JP6601141B2 - Hybrid vehicle and control method thereof - Google Patents

Description

  In the present invention, when the charge amount of the battery is close to full charge and it is necessary to apply a braking force to the drive mechanism, the electric power generated by the traveling motor is maintained while maintaining the braking force applied to the drive mechanism. The present invention relates to a hybrid vehicle and a control method therefor, in which the battery is prevented from being overcharged.

  In recent years, from the viewpoints of improving fuel efficiency and environmental measures, a hybrid vehicle that uses an engine (internal combustion engine) and a travel motor (electric motor) as power sources and travels with either or both driving forces. Is attracting attention.

  In hybrid vehicles, an engine and a travel motor are directly connected to each other, and the power generated by driving a generator (generator) with the engine is stored in a battery, and the electric power stored in the battery is supplied to the travel motor. There is a series-type hybrid vehicle configured to obtain a driving force for traveling.

  On the other hand, the battery is charged by the engine in the same way as the above-mentioned series-type hybrid vehicle, but it is configured not only to run by the driving motor but also to run by the engine alone or by both the engine and the driving motor. There are also parallel-type hybrid vehicles.

  These hybrid vehicles, for example, when driving down a slope, regeneratively control a traveling motor to apply a braking force to a drive mechanism such as a propeller shaft, and also generate electric power generated when the braking force is applied to a battery. It is configured to charge.

  However, if the battery is overcharged, problems such as a significant decrease in battery life occur. Therefore, if the battery charge is close to full charge (100% charge), the battery Can not be charged. In such a case, the regenerative control itself must be suppressed, and as a result, the braking force that should be applied to the drive mechanism is insufficient. Then, the insufficient braking force is compensated by engine brake or the like. However, when the engine brake is frequently used, a feeling of shock and engine sound increase, and drivability deteriorates.

  Accordingly, there has been proposed a hybrid vehicle including a power generation amount reduction unit that reduces the power generation amount without changing the torque of the generator when all of the power generated by the generator cannot be received by the battery (for example, Patent Document 1).

  More specifically, this hybrid vehicle has a current phase (current advance) determined by the d-axis current and q-axis current when the battery charge is close to full charge and the braking force by the regenerative operation of the travel motor is required. Angle) and current value are controlled to increase the copper loss of the travel motor, thereby increasing the motor loss of the travel motor and realizing low-efficiency regenerative control.

  As a result, the braking force determined based on the driving state of the hybrid vehicle continues to be output, and at the same time, the generated power of the traveling motor is reduced to a level that can be accepted by the battery, and surplus generated power is consumed as a loss due to a decrease in driving efficiency. ing.

However, the braking force required for the traveling motor varies greatly depending on the state of the traveling road such as a slope and the weight of the hybrid vehicle. In particular, in a heavy vehicle such as a truck such as a truck, when the amount of charge of the battery is close to full charge as described above, only the control for increasing the copper loss described in Patent Document 1 provides the necessary braking force. Since it cannot be obtained and engine brake is used together, the traveling performance of the hybrid vehicle may be deteriorated.

  In addition, the copper loss originally increases at low rotation and high torque. For example, when a hybrid vehicle tries to obtain braking force during high-speed driving, the travel motor rotates at high speed, so only copper loss is necessary. It may be difficult to obtain a sufficient braking force.

JP 2000-152409 A

  The present invention has been made in view of the above-described problems, and the problem is that the battery is charged to the drive mechanism when the amount of charge is close to full charge and it is necessary to apply a braking force to the drive mechanism. An object of the present invention is to provide a hybrid vehicle and a control method therefor that can prevent overcharging of a battery by reducing the electric power generated by a traveling motor while maintaining the braking force applied.

In order to solve the above-described problems, a hybrid vehicle according to the present invention controls an engine, a travel motor that is regeneratively and powered by an inverter, and a drive mechanism that regeneratively controls the travel motor to transmit the driving force of the engine. A hybrid vehicle including a control device that applies power and controls the charged electric power to be charged in a battery. The hybrid vehicle includes iron loss increasing means for increasing iron loss of the travel motor, and the driving mechanism has braking force. when granting, the control device, and when the above low efficiency judgment value the charge amount is determined in advance of the battery, the charging amount of the battery is less than the low efficiency judgment value, and the voltage of said battery when a predetermined or more deterioration determination value, also characterized in that it is configured to perform control of increasing the loss of the traveling motor by the iron loss increasing means It is.

