge control command calculation circuit. A circuit is provided.

  According to the first aspect of the invention, the required power command of the second power source is calculated from the total required power to be actuated and the charge / discharge request of the second power source determined from the charge / discharge state of the electrical storage device, By controlling the charging / discharging current of the second power source, when the power is excessive or insufficient, the first power source using the engine whose engine output is automatically reduced by governor control is automatically discharged power of the second power source. Therefore, the required power of the motor generator can be shared by the first power source and the second power source in a coordinated manner so that the energy loss can be comprehensively controlled. Further, since the first power source can automatically supplement the discharge power of the second power source, the control system can be simplified.

  According to the second aspect of the present invention, by performing power running or regeneration between the plurality of motor generators and supplying power from the regeneration side to the power running side, the burden on the first power source and the second power source is reduced. The energy loss in the first power source and the second power source can be reduced, and the loss can be reduced in comprehensive control. This control can be applied not only to a parallel system in which the first power source and the second power source are connected in parallel, but also to a series system hybrid in which the first power source and the second power source are connected in series.

  According to the third aspect of the present invention, when power is not sufficient only by combining power between a plurality of motor generators and discharging from the second power source, the motor generator in parallel connection with the first power source. By using the machine as a power generator using the first power source as a power source, the required power of the motor generator exceeding the capacity of the second power source can be supplied or recovered interchangeably from the first power source. In addition, a flexible power supply system suitable for the parallel hybrid can be provided, and the capacity of the second power source can be reduced, which is advantageous in terms of cost and space factor.

  According to the fourth aspect of the present invention, the first power supplied to the first controller that controls the motor generator from the power command calculated by the priority determination circuit that calculates the power command to the first controller in total. 1 controller control command is calculated by the first controller control command calculation circuit, and the charge / discharge control command supplied to the second controller of the second power source from the charge / discharge request power command calculated by the priority determination circuit Is calculated by the charge / discharge control command calculation circuit, so that the first controller of the motor generator and the second controller of the second power source can be comprehensively controlled, and the energy loss can be controlled to a minimum. Allows long-term (semi-permanent) continuous operation of the power source.

  According to the fifth aspect of the present invention, the bus voltage deviation correction circuit performs a correction operation so as to maintain the bus voltage within an allowable range, so that the steady and transient imbalance between the required power and the supplied power can be reduced. By correcting, the system can be kept within the operable range, and the stability of the system can be improved.

  Hereinafter, the present invention will be described in detail with reference to one embodiment shown in FIGS.

  As shown in FIG. 4, the work machine 1 is provided with an upper swing body 3 that is rotated by a swing motor 3m with respect to a lower travel body 2 that has a crawler belt that is driven by a travel motor 2m. A work device 5 is mounted on the body 3, and the work device 5 is pivotally supported by a boom cylinder 6 c that is pivoted up and down by a boom cylinder 6 c with respect to the upper swing body 3, and a stick is attached to the tip of the boom 6. A stick 7 rotated by a cylinder 7c is pivotally supported, and a bucket 8 rotated by a bucket cylinder 8c is pivotally supported at the tip of the stick 7.

  The upper swing body 3 is a load of the swing motor 3m, and this swing motor 3m is operated by electric power supplied from a generator or a battery driven by an in-vehicle engine (not shown) mounted on the upper swing body 3. Use a motor generator. The traveling motor 2m, the boom cylinder 6c, the stick cylinder 7c, the bucket cylinder 8c, and the like are supplied from a hydraulic pump (not shown) as a fluid pressure pump that is operated by the engine or the motor generator during power running. It functions as a hydraulic actuator (hydraulic cylinder, hydraulic motor) as a fluid pressure actuator that is actuated by hydraulic fluid as fluid, and functions as a hydraulic pump driven by a load or inertia force during regeneration. Is driven as a hydraulic motor.

  From such a hydraulic pump as a fluid pressure pump, hydraulic oil as a working fluid controlled by a control valve is supplied to a hydraulic actuator such as a hydraulic cylinder or a hydraulic motor as a fluid pressure actuator to operate. The device group is a hydraulic device as an operation target.

