JP4798638B2 - Control device for synchronous motor - Google Patents

Description

  The present invention relates to a control device for a synchronous motor mounted on an electric vehicle such as a forklift, and more particularly, a high-efficiency synchronous motor control device that achieves both high torque and high rotation in a wide range of operation from low speed to high speed. About.

FIG. 11 is a schematic configuration diagram of a conventional synchronous motor control device mounted on a forklift. FIG. 12 is an equivalent circuit diagram of the stator-side coil of the synchronous motor of FIG.
Referring to FIG. 11, synchronous motor control device 23 includes a synchronous motor 25, an inverter circuit 24 connected to synchronous motor 25, and a battery (DC power supply) B that supplies a DC voltage to inverter circuit 24. ing.
Referring to FIG. 12, synchronous motor 25 is a known motor including a rotor and a stator (not shown), and has a permanent magnet by a rotating magnetic field generated by three-phase coils U, V, and W on the stator side. The rotor is rotated at a desired rotational speed.
The inverter circuit 24 includes, for example, six semiconductor switching elements Q18 to Q23 such as a MOS FET (field effect transistor) and an IGBT (insulated gate bipolar transistor), and is synchronized by the switching operation of the semiconductor switching elements Q18 to Q23. The synchronous motor 25 is driven by applying a three-phase AC output to the motor 25 and rotating a rotor having a permanent magnet. A main contactor 5 is interposed between the inverter circuit 24 and the battery B, and a capacitor C is connected in parallel to the input side of the inverter circuit 24 (see, for example, Patent Document 1).

JP 2001-89098 A (paragraphs 0019 to 0022, 0040 and FIG. 1)

  By the way, in the synchronous motor 25, the direction in which the induced voltage (counterelectromotive force) proportional to the rotational speed of the rotor cancels the voltage applied from the inverter circuit 24 to the stator side coil by the rotation of the rotor having the permanent magnet. Occurs. For this reason, the maximum number of rotations of the synchronous motor 25 is limited to a number of rotations such that the induced voltage is equal to or lower than the AC voltage applied from the inverter circuit 24. Here, in order to reduce this induced voltage, the maximum number of rotations of the synchronous motor 25 can be increased by a method such as reducing the number of turns of the coils U, V, W on the stator side. The maximum torque to be reduced. That is, the synchronous motor 25 has a problem that high torque and high rotation cannot be realized simultaneously because the maximum rotation speed and maximum torque obtained are in a trade-off relationship.

  In order to increase the maximum number of revolutions of the synchronous motor 25, there is field weakening control in which a current that cancels the magnetic field generated by the permanent magnets of the rotor is passed through the coils U, V, and W on the stator side to lower the induced voltage. However, the field weakening control has a problem that the permanent magnet is demagnetized to apply a magnetic field in the opposite direction to the field of the permanent magnet, and a copper loss increases because a current that does not contribute to torque flows through the coil. As a result, the motor efficiency is deteriorated and the power consumption of the battery is increased.

  The present invention has been made in view of such circumstances, and provides a highly efficient synchronous motor control device that achieves both high torque and high rotation in a wide range of operation from low speed to high speed.

In order to solve the above problems, the present invention provides: (1) a synchronous motor having a plurality of multiphase coils including at least first and second multiphase coils in a stator; and a rotating magnetic field with respect to the plurality of multiphase coils. A plurality of inverter circuits including at least first and second inverter circuits for individually applying an AC output for generating a power supply, and a battery for supplying a common DC voltage to the plurality of inverter circuits. A control device for a synchronous motor of an electric vehicle, wherein the main contactor is provided between the battery and the plurality of inverter circuits and performs switching of supply or stop of supply of the DC voltage from the battery, and the plurality of inverters At least one sub-contactor provided between the circuits for switching the connection between the plurality of inverter circuits; By controlling the switching of each of the main contactor and the sub contactor and controlling the AC output of each of the plurality of inverter circuits based on the force, at least the first motor and the second motor are controlled by the synchronous motor. A control unit for driving in a plurality of different drive modes including a first drive mode for driving with both AC outputs of the inverter circuit and a second drive mode for driving with AC output of only the first inverter circuit A speed detection unit that detects a rotation speed of the synchronous motor, an accelerator command amount detection unit that detects an accelerator command amount of the electric vehicle, and a battery voltage detection unit that detects a voltage of the battery, Speed signal detected by the speed detection unit as an external signal, accelerator command signal detected by the accelerator command amount detection unit, And the control unit compares the speed signal with a preset speed reference signal based on the input of the battery voltage signal detected by the battery voltage detection unit, and the speed signal is greater than the speed reference signal. When it is determined that the synchronous motor is smaller, the synchronous motor is driven in the first drive mode, and when it is determined that the speed signal is larger than the speed reference signal, the synchronous motor is driven in the second drive mode. to provide a control system for a synchronous motor, characterized in that letting.