  Note that the iron loss of the travel motor here is the total loss of hysteresis loss and eddy current loss caused by the change in the magnetic field of the magnetic circuit of the travel motor, and the electric resistance in the winding wire. The efficiency of the travel motor is determined in combination with the copper loss caused by the mechanical loss and the mechanical loss caused by mechanical factors such as friction.

  The iron loss increasing means for increasing the iron loss may be any means that can increase the iron loss of the traveling motor, and includes an increase in magnetic density and an increase in magnetic change speed, and is not particularly limited. For example, by increasing the switching frequency of an inverter that can be controlled by PWM (Pulse Width Modulation) and increasing the number of pulses and frequency for one cycle, the speed of change in the magnetism of the traveling motor can be made faster and the vortex can be increased. There are means to increase the current loss. In the case of this means, by increasing the switching frequency, the iron loss of the traveling motor is increased, and the switching elements in the inverter are turned ON and OFF, and the switching loss generated at the time of ON and OFF is also increased. Thereby, since the switching loss of an inverter is added to the iron loss of a traveling motor, more efficient regeneration control can be performed. Further, since the magnetic permeability decreases as the temperature increases, there is a means for increasing the hysteresis loss by raising the temperature of the rotor to intentionally lower the magnetic permeability.

Further, the predetermined low efficiency judgment value is a value set before full charge (a state where the charge amount is 100%), and preferably, even if the generated power generated by the low efficiency regenerative control is charged. Set the value so that it does not charge. The low efficiency determination value is set stepwise depending on the battery condition, for example, the first low efficiency determination value is set to 80% charge amount and the next low efficiency determination value is set to 90% charge amount. Then, overcharging of the battery can be surely prevented.

  According to this configuration, when the charge amount of the battery is close to full charge and it is necessary to apply a braking force to the drive mechanism, the iron loss of the travel motor is increased and the travel motor is regenerated with low efficiency. By controlling, the braking force required by the hybrid vehicle can be applied, the generated power charged in the battery can be reduced, and the overcharge of the battery can be suppressed. As a result, the battery can be protected without changing the drivability of the hybrid vehicle even when the amount of charge of the battery is nearly full.

  For example, if the iron loss increasing means is implemented when the battery charge is close to full charge, the iron loss of the travel motor increases, so the braking force does not change, but the generated power is small. Low-efficiency regeneration control can be performed. As a result, the required braking force can be applied to the drive mechanism, so there is no need to bother to engage the clutch and use the engine brake together, and to suppress the feeling of shock and engine noise. Further, since the generated electric power is reduced, the battery is not overcharged, and it is possible to protect against damage related to the life of the battery, over-design voltage, and the like.

In addition, a hybrid vehicle of the present invention for solving the above problems includes an engine, a travel motor that is regeneratively and power-running controlled by an inverter, and a drive mechanism that regeneratively controls the travel motor to transmit the driving force of the engine. In the hybrid vehicle comprising a control device for applying a braking force to the battery and controlling the generated power to be charged in the battery, the iron loss increasing means for increasing the iron loss of the travel motor, and the copper of the travel motor A copper loss increasing means for increasing the loss , and when applying a braking force to the drive mechanism, the control device is configured to charge the battery when the charge amount of the battery is equal to or higher than the low efficiency determination value. the amount is less than the low efficiency judgment value, and, when the voltage is not less than the degradation determination value determined in advance of the battery, the less of the iron loss increase means and the copper loss increasing means On the other hand, or by both and is characterized in that is configured to perform control of increasing the loss of the traveling motor. According to this configuration, even when the charge amount of the battery is close to full charge, both the iron loss and the copper loss of the travel motor can be increased, and the braking force required by the hybrid vehicle can be applied. Battery overcharging can be prevented more reliably.

  For example, if the required braking force is small, select either iron loss increasing means or copper loss increasing means, and if the required braking force is large, both iron loss increasing means and copper loss increasing means Select. Alternatively, the iron loss increasing means may be selected during high-speed rotation and the copper loss increasing means may be selected during low-speed rotation according to the rotational speed of the travel motor.

  As a result, the traveling motor can apply the required braking force to the drive mechanism without using the engine brake even in a heavy vehicle such as a truck or during high-speed driving. Therefore, drivability can be improved. Moreover, even when the battery capacity is small, overcharging can be prevented.

