阅读说明：本技术 电机供电系统 (Motor power supply system ) 是由 张宇航 张磊 梁佳杰 于 2020-12-16 设计创作，主要内容包括：本发明公开了一种电机供电系统,变频器由交-直-交电路构成,用于给电动机供电；STO电路充电输入端接变频器直流侧正,其放电输入端接蓄电器负端及双向直流转换器负端,其放电输出端接变频器直流侧正,其充电输出端接双向直流转换器的充电侧输入正,其工作电源输出端用于为驱动模块提供工作电压；双向直流转换器采用桥式电路,其储能侧输出正接蓄电器正端；双向直流转换器设置有一故障采样信号输出端；故障采样信号输出端输出故障采样信号到驱动模块；驱动模块输出诊断信号到STO电路控制端。本发明的电机供电系统,使用STO电路控制储能端蓄电器和电机侧的电流通断,成本低,而且可以解决瞬时大电流的问题。(The invention discloses a motor power supply system.A frequency converter consists of an alternating current-direct current-alternating current circuit and is used for supplying power to a motor; the charging input end of the STO circuit is connected with the direct current side positive end of the frequency converter, the discharging input end of the STO circuit is connected with the negative end of the current condenser and the negative end of the bidirectional direct current converter, the discharging output end of the STO circuit is connected with the direct current side positive end of the frequency converter, the charging output end of the STO circuit is connected with the charging side positive end of the bidirectional direct current converter, and the working power supply output end of the STO circuit is used for; the bidirectional direct current converter adopts a bridge circuit, and the output of the energy storage side of the bidirectional direct current converter is positively connected with the positive end of the accumulator; the bidirectional direct current converter is provided with a fault sampling signal output end; the fault sampling signal output end outputs a fault sampling signal to the driving module; the driver module outputs a diagnostic signal to the control terminal of the STO circuit. The motor power supply system of the invention uses the STO circuit to control the current on-off of the accumulator at the energy storage end and the motor side, has low cost and can solve the problem of instantaneous heavy current.)

1. A motor power supply system is characterized by comprising a frequency converter (11), an accumulator on-off device (30) and an accumulator (23);

the frequency converter (11) is composed of an alternating current-direct current-alternating current circuit and is used for supplying power to the motor (12) and driving the motor (12) to operate;

the inlet wire end of the frequency converter (11) is used for connecting an external network alternating current power supply, and the outlet wire end is connected with the motor (12);

the accumulator on-off device (30) comprises an STO circuit (301), a driving module (302) and a bidirectional direct-current converter (303);

the charging input end (STO1) of the STO circuit (301) is connected with the direct current side positive of the frequency converter (11), the discharging input end (STO2) of the STO circuit is connected with the negative end of the electric storage device (23) and the negative end of the bidirectional direct current converter (303), the discharging output end (PWR _ OUT _2) of the STO circuit is connected with the direct current side positive of the frequency converter (11), and the charging output end (PWR _ OUT _1) of the STO circuit is connected with the charging side input positive of the bidirectional direct current converter (303); the working power supply output end of the driving module is used for providing working Voltage (VCC) for the driving module (302);

the bidirectional direct current converter (303) adopts a bridge circuit, and the output of the energy storage side of the bridge circuit is positively connected with the positive end of the accumulator (23);

the bidirectional direct current converter (303) is provided with a fault sampling signal output end;

the fault sampling signal output end outputs a fault sampling signal (FB) to the driving module (302);

each PWM signal output end of the driving module (302) is used for respectively outputting a PWM control signal to the control end of each bridge arm power switching tube of the bidirectional direct current converter (303), and the diagnosis signal output end of the driving module outputs a diagnosis signal (DIAG) to the control end of the STO circuit (301);

the driving module (302) outputs PWM control signals normally at each PWM signal output end when in work, and if the fault sampling signal (FB) is inconsistent with the set reference signal, the diagnosis signal (DIAG) output by the diagnosis signal output end is in a first state; if the fault sampling signal (FB) is consistent with the set reference signal, the diagnosis signal (DIAG) output by the diagnosis signal output end is in a second state;

the STO circuit (301) is used for enabling the working power supply output end to be 0 voltage when the diagnosis signal output end (DIAG) is in a second state, enabling the driving module (302) to be powered off, enabling the charging input end (STO1) to be disconnected with the charging output end (PWR _ OUT _1), and enabling the discharging input end (STO2) to be disconnected with the discharging output end (PWR _ OUT _ 2); when the diagnosis signal output end (DIAG) is in a first state, the working power supply output end outputs the working voltage of the driving module (302), so that the driving module (302) is powered on to normally work, the charging input end (STO1) is connected with the charging output end (PWR _ OUT _1), and the discharging input end (STO2) is connected with the discharging output end (PWR _ OUT _ 2).

2. Motor power supply system according to claim 1,

the reference signal is set according to a fault sampling signal when the bidirectional direct current converter (303) works normally without a fault.

3. Motor power supply system according to claim 1,

the first state is high level, and the second state is low level; or the first state is low and the second state is high.

4. Motor power supply system according to claim 1,

the accumulator (23) adopts a super capacitor.

5. Motor power supply system according to claim 1,

the motor (12) is a traction motor for driving the elevator car to move up and down.

6. Motor power supply system according to claim 1,

the motor power supply system also comprises a main contactor (10);

the main contactor (10) is arranged between an external network alternating current power supply and a wire inlet end of the frequency converter (11) and controls the on-off of a power supply loop of the external network alternating current power supply to the motor (12).

7. Motor power supply system according to claim 1,

the frequency converter (11) comprises a rectifier (111) and an inverter (112);

the input end of the rectifier (111) is connected with an external network alternating current power supply, and outputs direct current voltage to the input end of the inverter (112);

the inverter (112) inverts the DC voltage at its input to an AC voltage to power the motor (12).