According to the configuration (1) , in the synchronous motor control device, the stator-side multiphase coil is configured by at least the first and second multiphase coils, and the inverter circuit is configured by at least the first and second multiphase coils. Based on the input of the speed signal detected by the speed detection unit as an external signal , the control unit is configured with the speed signal and the first and second inverter circuits that apply AC outputs corresponding to the coils, respectively. The speed reference signal is compared, and according to the comparison result , at least the first drive mode in which the synchronous motor is driven by at least the AC output of both the first and second inverter circuits, and only the first inverter circuit It was constructed so that is driven by the second driving mode for driving an AC output. Therefore , the synchronous motor can be driven with high torque in the first drive mode, and further driven to high rotation speed in the second drive mode. As a result, both high torque in the low speed range and high rotation in the high speed range can be achieved. Thus, it is possible to provide a high-efficiency synchronous motor control device that does not require complicated control such as field weakening.

Here, in the configuration (1), (2) the speed reference signal is preferably determined by a product of the battery voltage signal and a predetermined gain.

In the configuration (1) or (2) , more preferably, (3) the number of turns of the first multiphase coil is set to be smaller than the number of turns of the second multiphase coil.

According to the configuration (3) , high torque and high rotation can be variably controlled in a wide range of operation from low speed to high speed only by changing the number of turns of the first and second multiphase coils on the stator side. A highly efficient synchronous motor control device can be provided.

In any one of the configurations (1) to (3) , more preferably, (4) based on the input of the speed signal and the accelerator command signal, the control unit further sets a required torque value for the synchronous motor. Calculating the required torque value for each of the first and second inverter circuits to output the required torque value from the synchronous motor, and supplying the first and second inverter circuits with an AC output as the AC output. Each is configured to command a necessary torque value.

According to this configuration (4) , the required torque value for the synchronous motor is calculated by the control unit based on the input of the speed signal and the accelerator command signal as the external signal, and this required torque value should be output from the synchronous motor. The required torque values (current values corresponding to the torque values) are commanded to the first and second inverter circuits as AC outputs, respectively. In response to this command, the first and second inverter circuits output these calculated torques (currents), respectively, so that it is possible to provide a synchronous motor control device that can control torque more efficiently.

  According to the present invention, it is possible to provide a highly efficient synchronous motor control device that achieves both high torque and high rotation in a wide range of operation from low speed to high speed.

It is a schematic block diagram of the control apparatus of the synchronous motor mounted in the forklift by 1st Example of this invention. FIG. 2 is an equivalent circuit diagram of a stator side coil of the synchronous motor of FIG. 1. It is a flowchart explaining operation | movement of the control apparatus of the synchronous motor of FIG. 2 is a graph showing a torque-rotation speed (rotation speed) characteristic for explaining a driving state of the synchronous motor control device of FIG. 1. 2 is a graph showing torque-rotation speed (rotation speed) characteristics for comparing the synchronous motor control device of FIG. 1 with a conventional synchronous motor control device. It is a schematic block diagram of the control apparatus of the synchronous motor mounted in the forklift by the modification of this invention. FIG. 7 is an equivalent circuit diagram of a coil on the stator side of the synchronous motor of FIG. 6. It is a flowchart explaining operation | movement of the control apparatus of the synchronous motor of FIG. It is the graph which showed the torque-rotation speed (rotation speed) characteristic for demonstrating the drive state of the control apparatus of the synchronous motor of FIG. It is the graph which showed the torque-rotation speed (rotation speed) characteristic for comparing the control apparatus of the synchronous motor of FIG. 6, and the control apparatus of the conventional synchronous motor. It is a schematic block diagram of the control apparatus of the conventional synchronous motor mounted in a forklift. FIG. 12 is an equivalent circuit diagram of a coil on the stator side of the synchronous motor of FIG. 11.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram of a control device for a synchronous motor mounted on a forklift according to a first embodiment of the present invention. FIG. 2 is an equivalent circuit diagram of a stator side coil of the synchronous motor of FIG. Here, in order to clarify the correspondence with the conventional synchronous motor control device described with reference to FIG. 11, the same reference numerals are given to the components common to the components shown in FIG. 11, The description is omitted.

  Referring to FIG. 1, a synchronous motor control device 1 includes a control unit 2, a synchronous motor 7, and a high-speed continuous rotation inverter circuit connected to each of the synchronous motors 7 (the first inverter circuit of the claims of the present application). 3) and a low-speed rotation inverter circuit (corresponding to the second inverter circuit in the claims of the present application) 4, a high-speed continuous rotation inverter circuit 3 and a low-speed rotation inverter circuit 4 are supplied with a common DC voltage. A battery (DC power supply) B, a main contactor 5, a sub contactor 6, current sensors 8 to 11, a speed detector (PG) 12, an accelerator command amount detector 13, a battery voltage detector 14, It has. The speed detector 12 includes a pulse generator (pulse generator) PG provided in the synchronous motor 7, and detects the rotational speed (number of rotations) of the synchronous motor 7. The accelerator command amount detection unit 13 detects an accelerator command amount corresponding to an operation amount of an accelerator lever (not shown) of the forklift. The battery voltage detection unit 14 detects a DC voltage of the battery B.