In addition, the hybrid vehicle control method of the present invention for solving the above-described problems regenerates a traveling motor that is regenerated and powered by an inverter, and applies a braking force to a drive mechanism that transmits the drive force from the engine. In addition, in the hybrid vehicle control method for charging the generated electric power to the battery, when the braking force is applied to the drive mechanism, when the amount of charge of the battery is equal to or higher than a predetermined low efficiency determination value , When the amount of charge of the battery is less than the low efficiency determination value and the voltage of the battery is equal to or higher than a predetermined deterioration determination value , the iron loss of the travel motor is increased and the control applied to the drive mechanism is increased. In this method, the electric power generated by the traveling motor is reduced without reducing the power.

Furthermore, the hybrid vehicle control method of the present invention for solving the above-described problems regenerates a traveling motor that is regenerated and powered by an inverter, and applies a braking force to a drive mechanism that transmits the drive force from the engine. In addition, in the hybrid vehicle control method for charging the generated electric power to the battery, when the braking force is applied to the drive mechanism, when the charge amount of the battery is equal to or higher than the low efficiency determination value , When the amount of charge is less than the low efficiency determination value and the voltage of the battery is equal to or higher than a predetermined deterioration determination value , at least one of the iron loss and copper loss of the travel motor, or both is increased, In this method, the electric power generated by the travel motor is reduced without reducing the braking force applied to the drive mechanism .

  According to the present invention, even when the amount of charge of the battery is near full charge, the iron loss of the travel motor is increased, and the travel motor is subjected to low-efficiency regenerative control, thereby providing the braking force required by the hybrid vehicle. In addition, it is possible to reduce the electric power generated by the battery and to suppress overcharge of the battery. Thereby, even when the charge amount of the battery is close to full charge, deterioration of the battery can be suppressed without changing the drivability of the hybrid vehicle.

It is a block diagram which shows the control system of the hybrid vehicle of embodiment which concerns on this invention. FIG. 2 is a block diagram illustrating a travel motor, an inverter, a relay circuit, a battery, and a control device that controls them as illustrated in FIG. 1. It is a graph which shows the principle of the iron loss increasing means shown in FIG. 2, (a) shows the time of normal regeneration, (b) shows the time of low efficiency regeneration. It is a flowchart which shows the control method of the hybrid vehicle of embodiment which concerns on this invention. It is a graph which shows the ratio of the low efficiency regeneration with respect to the braking force of the hybrid vehicle of embodiment which concerns on this invention, and the hybrid vehicle of a prior art.

  Hereinafter, a hybrid vehicle and a control method thereof according to an embodiment of the present invention will be described with reference to the drawings. In the following embodiment, a parallel type hybrid vehicle that generates a driving force by combining an engine and a traveling motor will be described as an example. However, the present invention can also be applied to a series type hybrid vehicle. Further, among parallel hybrid vehicles, a description will be given by taking, as an example, a vehicle having a heavy vehicle weight such as a truck and requiring a large braking force in the drive system.

  In addition, the dimensions of the drawings are changed so that the configuration is easy to understand. In particular, the ratios of the width and length of the graph do not always match the ratios of the actually manufactured products.

  First, a hybrid vehicle (hereinafter referred to as HV) 1 according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the HV 1 includes a diesel engine (an internal combustion engine; hereinafter referred to as an engine) 2 and a travel motor 3, and a battery 6 is electrically connected to the travel motor 3 through an inverter 4 and a relay circuit 5. Has been.

  The HV 1 includes a clutch unit 7, a transmission (transmission) 8, a propeller shaft 9, a differential 10, and a drive shaft 11 as a drive mechanism that transmits the driving force generated by the engine 2, and drives the drive wheels 12. To do. In addition, a starter 13 for applying a starting torque to the engine 2 is provided, and the clutch unit 7 includes a fluid coupling 14 and a hydraulic multi-plate clutch (hereinafter referred to as an engine clutch) 15.

  In addition, the HV 1 transmits a driving force generated by the traveling motor 3 and a mechanism for transmitting the driving force generated by the engine 2 to the traveling motor 3, as a traveling motor gear unit 16, a traveling motor output shaft 17, and A PTO (power input / output mechanism) 18 is provided, and the PTO 18 is provided with a slave dog clutch (hereinafter referred to as a dog clutch) 19.