(A) FIG. 1 shows a parallel-type hybrid power control system applied to such a work machine 1, and has two or more power sources as a plurality of hydraulic devices or operating bodies (hereinafter referred to as operating objects). , "Hydraulic device / actuator") in a plurality of subsystem configurations that are driven by a plurality of motor generator devices (motors, inverters), power supply (or recovery) to each subsystem (motor generator device), A first power source 11 such as an engine, and a second power source 14 of a single (or a plurality of) electric energy storage system composed of an electric storage device 12 such as a battery and a converter 13 as a second controller. It is a system that performs comprehensive and coordinated control.

  The first power source 11 is mechanically connected to the hydraulic device / actuator 16 as the operation target as described above via the power transmission device 15 and mechanically connected to the motor generator 17. The converter 13 of the second power source 14 is mechanically connected to an inverter 18 as a first controller for controlling the motor generator 17, a hydraulic device / actuator 16a as another operation target, or a load 16b as the operation target. The buses 19 are connected to inverters 18a and 18b as first controllers for controlling the connected motor generators 17a and 17b, respectively. The motor generator 17 and the inverter 18, the motor generator 17a and the inverter 18a, the motor generator 17b and the inverter 18b each constitute a motor generator device.

(B) Next, a control circuit 21 constructed by a combination of hardware and software as described below is provided to calculate the output (charge or discharge command) of the second power source 14. The meaning of each symbol is displayed in FIG.

  The control circuit 21 measures the required power of each subsystem (motor generator device) required based on the operation amount of the operating device that operates the hydraulic device / actuators 16, 16a and the load 16b. A total required power calculation circuit 23 is connected to the measurement circuit 22. In addition, an electric storage device charge / discharge request value calculation circuit 25 as a charge / discharge request value calculation circuit is connected to the electric storage device 12 via a charge / discharge state measurement circuit 24. Each inverter current command calculation circuit 27 serving as a first controller control command calculation circuit is connected to the bus 19 via a bus voltage measurement circuit 26. The total required power calculation circuit 23 and the electrical storage device charge / discharge request value calculation circuit 25 are connected to the priority determination circuit 28. The bus voltage measurement circuit 26 is also connected to a bus voltage deviation correction circuit 29.

  The bus voltage measurement circuit 26 and the priority determination circuit 28 are connected to each inverter current command calculation circuit 27, and each inverter current command calculation circuit 27 outputs an inverter current as a control signal to each inverter 18, 18a, 18b. Each command value is output.

  The priority determination circuit 28 and the bus voltage deviation correction circuit 29 are connected to a charge / discharge current calculation circuit 30 as a charge / discharge control command calculation circuit, and the charge / discharge current calculation circuit 30 is connected to the converter 13 of the second power source 14. In response, a control signal is output.

(1) The total required power calculation circuit 23 is a calculation circuit for each actuator required power Pi ^** and the total required power ΣPi ^** , and corrects the equipment efficiency to calculate each Pi ^* and ΣPi ^* . Further, the electrical storage device charge / discharge request value calculation circuit 25 calculates the charge / discharge request power A corresponding to the charge / discharge state SOC.

  (2) Each inverter current command calculation circuit 27 calculates a power command value that satisfies each actuator power requirement, performs a correction operation using the bus voltage deviation and the total power that can be supplied, and the following comprehensive control function. Determine the value.

(3) The priority determination circuit 28 determines which of the total actuator required power ΣPi ^* and the charge / discharge required power A is given priority as a command to the second power source 14, and can balance the power in the bus. In this way, each inverter power command as a first controller control command that is controlled in total is calculated, and it is determined (Pr ^* is calculated) which is used for the charge / discharge current command calculation.

For example, when the total actuator required power ΣPi ^* is negative (regenerative) and the second power source 14 requests charging more than the regenerative power from that state, the charging request value is used as a control command, and the shortage is This is a method supplemented by one power source 11.

