Control method for inverter and inverter control device

Abstract

This control method for an inverter that connects a DC power supply and a rotary electric machine through a smoothing capacitor and has a pair of switching elements constituting an upper arm and a lower arm for each phase of the rotary electric machine, alternately executes: an upper-side short-circuit control for turning on the upper arm of each phase and turning off the lower arm of each phase; and a lower-side short-circuit control for turning off the lower arm of each phase and turning on the lower arm of each phase. When switching between the upper-side short-circuit control and the lower-side short-circuit control is performed, pairs of the upper arm and the lower arm are classified into either a first group or a second group, and with respect to the start state in which one of the upper arm and the lower arm of each phase is turned on, a transition state in which the switching of the arms belonging to the first group is started in advance is formed. After passage of predetermined time from the point of the time at which the switching of the arms belonging to the first group starts, a final state in which the other of the upper arm or the lower arm of each phase is turned on is formed, by starting the switching of the arms belonging to the second group.

Description

Inverter control method and inverter control device

[0001] The present invention relates to a method and a control device for an inverter that connects a DC power source and a rotating electric machine via a smoothing capacitor.

[0002] JP 5857394B2 discloses an inverter device that alternately performs first switching control and second switching control. The first switching control is a control that turns on all switching elements connected to the positive side of a DC power supply and turns off all switching elements connected to the negative side of the DC power supply. The second switching control is a control that turns off all switching elements connected to the positive side of the DC power supply and turns on all switching elements connected to the negative side of the DC power supply.

[0003] The inverter has a pair of switching elements that constitute an upper arm and a lower arm for each phase of the rotating electric machine. The inverter also connects a DC power source to the rotating electric machine via a smoothing capacitor. When an abnormality occurs in the control of the rotating electric machine, such as when the rotating electric machine reaches overspeed, a short circuit may be formed between the inverter and the rotating electric machine by turning on all of either the upper arms or the lower arms of each phase and turning off all of the other arms. This type of short circuit control is called ASC (active short circuit) control or three-phase short circuit control.

[0004] The ASC control can be performed by short-circuit control in which all upper arms are turned on and all lower arms are turned off (hereinafter referred to as upper-side short-circuit control), or by short-circuit control in which all upper arms are turned off and all lower arms are turned on (hereinafter referred to as lower-side short-circuit control). However, when the rotating electric machine is rotating, heat and current may be concentrated in a specific arm, making that specific arm more susceptible to deterioration. For this reason, when the rotating electric machine is rotating, it is preferable to perform the ASC control by alternately switching between the upper-side short-circuit control and the lower-side short-circuit control.

[0005] To switch between upper-side short-circuit control and lower-side short-circuit control, the upper arm and lower arm of each phase must be switched. If the upper arm and lower arm are simultaneously turned on and a through current flows, there is a risk of damage to switching elements, etc. For this reason, a dead time is provided when switching a pair of upper and lower arms to ensure that both are turned off. However, if a dead time is simply provided when switching between upper-side short-circuit control and lower-side short-circuit control, a large current may flow into a smoothing capacitor during the dead time, depending on the current that flowed into the rotating electric machine before the dead time (the induced voltage of the rotating electric machine), which could damage the smoothing capacitor.

[0006] An object of the present invention is to provide an inverter control method and control device that can protect a smoothing capacitor when switching between upper-side short-circuit control and lower-side short-circuit control.

[0007] One aspect of the present invention is a control method for an inverter that connects a DC power source to a rotating electric machine via a smoothing capacitor and has a pair of switching elements constituting an upper arm and a lower arm for each phase of the rotating electric machine. This inverter control method alternates between upper-side short-circuit control, which turns on the upper arm of each phase and turns off the lower arm of each phase, and lower-side short-circuit control, which turns off the lower arm of each phase and turns on the lower arm of each phase. When switching between the upper-side short-circuit control and the lower-side short-circuit control, the pairs of upper and lower arms are classified into either a first group or a second group. A transition state is formed in which switching of the arms belonging to the first group is initiated prior to an initial state in which one of the upper arms or the lower arms of each phase is on. Then, after a predetermined time has elapsed since the start of switching of the arms belonging to the first group, switching of the arms belonging to the second group is initiated, thereby forming a final state in which the other of the upper arms or the lower arms of each phase is on.

[0008] FIG. 1 is a block diagram showing the configuration of an electric vehicle according to a first embodiment. FIG. 2 is a circuit diagram showing the configuration of an inverter. FIG. 3 is a graph schematically showing phase currents. FIG. 4 is an explanatory diagram showing PWM signals in a normal mode. FIG. 5 is a block diagram showing the configuration of a portion of a PWM control unit related to ASC control. FIG. 6 is an explanatory diagram related to zero current avoidance processing. FIG. 7 is a flowchart related to ASC control. FIG. 8 is a time chart showing an example of a PWM signal in a first ASC mode. FIG. 9 is a time chart showing an example of a PWM signal in a second ASC mode. FIG. 10 is a time chart showing an example of a PWM signal in a third ASC mode. FIG. 11 is an explanatory diagram showing transitions of phase currents in the first ASC mode. FIG. 12 is an explanatory diagram showing transitions of phase currents in the second ASC mode. FIG. 13 is an explanatory diagram showing transitions of phase currents in the third ASC mode. FIG. 14 is a block diagram showing the configuration of an electric vehicle according to a second embodiment. FIG. 15 is a circuit diagram showing configurations of a first inverter and a second inverter. Fig. 16 is an explanatory diagram showing transitions of phase currents in a first ASC mode. Fig. 17 is an explanatory diagram showing transitions of phase currents in a second ASC mode. Fig. 18 is an explanatory diagram showing transitions of phase currents in a third ASC mode. Fig. 19 is a block diagram showing the configuration of a PWM control unit according to a modified example.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] [First Embodiment] Fig. 1 is a block diagram showing the configuration of an electric vehicle 100 according to a first embodiment. The electric vehicle 100 is a vehicle driven by electric power, and specifically, is an electric vehicle, a hybrid vehicle, or the like. As shown in Fig. 1, the electric vehicle 100 includes a rotating electric machine 10, a battery 11, an inverter 12, and a controller 13.

[0011] The rotating electric machine 10 is a motor or a generator. In this embodiment, the rotating electric machine 10 is a motor and functions as a driving force source for the electric vehicle 100. More specifically, the rotating electric machine 10 in this embodiment is a three-phase AC synchronous motor having three phases: U-phase, V-phase, and W-phase. Currents flowing through the U-, V-, and W-phases (hereinafter collectively referred to as phase currents i ｕ , i ｖ , i ｗ The electrical angle θ of the rotor (not shown) is acquired by the rotation sensor 15 as needed.

[0012] The battery 11 is a DC power supply that supplies power to the rotating electrical machine 10. The battery 11 is, for example, a lithium ion battery. In this embodiment, the battery 11 is rechargeable.

[0013] The inverter 12 (INV) converts DC power input from the battery 11 into AC power by PWM (Pulse Width Modulation) control and supplies it to the rotating electrical machine 10. The inverter 12 is connected to the battery 11 via a relay 16. The DC voltage V ｄｃ is acquired by the voltage sensor 17 as needed.

[0014] The controller 13 is a control device that comprehensively controls the operation of each part of the electric vehicle 100. In this embodiment, the controller 13 particularly functions as a control device for the inverter 12. The controller 13 is configured, for example, with one or more computers or circuits. The controller 13 is also programmed to control the operation of each part at a predetermined control cycle τ.

[0015] Specifically, the controller 13 includes a torque control unit 21, a coordinate conversion unit 22, a PWM control unit 23, a PWM signal generator 24, a coordinate conversion unit 25, a rotation speed calculation unit 26, an abnormality detection unit 27, and the like.

[0016] The torque control unit 21 controls the output torque of the rotary electric machine 10 to be equal to the torque command value T ＊The d- and q-axis voltage command values ​​v ｄ ＊ , v ｑ ＊ Calculate the following.

[0017] Torque command value T ＊ is a command value (target value) for the torque to be output by the rotary electric machine 10, and represents a torque requested by a driver or the like to the electric vehicle 100. The controller 13 controls the torque command value T ＊ The controller 13 also calculates (determines) the torque command value T ＊ Instead of calculating it by itself, the torque command value T ＊ In this embodiment, for simplicity, the torque command value T ＊ is assumed to be known.

[0018] dq axis voltage command value v ｄ ＊ , v ｑ ＊ is a command value (target value) for the voltage in the dq-axis coordinate system that rotates together with the rotor. ｄ ＊ , v ｑ ＊ is the d-axis voltage v ｄ The d-axis voltage command value v ｄ ＊ and the q-axis voltage v ｑ The q-axis voltage command value v ｑ ＊ It consists of:

[0019] More specifically, the torque control unit 21 calculates the torque command value T ＊ , DC voltage V ｄｃ , dq-axis current i ｄ , i ｑ , and the rotation speed N, the dq axis voltage command value v ｄ ＊ , v ｑ ＊ Calculate the dq axis current i ｄ , i ｑ is the d-axis current iｄ and q-axis current i ｑ In this embodiment, the d-axis voltage v ｄ , v ｑ is a detected value, and in the coordinate conversion unit 25, the phase current i ｕ , i ｖ , i ｗ and the electrical angle θ. The rotation speed N [rpm] is a detected value or an estimated value. In this embodiment, the rotation speed N is calculated by the rotation speed calculation unit 26 based on the electrical angle θ.

[0020] The coordinate conversion unit 22 converts the dq-axis voltage command value v ｄ ＊ , v ｑ ＊ and the electrical angle θ, the three-phase voltage command value v ｕ ＊ , v ｖ ＊ , v ｗ ＊ The three-phase voltage command value v ｕ ＊ , v ｖ ＊ , v ｗ ＊ is a command value (target value) for voltage in the UVW coordinate system. Specifically, the coordinate conversion unit 22 calculates the three-phase voltage command value v ｕ ＊ , v ｖ ＊ , v ｗ ＊ The three-phase voltage command value v ｕ ＊ , v ｖ ＊ , v ｗ ＊ is the voltage command value v of the U phase ｕ ＊ , V-phase voltage command value v ｖ ＊ , and the W-phase voltage command value v ｗ ＊ It consists of:

[0021]

[0022] The PWM control unit 23 calculates duty command values, which are command values ​​for determining the duty ratio in PWM control. The PWM control unit 23 calculates duty command values ​​Duty_U, Duty_V, and Duty_W (hereinafter abbreviated as duty command values ​​Duty_UVW, etc.) for the UVW phases, respectively.

[0023] The PWM control unit 23 also outputs a gate enable signal S ＧＰ The gate enable signal S ＧＰ is a signal that uniformly permits or prohibits gate voltage control of the switching elements. ＧＰ is "enabled", the inverter 12 is enabled. ＧＰ When is "prohibited", the inverter 12 is effectively disabled.

[0024] In this embodiment, the PWM control unit 23 receives the status signal S output from the abnormality detection unit 27. ｓｔａｔｅ , the absolute value |N| of the rotation speed N, and the DC voltage V ｄｃ Based on this, the gate enable signal S ＧＰ and a generation mode of the duty command value Duty_UVW (hereinafter, the duty command value generation mode S ｍｏｄｅ Specifically, the PWM control unit 23 sets or changes the gate enable signal S ＧＰ and duty command value generation mode S ｍｏｄｅ Set or change the

[0025]

[0026] Status signal S ｓａｔｅ indicates "normal" and the rotating electrical machine 10 can be driven without any problems, the PWM control unit 23 calculates the absolute value |N| of the rotation speed N and the DC voltage V ｄｃ Regardless of the gate enable signal S ＧＰ is set to "Permitted" and the duty command value generation mode S ｍｏｄｅis set to the normal mode. The normal mode is a mode in which a duty command value Duty_UVW for driving the rotary electric machine 10 is generated. In the normal mode, the duty command value Duty_UVW is generated according to the following equation (2). Note that equation (2) shows a method for calculating the duty command value Duty_U of the U phase, but in equation (2), the voltage command value v ｕ ＊ is the voltage command value v of the V phase or W phase. ｖ ＊ , v ｗ ＊ By replacing the above with the above, the duty command values ​​Duty_VW of the V phase and W phase can be calculated in the same manner.

[0027]

[0028] Status signal S ｓｔａｔｅ indicates an "abnormality" and there is a problem in driving the rotating electric machine 10, the PWM control unit 23 calculates the absolute value |N| of the rotation speed N and the DC voltage V ｄｃ Based on this, the gate enable signal S ＧＰ and duty command value generation mode S ｍｏｄｅ Set.

[0029] Specifically, the status signal S ｓｔａｔｅ is "abnormal" and the absolute value |N| of the rotation speed N is greater than the rotation speed upper limit value N ＭＡＸ When |N|>N ＭＡＸ ), the PWM control unit 23 outputs a gate enable signal S ＧＰ is set to "Permitted" and the duty command value generation mode S ｍｏｄｅ Set to ASC mode. Upper limit of rotation speed N ＭＡＸ is determined in advance by adaptation based on experiments, simulations, etc. The ASC mode is a mode in which a duty command value Duty_UVW is generated to form a short circuit between the inverter 12 and the rotating electric machine 10.

[0030] In particular, in this embodiment, the PWM control unit 23 controls the DC voltage V ｄｃ According to the above, the duty command value generation mode S ｍｏｄｅto either the first ASC mode (ASC1), the second ASC mode (ASC2), or the third ASC mode (ASC3).

[0031] As shown in Table 1, the first ASC mode is ｄｃ is the upper voltage limit V ｄｃ－ＭＡＸ The second ASC mode is selected when the DC voltage V ｄｃ is the voltage lower limit V ｄｃ－ｍｉｎ and the voltage upper limit V ｄｃ－ＭＡＸ The third ASC mode is selected when the DC voltage V ｄｃ is the voltage lower limit V ｄｃ－ｍｉｎ The ASC mode is selected when the DC voltage V ｄｃ Voltage upper limit value V ｄｃ－ＭＡＸ and the voltage lower limit V ｄｃ－ｍｉｎ is determined in advance by adaptation based on experiments, simulations, etc.