Further, the HV 1 includes an engine ECU (engine control device) 20, a transmission ECU (transmission control device) 21, a hybrid ECU (hybrid control device) 22, and a brake ECU (brake control device) 23. Moreover, each ECU20-23 is mutually connected in parallel by the vehicle-mounted network 24, and is comprised so that information may be sent mutually.

Accelerator opening signal D _ACC of accelerator pedal 25, shift signal D _{T / M of} shift lever 26, brake signal D _BRA of brake pedal 27, brake pressure signal D _BP of brake device 28, actuation signal D _{ABS of ABS} , and inverter including 4 of the motor torque signal _{D TOR} is sent to each ECU20～23.

  Based on these signals, the engine ECU 20 controls the driving of the engine 2, the transmission ECU 21 controls the shift device 29 for connecting / disconnecting the engine clutch 15 and the transmission operation of the transmission 8, and the hybrid ECU 22 The driving of the battery 6 is controlled, the connection / disconnection of the dog clutch 19 is controlled, and the brake ECU 23 controls the operation of the ABS.

  In addition, the HV 1 includes a motor ECU 30 that is provided in the inverter 4 and controls the inverter 4 in response to a command from the hybrid ECU 22, and a battery ECU 31 that manages the charge amount and voltage of the battery 6. In addition, a cooling system 32 that cools the traveling motor 3 and the inverter 4 with cooling water is provided. The cooling system 32 includes a pump 33, a radiator 34, and a cooling fan 35. The cooling fan 35 is configured to cool the battery 6.

  The above configuration is an example, and the HV1 exemplified in the embodiment is not limited to the above configuration and may be a hybrid vehicle.

  In this embodiment, the traveling motor 3 is mainly used as an assist. Therefore, by reducing the charging capacity of the battery 6 and reducing the weight, a significant increase in vehicle weight is suppressed. Yes. However, reducing the charge capacity of the battery 6 increases the frequency at which the charge amount of the battery 6 becomes nearly fully charged (a state where the charge amount is 100%).

  Therefore, the HV 1 of the present invention is configured to include an inverter circuit (iron loss increasing means) 40 that increases the iron loss of the traveling motor 3 as shown in FIG. When the hybrid ECU 22 has a charge amount of the battery 6 equal to or higher than a predetermined low efficiency determination value and it is necessary to apply a braking force to a drive mechanism such as the propeller shaft 9, the hybrid ECU 22 controls the inverter circuit 40, It is comprised so that the control which increases the loss of the traveling motor 3 may be performed.

  In addition, when the hybrid ECU 22 has a charge amount of the battery 6 equal to or higher than a predetermined low efficiency determination value and it is necessary to apply a braking force to the drive mechanism, the inverter circuit 40 (iron loss increasing means and copper loss increasing) By means), it is configured to perform control to increase at least one or both of the iron loss and the copper loss of the travel motor 3.

  The inverter 4 of this embodiment divides a voltage waveform of one cycle and is constituted by a large number of pulse trains P1, changes the number, interval, pulse width H1, etc. of the pulse trains P1 with time, and calculates the average value as a sine In the case of an inverter capable of PWM (Pulse Width Modulation) control that is controlled so as to have a wave shape, and the inverter circuit 40 provided therein performs power running control of the traveling motor 3, for example, the switching frequency Thus, the frequency of the traveling motor 3 is controlled.

Here, a method for increasing the iron loss and a method for increasing the copper loss will be described. The iron loss of the traction motor 3 is a total loss of hysteresis loss and eddy current loss caused by the change of the magnetic field of the magnetic circuit, and the copper loss is caused by the electric resistance in the conducting wire of the winding. It is a loss to do.

  First, an example of a method for increasing the iron loss is to increase the switching frequency of the inverter circuit 40 so as to increase the number of pulses and the frequency of one cycle of generated power, thereby changing the magnetic change speed of the traveling motor 3. To increase eddy current loss. When the frequency of the generated power and the number of pulse trains P1 in one cycle are compared between the normal regeneration control of FIG. 3A and the low efficiency regeneration control of FIG. There are many pulse trains P1 in the low-efficiency regenerative control shown in (b). Thereby, compared with the time of the normal regenerative control of FIG. 3A, the change in the magnetic field increases and the iron loss increases during the low efficiency regenerative control of FIG. 3B.