  Further explaining that the priority determination circuit 28 performs total control, the charge / discharge power command to the second power source 14 is a, and the inverter of the motor generator 17 marked with * (* / M / INV) If the power command to 18 is b, and c is the power command to the inverters (M / INV) 18a, 18b of motor generators 17a, 17b not marked with *, a is a priority discrimination Calculated by the circuit 28, c is the operating target required power of the M / INVs 18a and 18b without *, and b is calculated so that a + b = c so that the power balance in the bus is balanced.

(4) The charge / discharge current calculation circuit 30 calculates the charge / discharge current command and uses the output of the bus voltage deviation correction circuit 29 (correction amount C), engine maximum power Emax, based on Pr ^* of the priority determination circuit 28. Then, a correction calculation is performed from the electric storage device maximum power Smax, and finally a charge / discharge power command value (Ps) or a charge / discharge current command value (I) is calculated.

  The charge / discharge current control method of the electrical storage device 12 includes (i) a current control method of the converter 13 and (ii) a bus voltage control method. In this bus voltage control method, the high bus voltage is controlled during charging and the low bus voltage is controlled during discharging. At this time, the converter is not essential, the command value I = 0, and the charge / discharge current is the bus voltage. And a value physically determined by the internal voltage of the electrical storage device 12.

  (5) If there is an imbalance between the supply (regeneration) of the second power source 14 and the required values of the motor generator devices (motor generators 17, 17a, 17b, inverters 18, 18a, 18b), the bus voltage And the correction calculation (changing the inverter current, etc.) is performed (see (2) above).

(C) The first power source 11 compensates for the excess and deficiency of the second power source 14 and supplies the total power correction (or recovery: performed by the second power source 14) as a whole. ).

  That is, the actuator required power may not be ensured only from the second power source 14 in the above (3) and (4). The excess and deficiency at the second power source 14 is compensated by regeneration from other actuators. When the first power source 11 is an engine, the engine output is controlled by governor control when the power is insufficient (when excess). Since it automatically goes up (down), this first power source 11 is also compensated. If the output of the first power source 11 is not automatically increased (down), this is dealt with by increasing (down) the output of the first power source 11 according to a control command.

  The drive of the inverters 18a and 18b without * can supply the power of the first power source 11 via the inverter 18 with *. Thus, the inverter current command is a command value that is comprehensively determined without being determined only from the load.

(D) The regenerative energy is stored in the second power source 14 by (B) above, and can be charged by the output of the first power source 11 by (B)-(3) at the time of overdischarge. The overdischarge of the source 14 can be prevented.

(E) The parallel hybrid configuration can be applied to a system having a single actuator.

(F) A circuit that can be calculated for each subsystem (motor generator device) as a required power and a bus voltage monitoring circuit are provided to improve control flexibility.

  The terms (B)-(3), (4), and (C) are control methods corresponding to the features of the parallel hybrid.

  Next, an example of a calculation step and a calculation formula will be shown. There are various variations in these details.

1. Definition
SOC indicates the state of charge of the electrical storage device 12, and detects the state of charge by detecting the voltage of the electrical storage device 12, for example.

Pi (t) ^** is the required power (a function of time) of each hydraulic device / actuator 16, 16a and load 16b, and each motor generator 17, 17a, 17b and inverter 18 is corrected by correcting the device efficiency. , 18a, 18b is the base of the required power (a function of time), and is positive during power running and negative during regeneration.

Pi (t) ^* is a correction value of Pi (t) ^** . First, Pi (t) ^* = K1 · Pi (t) ^**, and then corrected so that the priority determination circuit 28 can perform total control. Is done.

  Pi (t) is an inverter control command to each inverter 18, 18a, 18b and is displayed as power. Normally, the command to inverter 18, 18a, 18b is the speed of each inverter current command calculation circuit 27. (Or torque) is converted and commanded.

  n is the number of inverters 18 marked with * in FIG.