[0032] Also, as shown in Table 1, the status signal S ｓｔａｔｅ is "abnormal" and the absolute value |N| of the rotation speed N is greater than the rotation speed upper limit value N ＭＡＸ When |N|≦N ＭＡＸ ), the PWM control unit 23 controls the DC voltage V ｄｃ Regardless of this, the gate enable signal S ＧＰ is set to "prohibited." In this case, the PWM control unit 23 does not generate the duty command value Duty_UVW.

[0033] The PWM signal generator 24 generates a gate enable signal S ＧＰ When the duty command value Duty_UVW is "enabled", the drive signal (hereinafter referred to as PWM signal) D of each switching element of the inverter 12 is generated by a compare match between the carrier signal CS and the duty command value Duty_UVW. ｕｕ ＊ ~D ｗｌ ＊ The inverter 12 generates the PWM signal D ｕｕ ＊ ~D ｗｌ ＊By controlling the on / off of the switching elements in accordance with the above, drive control or ASC control of the rotary electric machine 10 is performed. For simplicity, in this embodiment, the carrier signal CS is assumed to be a triangular wave having a constant period (2τ).

[0034] The coordinate conversion unit 25 converts the phase current i ｕ , i ｖ , i ｗ and the electrical angle θ, the dq-axis current i ｄ , i ｑ Specifically, the coordinate conversion unit 25 calculates the dq-axis current i ｄ , i ｑ Calculate the following.

[0035]

[0036] The rotation speed calculation unit 26 calculates the rotation speed N based on the electrical angle θ. Specifically, the rotation speed calculation unit 26 calculates the rotation speed N by converting the amount of change per unit time (dθ / dt) of the electrical angle θ using the number of pole pairs p of the rotating electric machine 10 in accordance with the following equation (4).

[0037]

[0038] In this embodiment, the rotation speed N is used as a parameter representing the rotation state of the rotating electric machine 10 in the drive control and ASC control of the rotating electric machine 10, but this is not limiting. For example, instead of the rotation speed N, an electrical angle θ, an electrical angular velocity, a mechanical angle, a mechanical angular velocity, or the like can be used as a parameter representing the rotation state of the rotating electric machine 10. In this case as well, the drive control and ASC control of the rotating electric machine 10 can be performed.

[0039] The abnormality detection unit 27 detects an abnormality in the system that drives the rotating electrical machine 10, i.e., whether or not there is a problem in driving the rotating electrical machine 10. In this embodiment, the abnormality detection unit 27 monitors the rotation speed N of the rotating electrical machine 10, and detects whether or not the absolute value |N| of the rotation speed N is equal to or exceeds the rotation speed upper limit value N ＭＡＸ When the phase current i exceeds the phase current i and the rotating electrical machine 10 reaches an over-rotation state, the abnormality detection unit 27 determines that an abnormality has occurred in the system. ｕ , i ｖ , iｗ and monitor these phase currents i ｕ , i ｖ , i ｗ When any of the above exceeds a predetermined threshold and reaches an overcurrent state, it is determined that an abnormality has occurred in the system. The abnormality detection unit 27 can also monitor parameters other than those described above, such as the voltage and temperature of the rotating electric machine 10 and the inverter 12 (switching element), to determine that an abnormality has occurred in the system. The abnormality detection unit 27 can also determine that an abnormality has occurred in the system when it detects a failure in the current sensor 14, the voltage sensor 17, or another detector not shown. In this embodiment, for simplicity, it is assumed that the abnormality detection unit 27 detects overspeed and overcurrent as system abnormalities, as described above.

[0040] The abnormality detection unit 27 outputs the result of the abnormality detection as a status signal S ｓｔａｔｅ In this embodiment, the state signal S ｓｔａｔｅ is a signal that indicates either "normal" or "abnormal."

[0041] Furthermore, when the abnormality detection unit 27 detects an abnormality in the system, if necessary depending on the cause of the abnormality, it further outputs a relay cut signal S ＲＣ In this case, the relay 16 is turned off, and the connection between the battery 11 and the inverter 12 is forcibly released. In this embodiment, the abnormality detection unit 27 outputs the relay cut signal S when it detects an over-speed or an over-current. ＲＣ Therefore, when overspeed or overcurrent occurs, the relay 16 is forcibly turned off, and the connection between the battery 11 and the inverter 12 is released.

[0042] 2 is a circuit diagram showing the configuration of the inverter 12. As shown in FIG. 2, the inverter 12 includes a smoothing capacitor 28 and a plurality of switching elements Q １ ~Q ６ A smoothing capacitor 28 is provided at the input terminal to smooth the input voltage from the battery 11. The voltage at the smoothing capacitor 28 is the DC voltage V ｄｃ Switching element Q１ ~Q ６ is configured using power semiconductor elements such as IGBTs (insulated gate bipolar transistors) and MOSFETs (metal oxide semiconductor field effect transistors), and each includes a free wheel diode. １ ~Q ６ When controlled to be on, the switching element Q is capable of conducting in the forward direction (from the positive electrode side to the negative electrode side of the battery 11), and when controlled to be off, it is not capable of conducting. １ ~Q ６ can be made conductive in the reverse direction (from the negative electrode side to the positive electrode side of the battery 11) by the free wheel diode.

[0043] Switching element Q １ , Q ２ constitutes the U-phase leg. That is, the series-connected switching element Q １ , Q ２ The U-phase stator coil (U) of the rotating electrical machine 10 is connected between the switching element Q １ is the upper arm of the U-phase leg, and is connected to the positive side (high side) of the battery 11. Also, the switching element Q ２ is the lower arm of the U-phase leg, and is connected to the negative side (low side) of the battery 11. １ The PWM signal that controls the on / off of ｕｕ ＊ and the switching element Q ２ The PWM signal that controls the on / off of ｕｌ ＊ is.

[0044] Switching element Q ３ , Q ４ constitutes the V-phase leg. That is, the series-connected switching element Q ３ , Q ４ The V-phase stator coil (V) of the rotary electric machine 10 is connected between the switching element Q ３ is the upper arm of the V-phase leg, and switching element Q ４ is the lower arm of the V-phase leg.３ The PWM signal that controls the on / off of ｖｕ ＊ and the switching element Q ４ The PWM signal that controls the on / off of ｖｌ ＊ is.

[0045] Similarly, switching element Q ５ , Q ６ constitutes the W-phase leg. That is, the series-connected switching element Q ５ , Q ６ The W-phase stator coil (W) of the rotating electrical machine 10 is connected between the switching element Q ５ is the upper arm of the W-phase leg, and switching element Q ６ is the lower arm of the W-phase leg. ５ The PWM signal that controls the on / off of ｗｕ ＊ and the switching element Q ６ The PWM signal that controls the on / off of ｗｌ ＊ is.

[0046] FIG. 3 shows the phase current i ｕ , i ｖ , i ｗ 3, when the rotating electric machine 10 is driven, the phase current i ｕ , i ｖ , i ｗ The switching element Q is set to a sine wave with a 1 / 3 period shift. １ ~Q ６ In addition, even if an abnormality occurs in the system and the relay 16 is turned off, the induced voltage generated in the rotating electrical machine 10 causes the same sinusoidal phase current i ｕ , i ｖ , i ｗ In the following figures, as in FIG. 3, the U-phase current i ｕ is represented by a solid line, and the V-phase current i ｖ is represented by a two-dot chain line, and the W-phase current i ｗ is represented by a dashed line.

[0047] 4 is an explanatory diagram showing a PWM signal in the normal mode. In FIG. 4, the duty command value Duty_U of the U phase and the PWM signal D ｕｕ ＊ , D ｕｌ ＊ The duty command values ​​Duty_VW of the V-phase and W-phase, and the PWM signals D ｖｕ ＊ ~D ｗｌ ＊ The same is true for .

[0048] As shown in Fig. 4, the PWM control unit 23 calculates and updates the duty command value Duty_U of the U phase for each predetermined control period (τ). However, the duty command value Duty_U calculated in a certain control period is reflected in the next control period. For example, in the control period P １ The duty command value Duty_U calculated in the control period P ２ Similarly, the control period P ２ The duty command value Duty_U calculated in the control period P ３ is used in the control period P ３ The duty command value Duty_U calculated in the control period P ４ Used in.

[0049] In principle, when the carrier signal CS matches the duty command value Duty_U calculated and updated as described above, the PWM signal generator 24 generates the PWM signal D ｕｕ ＊ , D ｕｌ ＊ Also, the PWM signal D for the upper arm is switched on (ON) / off (OFF). ｕｕ ＊ and the PWM signal D for the lower arm ｕｌ ＊ are complementary. That is, the PWM signal D for the upper arm ｕｕ ＊ When switching from ON to OFF, the PWM signal D ｕｌ ＊is switched from OFF to ON. Also, the PWM signal D ｕｌ ＊ When switching from ON to OFF, the PWM signal D ｕｕ ＊ can be switched from off to on.

[0050] However, in order to prevent a through current from flowing through the U-phase leg when the upper arm and the lower arm are simultaneously turned on, the PWM signal generator 24 provides a dead time DT. ｕｕ ＊ and the PWM signal D for the lower arm ｕｌ＊ In this embodiment, the PWM signal generator 24 inserts a dead time DT into the PWM signal of the arm that is switched from off to on. That is, when the upper arm is switched on, the PWM signal D ｕｕ ＊ Similarly, when the lower arm is switched on, the timing at which the PWM signal D for the lower arm is turned on is delayed by the dead time DT. ｕｌ ＊ The timing of turning on is delayed by the dead time DT.

[0051] 5 is a block diagram showing the portion related to ASC control in the configuration of the PWM control unit 23. As shown in FIG. 5, the PWM control unit 23 includes an up / down switching signal generation unit 31, a zero current avoidance processing unit 32, and an ASC switching processing unit 33.

[0052] The upper / lower switching signal generator 31 generates an ASC switching signal S that specifies the timing for switching between the upper short-circuit control and the lower short-circuit control. ＵＬ１ The upper side short circuit control is an ASC control that turns on the upper arms of the UVW phases and turns off the lower arms of the UVW phases, thereby forming a short circuit between the inverter 12 and the rotating electric machine 10. The lower side short circuit control is an ASC control that turns off the upper arms of the UVW phases and turns on the lower arms of the UVW phases, thereby forming a short circuit between the inverter 12 and the rotating electric machine 10. ASC switching signal S ＵＬ１is represented by "ON" which specifies the upper short circuit control or "OFF" which specifies the lower short circuit control. ＡＳＣ (See FIG. 6) are common in principle. The execution time t ＡＳＣ is set to a time that is at least sufficiently longer than the control period τ. ＡＳＣ is determined in advance by adaptation based on experiments, simulations, etc.

[0053] The zero current avoidance processing unit 32 performs the zero current avoidance processing to change the ASC switching signal S ＵＬ１ By correcting the ASC switching signal S ＵＬ２ The zero current avoidance process is carried out by controlling the timing of switching between the upper short circuit control and the lower short circuit control and the phase current i ｕ , i ｖ , i ｗ This is a process of delaying the timing of switching between the upper side short-circuit control and the lower side short-circuit control so that it does not overlap with the timing when either of the above two conditions becomes substantially zero.

[0054] 6 is an explanatory diagram relating to the zero current avoidance process. As shown in FIG. 6, for example, when the ASC switching signal S ＵＬ１ The timing of switching between the upper short circuit control and the lower short circuit control is determined by the U-phase current i ｕ In this case, the zero current avoidance processing unit 32 adjusts at least the U-phase current i ｕ The ASC switching signal S is set to delay the timing of switching between the upper short-circuit control and the lower short-circuit control until the time when the ASC switching signal S ＵＬ１ As a result, the final ASC switching signal S ＵＬ２ In this embodiment, the zero current avoidance processing unit 32 generates the phase current i ｕ , i ｖ , i ｗ When the absolute value of the phase current i is smaller than a predetermined threshold value ε, ｕ , i ｖ , i ｗ is determined to be substantially within a range that can be regarded as zero.

[0055] The ASC switching processing unit 33 (see FIG. 5) determines the current switching state and the phase current i ｕ , i ｖ , i ｗ Then, the ASC switching processor 33 classifies the pair of upper and lower arms (legs) into either the first group G1 or the second group G2 based on the direction of the carrier signal CS and the final ASC switching signal S ＵＬ２ , and duty command value generation mode S ｍｏｄｅ The duty command value Duty_UVW for the ASC mode is generated in accordance with the above.

[0056] Specifically, the ASC switching processing unit 33 classifies the pair of upper and lower arms of each phase into either the first group G1 or the second group G2 in accordance with Table 2 below.

[0057]

[0058] That is, when all the upper arms are currently ON (all the lower arms are OFF) and ASC control is being performed under the upper-side short-circuit control, the ASC switching processing unit 33 receives the phase current i ｕ , i ｖ , i ｗ The arms (legs) into which the phase current i flows are classified into a first group G1, and the phase current i ｕ , i ｖ , i ｗ In addition, when all the lower arms are currently ON (all the upper arms are OFF) and ASC control is being performed using lower-side short-circuit control, the ASC switching processing unit 33, inversely to the above, selects the arms (legs) into which the phase current i ｕ , i ｖ , i ｗ The arms (legs) into which the phase current i flows are classified into a second group G2, and the phase current i ｕ , i ｖ , i ｗ The arm (leg) into which the powder is poured is classified into the first group G1.

[0059] In this embodiment, the phase current i ｕ , i ｖ , i ｗThe direction of the phase current i flows between the connection point of the upper arm and the lower arm and the stator coil of the rotating electrical machine 10. ｕ , i ｖ , i ｗ For example, the direction from the U-phase stator coil (U) to the upper arm (Q) of the U-phase leg １ ) and lower arm (Q ２ ) U-phase current i ｕ When this U-phase current i ｕ The direction of is "rotating electric machine → arm". Conversely, the upper arm of the U-phase leg (Q １ ) and lower arm (Q ２ ) to the U-phase stator coil (U), a U-phase current i ｕ When this U-phase current i ｕ The direction is "arm → rotating electric machine".