  In the case of this method, by increasing the switching frequency of the inverter circuit 40, the iron loss of the traveling motor 3 is increased, and the ON operation and the OFF operation of the switching elements 41 to 46 in the inverter 4 are increased. The switching loss that occurs at ON and OFF also increases. Thereby, since the switching loss of the inverter 4 is added to the iron loss of the traveling motor 3, more efficient regenerative control can be performed.

  In addition to the above method, as a method of increasing the iron loss, for example, the hysteresis loss is increased by raising the temperature of the rotor formed by the permanent magnet of the traveling motor 3 and intentionally lowering the magnetic permeability. There is also a method. In this embodiment, a method for increasing the switching frequency will be described as an example, but the present invention is not limited to this.

  Next, there is a method for increasing the copper loss. For example, a known method described in Patent Document 1 (Japanese Patent Laid-Open No. 2000-152409) can be used. It is not limited.

  By providing the inverter circuit 40 that increases the iron loss and the copper loss as described above, the iron loss and the copper loss of the traveling motor 3 are increased, and the power generation is reduced in efficiency. The electric power charged in the battery 6 can be reduced without reducing the power. Thereby, even when the amount of charge of the battery 6 is close to full charge and when the driving mechanism requires a braking force, the engine brake is not required and overcharge of the battery 6 can be suppressed.

  Also, by providing the inverter circuit 40 that increases iron loss and copper loss, the braking force required by heavy vehicles such as trucks can be obtained because the conventional technology can only obtain the effect of copper loss. This problem can be solved by using both iron loss and copper loss.

  Furthermore, the problem that the conventional technique using only copper loss is difficult to achieve its effect at high speed rotation can be solved by using iron loss that increases loss especially at high speed rotation.

  As shown in FIG. 2, the hybrid ECU 22 includes a battery state determination unit M1, a normal regeneration control unit M2, and a low efficiency regeneration control unit M3 as a program.

  The battery state determination means M1 determines whether or not to reduce the power charged in the battery 6 based on the battery information sent from the battery ECU 31, more specifically, the charge amount CL of the battery 6 and the voltage BV of the battery 6. It is.

The charge amount CL here indicates what percentage at the present time when the full charge of the battery 6 at that time (the upper limit that can be actually charged) is 100% of the charge amount. For example, when the battery 6 is controlled by SOC (State of Charge) 10% to 90%, the SOC 90% is fully charged, the charge amount 100%, and the SOC 10% is the charge amount 0%.

  Further, the voltage BV indicates an average voltage of each cell of the battery 6. When the battery 6 of the embodiment has 100 cells, the average voltage is obtained. In this embodiment, the average voltage is used, but instead of the average voltage, a voltage state indicating each cell may be used. For example, when the battery 6 of the embodiment has 100 cells, the voltage is every 100 cells.

  The low-efficiency regenerative control means M3 is an inverter circuit when it is determined by the battery state determination means M1 that the charge amount of the battery 6 needs to be reduced and a regenerative torque as a braking force is requested from each ECU 20-23. The low-efficiency regeneration that generates a power less than the electric power charged in the battery 6 by the normal regeneration control means M2 can be applied to the drive mechanism by controlling the motor 40. This is means for controlling the travel motor 3 by control. The increase in the iron loss and the increase in the copper loss performed when the low-efficiency regeneration control unit M3 is performed are as described above.

  Next, a method for controlling the HV1 will be described with reference to the flowchart of FIG. In this flowchart, i is used as a variable. As this variable i, any number of 1 or more is inputted in order, but 1 is inputted at the start time.

First, each ECU20-23 performs step S10 which judges whether regeneration control is required. In this step S10, the ECUs 20 to 23 are operated by the propeller shaft from the traveling motor 3 based on the traveling state of the HV1 obtained from information such as the accelerator opening signal D _ACC , the shift signal D _{T / M} , and the brake signal D _BRA. It is determined whether a braking force is necessary for the driving mechanism such as 9. For example, when going down a slope. The determination result of step S10 is transmitted to the hybrid ECU 22 via the in-vehicle network 24.

  If it is determined in step S10 that regenerative control is necessary, the battery state determination means M1 next determines whether or not the charge amount CL is smaller than the i-th low efficiency determination value CLi (i = 1). I do. The first low efficiency determination value CL1 in step S20 is a predetermined charge amount, and is preferably a value that is close to full charge and that can charge a certain amount of power. The first low efficiency determination value CL1 is set to, for example, a charge amount of 80%. In this step S20, it is only necessary to be able to determine whether or not the charge amount CL is nearly full. For example, if the battery capacity is small, the first low efficiency determination value CL1 is set to a smaller value. Good.