The synchronous motor 7 is a known motor including a rotor and a stator (not shown). Referring to FIG. 2, the synchronous motor 7 has a high-speed continuous rotation three-phase coil to which an alternating current output is applied from the high-speed continuous rotation inverter circuit 3 on the stator side (the first multiphase coil in the claims of the present application). U _H , V _H , W _H , and low-speed rotation three-phase coil to which an AC output is applied from the low-speed rotation inverter circuit 4 (corresponding to the second multi-phase coil in the claims of this application) _UL has a _{V L, W} L. The synchronous motor 7 rotates a rotor having a permanent magnet at a desired rotation speed by a rotating magnetic field generated by these three-phase coils. Here, high-speed type continuous rotation for three-phase coils _{U H,} V _{H, W} H is a low-speed rotation for three-phase coils _{U L,} V L, number of coil turns is less than _{W L.}
Although not shown, synchronous motor 7, a high speed type continuous rotation for three-phase coils U _H, V _H, W _H and a low-speed rotation for three-phase coils U _L, V _L, the rotating magnetic field generated in each of the W _L It has a shaft mechanism that can output the corresponding rotational force (torque) separately or combine them.

Fast-type continuous rotation inverter circuit 3, _{U H-phase} upper, _{U H-phase} lower, _{V H-phase} upper, _{V H} phase lower, _{W H} phase upper six known semiconductor switching elements under _{W H} phase Q1~ The synchronous motor 7 is driven by applying a three-phase AC output to the synchronous motor 7 by the switching operation of these semiconductor switching elements Q1 to Q6.
A low-speed rotation inverter circuit 4, _{U L-phase} upper, _{U L-phase} lower, _{V L-phase} upper, _{V L-phase} lower, _{W L-phase} upper, _{W L} 6 or under phase known semiconductor switching elements Q7~Q12 The three-phase AC output is applied to the synchronous motor 7 by the switching operation of these semiconductor switching elements Q7 to Q12, and the synchronous motor 7 is driven.
Semiconductor switching elements Q1 and Q2 corresponding to the upper and lower U _H phases, semiconductor switching elements Q3 and Q4 corresponding to the upper and lower V _H phases, and semiconductor switching elements Q5 and Q6 corresponding to the upper and lower _WH phases connected in series with each other a semiconductor switching element Q7, Q8 corresponding to the upper and lower _{U L-phase,} the semiconductor switching element Q9, Q10 corresponding to _{V L-phase} upper and lower, the semiconductor switching devices Q11, Q12 corresponding to _{W L-phase} upper and lower, of the battery B It is connected in parallel between the power lines connected to both ends. As the semiconductor switching element, for example, an element capable of high-speed switching operation such as a MOS FET (field effect transistor) or an IGBT (insulated gate bipolar transistor) is used. Although not shown, a diode is preferably connected in parallel to each semiconductor switching element.
Further, from the connection point of the semiconductor switching devices Q1~12 each other which are connected to each other in series, _{U H} phase voltage _V UH AC for driving a synchronous motor 7, _{V H} phase voltage _V VH, _{W H} phase voltage _{V WH} , _{U L-phase} voltage _V UL, _{V L-phase} voltage _V VL, _{W L-phase} voltage _{V WL} is supplied to the synchronous motor 7. _{Here, I UH, I VH, I} WH, I UL, I VL, I WL , respectively _{U H-phase} current, _{V H-phase} current, _{W H-phase} current, _{U L-phase} current, _{V L-phase} current, _{W L} The phase current is shown. Reference numerals 8 to 11 in FIG. 1 denote current sensors that detect U _H phase current, V _H phase current, _UL phase current, and _VL phase current, respectively. Incidentally, W _H-phase current and W _L-phase current, respectively, obtained by summing the U _H-phase current and the V _H phase current, and so the that the sum of the U _L-phase current and the V _L-phase current, W a current sensor for _H-phase current and W _L-phase current is not provided. Capacitors C _H and C _L are connected in parallel to the input sides of the high-speed continuous rotation inverter circuit 3 and the low-speed rotation inverter circuit 4, respectively.

  The main contactor 5 is provided between the battery B and the high-speed continuous rotation inverter circuit 3 and the low-speed rotation inverter circuit 4 to supply a DC voltage from the battery B to the inverter circuits 3 and 4. This is to switch the supply stop. The sub-contactor 6 is provided between the high-speed continuous rotation inverter circuit 3 and the low-speed rotation inverter circuit 4 and switches the connection between the inverter circuits 3 and 4.

The control unit 2 includes an input unit 2a, an MPU (Micro Processor Unit) 2b, and an output unit 2c, and controls the AC output of each of the high-speed continuous rotation inverter circuit 3 and the low-speed rotation inverter circuit 4, and The switching of each of the main contactor 5 and the sub contactor 6 is controlled.
The input unit 2a includes, for example, a speed signal V detected by the speed detection unit (PG) 12, an accelerator command signal A detected by the accelerator command amount detection unit 13, and a battery voltage signal detected by the battery voltage detection unit 14. V _{B, U H} phase signal related to _{U H-phase} current, _{V H} phase signal related to _{V H-phase} current, _{U L-phase} signal related to _{U L-phase} current, and _{V L-phase} signal related to _{V L-phase} current is inputted.
The MPU 2b executes processing necessary for controlling the synchronous motor 7 based on the signal input to the input unit 2a.
The output unit 2c uses the control signal processed by the MPU 2b to give necessary instructions (outputs) to the high-speed continuous rotation inverter circuit 3, the low-speed rotation inverter circuit 4, the main contactor 5 and the sub contactor 6. Do.