[0060] The ASC switching processing unit 33 outputs the carrier signal CS and the final ASC switching signal S according to Table 3 below. ＵＬ２ , and duty command value generation mode S ｍｏｄｅ The duty command value Duty_UVW for the ASC mode is generated according to the above.

[0061]

[0062] That is, the duty command value generation mode S ｍｏｄｅ is in the first ASC mode (ASC1) or the second ASC mode (ASC2), the ASC switching processor 33 sets the duty command value Duty_G1 for the arms belonging to the first group G1 and the duty command value Duty_G2 for the arms belonging to the second group G2 to different values ​​when switching between the upper side short-circuit control and the lower side short-circuit control. More specifically, the ASC switching processor 33 sets the duty command values ​​Duty_G1 and Duty_G2 for the first group G1 and the second group G2 so that the arms belonging to the first group G1 are switched first, and then the arms belonging to the second group G2 are switched with a delay. As is clear from the calculation formula shown in Table 2, the delay time T ｄｅｌａｙ (predetermined time) is equal to the dead time DT in the second ASC mode (Tｄｅｌａｙ =DT), and in the first ASC mode, the sum of the dead time DT and the additional time tp (T ｄｅｌａｙ =DT+tp) The additional time tp is determined in advance based on an experiment, a simulation, or the like.

[0063] As a result, when switching between upper side short-circuit control and lower side short-circuit control, the ASC switching processor 33 creates a transition state in which switching of the arms belonging to the first group G1 is started prior to an initial state in which one of the upper arms or the lower arms of each phase is turned on. Then, the ASC switching processor 33 starts switching of the arms belonging to the second group G2 after a predetermined time (DT or DT+tp) has elapsed since starting switching of the arms belonging to the first group G1, thereby creating a final state in which the other of the upper arms or the lower arms of each phase is turned on.

[0064] As described above, the duty command values ​​Duty_G1 and Duty_G2 of each group that are shifted from the initial state through the transition state to the final state are determined by the rise or fall of the carrier signal CS and the final ASC switching signal S. ＵＬ２ Therefore, as shown in Table 3 above, the ASC switching processing unit 33 changes depending on the combination of the change modes of the carrier signal CS and the final ASC switching signal S ＵＬ２ Based on this, the duty command values ​​Duty_G1 and Duty_G2 of the respective groups are calculated.

[0065] In addition, in Table 2, the duty command value Duty_G1 for the first group G1, which is switched on first to form the transition state, is set to 50%, but this is just an example. The duty command value Duty_G1 for the first group G1, which is switched on first to form the transition state, can be set to any value other than 50%, as long as the switching of the second group G2 can be delayed by a predetermined time relative to the first group G1.

[0066] In addition, in the third ASC mode (ASC3), the duty command values ​​Duty_G1 and Duty_G2 of the first group G1 and the second group G2 are equal. In this embodiment, both are 50%. That is, the delay time T ｄｅｌａｙ (predetermined time) is zero (T ｄｅｌａｙ = 0) Therefore, in the third ASC mode, the arms belonging to the first group G1 and the second group G2 are switched at the same timing. Note that the "same timing" here describes the relationship between the first group G1 and the second group G2, and in the relationship between the upper arm and the lower arm, the dead time DT is provided as described above even in the third ASC mode.

[0067] The operation of the ASC control performed in the electric vehicle 100 configured as described above will be described below.

[0068] 7 is a flowchart relating to the ASC control. As shown in FIG. 7, in step S10, the controller 13 controls the phase current i ｕ , i ｖ , i ｗ , DC voltage V ｄｃ , and the electrical angle θ. The controller 13 also calculates the rotation speed N of the rotating electrical machine 10 based on the electrical angle θ using the rotation speed calculation unit 26. In step S11, the abnormality detection unit 27 detects whether or not there is an abnormality in the system that drives the rotating electrical machine 10, such as over-rotation or overcurrent.

[0069] If no abnormality is detected in step S11, the process proceeds to step S12, where the PWM control unit 34 calculates a duty command value Duty_UVW in the normal mode for driving the rotating electric machine 10. Then, the PWM signal generator 24 generates the PWM signal D in accordance with this duty command value Duty_UVW in the normal mode. ｕｕ ＊ ~D ｗｌ ＊ and drives the rotating electric machine 10. As a result, the rotating electric machine 10 generates a torque command value T ＊ The rotation is controlled so as to output a torque according to the

[0070] On the other hand, if an abnormality such as over-rotation or over-current is detected in step S11, the abnormality detection unit 27 outputs a relay cut signal S ＲＣ In step S13, the PWM control unit 23 sets the absolute value |N| of the rotation speed N to the rotation speed upper limit value N ＭＡＸ Compare with.

[0071] In step S13, the absolute value |N| of the rotation speed N is equal to the rotation speed upper limit value N ＭＡＸ If it is equal to or less than this, the process proceeds to step S14, and the PWM control unit 23 outputs the gate permission signal S ＧＰ is set to "prohibited". Therefore, ASC control is not performed. Even if some abnormality occurs during operation of the rotating electrical machine 10, the absolute value |N| of the rotation speed N is set to "prohibited". ＭＡＸ This is because when the voltage induced in the rotating electrical machine 10 is not so large, the system can be shut down without performing ASC control.

[0072] On the other hand, in step S13, the absolute value |N| of the rotation speed N is equal to or exceeds the rotation speed upper limit value N ＭＡＸ Specifically, the process proceeds to step S15, where the upper / lower switching signal generator 31 generates an ASC switching signal S for switching between the upper short-circuit control and the lower short-circuit control. ＵＬ１ In step S16, the zero current avoidance processing unit 32 generates the ASC switching signal S ＵＬ１ By correcting the ASC switching signal S ＵＬ２ Generate.

[0073] In step S17, the ASC switching processing unit 33 classifies pairs (legs) of upper and lower arms of each phase into either the first group G1 or the second group G2. ｕ , i ｖ , i ｗ The arms (legs) into which the phase current i flows are classified into a first group G1, and the rotating electrical machine 10 ｕ , i ｖ , i ｗ The arm (leg) that pours the lens is classified as the second group G2.

[0074] In step S18, the PWM control unit 23 controls the DC voltage V ｄｃ The voltage upper limit value V ｄｃ－ＭＡＸ In step S18, the DC voltage V ｄｃ is the upper voltage limit V ｄｃ－ＭＡＸ If it is greater than , the duty command value generation mode S ｍｏｄｅ Therefore, in the subsequent step S19, the ASC switching processing unit 33 sets the delay time T ｄｅｌａｙ is set to the sum of the dead time DT and the additional time tp.

[0075] In step S18, the DC voltage V ｄｃ is the upper voltage limit V ｄｃ－ＭＡＸ If it is equal to or less than the DC voltage V ｄｃ Further, the voltage lower limit value V ｄｃ－ｍｉｎ In step S20, the DC voltage V ｄｃ is the voltage lower limit V ｄｃ－ｍｉｎ or greater, i.e., V ｄｃ－ＭＡＸ ≧V ｄｃ ≧V ｄｃ－ｍｉｎ If so, the duty command value generation mode S ｍｏｄｅ Therefore, in the next step S21, the ASC switching processing unit 33 sets the delay time T ｄｅｌａｙ is set to the dead time DT.

[0076] In step S20, the DC voltage V ｄｃ is the voltage lower limit V ｄｃ－ｍｉｎ If it is smaller than , the duty command value generation mode S ｍｏｄｅ Therefore, in the subsequent step S22, the ASC switching processing unit 33 sets the delay time T ｄｅｌａｙ Set to zero.

[0077] As mentioned above, the DC voltage V ｄｃ Based on the duty command value generation mode S ｍｏｄｅ is determined, and the corresponding delay time T ｄｅｌａｙWhen the signal S is set, the ASC switching processing unit 33 generates a duty command value Duty_UVW for the ASC in step S23. That is, the ASC switching processing unit 33 generates duty command values ​​Duty_G1 and Duty_G2 for the first group G1 and the second group G2, and outputs either the duty command value Duty_G1 for the first group G1 or the duty command value Duty_G2 for the second group G2 as the duty command value Duty_UVW for each phase in accordance with the classification of the arm. Also, in step S24, the PWM control unit 23 outputs a gate permission signal S ＧＰ is set to "Permitted." As a result, ASC control is executed in any one of the first ASC mode, the second ASC mode, and the third ASC mode.

[0078] FIG. 8 shows the PWM signal D in the first ASC mode (ASC1). ｕｕ ＊ ~D ｗｌ ＊ 8 is a time chart showing an example of four control periods P １ ~P ４ Regarding PWM signal D ｕｕ ＊ ~D ｗｌ ＊ In FIG. 8, the control period P １ From the control period P ２ The time t when ０ In this case, the ASC switching signal S ＵＬ２ is changed from ON (upper short circuit control) to OFF (lower short circuit control). ｕ The direction of is "arm → rotating electric machine", and the V-phase current i ｖ and W-phase current i ｗ The direction of the U-phase arm (Q １ , Q ２ ) are classified into the second group G2, and the V-phase and W-phase arms (Q ３ ~Q ６ ) are classified into the first group G1.

[0079] As shown in FIG. ０ ASC switching signal S ＵＬ２When the control period P ２ In the above, duty command values ​​Duty_G1 and Duty_G2 are generated to form a transition state in switching from the upper side short-circuit control to the lower side short-circuit control.

[0080] Here, the V-phase and W-phase arms (Q ３ ~Q ６ ) are classified into the first group G1, so the duty command value Duty_G1 for the first group G1 is output as the duty command value Duty_VW of the V-phase and W-phase. Also, the U-phase arm (Q1, Q2) is classified into the second group G2, so the duty command value Duty_G2 for the second group G2 is output as the duty command value Duty_U of the U-phase. More specifically, the ASC switching signal S ＵＬ２ From the change in the duty command value Duty_U of the U phase and the timing of the rise / fall of the carrier signal CS, the duty command value Duty_U of the U phase is Duty_U=Duty_G2=50+(DT+tp) / τ [%], and the duty command values ​​Duty_VW of the V and W phases are Duty_VW=Duty_G1=50 [%]. Therefore, the duty command value Duty_U of the U phase is larger than the duty command values ​​Duty_VW of the V and W phases (Duty_U>Duty_VW). These duty command values ​​Duty_UVW are used for the next control period P ３ In the PWM signal D ｕｕ ＊ ~D ｗｌ ＊ This is reflected in the generation of

[0081] Control period P ３ In this case, the PWM signal generator 24 compares and matches the duty command value Duty_UVW with the carrier signal CS to generate the PWM signal D ｕｕ ＊ ~D ｗｌ ＊ However, during the control period P ３ In this case, the carrier signal CS rises, and the duty command value Duty_VW of the V-phase and W-phase is smaller than the duty command value Duty_U of the U-phase. ｖｕ ＊ ~D ｗｌ＊ After a predetermined time (DT+tp) has elapsed, the PWM signal D ｕｕ ＊ , D ｕｌ ＊ Furthermore, the PWM signal generator 24 inserts a dead time DT into the PWM signal of the arm that switches from off to on.

[0082] Specifically, first, at time t ａ The upper arms of the V and W phases (Q ３ , Q ５ ) PWM signal D ｖｕ ＊ , D ｗｕ ＊ is switched from ON to OFF, and the switching of the first group G1 begins. ａ The time t when the dead time DT has elapsed since ｂ In this case, the lower arms of the V-phase and W-phase (Q ４ , Q ６ ) PWM signal D ｖｌ ＊ , D ｗｌ ＊ is switched from OFF to ON, completing the switching of the first group G1. After that, at time t ｃ In the U-phase upper arm (Q １ ) PWM signal D ｕｕ ＊ is switched from ON to OFF, and the switching of the second group G2 begins. ｃ The time t when the dead time DT has elapsed since ｄ In this case, the lower arm of the U phase (Q ２ ) PWM signal D ｕｌ ＊ is switched from OFF to ON, completing the switching of the second group G2.

[0083] That is, in the first ASC mode, when switching between the upper side short circuit control and the lower side short circuit control, the initial state (time t ａ A transition state (time tａ ~t ｃ Then, at the time t ａ from a predetermined time (T ｄｅｌａｙ After the time t = DT + tp has elapsed, the switching of the arms belonging to the second group G2 is started, and the final state (time t ｄ The following state) is formed.

[0084] FIG. 9 shows the PWM signal D in the second ASC mode (ASC2). ｕｕ ＊ ~D ｗｌ ＊ 9 is a time chart showing an example of the PWM signal D in the same scene as in FIG. 8, except that the second ASC mode is selected. ｕｕ ＊ ~D ｗｌ ＊ An example is shown below.

[0085] When the second ASC mode is selected, the control period P ３ In this example, the duty command value Duty_U of the U phase is Duty_U = Duty_G2 = 50 + DT / τ [%], and the duty command values ​​Duty_VW of the V and W phases are Duty_VW = Duty_G1 = 50 [%]. Therefore, as shown in FIG. 9 , the relationship in which the duty command value Duty_U of the U phase is larger than the duty command values ​​Duty_VW of the V and W phases is the same as when the first ASC mode is selected, but the difference between the duty command value Duty_U of the U phase and the duty command values ​​Duty_VW of the V and W phases is small. As a result, the PWM signal D ｖｌ ＊ , D ｗｌ ＊ The time t when ｂ and the PWM signal D for the upper arm of the U phase belonging to the second group G2. ｕｕ ＊ The time t when ｃ and are substantially at the same time (t ｂ = t ｃ )

[0086] Therefore, in the second ASC mode, when switching between the upper side short circuit control and the lower side short circuit control, the initial state in which either the upper arm or the lower arm of each phase is turned on (time t ａ A transition state (time t ａ ~t ｃ Then, at the time t ａ From a predetermined time (T ｄｅｌａｙ After the time t =DT has elapsed, the switching of the arms belonging to the second group G2 is started, and the other of the upper arms or the lower arms of each phase is turned on. ｄ The following state) is formed.