Pmg (t) ^** = ΣPi (t) ^** is the sum (function of time) of required power Pi (t) ^** of each motor generator 17, 17a, 17b and inverter 18, 18a, 18b, The total is positive during power running and negative during regeneration.

Pmg (t) ^* is a correction value for Pmg (t) ^** , and Pmg (t) ^* = K1 · Pmg (t) ^**
Ps (SOC) max = Smax is an allowable maximum power (a function of SOC) that can be supplied or received by the electric storage device 12, and is positive during power running (supply) and negative during regeneration (acceptance). It is set according to the characteristics of the electrical storage device 12 (generally, the value differs on the plus side and the minus side).

  Ps (SOC) c is a power level that becomes a transition point from the normal control to the voltage fluctuation allowable control.

Ps (SOC) ^* = A is a charge / discharge required power (a function of SOC) required by the state of charge of the electrical storage device 12, and is positive during power running (supply) and negative during regeneration (acceptance).

Ps (t) ^* = Pr ^* is a required power calculation value of the electrical storage device 12 and a calculation result of the priority discrimination circuit 28.

  Pmg (t) = Pn is the sum of control commands (functions of time) to the inverters 18, 18a, 18b, and is positive during power running and negative during regeneration. Although shown with electric power, it can also be converted into a current command.

  Ps (t) = Pr is a charge / discharge control command (a function of time) to the converter 13 of the electrical storage device 12, and is positive during power running and negative during regeneration. Although shown with electric power, it can also be converted into a current command.

  V is the bus voltage.

V0 ^* is a control target value at the time of steady state of the bus voltage.

ΔV is a bus voltage deviation and ΔV = V−V0 ^* .

  Vlo and Vhi are the lower limit and upper limit of the allowable range of the bus voltage, and are determined by the restrictions of the equipment.

  K1 is an output suppression coefficient (1) (≦ 1), and is calculated in the control algorithm.

  K2 is a voltage correction coefficient, and is a coefficient for correcting the control command in accordance with the bus voltage deviation ΔV.

  K3 is an output suppression coefficient (2) (≦ 1), and is calculated in the control algorithm.

  ΔP is a voltage deviation correction amount, and ΔP = −K 2 · ΔV.

  E is the engine output, and Emax is the maximum value (engine maximum power) of the engine output.

2. Control Algorithm As shown in FIG. 2, control calculation is performed in the following steps. The numbers in parentheses described in each circuit block in FIG. 1 correspond to the following step numbers.

(Step 1)
The required power Pi (t) ^** of each load by each required power measurement circuit 22, the bus voltage V by the bus voltage measurement circuit 26, and the charge / discharge state SOC signals of the electrical storage device 12 by the charge / discharge state measurement circuit 24 Are detected respectively.

(Step 2)
Also, the total required power calculating circuit 23, the electric generator and thereby calculates the sum of the required power of the inverter ^{ΣPi (t) ** = Pmg (} t) **, by electrical storage device charging and discharging requirement value calculating circuit 25 The charge / discharge required power A = Ps (SOC) ^* required by the state of charge of the electrical storage device 12 is calculated.

(Step 3)
The total required power calculation circuit 23 determines power running / regeneration based on the sign of the total required power Pmg (t) ^** .

Case 1: Pmg (t) ^** > 0 is power running.

Case 2: Pmg (t) ^{** If} <0, regeneration.

Case 3: When Pmg (t) ^** = 0, it is an idle state or a balance between power running / regeneration, and the control algorithm may be in either power running / regeneration.

(Step 4)
The total required power calculation circuit 23 compares the above total required power Pmg (t) ^** with the maximum power Ps (SOC) max that can be supplied or received by the electrical storage device 12 + the maximum engine power Emax, and the output suppression coefficient K1 (0≤K1 <1) is calculated.

(During power running)
Case 1: When Pmg (t) ^** ≦ Ps (SOC) max + Emax, K1 = 1.

Case 2: If Pmg (t) ^** > Ps (SOC) max + Emax, K1 = Pmg (t) ^** / (Ps (SOC) max + Emax).