  FIG. 3 is a flowchart for explaining the operation of the synchronous motor control device 1 of the present invention, and shows a procedure executed by the control unit 2. FIG. 4 is a graph showing a torque-rotation speed (rotation speed) characteristic for explaining a driving state of the synchronous motor control device 1 of FIG. This procedure will be described below with reference to FIGS.

First, the main contactor 5 is turned on by the control unit 2 (step S1). Subsequently, a battery voltage signal V _B is input to the input unit 2a (step S2), the speed signal V and the accelerator instruction signal A is input to the input unit 2a (step S3).
Then, MPU2b by a speed reference signal _{V 0} set in advance and the speed signal V is compared (step S4). Here, the preset speed reference signal V ₀ is determined by the product of the battery voltage signal V _B and a predetermined gain G ₀ .
In step S4 described above, less than the speed signal V is the speed reference signal V ₀ (V <V _0), i.e. if it is determined that the driving state of low-speed (low rotation), sub contactor 6 is turned on (step S5). By this step S5, the synchronous motor 7 can be driven with a torque value (current value corresponding to the torque value) as an AC output of both the high-speed continuous rotation inverter circuit 3 and the low-speed rotation inverter circuit 4. (First driving mode). This corresponds to the driving state in region 1 and region 2 shown in FIG.
Further, in step S4 described above, the speed signal V is the speed reference signal greater than or equal _to V ₀ (V ≧ V _0), i.e. if it is determined that the driving state of the high-speed (high rotational), sub contactor 6 is turned off (step S6) . By this step S6, the synchronous motor 7 is driven by a torque value (current value corresponding to the torque value) as an AC output of only the high-speed continuous rotation inverter circuit 3 (second drive mode). This corresponds to the driving state in the region 3 shown in FIG. At this time, the low-speed inverter circuit 4 for rotation is disconnected from the battery B, but is controlled by the control unit 2 so that a torque value 0 (current value 0) is commanded.

Next, in order to realize a high torque in the low-speed driving state, the MPU 2b calculates a necessary torque value T for the synchronous motor 7 based on the speed signal V and the accelerator command signal A (steps S7 and S8). . In order to cause the synchronous motor 7 to output the necessary torque value T, the torque values (current values corresponding to the torque values) necessary for the high-speed continuous rotation inverter circuit 3 and the low-speed rotation inverter circuit 4 are respectively It is calculated as follows. However, in order to simplify the explanation, the inverter circuit 3 for high-speed continuous rotation is always driven with an AC output corresponding to the maximum torque value (output), and the inverter circuit 3 is set to the required torque value T for the synchronous motor 7. The case where both inverter circuits 3 and 4 are driven so that the low-speed rotation inverter circuit 4 can output the AC output corresponding to the difference torque value only when the corresponding AC output cannot be output will be described.
First, a preset torque reference value required torque value T (the maximum torque value of the high speed type continuous rotation inverter circuit 3) T ₀ are compared (step S9). In step S9, if the control unit 2 determines that the necessary torque value T calculated in step S7 is less than the torque reference value T ₀ (T <T ₀ ), the control unit 2 is required for the low-speed rotation inverter circuit 4. A torque value of 0 is commanded as a torque value (step S10). This corresponds to the driving state in the region 1 shown in FIG. In Step S9, if the control unit 2 determines that the necessary torque value T calculated in Step S7 is equal to or greater than the torque reference value T ₀ (T ≧ T ₀ ), the control unit 2 As a necessary torque value, a difference value (T−T ₀ ) between the necessary torque value T and the torque reference value T ₀ is commanded (step S11). This corresponds to the driving state in the region 2 shown in FIG.
Then, according to the result of step S10, S11, an AC output corresponding to the torque value required for the low-speed rotary inverter circuit 4 0 or (T-T ₀₎ is, for synchronous motor 7 from the inverter circuit 4 Is output (step S12). Further, an AC output corresponding to a torque value necessary for the high-speed continuous rotation inverter circuit 3 is output from the inverter circuit 3 to the synchronous motor 7 (step S13). Accordingly, since the synchronous motor 7 can be driven by the AC outputs of both the high-speed continuous rotation inverter circuit 3 and the low-speed rotation inverter circuit 4 in the low speed range, high torque in the control apparatus 1 for the synchronous motor can be obtained. realizable.
After step S8, the control unit 2 commands the low-speed rotation inverter circuit 4 to have a torque value of 0 as a necessary torque value (step S14). This corresponds to the driving state in the region 3 shown in FIG. 4. As described above, the control unit 2 disconnects the low-speed rotation inverter circuit 4 from the battery B, but the torque value is 0 (current value is 0). It is in a controlled state. And according to the result of step S14, the alternating current output corresponding to the torque value required for the inverter circuit 3 for high speed type | mold continuous rotation is output with respect to the synchronous motor 7 from the said inverter circuit 3 (step S13). Therefore, in the high speed range, the synchronous motor 7 can be driven up to a high speed with an AC output of only the high-speed continuous rotation inverter circuit 3, so that a high speed in the control apparatus 1 for the synchronous motor can be realized.
Finally, the control unit 2 repeats steps S2 to S14 until the synchronous motor 7 is driven in a desired operation, and performs control so as to obtain an optimal drive mode and necessary torque value.