If it is determined in step S20 that the charge amount CL is close to full charge, the process proceeds to step S60. On the other hand, if it is determined that the charge amount CL is not close to full charge, the battery state determination means M1 next performs step S30 to determine whether or not the voltage BV is smaller than the deterioration determination value BV1. The deterioration determination value BV1 in step S30 is a predetermined voltage value, and is preferably a value slightly lower than the voltage value BV _{MAX at} which there is a risk that deterioration of the battery 6 proceeds. This step S30 is a step of comparing the voltage BV, which is an average value of the voltages of all the cells of the battery 6, and the deterioration determination value BV1, but if the deterioration of the battery 6 is more reliably suppressed, It is good also as a step which compares each of the voltage of this cell, and deterioration determination value BV1.

  If the voltage BV is greater than or equal to the deterioration determination value BV1 in step S30, the process proceeds to step S60. On the other hand, if the voltage BV is smaller than the deterioration determination value BV1, next, step S40 for determining whether or not the variable i is 1 is performed. At this time point, since i = 1, the normal regeneration control means M2 performs step S50 for performing normal regeneration control of the traveling motor 3 and returns to step S10.

  By performing Step S20 and Step S30, the battery 6 is fully charged, and the battery 6 is charged before being overcharged and before being charged with a voltage at which the deterioration of the battery 6 tends to proceed. Since control can be performed so as to reduce the electric power, overcharge of the battery 6 can be suppressed, and progress of deterioration of the battery 6 can be suppressed. In step S30, when the voltage BV is equal to or higher than the deterioration determination value BV1, it is preferable to add control to lower the voltage BV.

  Further, by performing step S30, even when the charge amount CL of the battery 6 is less than the i-th low efficiency determination value CLi, it is determined whether or not the voltage BV of the battery 6 is smaller than the deterioration determination value BV1. The state in which the battery 6 cannot be charged normally can be determined. Thus, when the voltage BV of the battery 6 is equal to or higher than the deterioration determination value BV1, step S60 is performed, so that it is possible to avoid the deterioration of the battery 6 due to the increase in the temperature of the battery 6 when charging is performed as usual. .

If it is determined in step S20 that the charge amount CL is close to full charge, or if it is determined in step S30 that the voltage BV is greater than or equal to the deterioration determination value BV1, then the battery state determination means M1 Step S60 is performed to determine whether the low efficiency determination value CL1 is smaller than the charge upper limit value CL _MAX . This charge upper limit CL _MAX is a value that is as close as possible to the fully charged charge amount of 100%, and is set to, for example, a charged amount of 95%. At this time point, i = 1, and the first low efficiency determination value CL1 is 80% charged. Next, step S70 in which i = i + 1 is input is performed. Since i = 1 before step S70, i = 2 in step S70.

  Next, the battery state determination means M1 performs step S80 for calculating the second low efficiency determination value CL2. The second low efficiency determination value CL2 is a value used in the next step S20, and is a value larger than the first low efficiency determination value CL1. For example, the charge amount is set to 90%. As described above, in the control method of the present invention, the overcharge of the battery 6 is prevented by calculating each determination value step by step so that the charge amount CL of the battery 6 never becomes 100% of the fully charged amount. can do. Each i-th low efficiency determination value CLi determined by the variable i is set to a value described in a predetermined low efficiency determination value map based on parameters such as the voltage BV and the temperature of the battery 6, for example. Etc.

  By performing this step S80, the state immediately before the battery 6 is fully charged can be detected, so that overcharging of the battery 6 can be prevented.

Next, the low-efficiency regeneration control means M3 performs Step S90 for calculating the motor loss amount P _LOSS . This step S90 is a travel that is determined so that the charge amount of the battery 6 gradually increases toward the braking force (regenerative torque) requested in step S10 and the second low efficiency determination value CL2 calculated in step S80. This is a step of calculating a motor loss amount P _LOSS based on the electric power generated by the motor 3. The method of calculating the motor loss amount P _LOSS may be calculated as, for example, the power over amount known in Patent Document 1 (paragraphs [0015] to [0020] in Japanese Patent Laid-Open No. 2000-152409). Good.