(At regeneration)
Case 3: When Pmg (t) ^** ≧ Ps (SOC) max, K1 = 1.

Case 4: When Pmg (t) ^** <Ps (SOC) max, K1 = Pmg (t) ^** / Ps (SOC) max. Engine power cannot be used during regeneration. A means for suppressing the regenerative output is provided separately.

(Step 5)
The total required power calculation circuit 23 corrects Pmg (t) ^** and required power Pi (t) ^** of each load with K1, and calculates Pmg (t) ^* and Pi (t) ^* .

^{Pmg (t) * = K1 ·} Pmg (t) ** = K1 · ΣPi (t) **
Pi (t) ^* = K1 · Pi (t) ^**

(Step 6)
The priority discriminating circuit 28 compares Pmg (t) ^* and Ps (SOC) ^* for each power running / regeneration and obtains further corrected required power Pi (t) ^* of each inverter 18, 18a, 18b. Perform correction calculation. Further, the required power calculation value Ps (t) ^* = Pr ^{* of} the electrical storage device 12 is also calculated.

(During power running)
Case 1: When Pmg (t) ^* ≦ Ps (SOC) ^* , Pi (t) ^* = Pi (t) ^*
Case 2: When Pmg (t) ^* > Ps (SOC) ^*
Pi (t) ^* = (Ps (SOC) ^* -ΣPi (t) ^* ) / n for the inverter 18 marked with * in FIG.
Pi (t) ^* = Pi (t) ^* for the inverters 18a and 18b not marked with ^* in FIG.

    The difference between the load demand power and the demand power correction value is supplied by the engine of the first power source 11 whose output is automatically controlled by the governor. Further, when the engine output of the first power source 11 is not automatically increased (down), this is dealt with by increasing (down) the output of the first power source 11 by a control command.

(At regeneration)
Case 3: When Pmg (t) ^* ≦ Ps (SOC) ^* , Pi (t) ^* = Pi (t) ^*
Case 4: If Pmg (t) ^* > Ps (SOC) ^* ,
Pi (t) ^* = (Ps (SOC) ^* -ΣPi (t) ^* ) / n for the inverter 18 marked with * in FIG.
Pi (t) ^* = Pi (t) ^* for the inverters 18a and 18b not marked with ^* in FIG.

In any of cases 1 to 4, Ps (t) ^* = ΣPi (t) ^* . This is the same as calculating Ps (t) ^* = min (Pmg (t) ^* , Ps (SOC) ^* ) in both power running and regeneration modes. This operation is performed so that Pmg (t) ^* = ΣPi (t) ^* = Ps (SOC) ^* .

(Step 7)
Each inverter current command calculation circuit 27 calculates a control command Pi (t) to each inverter 18, 18a, 18b, and a charge / discharge current calculation circuit 30 controls a control command Ps (t ) Or I. Also, bus voltage deviation correction is performed as follows.

  7-1 Calculate the bus voltage deviation ΔV. The calculation formula is shown in the definition.

  7-2 Calculate the voltage deviation correction amount ΔP. The calculation formula is shown in the definition.

  7-3 Calculate the control command.

7-3-1 Initial operation Pi (t) = Pi (t) ^*
Pmg (t) 1 = ΣPi (t)
Ps (t) 1 = (Ps (SOC) ^* + ΔP) = (Pmg (t) 1 + ΔP)

7-3-2 Final calculation Compare Ps (t) 1 and Ps (SOC) max, correct the calculated value, and determine the final control command. For Ps (SOC) max, a positive value is selected during power running and a negative value is selected during regeneration. Abs is an absolute value calculation.

    Case 1: If Abs (Ps (t) 1) <Abs (Ps (SOC) max), Pi (t) = Pi (t), Pmg (t) = Pmg (t) 1 (reference calculation), Ps (t) = Ps (t) 1.

    Case 2: When Abs (Ps (t) 1) ≧ Abs (Ps (SOC) max), Pi (t) = K3 · Pi (t), Pmg (t) = K3 · Pmg (t) 1 (reference) Calculation), Ps (t) = K3 · Ps (t) 1.