[0087] That is, when switching between the upper side short-circuit control and the lower side short-circuit control, the transition state is formed by delaying the switching of the arm belonging to the second group G2, which is common to the first ASC mode and the second ASC mode. On the other hand, in the first ASC mode and the second ASC mode, the delay time T ｄｅｌａｙ Specifically, as described above, in the second ASC mode, the delay time T ｄｅｌａｙ is adjusted to be equal to the dead time DT, whereas in the first ASC mode, it is longer and the delay time T ｄｅｌａｙ is adjusted to be the sum of the dead time DT and the additional time tp.

[0088] FIG. 10 shows the PWM signal D in the third ASC mode (ASC3). ｕｕ ＊ ~D ｗｌ ＊ 10 is a time chart showing an example of the PWM signal D in a scene similar to that shown in FIGS. 8 and 9, except that the third ASC mode is selected. ｕｕ ＊ ~D ｗｌ ＊ An example is shown below.

[0089] When the third ASC mode is selected, the control period P ３In the above, the duty command value Duty_U of the U phase is Duty_U=Duty_G2=50[%], and the duty command values ​​Duty_VW of the V and W phases are Duty_VW=Duty_G1=50[%]. Therefore, the duty command values ​​Duty_UVW of the U, V, and W phases are common (all 50%). As a result, the PWM signal D ｖｕ ＊ , D ｗｕ ＊ The time t when ａ and the PWM signal D for the upper arm of the U phase belonging to the second group G2. ｕｕ ＊ The time t when ｃ and are substantially at the same time (t ａ = t ｃ ) The PWM signal D for the lower arms of the V-phase and W-phase belonging to the first group G1 is ｖｌ ＊ , D ｗｌ ＊ The time t when ｂ and the PWM signal D for the lower arm of the U phase belonging to the second group G2. ｕｌ ＊ The time t when ｄ and are substantially at the same time (t ｂ = t ｄ )

[0090] Therefore, in the third ASC mode, when switching between the upper side short circuit control and the lower side short circuit control, the initial state in which either the upper arm or the lower arm of each phase is turned on (time t ａ From the previous state), the switching of the arms belonging to the first group G1 and the switching of the arms belonging to the second group G2 start simultaneously, and the final state (at time t ｄ The following state) is formed.

[0091] That is, in the first ASC mode and the second ASC mode, the transition state is formed by delaying the switching of the arm belonging to the second group G2, whereas in the third ASC mode, the transition state is formed by delaying the switching of the arm belonging to the second group G2. ｄｅｌａｙThe difference is that by setting t to zero, these transition states are prevented from forming.

[0092] FIG. 11 shows the phase current i in the first ASC mode (ASC1). ｕ , i ｖ , i ｗ 11 is an explanatory diagram showing the transition of the U-phase current i ｕ is the U-phase arm (Q １ , Q ２ ) to the rotating electrical machine 10 (U-phase stator coil), and the V-phase current i ｖ and W-phase current i ｗ The V-phase and W-phase arms (Q ３ ~Q ６ 11 shows a scene where the control is switched from the upper short-circuit control to the lower short-circuit control when current flows from the U-phase arm (Q １ , Q ２ ) are classified into the second group G2, and the V-phase and W-phase arms (Q ３ ~Q ６ 10 shows a scene in which the upper short-circuit control is switched to the lower short-circuit control when the upper short-circuit control is switched to the lower short-circuit control when the upper short-circuit control is switched to the lower short-circuit control when the upper short-circuit control is switched to the lower short-circuit control when the lower ...

[0093] Specifically, FIG. 11(A) shows the upper arm (Q １ , Q ３ , Q ５ ) is on, and the lower arm (Q ２ , Q ４ , Q ６ 11(B) to 11(D) show transition states. In particular, FIG. 11(C) shows the state at the additional time tp in the transition state. FIG. 11(E) shows the upper arm (Q １ , Q ３ , Q ５ ) is off, and the lower arm (Q ２ , Q ４ , Q ６ ) indicates the final state where it is turned on.

[0094] As shown in Fig. 11A, the initial state is a state in which the upper short circuit control is being performed. In this initial state in which the upper short circuit control is being performed, the V-phase current i ｖ and W-phase current i ｗare the upper arms of the V-phase and W-phase (Q ３ , Q ５ ) and join through the freewheeling diode of the upper arm of the U phase (Q １ ) and returns to the rotating electrical machine 10. ｕ That is, in the initial state where the upper short circuit control is performed, the phase current i generated by the induced voltage of the rotating electrical machine 10 ｕ , i ｖ , i ｗ is consumed by circulating through the inverter 12 and the rotating electrical machine 10. At this time, the smoothing capacitor 28 is neither charged nor discharged.

[0095] As shown in FIG. 11B, the transition state is such that the upper arms (Q ３ , Q ５ ) is turned off. Here, each arm (Q ３ , Q ５ ) is the phase current i ｖ , i ｗ is the arm that flows through the freewheeling diode. Therefore, even if these are turned off, the phase current i ｕ , i ｖ , i ｗ As a result, even in the state of FIG. 11B, the flow of the phase current i generated by the induced voltage of the rotating electrical machine 10 remains unchanged. ｕ , i ｖ , i ｗ is consumed by circulating through the inverter 12 and the rotating electrical machine 10. Furthermore, the smoothing capacitor 28 is neither charged nor discharged.

[0096] After that, when the dead time DT has elapsed, in the first ASC mode, as shown in FIG. 11(C), first, the lower arms (Q ４ , Q ６ ) is turned on. This causes the V-phase current i ｖ and W-phase current i ｗ is the lower arm of each phase (Q ４ , Q ６ ) flows. Then, the V-phase current i ｖ and W-phase current i ｗ The lower arm of the U phase (Q２ ) and return to the rotating electrical machine 10 through the freewheeling diode of ｕ Therefore, in the state of FIG. 11C, the phase current i ｕ , i ｖ , i ｗ is consumed by circulating through the inverter 12 and the rotating electrical machine 10. In the state of FIG. 11C, the upper arm (Q １ ) remains on. Therefore, as shown by the two-dot chain line, the DC current I ｄｃ flows out and is consumed in the short circuit formed by the inverter 12 and the rotating electrical machine 10 .

[0097] That is, the delay time T ｄｅｌａｙ 11C is created in the transition state in the first ASC mode by adding an additional time tp to the phase current i ｕ , i ｖ , i ｗ This is the ASC mode, which not only allows the short circuit formed by the inverter 12 and the rotating electrical machine 10 to consume the current, but also allows the smoothing capacitor 28 to be discharged.

[0098] When the time corresponding to the sum of the dead time DT and the additional time tp has elapsed since the start of the transition state, the upper arm (Q １ At this time, the phase current i ｕ , i ｖ , i ｗ The flow of the phase current i generated by the induced voltage of the rotating electric machine 10 is the same as in the case of FIG. ｕ , i ｖ , i ｗ is consumed by circulating through the inverter 12 and the rotating electrical machine 10. However, the discharge of the smoothing capacitor 28 (DC current I ｄｃ The flow of current (current flow) stops, and the smoothing capacitor 28 is no longer charged or discharged.

[0099] After that, when the dead time DT has elapsed, as shown in FIG. 11(E), the lower arm (Q ２ ) turns on. This turns on the upper arm (Q １ , Q ３ , Q ５ ) is off, and the lower arm (Q ２ , Q ４ , Q ６ ) is turned on. In this way, in the state where the low-side short-circuit control is switched on, the phase current i ｕ , i ｖ , i ｗ is consumed by circulating through the inverter 12 and the rotating electrical machine 10. Furthermore, the smoothing capacitor 28 is neither charged nor discharged.

[0100] FIG. 12 shows the phase current i in the second ASC mode (ASC2). ｕ , i ｖ , i ｗ 12 is an explanatory diagram showing the transition of the U-phase current i ｕ is the arm (Q １ , Q ２ ) to the rotating electrical machine 10 (U-phase stator coil), and the V-phase current i ｖ and W-phase current i ｗ The V-phase and W-phase arms (Q ３ ~Q ６ ) toward the rotating electrical machine 10, that is, when the U-phase arm (Q １ , Q ２ ) are classified into the second group G2, and the V-phase and W-phase arms (Q ３ ~Q ６ 12A shows a scene in which the upper arm (Q １ , Q ３ , Q ５ ) is on, and the lower arm (Q ２ , Q ４ , Q ６ 12(B) and 12(C) show the transition state. FIG. 12(D) shows the upper arm (Q １ , Q ３ , Q ５) is off, and the lower arm (Q ２ , Q ４ , Q ６ ) indicates the final state where it is turned on.

[0101] As shown in Fig. 12A, the initial state is a state in which the upper short circuit control is being performed. In this initial state in which the upper short circuit control is being performed, even in the second ASC mode, the V-phase current i ｖ and W-phase current i ｗ are the upper arms of the V-phase and W-phase (Q ３ , Q ５ ) and join through the freewheeling diode of the upper arm of the U phase (Q １ ) and returns to the rotating electrical machine 10. ｕ Therefore, in the initial state in which the upper short circuit control is being performed, even in the second ASC mode, the phase current i ｕ , i ｖ , i ｗ is consumed by circulating through the inverter 12 and the rotating electrical machine 10. Furthermore, the smoothing capacitor 28 is neither charged nor discharged.

[0102] As shown in FIG. 12B, in the second ASC mode, the transition state is also the upper arms (Q ３ , Q ５ At this time, the phase current i generated by the induced voltage of the rotating electric machine 10 ｕ , i ｖ , i ｗ is consumed by circulating through the inverter 12 and the rotating electrical machine 10. Furthermore, the smoothing capacitor 28 is neither charged nor discharged.

[0103] After that, when the dead time DT has elapsed, as shown in FIG. 12C, in the second ASC mode, the lower arms (Q ４ , Q ６ ) is turned on, and at the same time, the upper arm (Q １ ) is turned off. As a result, the V-phase current i ｖ and W-phase current i ｗ is the lower arm of each phase (Q ４ , Q６ ) flows. Then, the V-phase current i ｖ and W-phase current i ｗ The lower arm of the U phase (Q ２ ) and return to the rotating electrical machine 10 through the freewheeling diode of ｕ Therefore, in the state of FIG. 12C, the phase current i ｕ , i ｖ , i ｗ is consumed by circulating through the inverter 12 and the rotating electrical machine 10. Furthermore, the smoothing capacitor 28 is neither charged nor discharged.

[0104] After that, when the dead time DT has elapsed, as shown in FIG. 12(D), the lower arm (Q ２ ) is turned on. This turns on the upper arm (Q １ , Q ３ , Q ５ ) is off, and the lower arm (Q ２ , Q ４ , Q ６ ) is turned on. In this way, in the state where the low-side short-circuit control is switched on, the phase current i ｕ , i ｖ , i ｗ is consumed by circulating through the inverter 12 and the rotating electrical machine 10. Furthermore, the smoothing capacitor 28 is neither charged nor discharged.

[0105] As described above, in the second ASC mode, the delay time T ｄｅｌａｙ By making the DC voltage V equal to the dead time DT, the state of FIG. 11C in the first ASC mode, that is, the state in which the smoothing capacitor 28 is discharged, is skipped. Therefore, in the first ASC mode, ｄｃ High (V ｄｃ >V ｄｃ－ＭＡＸ ), is selected when it is necessary to discharge the smoothing capacitor 28, and the second ASC mode is ｄｃ is not so high (V ｄｃ－ＭＡＸ ≧V ｄｃ ≧V ｄｃ－ｍｉｎ), is selected when there is no need to discharge the smoothing capacitor 28.

[0106] FIG. 13 shows the phase current i in the third ASC mode (ASC3). ｕ , i ｖ , i ｗ 13 is an explanatory diagram showing the transition of the U-phase current i ｕ is the arm (Q １ , Q ２ ) to the rotating electrical machine 10 (U-phase stator coil), and the V-phase current i ｖ and W-phase current i ｗ The V-phase and W-phase arms (Q ３ ~Q ６ ) toward the rotating electrical machine 10, that is, when the U-phase arm (Q １ , Q ２ ) are classified into the second group G2, and the V-phase and W-phase arms (Q ３ ~Q ６ 13A shows a scene in which the upper arm (Q １ , Q ３ , Q ５ ) is on, and the lower arm (Q ２ , Q ４ , Q ６ ) is off. FIG. 13(B) shows the initial state where all arms (Q １ ~Q ６ ) is turned off. １ , Q ３ , Q ５ ) is off, and the lower arm (Q ２ , Q ４ , Q ６ ) indicates the final state where it is turned on.

[0107] As shown in Fig. 13A, the initial state is a state in which the upper short circuit control is being performed. In this initial state in which the upper short circuit control is being performed, even in the third ASC mode, the V-phase current i ｖ and W-phase current i ｗ are the upper arms of the V-phase and W-phase (Q ３ , Q ５) and join through the freewheeling diode of the upper arm of the U phase (Q １ ) and returns to the rotating electrical machine 10. ｕ Therefore, in the initial state in which the upper short circuit control is being performed, even in the third ASC mode, the phase current i generated by the induced voltage of the rotating electrical machine 10 ｕ , i ｖ , i ｗ is consumed by circulating through the inverter 12 and the rotating electrical machine 10. Furthermore, the smoothing capacitor 28 is neither charged nor discharged.

[0108] When switching from the upper side short circuit control to the lower side short circuit control, in the third ASC mode, as shown in FIG. 13(B), the upper arm (Q １ , Q ３ , Q ５ However, the lower arm (Q ２ , Q ４ , Q ６ ) remains off. This means that the upper arm (Q １ , Q ３ , Q ５ ) and lower arm (Q ２ , Q ４ , Q ６ ) in order to prevent a through current from flowing, it is necessary to provide a dead time DT. ｖ and W-phase current i ｗ is the upper arm of each phase (Q ３ , Q ５ ) into the smoothing capacitor 28, and then flows from the smoothing capacitor 28 to the lower arm (Q ２ ) and return to the rotating electrical machine 10 through the freewheeling diode of ｕ Therefore, the arm of each phase (Q １ ~Q ６ ) are all turned off, the smoothing capacitor 28 is charged.