(Comparison result 1)
FIG. 5 is a graph showing torque-rotation speed (rotation speed) characteristics for comparing the synchronous motor control device 1 of FIG. 1 with the conventional synchronous motor control device 23.
Referring to FIG. 5, (a) is a graph showing torque-rotational speed characteristics when the synchronous motor 7 is driven by an AC output of only the high-speed continuous rotation inverter circuit 3, and (b) is a synchronous signal. 1A is a graph showing torque-rotation speed characteristics when the motor 7 is driven by an AC output of only the low-speed rotation inverter circuit 4, and FIG. It is a graph which shows the torque-rotation speed characteristic at the time of combining b).
As is apparent from FIG. 5, in the conventional synchronous motor control device 23, the synchronous motor 25 can be driven only within the range of the torque-rotational speed characteristics shown in either (a) or (b). In the synchronous motor control apparatus 1, the synchronous motor 7 can be driven within a wide range of torque-rotational speed characteristics shown in FIG.
Therefore, the synchronous motor control device 1 of FIG. 1 can achieve both high torque and high rotation as compared with the conventional synchronous motor control device 23.

(Modification)
FIG. 6 is a schematic configuration diagram of a control device for a synchronous motor mounted on a forklift according to a modification of the first embodiment of the present invention. FIG. 7 is an equivalent circuit diagram of a coil on the stator side of the synchronous motor of FIG.
Here, this modified example further includes a medium-speed rotation inverter circuit in the synchronous motor control device 1 of the first embodiment, and with the addition of this circuit, the number of stator-side multiphase coils, The difference from the first embodiment is that the number of contactors, the number of input / output signals of the control unit, and the number of drive modes are increased. Therefore, in order to clarify the correspondence with the conventional switching power supply device described with reference to FIGS. 1 and 11, the same reference numerals are given to the same components as those shown in FIGS. A description thereof will be omitted.

  Referring to FIG. 6, the synchronous motor control device 15 includes a control unit 16, a synchronous motor 17, and a high-speed continuous rotation inverter circuit connected to each of the synchronous motors 17 (the first inverter circuit of the claims of the present application). 3), a low-speed rotation inverter circuit (corresponding to the second inverter circuit in the claims of the present application) 4, a medium-speed rotation inverter circuit (third inverter circuit) 18, and the inverter circuits 3, 4 , 18 supplying a common DC voltage (DC power supply) B, main contactor 5, sub contactors 19, 20, speed detector (PG) 12, accelerator command amount detector 13, and battery voltage detection Unit 14 and current sensors 21 and 22.

The synchronous motor 17 is a known motor including a rotor and a stator (not shown). Referring to FIG. 7, the synchronous motor 17 has a high-speed continuous rotation three-phase coil to which an alternating current output is applied from the high-speed continuous rotation inverter circuit 3 on the stator side. U _H , V _H , W _H , and low-speed rotation three-phase coil to which an AC output is applied from the low-speed rotation inverter circuit 4 (corresponding to the second multi-phase coil in the claims of this application) _UL have _V L, and _{W L,} three-phase coils speed type rotary While AC output from the medium-speed rotary inverter circuit 18 is applied (third polyphase _coil) U _M, V M, and _{W M} . The synchronous motor 17 rotates a rotor having a permanent magnet at a desired rotation speed by a rotating magnetic field generated by these three-phase coils. Here, the high-speed continuous rotation three-phase coils U _H , V _H , and W _H have fewer coil turns than the medium-speed rotation three-phase coils U _M , V _M , and W _M. Further, the three-phase coils _U M speed type continuous rotation for a _medium, V M, _{W M} is a low-speed rotation for three-phase coils _{U L,} V L, number of coil turns is less than _{W L.}
Although not shown, the synchronous motor 17, high speed type continuous rotation for three-phase coils _{U H, V H, W H} , low-speed rotation phase coils _{U L,} V _{L, W} L and the medium-speed type continuous rotation for three-phase It has a shaft mechanism that can separately output or combine and output the rotational force corresponding to the rotating magnetic field generated by each of the coils U _M , V _M , and W _M.

Medium-speed rotary inverter circuit 18, _{U M-phase} upper, _{U M-phase} lower, _{V M-phase} upper, _{V M-phase} lower, _{W M} phase upper six known semiconductor switching elements under _{W M} phase Q13~ The synchronous motor 17 is driven by applying a three-phase AC output to the synchronous motor 17 by the switching operation of these semiconductor switching elements Q13 to Q18.
Connected in series, the semiconductor switching devices Q13, Q14 corresponding to the vertical _{U M} phase, the semiconductor switching elements Q15, Q16 corresponding to _{V M-phase} upper and lower, the semiconductor switching devices Q17, Q18 corresponding to _{W M-phase} upper and lower Are connected in parallel between the power supply lines connected to both ends of the battery B.
Further, from the connection point of the semiconductor switching devices Q13~Q18 each other which are connected to each other in series, _{U M-phase} voltage _V UM AC for driving the synchronous motor 17, _{V M-phase} voltage _V VM, _{W M-phase} voltage _{V WM} Is supplied to the synchronous motor 7. _{Here, I UM, I VM, I} WM , respectively _{U M-phase} current, _{V M-phase} current shows a _{W M-phase} current. 21 and 22 in FIG. 6, each _{U M-phase} current, a current sensor for detecting the _{V M-phase} current. Incidentally, W _M-phase current, since those obtained by summing the U _M-phase current and the V _M-phase current, a current sensor for W _M-phase current is not provided. A capacitor _CM is connected in parallel to the input side of the medium speed type inverter circuit 18 for rotation.