    K3 is a coefficient satisfying Abs (Ps (t)) <Abs (Ps (SOC) max). The capacity of the electrical storage device 12 is a capacity that satisfies the maximum regenerative power> Ps (SOC) max (regeneration side).

    However, if suppression is required during regeneration (when K3 <1), the means is provided separately.

  7-4 Check that the bus voltage V is within the allowable range.

  Vlo <V <Vhi

(Step 8)
A control command Pi (t) is output from each inverter current command calculation circuit 27, and Ps (t) or I is output from the charge / discharge current calculation circuit 30.

  Next, FIG. 3 shows an image diagram of the power source limit value. In this figure, Ps (SOC) max and Ps (SOC) c have two types of data during power running and regeneration. Note that FIG. 3 is not necessarily limited to this figure, and may be optimally set according to the power source characteristics.

  Next, the function and effect of the above embodiment will be described.

(1) Calculate the required power command of the second power source from the total required power of the hydraulic device / actuator 16, 16a and load 16b and the charge / discharge request of the second power source determined from the charge / discharge state of the electrical storage device. By controlling the charging / discharging current of the second power source 14, and calculating the power command to the motor generator device (each motor generator 17, 17a, 17b, each inverter 18, 18a, 18b) in a total control Therefore, the first power source that uses the engine whose engine output is automatically increased or decreased by governor control when the power is excessive or insufficient automatically controls to supplement the discharge power of the second power source 14. , The required power of each subsystem comprising the motor generator device (motor generators 17, 17a, 17b, inverters 18, 18a, 18b) is shared and shared by the first power source 11 and the second power source 14. , And can be comprehensively controlled to reduce energy loss. Further, since the second power source 14 is a control target and the first power source 11 automatically compensates for the shortage of discharge power of the second power source 14, the control system can be simplified. However, when the output of the first power source 11 is not automatically increased (down), it is necessary to cope with it by increasing (down) the output of the first power source 11 by a control command.

(2) When power running / regeneration coexists between multiple subsystems (motor generator 17, inverter 18, motor generator 17a, inverter 18a, motor generator 17b, inverter 18b), power is supplied from the regeneration side to the power running side. By supplying, the burden on the first power source 11 and the second power source 14 can be reduced, the energy loss in the first power source 11 and the second power source 14 can be reduced, and the loss can be reduced by comprehensive control. I can plan. This control can be applied not only to a parallel system in which the first power source 11 and the second power source 14 are connected in parallel but also to a series system hybrid in which the first power source 11 and the second power source 14 are connected in series.

(3) When the power is not sufficient by the interchange of power among the plurality of subsystems and the discharge from the second power source alone, the motor generator connected in parallel with the first power source 11 is connected to the first power source. By using 11 as a power generator, power is interchanged from the first power source 11, so that flexible power supply can supply and recover the subsystem required power that exceeds the capacity of the second power source 14. A system can be provided, and the capacity of the second power source 14 can be reduced, which is advantageous in terms of cost and space factor.

(4) The inverter current command supplied to the inverters 18, 18a, 18b for controlling the motor generators 17, 17a, 17b is converted from the power command calculated by the priority determination circuit 28 for calculating the control command in total. The charge / discharge current command supplied to the converter 13 of the second power source 14 is calculated by the charge / discharge current calculation circuit 30 from the charge / discharge request power command calculated by the command calculation circuit 27 and calculated by the priority determination circuit 28. Therefore, the inverters 18, 18a, 18b of the motor generators 17, 17a, 17b and the converter 13 of the second power source 14 can be comprehensively controlled, energy loss can be controlled to a minimum, and the second power source 14 can be controlled. Enables long-term (semi-permanent) continuous operation.