[0109] After that, when the dead time DT has elapsed, as shown in FIG. 13(C), the lower arm (Q ２ , Q ４ , Q ６ ) turns on. This turns on the upper arm (Q １, Q ３ , Q ５ ) is off, and the lower arm (Q ２ , Q ４ , Q ６ ) is turned on. In this way, in the state where the low-side short-circuit control is switched on, the phase current i ｕ , i ｖ , i ｗ is consumed by circulating through the inverter 12 and the rotating electrical machine 10. Furthermore, the smoothing capacitor 28 is neither charged nor discharged.

[0110] As described above, in the third ASC mode, when switching between the upper side short circuit control and the lower side short circuit control, the phase current i ｕ , i ｖ , i ｗ is consumed by a short circuit formed by the inverter 12 and the rotating electrical machine 10, and the arms (Q １ ~Q ６ ) are all turned off, the smoothing capacitor 28 is charged. Therefore, in this embodiment, the third ASC mode is ｄｃ is low (V ｄｃ <V ｄｃ－ｍｉｎ ), in a situation where it is desirable to charge the smoothing capacitor 28 in anticipation of restarting the system (recharging the smoothing capacitor 28), etc.

[0111] In the conventional ASC control, the upper side short circuit control and the lower side short circuit control are always switched by the third ASC mode. ｄｃ High (V ｄｃ >V ｄｃ－ＭＡＸ ), a situation where it is desirable to discharge the smoothing capacitor 28, or a situation where the DC voltage V ｄｃ is moderate (V ｄｃ－ＭＡＸ ≧V ｄｃ ≧V ｄｃ－ｍｉｎ ) The smoothing capacitor 28 is charged even in situations where it is desirable not to charge or discharge the smoothing capacitor 28. Therefore, in these situations, the smoothing capacitor 28 may be overcharged and damaged.

[0112] In contrast, in the ASC control of this embodiment, the arms (legs) of each phase are classified into a first group G1 and a second group G2. In the first ASC mode, when switching between the upper side short circuit control and the lower side short circuit control, a transition period is provided in which the switching of the first group G1 is started first, thereby reducing the phase current i generated by the induced voltage of the rotating electric machine 10. ｕ , i ｖ , i ｗ is consumed in the short circuit formed by the inverter 12 and the rotating electric machine 10, and the smoothing capacitor 28 is discharged. In the second ASC mode, when switching between the upper side short circuit control and the lower side short circuit control, a transition period is provided in which the switching of the first group G1 is started in advance, so that the phase current i generated by the induced voltage of the rotating electric machine 10 is not discharged or charged in the smoothing capacitor 28. ｕ , i ｖ , i ｗ is consumed in a short circuit formed by the inverter 12 and the rotating electrical machine 10. In the third ASC mode, the phase current i ｕ , i ｖ , i ｗ This is selected only when it is desirable to consume the power in the short circuit formed by the inverter 12 and the rotating electric machine 10 while charging the smoothing capacitor 28. Therefore, in the ASC control of this embodiment, the smoothing capacitor 28 is protected when switching between the upper side short circuit control and the lower side short circuit control.

[0113] Second Embodiment In the first embodiment, the rotating electric machine 10 has a standard structure in which coils of each phase are connected, but this is not limiting. In the second embodiment, ASC control in an electric vehicle 200 that uses a so-called open-winding rotating electric machine 210 will be described.

[0114] Fig. 14 is a block diagram showing the configuration of an electric vehicle 200 according to the second embodiment. As shown in Fig. 14, in the electric vehicle 200, in order to control an open-winding rotating electric machine 210, the inverter 12 is composed of a first inverter 211 connected to one end of the coils of each of the U, V, and W phases, and a second inverter 212 connected to the other end of the coils of each of the U, V, and W phases. Therefore, in the electric vehicle 200, a voltage distribution unit 213 is added to the configuration of the electric vehicle 100 of the first embodiment, and the configurations of the coordinate conversion unit 22, the PWM control unit 23, and the PWM signal generator 24 are changed. The other configurations are the same as those of the electric vehicle 100 of the first embodiment.

[0115] The voltage distribution unit 213 divides the d- and q-axis voltage command values ​​v calculated by the torque control unit 21. ｄ ＊ , v ｑ ＊ are used as the dq-axis voltage command values ​​for the first inverter 211 (hereinafter referred to as the first dq-axis voltage command values ​​v ｄ１ ＊ , v ｑ１ ＊ ) and the dq-axis voltage command value for the second inverter 212 (hereinafter referred to as the second dq-axis voltage command value v ｄ２ ＊ , v ｑ２ ＊ Specifically, the voltage distribution unit 213 distributes the d-axis and q-axis voltage command values ​​v calculated by the torque control unit 21 according to the following equation (5): ｄ ＊ , v ｑ ＊ The first dq-axis voltage command value v ｄ１ ＊ , v ｑ１ ＊ and the second dq-axis voltage command value v ｄ２ ＊ , v ｑ２ ＊ The first dq-axis voltage command value v ｄ１ ＊ , v ｑ１ ＊ are dq-axis voltage command values ​​for the first inverter 211, and the second dq-axis voltage command value v ｄ２ ＊ , v ｑ２ ＊are d-axis and q-axis voltage command values ​​for the second inverter 212.

[0116]

[0117] In the electric vehicle 200, the coordinate conversion unit 22 is configured by a first conversion unit 214 and a second conversion unit 215. The first conversion unit 214 converts the first dq-axis voltage command value v ｄ１ ＊ , v ｑ１ ＊ and the electrical angle θ, the first three-phase voltage command value v ｕ１ ＊ , v ｖ１ ＊ , v ｗ１ ＊ The first three-phase voltage command value v ｕ１ ＊ , v ｖ１ ＊ , v ｗ１ ＊ are voltage command values ​​of the U, V, and W phases for the first inverter 211. The second converter 215 converts the second dq-axis voltage command value v ｄ２ ＊ , v ｑ２ ＊ and the electrical angle θ, the second three-phase voltage command value v ｕ２ ＊ , v ｖ２ ＊ , v ｗ２ ＊ The second three-phase voltage command value v ｕ２ ＊ , v ｖ２ ＊ , v ｗ２ ＊ are voltage command values ​​of the U, V, and W phases for the second inverter 212. Specifically, the first conversion unit 214 converts the first three-phase voltage command value v ｕ１ ＊ , v ｖ１ ＊ , v ｗ１ ＊ The second conversion unit 215 calculates the second three-phase voltage command value v ｕ２ ＊ , vｖ２ ＊ , v ｗ２ ＊ The coordinate transformation method from the dq axis coordinate system to the UVW coordinate system is common.

[0118]

[0119] In the electric vehicle 200 , the PWM control unit 23 is made up of an output determination unit 216 , a first PWM control unit 217 , and a second PWM control unit 218 .

[0120] The output determination unit 216 determines whether the abnormality detection unit 27 outputs a status signal S ｓｔａｔｅ , the absolute value |N| of the rotation speed N, and the DC voltage V ｄｃ Based on this, the gate enable signal S ＧＰ and duty command value generation mode S ｍｏｄｅ In the second embodiment, since the first PWM control unit 217 and the second PWM control unit 218 are separated, part of the function of the PWM control unit 23 in the first embodiment is explicitly shown as the output determination unit 216 for convenience. Therefore, the output determination unit 216 sets or changes the gate enable signal S according to the above-mentioned Table 1, as in the first embodiment. ＧＰ and duty command value generation mode S ｍｏｄｅ configured to set or change

[0121] The first PWM control unit 217 determines whether the duty command value generation mode S set by the output determination unit 216 is selected. ｍｏｄｅ The first duty command value Duty_UVW1 is used to generate a PWM signal D ｕｕ１ ＊ ~D ｗｌ１ ＊ is a duty command value for determining

[0122] Duty command value generation mode S ｍｏｄｅ When the normal mode is selected, the first PWM control unit 217 calculates the first three-phase voltage command value v according to the following equation (8): ｕ１ ＊ , vｖ１ ＊ , v ｗ１ ＊ Note that, although equation (8) shows a method for generating the first duty command value Duty_U1 for the U phase, the first duty command values ​​Duty_VW1 for the V phase and the W phase are also generated in a similar manner.

[0123]

[0124] In addition, the duty command value generation mode S ｍｏｄｅ is in the first ASC mode (ASC1), the second ASC mode (ASC2), or the third ASC mode (ASC3), the first PWM control unit 217 generates the first duty command value Duty_UVW1 in the same manner as in the first embodiment. That is, the first PWM control unit 217 when performing ASC control is configured by an up / down switching signal generation unit 31, a zero current avoidance processing unit 32, and an ASC switching processing unit 33, similar to the PWM control unit 23 in the first embodiment (see FIG. 5 ).

[0125] Specifically, the duty command value generation mode S ｍｏｄｅ is in the first ASC mode (ASC1), the second ASC mode (ASC2), or the third ASC mode (ASC3), the first PWM control unit 217 outputs the ASC switching signal S ＵＬ１ is generated, and the final ASC switching signal S is obtained by correcting it using zero current avoidance processing. ＵＬ２ Furthermore, the first PWM control unit 217 generates the current switching state of the first inverter 211 and the phase current i ｕ , i ｖ , i ｗ Then, the first PWM control unit 217 classifies the pair of upper and lower arms (legs) in the first inverter 211 into either the first group G1 or the second group G2 based on the direction of the carrier signal CS and the final ASC switching signal S according to Table 3. ＵＬ２ , and duty command value generation mode S ｍｏｄｅ Based on this, a first duty command value Duty_UVW1 for ASC control is generated.

[0126] The second PWM control unit 218 is configured to operate in the duty command value generation mode S set by the output determination unit 216. ｍｏｄｅ The second duty command value Duty_U2, Duty_V2, Duty-W2 (hereinafter abbreviated as Duty_UVW2, etc.) is generated in accordance with the second duty command value Duty_UVW2. ｕｕ２ ＊ ~D ｗｌ２ ＊ is a duty command value for determining

[0127] The specific configuration of the second PWM control unit 218 is the same as that of the first PWM control unit 217. That is, the duty command value generation mode S ｍｏｄｅ When the normal mode is selected, the second PWM control unit 218 calculates the second three-phase voltage command value v according to the above-described equation (8). ｕ２ ＊ , v ｖ２ ＊ , v ｗ２ ＊ The second duty command value Duty_UVW2 is generated based on the above.

[0128] In addition, the duty command value generation mode S ｍｏｄｅ is in the first ASC mode (ASC1), the second ASC mode (ASC2), or the third ASC mode (ASC3), the second PWM control unit 218 generates the second duty command value Duty_UVW2 in the same manner as in the first embodiment. That is, the second PWM control unit 218 when performing ASC control is configured by an up / down switching signal generation unit 31, a zero current avoidance processing unit 32, and an ASC switching processing unit 33, similar to the PWM control unit 23 in the first embodiment (see FIG. 5).

[0129] Specifically, the duty command value generation mode S ｍｏｄｅ is in the first ASC mode (ASC1), the second ASC mode (ASC2), or the third ASC mode (ASC3), the second PWM control unit 218 outputs the ASC switching signal S ＵＬ１ is generated, and the final ASC switching signal S is obtained by correcting it using zero current avoidance processing. ＵＬ２In addition, the second PWM control unit 218 generates the current switching state of the second inverter 212 and the phase current i ｕ , i ｖ , i ｗ Then, the second PWM control unit 218 classifies the pairs of upper and lower arms (legs) in the second inverter 212 into either the first group G1 or the second group G2 based on the direction of the carrier signal CS and the final ASC switching signal S according to Table 3. ＵＬ２ , and duty command value generation mode S ｍｏｄｅ Based on this, a second duty command value Duty_UVW2 for ASC control is generated.

[0130] When ASC control is performed, the pairs of upper and lower arms (legs) in the first inverter 211 and the second inverter 212 are classified into either the first group G1 or the second group G2 in the same manner as described above, but it should be noted that the phases of the arms classified into the first group G1 and the second group G2 are reversed in the first inverter 211 and the second inverter 212. For example, in the first inverter 211, the U-phase current i ｕ When the U-phase current i flows in the direction of "arm → rotating electric machine", the second inverter 212 ｕ flows in the direction of "rotating electric machine → arm." Therefore, in the first inverter 211, the U-phase arm is classified into the first group G1, while in the second inverter 212, the U-phase arm is classified into the second group G2. The same applies to the other phases.

[0131] In the electric vehicle 200 , the PWM signal generator 24 is made up of a first PWM signal generator 219 and a second PWM signal generator 220 .

[0132] The first PWM signal generator 219 generates a gate enable signal S ＧＰ When the signal is "enabled", a PWM signal D ｕｕ１ ＊ ~D ｗｌ１ ＊In this embodiment, for simplicity, the carrier signal CS is also assumed to be a triangular wave having a constant period (2τ).

[0133] The second PWM signal generator 220 generates a gate enable signal S ＧＰ When the signal is "enabled", a PWM signal D ｕｕ２ ＊ ~D ｗｌ２ ＊ The carrier signal CS is the same as that used by the first PWM signal generator 219.

[0134] 15 is a circuit diagram showing the configuration of the first inverter 211 and the second inverter 212. As shown in FIG. 15, the first inverter 211 includes a plurality of switching elements Q １ ~Q ６ Similarly, the second inverter 212 is configured by a bridge circuit formed by a plurality of switching elements Q ７ ~Q １２ In this embodiment, for convenience, the smoothing capacitor 28 is included in the first inverter 211. In addition, each of the switching elements Q of the first inverter 211 and the second inverter 212 is １ ~Q １２ The specific configuration of the inverter 12 of the first embodiment is the switching element Q １ ~Q ６ is the same as:

[0135] Switching element Q of the first inverter 211 １ , Q ２ constitutes the U-phase leg of the first inverter 211. That is, the series-connected switching element Q １ , Q ２ One end of the U-phase stator coil (U) of the rotary electric machine 210 is connected between the first and second inverters 211 and 212. Similarly, the switching element Q ７ , Q ８ constitutes the U-phase leg of the second inverter 212. However, the series-connected switching element Q ７ , Q８ The other end of the U-phase stator coil (U) of the rotating electrical machine 210 is connected between the switching element Q １ , Q ７ is the upper arm of each U-phase leg, and is connected to the positive side (high side) of the battery 11. ２ , Q ８ is the lower arm of each U-phase leg and is connected to the negative side (low side) of the battery 11. １ , Q ２ , Q ７ , Q ８ The PWM signals that control the on / off of ｕｕ１ ＊ , D ｕｌ１ ＊ , D ｕｕ２ ＊ , D ｕｌ２ ＊ is.