Once the motor loss amount P _LOSS has been calculated, the low-efficiency regenerative control means M3 next performs step S100 of performing low-efficiency regenerative control of the traveling motor 3. In step S100, at least one of the increase in iron loss and the increase in copper loss of the travel motor 3 is selected or both are selected so that the motor loss amount P _LOSS calculated in step S90 is obtained.

  For example, when the regenerative torque requested by each of the ECUs 20 to 23 is not large, the inverter circuit 40 is controlled so as to increase only the iron loss as shown in the graph B of FIG. Further, when the required regenerative torque is large, the inverter circuit 40 is controlled to increase both the iron loss and the copper loss as shown in the graph D of FIG. In addition to this, it is preferable to control so that the iron loss is positively increased when the traveling motor 3 is rotated at a high speed and the copper loss is positively increased at a low speed. As described above, the copper loss increases at low rotation and high torque. On the other hand, the iron loss increases during high-speed rotation. Therefore, it is desirable to select whether to mainly increase the iron loss or mainly increase the copper loss according to the rotational speed of the traveling motor 3.

In this step S100, for example, when the iron loss is increased, control is performed using a map in which the ON operation timing and the OFF operation timing of each switching element 41 to 46 are described based on the motor loss amount P _LOSS. . In addition, in this step S100, it is only necessary to increase the iron loss and the copper loss so that the motor loss amount P _LOSS calculated in step S90 can be obtained, and the method is not limited.

Next, as shown in FIG. 4, when the low efficiency regenerative control is started in step S100, the process returns to step S10. From now on, the variable i = 2 is set and the steps are proceeded in the same manner as described above. For the i-th low efficiency determination value CLi calculated in step S80, for example, the charging amount is 80% when i = 1, the charging amount is 90% when i = 2, and the charging amount is 95% when i = 3. And In step S60 when the variable i = 3, the third low efficiency determination value CL3 and the charge upper limit value CL _MAX are equal to each other with a charge amount of 95%.

  In that case, next, step S110 which connects the clutch 15 for engines is performed, and this control method is completed. This step S110 is a step performed when it is determined in step S60 that it is better not to charge the battery 6 with any more power. As shown in the graph E of FIG. 5, the engine clutch 15 is connected. In this step, the braking force of the traveling motor 3 is lowered by using the engine brake together, and the generated electric power is further reduced accordingly.

  Note that if there is a case where the requested braking force cannot be applied to the drive mechanism even if the traveling motor 3 is normally regeneratively controlled in step S50, the low-efficiency regenerative control may be performed in that case.

  Further, when the low efficiency regenerative control is performed in step S100, the temperature of the traveling motor 3 and the inverter 4 rises as much as the iron loss and the copper loss of the traveling motor 3 increase, so that the cooling of the cooling system 32 shown in FIG. It is preferable to enhance the performance.

  According to the above control method, when the charge amount CL of the battery 6 is close to full charge, and when the voltage BV of the battery 6 is likely to progress deterioration, and when it is necessary to apply a braking force to the drive mechanism. By increasing the iron loss and copper loss of the traveling motor 3 and performing regenerative control of the traveling motor 3 with low efficiency, the braking force required by the HV 1 can be applied and the battery 6 is charged with power generation. Electric power can be reduced and overcharging of the battery 6 can be suppressed. Thereby, even if the charge amount CL of the battery 6 is almost full, the battery 6 can be protected without changing the drivability of the HV1.

  Further, as shown in the bluff G of FIG. 5, when only the copper loss of the prior art is increased, the braking force required by the heavy vehicle weight HV1 such as a truck cannot be obtained, and the engine brake is used together. However, in the present invention, the travel motor 3 can apply the required braking force to the drive mechanism without using the engine brake until the charge amount CL of the battery 6 is fully charged. Drivability can be improved. In addition, even when the capacity of the battery 6 is small, overcharging can be prevented.

  In this embodiment, the inverter circuit 40 that can increase both the iron loss and the copper loss is used. However, an inverter circuit that increases only the iron loss may be used. In addition to the above configuration, means for increasing the iron loss by increasing the hysteresis loss by raising the temperature of the rotor of the traveling motor 3 and intentionally lowering the magnetic permeability may be added. .