  That is, in general, since the force action force is larger than the regenerative power, the second power source 14 is gradually discharged, so that frequent charging work using a charging device is necessary. In the embodiment, the second power source 14 is devised so that the motor generator 17 and the inverter 18 marked with * (referred to as M / INVs 17 and 18 marked with *) are used as the generator. This can be performed regardless of whether the operation target is in a power running / regenerative state. For example, when the operation target of * / M / INVs 17 and 18 is in power running, the first power source 11 has power action force and charging power (marked with *). M / INV17 and 18 are controlled as a regeneration mode and share charging power), so that the operability and reliability of the system can be improved.

(5) Even when there is an imbalance between the required power and the supplied power, the bus power voltage deviation correction circuit 29 performs a correction operation so that the bus voltage V is maintained within the allowable range Vio to Vhi. The steady state and transient imbalances between the power supply and the supply power can be corrected to keep the system in the operable range and to increase the stability of the system.

  In this way, a power control system suitable for the parallel hybrid mounted on the work machine can be constructed.

  The present invention is not limited to a parallel type hybrid. For example, a technique for reducing the load of a power source by mutually supplying power between a plurality of subsystems is a series type hybrid. It is also applicable to.

1 is a block diagram showing an embodiment of a hybrid power control system according to the present invention. FIG. It is a flowchart which shows the control procedure of a control system same as the above. It is a characteristic view which shows the power source limit value of a control system same as the above. It is a side view of the working machine carrying a control system same as the above.

Explanation of symbols

11 First power source
12 Electric storage device
13 Converter as second controller
14 Second power source
16, 16a Hydraulic device / actuator as target
16b Load as target
17, 17a, 17b Motor generator
18, 18a, 18b Inverter as first controller
21 Control circuit
23 Total required power calculation circuit
25 Charge / Discharge Request Value Calculation Circuit for Electric Storage Device as Charge / Discharge Request Value Calculation Circuit
27 Each inverter current command calculation circuit as the first controller control command calculation circuit
28 Priority discrimination circuit
29 Bus voltage deviation correction circuit
30 Charge / discharge current calculation circuit as charge / discharge control command calculation circuit

Claims (5)

A motor generator controlled by a first controller and driving an operation target;
A first power source that drives an operation target by an engine output that automatically increases and decreases by governor control when power is excessive or insufficient;
A second power source having an electrical storage device capable of storing electrical energy generated from the motor generator and having a second controller for controlling charging and discharging of the electrical storage device;
A control circuit for calculating a required power command of the second power source from a discharge request of the second power source determined from a total required power of the operation target and a charge / discharge state of the electric storage device and controlling a charge / discharge current of the second power source; A hybrid power control system comprising: A plurality of motor generators and first controllers are provided,
The hybrid power control system according to claim 1, wherein the control circuit supplies power from the regenerative motor generator to the power running motor generator. The control circuit
When power is not sufficient only by the interchange of power between the plurality of motor generators and the discharge from the second power source, the motor generator connected in parallel with the first power source is used, and the first power source is used as the power source. The hybrid power control system according to claim 2, wherein the power is interchanged from the first power source by using the generator as described above. The control circuit
A total required power calculation circuit for calculating the total required power from each required power to be actuated;
A charge / discharge demand value calculation circuit for calculating charge / discharge demand power from the charge / discharge state of the electrical storage device of the second power source;
Decide which of the total required power from the operation target and the charge / discharge required power from the second power source should be given priority as a command to the second power source, and total so that the power balance in the bus can be balanced A priority discrimination circuit for calculating a power command to the first controller to be controlled;
A first controller control command calculation circuit for calculating a first controller control command supplied to a first controller for controlling the motor generator from the power command calculated by the priority determination circuit;
The charging / discharging control command calculation circuit which calculates the charging / discharging control command supplied to the 2nd controller of a 2nd power source from the charging / discharging request | requirement power command calculated by the priority determination circuit was provided. The hybrid power control system according to any one of claims 1 to 3. The hybrid power control system according to claim 4, further comprising: a bus voltage deviation correction circuit that calculates a correction amount so as to maintain the bus voltage within an allowable range and supplies the correction amount to the charge / discharge control command calculation circuit.

Images