[0136] Switching element Q of the first inverter 211 ３ , Q ４ constitutes the V-phase leg of the first inverter 211. That is, the series-connected switching element Q ３ , Q ４ One end of the V-phase stator coil (V) of the rotary electric machine 210 is connected between the V-phase stator coil (V) and the V-phase stator coil (V) of the second inverter 212. Similarly, the V-phase stator coil (V) of the second inverter 212 is connected between the V-phase stator coil (V) and the V-phase stator coil (V) of the second inverter 212. ９ , Q １０ constitutes the V-phase leg of the second inverter 212. However, the series-connected switching element Q ９ , Q １０ The other end of the V-phase stator coil (V) of the rotary electric machine 210 is connected between the switching element Q ３ , Q ４ is the upper arm of each V-phase leg and is connected to the positive side (high side) of the battery 11. ９ , Q １０ is the lower arm of each V-phase leg and is connected to the negative side (low side) of the battery 11. ３ , Q ４ , Q ９ , Q １０ The PWM signals that control the on / off ofｖｕ１ ＊ , D ｖｌ１ ＊ , D ｖｕ２ ＊ , D ｖｌ２ ＊ is.

[0137] Similarly, the switching element Q of the first inverter 211 ５ , Q ６ constitutes the W-phase leg of the first inverter 211. That is, the series-connected switching element Q ５ , Q ６ One end of the W-phase stator coil (W) of the rotary electric machine 210 is connected between the W-phase stator coil (W) and the W-phase stator coil (W) of the second inverter 212. １１ , Q １２ constitutes the W-phase leg of the second inverter 212. However, the series-connected switching element Q １１ , Q １２ The other end of the W-phase stator coil (W) of the rotating electrical machine 210 is connected between the switching element Q ５ , Q ６ is the upper arm of each W-phase leg, and is connected to the positive side (high side) of the battery 11. １１ , Q １２ is the lower arm of each W-phase leg and is connected to the negative side (low side) of the battery 11. ５ , Q ６ , Q １１ , Q １２ The PWM signals that control the on / off of ｗｕ１ ＊ , D ｗｌ１ ＊ , D ｗｕ２ ＊ , D ｗｌ２ ＊ is.

[0138] As described above, the ASC control in the electric vehicle 200 using the open-winding type rotating electric machine 210 operates in the same manner as in the first embodiment. ｕ , i ｖ , i ｗ The operation of the ASC control in the electric vehicle 200 will be described based on the transition of the above.

[0139] FIG. 16 shows the phase current i in the first ASC mode (ASC1). ｕ , i ｖ , i ｗ 16 is an explanatory diagram showing the transition of the U-phase current i ｕ is the U-phase arm (Q １ , Q ２ ) to the rotating electrical machine 210 (U-phase stator coil), and the V-phase current i ｖ and W-phase current i ｗ The V-phase and W-phase arms (Q ３ ~Q ６ 16 shows a scene where the control is switched from the upper side short-circuit control to the lower side short-circuit control when current flows from the U-phase arm (Q １ , Q ２ ) and the V-phase and W-phase arms (Q ９ ~Q １２ ) are classified into the second group G2, and the V-phase and W-phase arms (Q ３ ~Q ６ ) and the U-phase arm (Q ７ , Q ８ 10 shows a scene in which the upper short-circuit control is switched to the lower short-circuit control when the upper short-circuit control is switched to the lower short-circuit control when the upper short-circuit control is switched to the lower short-circuit control when the upper short-circuit control is switched to the lower short-circuit control when the lower ...

[0140] Specifically, FIG. 16A shows the upper arms (Q １ , Q ３ , Q ５ , Q ７ , Q ９ , Q １１ ) is on, and the lower arms (Q ２ , Q ４ , Q ６ , Q ８ , Q １０ , Q １２ 16(B) to 16(D) show transition states. In particular, FIG. 16(C) shows the transition state at the additional time tp. FIG. 16(E) shows the upper arm (Q １ , Q ３ , Q５ , Q ７ , Q ９ , Q １１ ) is off, and the lower arms (Q ２ , Q ４ , Q ６ , Q ８ , Q １０ , Q １２ ) indicates the final state where it is turned on.

[0141] As shown in Fig. 16A, the initial state is a state in which the upper short circuit control is being performed. In this initial state in which the upper short circuit control is being performed, the phase current i ｕ , i ｖ , i ｗ is the upper arm (Q １ , Q ３ , Q ５ ), the rotating electric machine 210, and the upper arm (Q ７ , Q ５ , Q １１ Specifically, the U-phase current i ｕ is the upper arm (Q １ ) into the U-phase stator coil (U), and then flows from the U-phase stator coil (U) to the U-phase upper arm (Q ７ ) and circulates through the freewheeling diode of V-phase current i ｖ is the V-phase upper arm (Q ９ ) into the V-phase stator coil (V), and then flows from the V-phase stator coil (V) to the V-phase upper arm (Q ３ Similarly, the W-phase current i ｗ is the W-phase upper arm (Q １１ ) into the W-phase stator coil (W), and then flows from the W-phase stator coil (W) to the W-phase upper arm (Q ５ ) circulates through the freewheel diode of the rotating electric machine 210. Therefore, in the initial state where the upper short circuit control is performed, the phase current i ｕ , i ｖ , i ｗis consumed by circulating through the first inverter 211, the second inverter 212, and the rotating electric machine 210. At this time, the smoothing capacitor 28 is neither charged nor discharged.

[0142] As shown in FIG. 16B, the transition state is such that the V-phase and W-phase upper arms (Q ３ , Q ５ ) and the U-phase upper arm (Q ７ ) is turned off. ３ , Q ５ , Q ７ ) is the phase current i ｕ , i ｖ , i ｗ is the arm that flows through the freewheeling diode. Therefore, even if these are turned off, the phase current i ｕ , i ｖ , i ｗ As a result, even in the state shown in FIG. 16B, the flow of the phase current i generated by the induced voltage of the rotating electric machine 210 remains unchanged. ｕ , i ｖ , i ｗ is consumed by circulating through the first inverter 211, the second inverter 212, and the rotating electric machine 210. Furthermore, the smoothing capacitor 28 is neither charged nor discharged.

[0143] After that, when the dead time DT has elapsed, in the first ASC mode, as shown in FIG. 16(C), first, the V-phase and W-phase lower arms (Q ４ , Q ６ ) and the U-phase lower arm (Q ８ ) turns on.

[0144] As a result, the U-phase current i ｕ is the upper arm (Q １ ) into the U-phase stator coil (U), and then flows from the U-phase stator coil (U) to the U-phase lower arm (Q ８ At this time, the U-phase current i ｕflows through the smoothing capacitor 28 in the direction of discharging. ｖ is the V-phase upper arm (Q ９ ) into the V-phase stator coil (V), and then flows from the V-phase stator coil (V) to the V-phase lower arm (Q ４ At this time, the V-phase current i ｖ flows through the smoothing capacitor 28 in the direction of discharging. Similarly, the W-phase current i ｗ is the W-phase upper arm (Q １１ ) into the W-phase stator coil (W), and then flows from the W-phase stator coil (W) to the W-phase lower arm (Q ６ At this time, the W-phase current i ｗ flows through the smoothing capacitor 28 in the direction of discharging.

[0145] That is, in the electric vehicle 200, the delay time T ｄｅｌａｙ 16C is created in the transition state in the first ASC mode by adding an additional time tp to the phase current i ｕ , i ｖ , i ｗ In this case, the ASC mode is entered, which not only allows the power to be consumed in the short circuit formed by the first inverter 211, the second inverter 212 and the rotating electric machine 210, but also allows the smoothing capacitor 28 to be discharged.

[0146] When a time corresponding to the sum of the dead time DT and the additional time tp has elapsed since the start of the transition state, the U-phase upper arm (Q １ ) and the V-phase and W-phase upper arms (Q ９ , Q １１ ) will be turned off.

[0147] As a result, the U-phase current i ｕ is the U-phase lower arm (Q ２) into the U-phase stator coil (U), and then flows from the U-phase stator coil (U) to the U-phase lower arm (Q ８ ) and circulates through the V-phase current i ｖ is the V-phase lower arm (Q １０ ) into the V-phase stator coil (V), and then flows from the V-phase stator coil (V) to the V-phase lower arm (Q ４ Similarly, the W-phase current i ｗ is the W-phase lower arm (Q １２ ) into the W-phase stator coil (W), and then flows from the W-phase stator coil (W) to the W-phase lower arm (Q ８ ) circulates through the phase current i generated by the induced voltage of the rotating electric machine 210. ｕ , i ｖ , i ｗ is consumed by circulating through the first inverter 211, the second inverter 212, and the rotating electric machine 210. However, the discharge of the smoothing capacitor 28 (DC current I ｄｃ The flow of current (current flow) stops, and the smoothing capacitor 28 is no longer charged or discharged.

[0148] After that, when the dead time DT has elapsed, as shown in FIG. 16(E), the U-phase lower arm (Q ２ ) and the V-phase and W-phase lower arms (Q １０ , Q １２ ) is turned on. As a result, the upper arms (Q １ , Q ３ , Q ５ , Q ７ , Q ９ , Q １１ ) is off, and the lower arms (Q ２ , Q ４ , Q ６ , Q ８ , Q １０ , Q １２ ) is turned on in the final state.

[0149] In this way, in the state switched to the lower side short circuit control, the U-phase lower arm (Q ２ ) into the U-phase stator coil (U), and then flows from the U-phase stator coil (U) to the U-phase lower arm (Q ８ ) and circulates through the V-phase current i ｖ is the V-phase lower arm (Q １０ ) into the V-phase stator coil (V), and then flows from the V-phase stator coil (V) to the V-phase lower arm (Q ４ Similarly, the W-phase current i ｗ is the W-phase lower arm (Q １２ ) into the W-phase stator coil (W), and then flows from the W-phase stator coil (W) to the W-phase lower arm (Q ８ ) circulates through the phase current i generated by the induced voltage of the rotating electric machine 210. ｕ , i ｖ , i ｗ is consumed by circulating through the inverter 12 and the rotating electrical machine 210. Furthermore, the smoothing capacitor 28 is neither charged nor discharged.

[0150] FIG. 17 shows the phase current i in the second ASC mode (ASC2). ｕ , i ｖ , i ｗ 17 is an explanatory diagram showing the transition of the U-phase current i ｕ is the U-phase arm (Q １ , Q ２ ) to the rotating electrical machine 210 (U-phase stator coil), and the V-phase current i ｖ and W-phase current i ｗ The V-phase and W-phase arms (Q ３ ~Q ６ 17 shows a scene where the control is switched from the upper side short-circuit control to the lower side short-circuit control when current flows from the U-phase arm (Q １ , Q ２ ) and the V-phase and W-phase arms (Q ９ ~Q １２) are classified into the second group G2, and the V-phase and W-phase arms (Q ３ ~Q ６ ) and the U-phase arm (Q ７ , Q ８ 10 shows a scene in which the upper short-circuit control is switched to the lower short-circuit control when the upper short-circuit control is switched to the lower short-circuit control when the upper short-circuit control is switched to the lower short-circuit control when the upper short-circuit control is switched to the lower short-circuit control when the lower ...

[0151] Specifically, FIG. 17A shows the upper arms (Q １ , Q ３ , Q ５ , Q ７ , Q ９ , Q １１ ) is on, and the lower arms (Q ２ , Q ４ , Q ６ , Q ８ , Q １０ , Q １２ 17(B) and 17(C) show transition states. FIG. 17(D) shows the upper arm (Q １ , Q ３ , Q ５ , Q ７ , Q ９ , Q １１ ) is off, and the lower arms (Q ２ , Q ４ , Q ６ , Q ８ , Q １０ , Q １２ ) indicates the final state where it is turned on.

[0152] As shown in Fig. 17A, the initial state is a state in which the upper side short circuit control is being performed. In this initial state in which the upper side short circuit control is being performed, even in the second ASC mode, the phase current i ｕ , i ｖ , i ｗ is the upper arm (Q １ , Q ３ , Q ５ ), the rotating electric machine 210, and the upper arm (Q ７ , Q ５ , Q １１Therefore, in the initial state where the upper short circuit control is performed, even in the second ASC mode, the phase current i ｕ , i ｖ , i ｗ is consumed by circulating through the first inverter 211, the second inverter 212, and the rotating electric machine 210. Furthermore, the smoothing capacitor 28 is neither charged nor discharged.

[0153] As shown in FIG. 17B, even in the second ASC mode, the transition state is such that the V-phase and W-phase upper arms (Q ３ , Q ５ ) and the U-phase upper arm (Q ７ ) is turned off. Therefore, the phase current i ｕ , i ｖ , i ｗ is consumed by circulating through the first inverter 211, the second inverter 212, and the rotating electric machine 210. Furthermore, the smoothing capacitor 28 is neither charged nor discharged.

[0154] After that, when the dead time DT has elapsed, as shown in FIG. 17C, in the second ASC mode, the V-phase and W-phase lower arms (Q ４ , Q ６ ) and the U-phase lower arm (Q ８ ) is turned on, and at the same time, the U-phase upper arm (Q １ ) and the V-phase and W-phase upper arms (Q ９ , Q １１ ) is turned off.

[0155] As a result, the U-phase current i ｕ is the U-phase lower arm (Q ２ ) into the U-phase stator coil (U), and then flows from the U-phase stator coil (U) to the U-phase lower arm (Q ８ ) and circulates through the V-phase current i ｖ is the V-phase lower arm (Q１０ ) into the V-phase stator coil (V), and then flows from the V-phase stator coil (V) to the V-phase lower arm (Q ４ Similarly, the W-phase current i ｗ is the W-phase lower arm (Q １２ ) into the W-phase stator coil (W), and then flows from the W-phase stator coil (W) to the W-phase lower arm (Q ８ ) circulates through the phase current i generated by the induced voltage of the rotating electric machine 210. ｕ , i ｖ , i ｗ is consumed by circulating through the first inverter 211, the second inverter 212, and the rotating electric machine 210. Furthermore, the smoothing capacitor 28 is neither charged nor discharged.