  The main contactor 5 is provided between the battery B and each of the inverter circuits 3, 4, 18, and switches supply of DC voltage from the battery B to the inverter circuits 3, 4, 18 or switching of supply stop. Is what you do. The sub-contactor 19 is provided between the high-speed continuous rotation inverter circuit 3 and the low-speed rotation inverter circuit 4 and switches the connection between the inverter circuits 3 and 4. The sub-contactor 20 is provided between the high-speed continuous rotation inverter circuit 3 and the medium-speed rotation inverter circuit 18 and switches the connection between the inverter circuits 3 and 18.

The control unit 16 includes an input unit 16a, an MPU (Micro Processor Unit) 16b, and an output unit 16c. The control unit 16 controls the AC output of each of the inverter circuits 3, 4, and 18, as well as the main contactor 5 and the sub contactor 19. , 20 is controlled.
The input unit 16a, _{U M-phase} signal related to _{U M-phase} current, _{V M-phase} signal related to _{V M-phase} current, is input.
The MPU 16b executes processing necessary for controlling the synchronous motor 17 based on the signal input to the input unit 16a.
The output unit 16c uses the control signal processed by the MPU 16b to give necessary instructions (outputs) to the inverter circuits 3, 4, 18, the main contactor 5 and the sub contactors 19, 20.

  FIG. 8 is a flowchart for explaining the operation of the control device 15 for the synchronous motor of the present invention, and shows a procedure executed by the control unit 16. FIG. 9 is a graph showing a torque-rotation speed (rotation speed) characteristic for explaining a driving state of the synchronous motor control device 15 of FIG. Hereinafter, this procedure will be described with reference to FIGS.

First, the main contactor 5 is turned on by the control unit 16 (step S15). Subsequently, a battery voltage signal _{V B} is input to the input unit 16a (step S16), and the speed signal V and the accelerator instruction signal A is input to the input unit 16a (step S17).
Then, the MPU 16b compares the speed signal V with preset speed reference signals V ₁ and V ₂ (where V ₁ <V ₂ ) (step S18). Here, the speed reference signal V _1, V _2, which is set in advance, respectively, the battery voltage signal V _B and a predetermined product of the gain G _1, defined by the product of the battery voltage signal V _B and a predetermined gain G ₂ ( _{However, G} 1 _<G 2).
In step S18 described above, if the speed signal V is less than the speed reference signal _{V 0} (V _<V 0), i.e. it is determined that the driving state of the low-speed (low rotation), the sub-contactors 19 and 20 are both turned on (step S19 ). By this step S19, the synchronous motor 17 corresponds to the torque values (torque values) as three AC outputs of the high-speed continuous rotation inverter circuit 3, the low-speed rotation inverter circuit 4, and the medium-speed rotation inverter circuit 18. It is in a state where it can be driven at (current value) (first 'drive mode). This corresponds to the driving state in the region 1 ′ and the region 2 ′ shown in FIG.
Further, in step S18 described above, if the speed signal V is determined that the driving state of the speed reference signal _{V 1} or _V less than _{2 (V 1} ≦ V _<V 2), i.e. medium speed (middle speed), the sub-contactor 19 It is turned off and the sub-contactor 20 is turned on (step S20). By this step S20, the synchronous motor 17 is driven by the torque value (current value corresponding to the torque value) as the AC output of both the high-speed continuous rotation inverter circuit 3 and the medium-speed rotation inverter circuit 18. (Second driving mode). This corresponds to the driving state in the region 3 ′ shown in FIG. At this time, the low-speed rotation inverter circuit 4 is disconnected from the battery B, but is controlled by the control unit 16 so that the torque value 0 (current value 0) is commanded.
Further, if it is determined in step S18 that the speed signal V is equal to or higher than the speed reference signal V ₂ (V ₂ ≦ V), that is, a high speed (high rotation) driving state, both the sub contactors 19 and 20 are turned off ( Step S21). By this step S21, the synchronous motor 17 is driven with a torque value (current value corresponding to the torque value) as an AC output of only the high-speed continuous rotation inverter circuit 3 (third 'drive mode). . This corresponds to the driving state in the region 4 ′ shown in FIG. At this time, the low-speed rotation inverter circuit 4 and the medium-speed rotation inverter circuit 18 are both disconnected from the battery B, but controlled so that the torque value 0 (current value 0) is commanded by the control unit 16. Is done.