  The hybrid vehicle of the present invention increases the iron loss of the travel motor even in a state where the charge amount of the battery is close to full charge, and controls the travel motor with low-efficiency regenerative control so that the braking force required by the hybrid vehicle is increased. In addition to being able to be applied, it is possible to reduce the generated electric power charged in the battery and suppress overcharge of the battery. This makes it possible to suppress battery deterioration without changing the drivability of the hybrid vehicle even when the battery charge is close to full charge, so it should be used especially for heavy vehicles such as trucks. Can do.

1 HV (hybrid vehicle)
2 Engine 3 Traveling motor 4 Inverter 6 Battery 15 Engine clutch 22 Hybrid ECU (control device)
30 motor ECU
31 Battery ECU
32 Cooling system 33 Pump 34 Radiator 35 Cooling fan 40 Inverter circuit (iron loss increasing means)
41-46 Switching element M1 Battery state determination means M2 Normal regeneration control means M3 Low efficiency regeneration control means

Claims (6)

Regenerative control of the engine, a regenerative and power running control by an inverter, and regenerative control of the travel motor to apply a braking force to the drive mechanism that transmits the driving force of the engine and charge the generated power to the battery In a hybrid vehicle including a control device that performs control,
Comprising iron loss increasing means for increasing the iron loss of the travel motor;
When the braking force is applied to the drive mechanism, the control device is configured such that when the charge amount of the battery is equal to or higher than a predetermined low efficiency determination value , the charge amount of the battery is less than the low efficiency determination value, and The hybrid vehicle is configured to perform control to increase the loss of the travel motor by the iron loss increasing means when the voltage of the battery is equal to or higher than a predetermined deterioration determination value . Regenerative control of the engine, a regenerative and power running control by an inverter, and regenerative control of the travel motor to apply a braking force to the drive mechanism that transmits the driving force of the engine and charge the generated power to the battery In a hybrid vehicle including a control device that performs control,
Iron loss increasing means for increasing the iron loss of the traveling motor; and copper loss increasing means for increasing the copper loss of the traveling motor ;
When applying a braking force to the drive mechanism, the control device is configured such that when the charge amount of the battery is equal to or higher than the low efficiency determination value , the charge amount of the battery is less than the low efficiency determination value, and when the voltage of the battery is more than the degradation determination value determined in advance, at least one of the iron loss increase means and the copper loss increasing means, or that is configured to perform control of increasing the loss of the traveling motor by both A hybrid vehicle characterized by The control device selects at least the iron loss increasing means among the iron loss increasing means and the copper loss increasing means when the rotational speed of the traveling motor is in a predetermined high speed rotation region,
3. The apparatus according to claim 2, wherein when the rotational speed of the traveling motor is in a predetermined low-speed rotation region, at least the copper loss increasing means is selected from the iron loss increasing means and the copper loss increasing means. Hybrid vehicle.   The control device is configured to perform control to increase the loss of the travel motor in proportion to the magnitude of the low efficiency determination value while increasing the low efficiency determination value in a stepwise manner. 4. The hybrid vehicle according to any one of 3. In a control method for a hybrid vehicle that regenerates a traveling motor that is regenerated and powered by an inverter, applies a braking force to a drive mechanism that transmits a driving force from an engine, and charges a battery with generated electric power.
When the braking force is applied to the drive mechanism, when the charge amount of the battery is equal to or higher than a predetermined low efficiency determination value , the charge amount of the battery is less than the low efficiency determination value, and the voltage of the battery When the value is equal to or greater than a predetermined deterioration determination value, the iron loss of the traveling motor is increased, and the electric power generated by the traveling motor is reduced without decreasing the braking force applied to the drive mechanism. A control method of a hybrid vehicle characterized by the above. In a control method for a hybrid vehicle that regenerates a traveling motor that is regenerated and powered by an inverter, applies a braking force to a drive mechanism that transmits a driving force from an engine, and charges a battery with generated electric power.
When the braking force is applied to the drive mechanism, when the charge amount of the battery is equal to or higher than the low efficiency determination value , the charge amount of the battery is less than the low efficiency determination value, and the voltage of the battery is set in advance. When the deterioration determination value is equal to or greater than a predetermined deterioration determination value , at least one or both of the iron loss and the copper loss of the travel motor are increased, and the travel motor generates power without reducing the braking force applied to the drive mechanism. A method for controlling a hybrid vehicle, characterized in that the generated electric power is reduced.