[0156] After that, when the dead time DT further elapses, as shown in FIG. 17(D), the U-phase lower arm (Q ２ ) and the V-phase and W-phase lower arms (Q １０ , Q １２ ) is turned on. As a result, the upper arms (Q １ , Q ３ , Q ５ , Q ７ , Q ９ , Q １１ ) is off, and the lower arms (Q ２ , Q ４ , Q ６ , Q ８ , Q １０ , Q １２ ) is turned on. ｕ , i ｖ , i ｗ is consumed by circulating through the inverter 12 and the rotating electrical machine 210. Furthermore, the smoothing capacitor 28 is neither charged nor discharged.

[0157] As described above, in the second ASC mode, the delay time T ｄｅｌａｙBy making the DC voltage V equal to the dead time DT, the state of FIG. 16C in the first ASC mode, that is, the state in which the smoothing capacitor 28 is discharged, is skipped. Therefore, in the electric vehicle 200 as well, the first ASC mode is ｄｃ High (V ｄｃ >V ｄｃ－ＭＡＸ ), is selected when it is necessary to discharge the smoothing capacitor 28, and the second ASC mode is ｄｃ is not so high (V ｄｃ－ＭＡＸ ≧V ｄｃ ≧V ｄｃ－ｍｉｎ ), is selected when there is no need to discharge the smoothing capacitor 28.

[0158] FIG. 18 shows the phase current i in the third ASC mode (ASC3). ｕ , i ｖ , i ｗ 18 is an explanatory diagram showing the transition of the U-phase current i ｕ is the U-phase arm (Q １ , Q ２ ) to the rotating electrical machine 210 (U-phase stator coil), and the V-phase current i ｖ and W-phase current i ｗ The V-phase and W-phase arms (Q ３ ~Q ６ 18 shows a scene where the control is switched from the upper side short-circuit control to the lower side short-circuit control when current flows from the U-phase arm (Q １ , Q ２ ) and the V-phase and W-phase arms (Q ９ ~Q １２ ) are classified into the second group G2, and the V-phase and W-phase arms (Q ３ ~Q ６ ) and the U-phase arm (Q ７ , Q ８ 10 shows a scene in which the upper short-circuit control is switched to the lower short-circuit control when the upper short-circuit control is switched to the lower short-circuit control when the upper short-circuit control is switched to the lower short-circuit control when the upper short-circuit control is switched to the lower short-circuit control when the lower ...

[0159] Specifically, FIG. 18A shows the upper arms (Q １ , Q ３, Q ５ , Q ７ , Q ９ , Q １１ ) is on, and the lower arms (Q ２ , Q ４ , Q ６ , Q ８ , Q １０ , Q １２ ) is off. FIG. 17(B) shows the initial state where all arms (Q １ ~Q １２ 18C shows a state in which the upper arms (Q １ , Q ３ , Q ５ , Q ７ , Q ９ , Q １１ ) is off, and the lower arms (Q ２ , Q ４ , Q ６ , Q ８ , Q １０ , Q １２ ) indicates the final state where it is turned on.

[0160] As shown in Fig. 18A, the initial state is a state in which the upper side short circuit control is being performed. In this initial state in which the upper side short circuit control is being performed, even in the third ASC mode, the phase current i ｕ , i ｖ , i ｗ is the upper arm (Q １ , Q ３ , Q ５ ), the rotating electric machine 210, and the upper arm (Q ７ , Q ５ , Q １１ Therefore, in the initial state where the upper short circuit control is performed, even in the third ASC mode, the phase current i ｕ , i ｖ , i ｗ is consumed by circulating through the first inverter 211, the second inverter 212, and the rotating electric machine 210. Furthermore, the smoothing capacitor 28 is neither charged nor discharged.

[0161] When switching from the upper side short circuit control to the lower side short circuit control, in the third ASC mode, as shown in FIG. 18B, the upper arms (Q １ , Q ３ , Q ５ , Q ７ , Q ９ , Q １１ However, the lower arms (Q ２ , Q ４ , Q ６ , Q ８ , Q １０ , Q １２ ) remains off. This means that the upper arm (Q １ , Q ３ , Q ５ , Q ７ , Q ９ , Q １１ ) and lower arm (Q ２ , Q ４ , Q ６ , Q ８ , Q １０ , Q １２ ) it is necessary to provide a dead time DT to prevent a through current from flowing.

[0162] At this time, the U-phase current i ｕ is the U-phase lower arm (Q ２ ) into the U-phase stator coil (U), and then flows into the U-phase upper arm (Q ７ ) and the U-phase current i ｕ flows through the smoothing capacitor 28 in the direction of charging. ｖ is the V-phase lower arm (Q １０ ) into the V-phase stator coil (V), and then flows from the V-phase stator coil (V) to the V-phase upper arm (Q ３ ) and the V-phase current i ｖ Similarly, the W-phase current iw flows through the W-phase lower arm (Q １２) into the W-phase stator coil (W), and then flows from the W-phase stator coil (W) to the W-phase upper arm (Q ５ ) and the W-phase current i ｗ flows through the smoothing capacitor 28 in the direction of charging. １ ~Q １２ ) are all turned off, the smoothing capacitor 28 is charged.

[0163] After that, when the dead time DT has elapsed, as shown in FIG. 18(C), the lower arms (Q ２ , Q ４ , Q ６ , Q ８ , Q １０ , Q １２ ) turns on. This turns on the upper arm (Q １ , Q ３ , Q ５ , Q ７ , Q ９ , Q １１ ) is off, and the lower arms (Q ２ , Q ４ , Q ６ , Q ８ , Q １０ , Q １２ ) is turned on. In this way, in the state where the control is switched to the low-side short-circuit control, the phase current i ｕ , i ｖ , i ｗ is consumed by circulating through the first inverter 211, the second inverter 212, and the rotating electric machine 210. Furthermore, the smoothing capacitor 28 is neither charged nor discharged.

[0164] As described above, in the third ASC mode, when switching between the upper side short circuit control and the lower side short circuit control, the phase current i ｕ , i ｖ , i ｗ is consumed by a short circuit formed by the first inverter 211, the second inverter 212 and the rotating electric machine 210, and the arms (Q １ ~Q １２) are all turned off, the smoothing capacitor 28 is charged. Therefore, in the electric vehicle 200, the third ASC mode is also set to ｄｃ is low (V ｄｃ <V ｄｃ－ｍｉｎ ), in a situation where it is desirable to charge the smoothing capacitor 28 in anticipation of restarting the system (recharging the smoothing capacitor 28), etc.

[0165] As described above, in the second embodiment, when ASC control is executed, the arms (legs) of the inverters 211 and 212 are classified into the first group G1 and the second group G2. In the first ASC mode, when switching between the upper side short-circuit control and the lower side short-circuit control, a transition period is provided in which the switching of the first group G1 is started first, thereby reducing the phase current i generated by the induced voltage of the rotating electric machine 210. ｕ , i ｖ , i ｗ is consumed in the short circuit formed by the inverter 12 (the first inverter 211 and the second inverter 212) and the rotating electric machine 210, and the smoothing capacitor 28 is discharged. In the second ASC mode, when switching between the upper side short circuit control and the lower side short circuit control, a transition period is provided in which the switching of the first group G1 is started in advance, so that the phase current i generated by the induced voltage of the rotating electric machine 210 is not discharged or charged in the smoothing capacitor 28. ｕ , i ｖ , i ｗ is consumed in a short circuit formed by the inverter 12 (the first inverter 211 and the second inverter 212) and the rotating electric machine 210. In the third ASC mode, the phase current i ｕ , i ｖ , i ｗ This is selected only when it is desirable to consume the power in the short circuit formed by the inverter 12 (the first inverter 211 and the second inverter 212) and the rotating electric machine 210, and to charge the smoothing capacitor 28. Therefore, also in the ASC control of the second embodiment, the smoothing capacitor 28 is protected when switching between the upper side short circuit control and the lower side short circuit control.

[0166] [Modification] In the first and second embodiments, overspeed and overcurrent are mainly detected as system abnormalities, and ASC control is performed when these abnormalities are present. However, as described above, when sensors such as the current sensor 14 fail, there are times when the relay 16 must be turned off and ASC control must be performed for safety. The ASC control of the first and second embodiments can also be used when sensors fail. However, in the first and second embodiments, when a duty command value for performing ASC control is generated, the phase current i ｕ , i ｖ , i ｗ Therefore, in the following description, it is assumed that the phase current i can be detected normally when the current sensor 14 fails. ｕ , i ｖ , i ｗ and the estimated phase current (hereinafter referred to as the estimated phase current i ｕ ', i ｖ ', i ｗ A modified example for performing ASC control of the first or second embodiment will be described below using the above-described arithmetic operation.

[0167] 19 is a block diagram showing the configuration of the PWM control unit 23 according to the modified example. As shown in FIG. 19, the PWM control unit 23 according to the modified example includes a current selection unit 301 in addition to an up / down switching signal generation unit 31, a zero current avoidance processing unit 32, and an ASC switching processing unit 33. In this modified example, the status signal S ｓｔａｔｅ represents the status of "normal" or "abnormal", and when the status is "abnormal", includes information indicating the location where the abnormality has occurred or the nature of the abnormality.

[0168] The current selection unit 301 receives the status signal S ｓｔａｔｅ When the status signal S is "abnormal", it is checked whether the abnormality is due to a failure of the current sensor 14. If the status signal S is abnormal due to a cause other than a failure of the current sensor 14, ｓｔａｔｅ indicates an "abnormality," the current selection unit 301 selects the phase current i ｕ , i ｖ , i ｗand obtain the phase current i ｕ , i ｖ , i ｗ The detected value is input to the zero current avoidance processing unit 32 and the ASC switching processing unit 33.

[0169] On the other hand, the status signal S ｓｔａｔｅ When the cause of indicating "abnormal" includes a failure of the current sensor 14, the current selection unit 301 selects the phase current i ｕ , i ｖ , i ｗ Specifically, the current selection unit 301 estimates the electrical angle θ and the magnet magnetic flux Φ according to the following equation (9): ａ , and d-axis inductance L ｄ Based on this, the estimated phase current i ｕ ', i ｖ ', i ｗ Then, the current selection unit 301 calculates the phase current i ｕ , i ｖ , i ｗ Instead of the detected value of the estimated phase current i ｕ ', i ｖ ', i ｗ The zero current avoidance processing unit 32 and the ASC switching processing unit 33 receive the duty command value Duty_UVW as the duty command value for ASC control.

[0170]

[0171] In addition, the magnetic flux Φ ａ and d-axis inductance L ｄ is a parameter specific to the rotating electrical machine 10 and is therefore a known parameter. ａ / L ｄ , 0] are the dq-axis currents [i ｄ , i ｑ ].

[0172] In this modification, the PWM control unit 23 of the first embodiment is configured to be able to execute ASC control even if a failure occurs in the current sensor 14, but the present invention is not limited to this. If the above-described current selection unit 301 is added to the first PWM control unit 217 and the second PWM control unit 218 of the second embodiment, ASC control can also be executed in the second embodiment even if a failure occurs in the current sensor 14. In the second embodiment, the current selection unit 301 may be added independently of the first PWM control unit 217 and the second PWM control unit 218, similar to the output determination unit 216.

[0173] As described above, the inverter control methods according to the first embodiment, the second embodiment, and the modified examples (hereinafter referred to as "embodiments") are methods for controlling an inverter 12 that connects a DC power supply (11) and a rotating electric machine (10, 210) via a smoothing capacitor (28) and has a pair of switching elements constituting an upper arm and a lower arm for each phase of the rotating electric machine (10, 210). In this control method for the inverter 12, upper-side short-circuit control, which turns on the upper arm of each phase and turns off the lower arm of each phase, and lower-side short-circuit control, which turns off the lower arm of each phase and turns on the lower arm of each phase, are alternately performed. When switching between the upper-side short-circuit control and the lower-side short-circuit control, the pairs of upper and lower arms are classified into either a first group (G1) or a second group (G2). A transition state is formed in which switching of the arms belonging to the first group (G1) is started prior to an initial state in which either the upper arm or the lower arm of each phase is turned on. Thereafter, a predetermined time (T) elapses after starting switching of the arms belonging to the first group (G1). ｄｅｌａｙ ) has elapsed, switching of the arms belonging to the second group (G2) is started, thereby forming a final state in which the other of the upper arm or the lower arm of each phase is turned on.

[0174] In this way, when switching between the upper side short circuit control and the lower side short circuit control, by classifying the arms (legs) into the first group G1 and the second group G2 and going through a transition state in which the arms belonging to the first group G1 are switched first, it is possible to switch between the upper side short circuit control and the lower side short circuit control while protecting the smoothing capacitor 28. Specifically, when switching between the upper side short circuit control and the lower side short circuit control without going through the transition state as described above, all the arms are turned off during the dead time DT, and the phase current i generated by the induced voltage of the rotating electric machines 10, 210 ｕ , i ｖ , i ｗ As a result, the smoothing capacitor 28 may be charged, resulting in overcharging and failure. In contrast, if the above-described transition state is provided when switching between the upper side short-circuit control and the lower side short-circuit control, the upper side short-circuit control and the lower side short-circuit control can be switched between without charging the smoothing capacitor 28. Therefore, according to the inverter control method according to the above-described embodiments, the smoothing capacitor 28 can be protected when switching between the upper side short-circuit control and the lower side short-circuit control.

[0175] In the inverter control method according to the above-described embodiments, the current (i ｕ , i ｖ , i ｗ Based on the orientation of the upper and lower arms of each phase, the upper and lower arms are classified into a first group (G1) and a second group (G2).