Next, in order to achieve a high torque in the low-speed driving state, the MPU 16b calculates a necessary torque value T for the synchronous motor 17 based on the speed signal V and the accelerator command signal A (Steps S22, S23, S24). In order to output the necessary torque value T to the synchronous motor 17, torque values (torques) required for the high-speed continuous rotation inverter circuit 3, the medium-speed rotation inverter circuit 18 and the low-speed rotation inverter circuit 4 are respectively set. Current value corresponding to the value) is calculated as follows. However, in order to simplify the description, the high-speed continuous rotation inverter circuit 3 and the medium-speed rotation inverter circuit 18 are always driven with an AC output corresponding to the maximum torque value (output), and the inverter circuits 3 , 18 can only output an AC output corresponding to the required torque value T for the synchronous motor 7 so that the low-speed rotation inverter circuit 4 can output an AC output corresponding to the difference torque value. The case of driving 3, 4, 18 will be described.
First, the required torque value T is compared with a preset torque reference value T ₀ (the sum of the maximum torque value of the high-speed continuous rotation inverter circuit 3 and the maximum torque value of the medium-speed rotation inverter circuit 18) T _0. (Step S25). In this step S25, the control unit 16, if determined necessary torque value T calculated in step S22 is less than the torque reference value T ₀ and (T <T _0), the low-speed rotation inverter circuit 4, the necessary A torque value of 0 is commanded as a torque value (step S26). This corresponds to the driving state in the region 1 ′ shown in FIG. In Step S25, if the control unit 16 determines that the necessary torque value T calculated in Step S22 is equal to or greater than the torque reference value T ₀ (T ≧ T ₀ ), the control unit 16 As a necessary torque value, a difference value (T−T ₀ ) between the necessary torque value T and the torque reference value T ₀ is commanded (step S27). This corresponds to the driving state in the region 2 ′ shown in FIG.
Then, according to the result of step S26, S27, an AC output corresponding to the torque value required for the low-speed rotary inverter circuit 4 0 or (T-T ₀₎ is, for synchronous motor 17 from the inverter circuit 4 This is output (step S28). Then, an AC output corresponding to a torque value necessary for the medium-speed rotating inverter circuit 18 is output from the inverter circuit 18 to the synchronous motor 17 (step S29). Further, an AC output corresponding to a torque value required for the high-speed continuous rotation inverter circuit 3 is output from the inverter circuit 3 to the synchronous motor 17 (step S30). Therefore, the synchronous motor 17 can be driven by three AC outputs of the high-speed continuous rotation inverter circuit 3, the medium-speed rotation inverter circuit 18, and the low-speed rotation inverter circuit 4 in the low speed range. High torque in the motor control device 15 can be realized.
After step S23, the control unit 16 commands the low-speed rotation inverter circuit 4 to have a torque value of 0 as a necessary torque value (step S31). This corresponds to the driving state in the region 3 ′ shown in FIG. 9, and, as described above, the low-speed rotation inverter circuit 4 is disconnected from the battery B by the control unit 16, but the torque is 0 (current 0). It is in a controlled state. Then, according to the result of step S31, an AC output corresponding to the torque value required for the medium-speed rotation inverter circuit 18 is output from the inverter circuit 18 to the synchronous motor 17 (step S29). Further, an AC output corresponding to a torque value required for the high-speed continuous rotation inverter circuit 3 is output from the inverter circuit 3 to the synchronous motor 17 (step S30).
Further, after step S24, the control unit 16 instructs the low-speed rotation inverter circuit 4 to have a torque value 0 as a necessary torque value (step 32), and then sends the medium-speed rotation inverter circuit 18 to the medium-speed rotation inverter circuit 18. A torque value 0 is commanded as a necessary torque value (step 33). This corresponds to the drive state in the region 4 ′ shown in FIG. 9, and, as described above, the control unit 16 causes the low-speed rotation inverter circuit 4 and the medium-speed rotation inverter circuit 18 to be connected to the battery B. However, it is in a state controlled by a torque value 0 (current value 0). And according to the result of step S32, S33, the alternating current output corresponding to the torque value required for the inverter circuit 3 for high speed type | mold continuous rotation is output with respect to the synchronous motor 17 from the said inverter circuit 3 (step S30). . Therefore, in the high speed range, the synchronous motor 17 can be driven up to a high speed with only the AC output of the high-speed continuous rotation inverter circuit 3, so that a high speed in the synchronous motor control device 15 can be realized.
Finally, the control unit 16 repeats steps S15 to S33 until the synchronous motor 17 is driven with a desired operation, and performs control so as to obtain an optimal drive mode and necessary torque value.

(Comparison result 2)
FIG. 10 is a graph showing torque-rotation speed (rotational speed) characteristics for comparing the synchronous motor control device 15 of FIG. 6 with the conventional synchronous motor control device 23.
Referring to FIG. 10, (a ′) is a graph showing the torque-rotation speed characteristics when the synchronous motor 17 is driven by the AC output of only the high-speed continuous rotation inverter circuit 3, and (b ′) is the graph. , A graph showing torque-rotation speed characteristics when the synchronous motor 17 is driven by an AC output of only the low-speed rotation inverter circuit 4, (c ′) is a graph showing the synchronous motor 17 and the medium-speed rotation inverter circuit; 18 is a graph showing torque-rotational speed characteristics when driven with only 18 AC outputs, (A ′) is a combination of (a ′) to (c ′) in the synchronous motor control device 15 of FIG. It is a graph which shows a torque-rotation speed characteristic.
As is apparent from FIG. 10, in the conventional synchronous motor control device 23, the synchronous motor is only within the range of the torque-rotation speed characteristics shown in (a ′), (b ′), or (c ′). However, in the synchronous motor control device 15 of FIG. 6, the synchronous motor 17 can be driven within the range of the torque-rotation speed characteristic shown in (A ′).
Therefore, the synchronous motor control device 15 of FIG. 6 can achieve both high torque and high rotation as compared with the conventional synchronous motor control device 23.