[0176] In this way, the phase current i ｕ , i ｖ , i ｗ By classifying the arms (legs) of the inverter 12 based on the direction of the arrows, it is possible to appropriately distinguish between a first group G1 that should be switched first to form a transition state and a second group G2 that should be switched later. Therefore, it is easy to protect the smoothing capacitor 28 particularly reliably when switching between the upper side short-circuit control and the lower side short-circuit control.

[0177] In the inverter control method according to the above-described embodiment, a current (i ｕ , i ｖ , i ｗ) flows into a first group (G1), and a current (i ｕ , i ｖ , i ｗ The arm through which the IVF solution flows is classified as group 2 (G2).

[0178] In this way, the phase current i ｕ , i ｖ , i ｗ The arms (legs) into which the phase current i flows are classified into a first group G1, and the phase current i ｕ , i ｖ , i ｗ By classifying the arms (legs) through which the current flows into the second group G2, the arms (legs) of the inverter 12 can be appropriately distinguished into the first group G1 that should be switched ahead to form a transition state and the second group G2 that should be switched with a delay. Therefore, it is easy to protect the smoothing capacitor 28 particularly reliably when switching between the upper side short-circuit control and the lower side short-circuit control.

[0179] In the inverter control method according to the above-described embodiment, ｄｅｌａｙ ) is variable, and the DC voltage (V ｄｃ ) for a predetermined time (T ｄｅｌａｙ ) to adjust the

[0180] In this way, the DC voltage V ｄｃ In response to this, a predetermined time (delay time T ｄｅｌａｙ ), it is possible to perform appropriate ASC control depending on the situation where the smoothing capacitor 28 should be discharged, the situation where the smoothing capacitor 28 does not need to be discharged or charged, and the situation where it is preferable to charge the smoothing capacitor 28. That is, ｄｃ In accordance with the state of the smoothing capacitor 28, the first ASC mode, the second ASC mode, and the third ASC mode can be switched appropriately to perform appropriate ASC control according to the state of the smoothing capacitor 28.

[0181] In the inverter control method according to the above-described embodiment, ｄｅｌａｙ) is set to a length equal to or greater than the dead time (DT) in the switching of the arms belonging to the first group (G1).

[0182] In this way, the predetermined time (the delay time T ｄｅｌａｙ When the ASC control in the first ASC mode or the second ASC mode is performed by setting the dead time DT or longer, the smoothing capacitor 28 generates a phase current i ｕ , i ｖ , i ｗ Therefore, the smoothing capacitor 28 can be easily and reliably protected particularly when switching between the upper side short-circuit control and the lower side short-circuit control.

[0183] In the inverter control method according to the above-described embodiment, ｄｅｌａｙ ) is equal to the dead time (DT), and when the switching of the arms belonging to the first group (G1) is completed due to the lapse of the dead time (DT), the switching of the arms belonging to the second group (G2) starts.

[0184] In this way, the predetermined time (the delay time T ｄｅｌａｙ ) is set equal to the dead time DT, the smoothing capacitor 28 is neither charged nor discharged when ASC control in the second ASC mode is performed. Therefore, the smoothing capacitor 28 can be easily and reliably protected when switching between the upper side short-circuit control and the lower side short-circuit control.

[0185] In the inverter control method according to the above-described embodiments, the DC voltage (V ｄｃ ) is within a predetermined range (V ｄｃ－ＭＡＸ ≧V ｄｃ ≧V ｄｃ－ｍｉｎ ) at a predetermined time (T ｄｅｌａｙ ) is set equal to the dead time (DT).

[0186] In a situation where the smoothing capacitor 28 does not need to be discharged or charged, the DC voltage V ｄｃ is within a predetermined range (V ｄｃ－ＭＡＸ ≧V ｄｃ ≧V ｄｃ－ｍｉｎ Therefore, it can be determined whether the DC voltage Vｄｃ is within a predetermined range (V ｄｃ－ＭＡＸ ≧V ｄｃ ≧V ｄｃ－ｍｉｎ ), a predetermined time (the delay time T ｄｅｌａｙ ) is set equal to the dead time DT and ASC control in the second ASC mode is performed, the smoothing capacitor 28 can be easily and reliably protected particularly when switching between the upper side short-circuit control and the lower side short-circuit control.

[0187] In the inverter control method according to the above-described embodiment, ｄｅｌａｙ ) is composed of a dead time (DT) and an additional time (tp), and the switching of the arms belonging to the first group (G1) is completed after the dead time (DT) has elapsed, and after the additional time (tp) has elapsed, the switching of the arms belonging to the second group (G2) begins.

[0188] In this way, the predetermined time (the delay time T ｄｅｌａｙ ) to be the sum of the dead time DT and the additional time tp, when ASC control in the first ASC mode is executed, the smoothing capacitor 28 is discharged for a period corresponding to this additional time tp. Therefore, when switching between the upper side short-circuit control and the lower side short-circuit control in a situation where it is desirable to discharge the smoothing capacitor 28, the smoothing capacitor 28 can be discharged while being protected.

[0189] In the inverter control method according to the above-described embodiments, the DC voltage (V ｄｃ ) is a predetermined upper limit value (V ｄｃ－ＭＡＸ ) exceeds a predetermined time (T ｄｅｌａｙ ) is composed of a dead time (DT) and an additional time (tp).

[0190] The situation where it is preferable to discharge the smoothing capacitor 28 is when the DC voltage V ｄｃ is a predetermined upper limit value (V ｄｃ－ＭＡＸ ) can be determined by whether or not the DC voltage Vdc exceeds a predetermined upper limit (V ｄｃ－ＭＡＸ ) exceeds a predetermined time (the delay time T ｄｅｌａｙ) is set to the sum of the dead time DT and the additional time tp, and ASC control in the first ASC mode is executed, the smoothing capacitor 28 can be discharged while being protected when switching between the upper side short-circuit control and the lower side short-circuit control.

[0191] In the inverter control method according to the above-described embodiments, the DC voltage (V ｄｃ ) is a predetermined lower limit value (V ｄｃ－ｍｉｎ ) or more, the predetermined time (T ｄｅｌａｙ ) is set to a length equal to or longer than the dead time (DT) in the switching of the arms belonging to the first group (G1), and the DC voltage (V ｄｃ ) is the lower limit (V ｄｃ－ｍｉｎ ) falls below a predetermined time (T ｄｅｌａｙ ) to zero.

[0192] The situation where it is preferable to charge the smoothing capacitor 28 is when the DC voltage V ｄｃ is a predetermined lower limit value (V ｄｃ－ｍｉｎ ) or not. ｄｃ is a predetermined lower limit value (V ｄｃ－ｍｉｎ ) or more, the ASC control is performed in the first ASC mode or the second ASC mode as described above to prevent the smoothing capacitor 28 from being charged in order to protect the smoothing capacitor 28. ｄｃ is a predetermined lower limit value (V ｄｃ－ｍｉｎ ), as described above, the predetermined time (the delay time T ｄｅｌａｙ ) to zero and perform ASC control in the third ASC mode, the smoothing capacitor 28 can be charged to a certain extent in order to restart the system (recharge the smoothing capacitor 28).

[0193] In the inverter control method according to the above-described embodiments, the timing for switching between the upper-side short-circuit control and the lower-side short-circuit control is determined based on the current (i ｕ , i ｖ , i ｗ ) becomes zero, the switching between the upper side short-circuit control and the lower side short-circuit control is delayed.

[0194] Phase current i ｕ , i ｖ , i ｗ When either of these becomes zero, the classification of the arms (legs) into the first group G1 and the second group G2 becomes unstable. Therefore, by performing the zero current avoidance process as described above, the smoothing capacitor 28 can be protected particularly reliably when switching between the upper side short-circuit control and the lower side short-circuit control.

[0195] In the inverter control method according to the above-described embodiments (especially the modified examples), the current (i ｕ , i ｖ , i ｗ When the current sensor (14) for detecting the current (i) fails, the current (i) is detected based on the electrical angle (θ) of the rotating electric machine (10, 210). ｕ , i ｖ , i ｗ ) and estimate the estimated current (i ｕ ', i ｖ ', i ｗ Based on the orientation of the upper and lower arms of each phase, the upper and lower arms are classified into a first group (G1) and a second group (G2).

[0196] In this way, the estimated phase current i ｕ ', i ｖ ', i ｗ By using the ', it is possible to perform ASC control in an appropriate mode even if the current sensor 14 fails. Therefore, it is possible to protect the smoothing capacitor 28 particularly reliably when switching between the upper side short-circuit control and the lower side short-circuit control.

[0197] The inverter control device according to the above embodiments is a control device (controller 13) for an inverter (12) that connects a DC power supply (11) and a rotating electric machine (10, 210) via a smoothing capacitor (28) and has a pair of switching elements that form an upper arm and a lower arm for each phase of the rotating electric machine (10, 210). The control device (controller 13) includes a PWM control unit (23) that alternately executes upper-side short-circuit control that turns on the upper arm of each phase and turns off the lower arm of each phase, and lower-side short-circuit control that turns off the lower arm of each phase and turns on the lower arm of each phase. When switching between upper-side short-circuit control and lower-side short-circuit control, the PWM control section (23) classifies pairs of upper and lower arms into either a first group (G1) or a second group (G2), and forms a transition state in which switching of the arms belonging to the first group (G1) starts in advance of an initial state in which one of the upper arms or the lower arms of each phase is turned on, and after a predetermined time (T ｄｅｌａｙ After the elapse of the period, the switching of the arms belonging to the second group (G2) is started, thereby forming a final state in which the other of the upper arm or the lower arm of each phase is turned on.

[0198] In this way, when switching ASC control between upper short-circuit control and lower short-circuit control, by classifying the arms (legs) into the first group G1 and the second group G2 and going through a transition state in which the switching of the arms belonging to the first group G1 begins first, it is possible to switch between upper short-circuit control and lower short-circuit control while protecting the smoothing capacitor 28.

[0199] Although the embodiments of the present invention have been described above, the configurations described in the above embodiments merely show some of the application examples of the present invention and are not intended to limit the technical scope of the present invention.

Claims

1. A method for controlling an inverter having a pair of switching elements constituting an upper arm and a lower arm for each phase of a rotating electric machine, the inverter being connected to a DC power supply via a smoothing capacitor, the method comprising: performing upper short-circuit control in which the upper arm of each phase is turned on and the lower arm of each phase is turned off, and lower short-circuit control in which the lower arm of each phase is turned off and the lower arm of each phase is turned on, alternately; when switching between the upper short-circuit control and the lower short-circuit control, classifying the pair of the upper arm and the lower arm into either a first group or a second group; forming a transition state in which switching of the arms belonging to the first group is started prior to a start state in which one of the upper arm or the lower arm of each phase is uniformly turned on; and starting switching of the arms belonging to the second group after a predetermined time has elapsed since the switching of the arms belonging to the first group was started, thereby forming an end state in which the other of the upper arm or the lower arm of each phase is uniformly turned on. A method for controlling an inverter.

2. The method for controlling an inverter according to claim 1, wherein the upper arm and the lower arm of each phase are classified into the first group and the second group based on the direction of the current flowing in each phase. A method for controlling an inverter.

3. The method for controlling an inverter according to claim 2, wherein the arm through which current flows into the rotating electric machine is classified into the first group, and the arm through which current flows toward the rotating electric machine is classified into the second group. A method for controlling an inverter.

4. The method for controlling an inverter according to any one of claims 1 to 3, wherein the predetermined time is variable, and the predetermined time is adjusted according to a DC voltage which is a voltage in the smoothing capacitor. A method for controlling an inverter.

5. The method for controlling an inverter according to claim 4, wherein the predetermined time is set to a length equal to or greater than a dead time in the switching of the arms belonging to the first group. A method for controlling an inverter.

6. The method for controlling an inverter according to claim 5, wherein the predetermined time is equal to the dead time, and switching of the arms belonging to the second group is started when the switching of the arms belonging to the first group is completed after the dead time has elapsed. A method for controlling an inverter.

7. A method for controlling an inverter according to claim 6, wherein when the DC voltage is within a predetermined range, the predetermined time is set to be equal to the dead time.

8. A method for controlling an inverter according to claim 5, wherein the predetermined time is composed of the dead time and an additional time, and after the switching of the arm belonging to the first group is completed by the elapse of the dead time and the additional time has elapsed, the switching of the arm belonging to the second group is started.

9. A method for controlling an inverter according to claim 8, wherein when the DC voltage exceeds a predetermined upper limit value, the predetermined time is composed of the dead time and the additional time.

10. A method for controlling an inverter according to claim 4, wherein when the DC voltage is equal to or higher than a predetermined lower limit value, the predetermined time is set to be longer than the dead time in the switching of the arm belonging to the first group, and when the DC voltage falls below the lower limit value, the predetermined time is set to zero.

11. A method for controlling an inverter according to claim 2, wherein when the timing of switching between the upper short-circuit control and the lower short-circuit control overlaps with the timing when the absolute value of the current flowing through any phase becomes zero, the switching between the upper short-circuit control and the lower short-circuit control is delayed.

12. A method for controlling an inverter according to claim 2, wherein when a current sensor for detecting the current flowing through each phase fails, the current is estimated based on the electrical angle of the rotating electrical machine, and based on the direction of the estimated current, the upper arm and the lower arm of each phase are classified into the first group and the second group.

13. A control device for an inverter having a pair of switching elements constituting an upper arm and a lower arm for each phase of a rotating electrical machine connected to a DC power supply via a smoothing capacitor, the control device comprising: a PWM control unit that alternately executes an upper short-circuit control for turning on the upper arm of each phase and turning off the lower arm of each phase, and a lower short-circuit control for turning off the lower arm of each phase and turning on the lower arm of each phase; the PWM control unit, when switching between the upper short-circuit control and the lower short-circuit control, classifies the pair of the upper arm and the lower arm into either a first group or a second group, forms a transition state in which switching of the arms belonging to the first group is started prior to a start state in which one of the upper arm or the lower arm of each phase is turned on uniformly, and after a predetermined time has elapsed since the switching of the arms belonging to the first group is started, starts the switching of the arms belonging to the second group to form an end state in which the other of the upper arm or the lower arm of each phase is turned on uniformly. A control device for an inverter.

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