The present invention is not limited to the above-described embodiments, and various modifications other than those described above can be made without departing from the spirit of the present invention.
For example, in the first embodiment and the modification, the case where two inverter circuits are provided has been described, but the case where three inverter circuits are provided has been described. However, the number of inverter circuits may be further increased, or the multi-phase on the stator side may be increased. The number of coils, the number of contactors, the number of input / output signals to the control unit, and the drive mode state can also be arbitrarily set.
In addition, the structure of the control unit is not limited to the present embodiment, and if it has a configuration for controlling the optimum driving state of the synchronous motor by comparing the speed or the torque value, You may have what kind of composition.
Furthermore, in the present embodiment, the control device for the synchronous motor has been described, but it can be applied to various motor control devices such as an induction motor.

DESCRIPTION OF SYMBOLS 1 Control apparatus of a synchronous motor 2 Control part 2a Input part 2b MPU (Micro Processor Unit)
A current sensor for detecting a current sensor 9 V _H phase current detected and 2c output unit 3 high speed type continuous rotation inverter circuit 4 low-speed rotary inverter circuit 5 main contactor 6 sub contactors 7 synchronous motor 8 U _H phase current 10 U _L Current sensor 11 for detecting phase current V Current sensor 12 for detecting phase _L current Speed detector (PG)
DESCRIPTION OF SYMBOLS 13 Accelerator command amount detection part 14 Battery voltage detection part 15 Synchronous motor control apparatus 16 Control part 16a Input part 16b MPU (Micro Processor Unit)
16c output unit 17 synchronous motor 18 medium-speed rotary inverter circuit 19 sub-contactor 20 sub contactors 21 _U current sensor 23 for detecting the current sensor 22 _{V M-phase} current for detecting the _M-phase current synchronous motor control device 24 Inverter circuit 25 Synchronous motor 26 Current sensor 27 that detects U-phase current Current sensor B that detects V-phase current B Battery C, C _H , C _L , C _M Capacitor PG Pulse generator (pulse generator)
Q1~18 semiconductor switching elements U phase coils U _H Fast type continuous rotation for three-phase coils U _L low-speed three-phase coils U phase coils V three-phase quick-type rotation in _M coil V _H Fast type continuous rotation for rotation three-phase coil V _L low-speed rotation for three-phase coil V _M during fast rotating for three-phase coil W three-phase coil W _H fast type continuous rotation for three-phase coil W _L low-speed rotation for three-phase coil W _M in quick-type Three-phase coils S1 to S33 for rotation Step

Claims (4)

A synchronous motor having a plurality of multi-phase coils including at least first and second multi-phase coils in the stator, and an AC output for generating a rotating magnetic field for each of the plurality of multi-phase coils is individually applied. A control device for a synchronous motor of an electric vehicle, comprising: a plurality of inverter circuits including first and second inverter circuits; and a battery that supplies a common DC voltage to the plurality of inverter circuits.
A main contactor that is provided between the battery and the plurality of inverter circuits and performs switching of supply or stop of supply of the DC voltage from the battery;
At least one sub-contactor provided between the plurality of inverter circuits for switching connection between the plurality of inverter circuits;
Based on the input of an external signal, the switching of each of the main contactor and the sub contactor and the control of the AC output of each of the plurality of inverter circuits are performed, so that the synchronous motor is at least the first and Driving in a plurality of different driving modes including a first driving mode for driving with both AC outputs of the second inverter circuit and a second driving mode for driving with AC output of only the first inverter circuit A control unit,
A speed detector for detecting the rotational speed of the synchronous motor;
An accelerator command amount detector for detecting an accelerator command amount of the electric vehicle;
A battery voltage detector for detecting the voltage of the battery,
Based on the input of the speed signal detected by the speed detection unit as the external signal, the accelerator command signal detected by the accelerator command amount detection unit, and the battery voltage signal detected by the battery voltage detection unit, When the control unit compares the speed signal with a preset speed reference signal and determines that the speed signal is smaller than the speed reference signal, the controller drives the synchronous motor in the first drive mode. When the speed signal is determined to be greater than the speed reference signal , the synchronous motor control device drives the synchronous motor in the second drive mode . The synchronous motor control device according to claim 1, wherein the speed reference signal is determined by a product of the battery voltage signal and a predetermined gain. 3. The synchronous motor control device according to claim 1, wherein the first multi-phase coil has a smaller number of coil turns than the second multi-phase coil. 4. Based on the input of the speed signal and the accelerator command signal, the control unit further calculates a required torque value for the synchronous motor and outputs the required torque value from the synchronous motor. 4. A torque value required for each of the two inverter circuits is calculated, and each of the required torque values is commanded to the first and second inverter circuits as an AC output. The control apparatus of the synchronous motor as described in 2.

Images