8. A motor power supply system according to claim 7,

the bidirectional direct current converter (303) comprises two power switching tubes, two diodes and a sampling resistor (R);

the power switch tube comprises a control end, a first end and a second end, and the conduction or the cut-off between the first end and the second end is controlled by a PWM signal applied to the control end;

the second end of the first power switch tube (T1) and the first end of the second power switch tube (T2) are connected with a first positive output node (POUT 1);

the positive terminal of the first diode (D1) and the negative terminal of the second diode (D2) are connected to the second positive output node (POUT 2);

the first end of a first power switch tube (T1) and the negative end of a first diode (D1) are connected with the charging output end (PWR _ OUT _1) of the STO circuit (301);

the second end of the second power switch tube (T2) is connected with a negative output Node (NOUT) through a sampling resistor (R);

the positive terminal of the second diode (D2) is connected to the negative output Node (NOUT);

the positive end of the accumulator (23) is connected with the second positive output node (POUT2) and the first positive output node (POUT1), and the negative end is connected with the negative output Node (NOUT);

the fault sampling signal output end is connected with the second end of the second power switch tube (T2);

the driving module (302) outputs a high-side PWM signal (HB _ EN) which is connected with the control end of the first power switch tube (T1), and outputs a low-side PWM signal (LB _ EN) which is connected with the control end of the second power switch tube (T2);

the driving module (302) is used for setting a diagnosis signal output end (DIAG) to be in a first state when the level of a low-side PWM signal (LB _ EN) of the driving module is consistent with the level of the fault sampling signal (FB); when the level of its low-side PWM signal (LB _ EN) does not coincide with the level of said fault sampling signal (FB), its diagnostic signal output (DIAG) is in a second state.

9. A motor power supply system according to claim 8,

the bidirectional direct current converter (303) further comprises a built-in inductor (L);

the built-in inductor (L) is connected between the second positive output node (POUT2) and the first positive output node (POUT 1).

10. A motor power supply system according to claim 8,

and a freewheeling built-in diode is respectively connected between the first end and the second end of each of the two power switching tubes.

11. A motor power supply system according to claim 8,

the first power switch tube (T1) and the second power switch tube (T2) are thyristors, IGBTs or field effect tubes.

Technical Field

The invention relates to elevator driving and control technology, in particular to a motor power supply system.

Background

With the continuous deepening of the urbanization process, more and more buildings start to be pulled out of the ground in the city, and the building space of the city is continuously extending towards the vertical direction, so that the use amount of the vertical lifting elevator is increased. Although vertical elevators provide great convenience for people to transport vertically in buildings, they consume a lot of power.

When the vertical lifting elevator runs, the traction motor is in a regeneration power generation state under the conditions that heavy load is downward, light load is upward and speed is reduced, at the moment, the elevator does not consume electric energy, but part of potential energy of an elevator system is converted into electric energy to be fed back to the elevator system. Currently, energy-saving methods of storing the regenerated energy by using an energy storage device such as a super capacitor and the like and then using the stored energy for an elevator are widely researched and used. Since energy storage devices such as supercapacitors are used to store dc energy, they are usually connected in parallel via a dc converter on the dc side of the elevator frequency converter driving the motor.

According to the requirements of the Chinese national elevator standard GB 7588.1:

5.9.2.5.4 static element power supply and control for AC or DC motor

……

b) A system consisting of:

1) contactor for cutting off current of each phase (pole)

The contactor coil should be released at least before each change of direction of travel. If the contactor is not released, the elevator should be prevented from re-operating. If the monitoring function has a fixed fault, the car is prevented from running again at the latest when the running direction is changed next time; and

2) control means for blocking the flow of current in the static element; and

3) a monitoring device for verifying the current flow interruption at each stop of an elevator.

During normal stopping, if the static element fails to effectively block the flow of current, the monitoring device should release the contactor and should prevent the elevator from re-running.

……

The energy storage device can also supply power to the motor, and a static element for power supply and control is arranged in the direct current converter, so that a direct current contactor for cutting off the current of each stage is required to be arranged. In addition, because the voltage at the direct current side of the direct current converter connected to the frequency converter is higher, and the applicable contactor model is available, the direct current contactor is usually arranged at the side of the direct current converter connected to the energy storage device.

Since direct current does not cross zero periodically like alternating current, it is much more difficult to cut off direct current than to cut off the same alternating current, because the arc it produces is more severe. Therefore, under the same specification, the direct current contactor is larger than the alternating current contactor in volume, and more importantly, the price of the direct current contactor is far higher than that of the alternating current contactor. This makes the cost of the whole installation high, which inhibits the need for such energy saving devices, so that a large energy consumption becomes a common situation when most people choose not to fit such energy saving devices.

Although manufacturers of ac contactors have mentioned in their specifications that ac products can be used on dc circuits, this requires a reduced use and may reduce the service life. More importantly, the class of the direct current circuit is DC-1, that is, the load is a pure resistance or a micro-inductance circuit, and a large inductor is often required to be configured for the direct current converter for charging and discharging the energy storage device. Therefore, it is not feasible to use the ac contactor directly in the above-described elevator apparatus.

As shown in fig. 1, the elevator control device disclosed in chinese patent document CN109516328A includes a first contactor 10, a second contactor 20, an inverter 11, a motor 12, a dc converter 21, a buffer capacitor 22, and an electric storage device 23. This scheme, accumulator 23 can adopt super capacitor, and second contactor 20 can use the lower ac contactor of price to replace dc contactor, has replaced dc contactor with ac contactor with buffer capacitor's mode to realize the electric current break-make of ac contactor control energy storage end and motor side, thereby played control cost, and reduced the effect in space. However, in this solution, when a sufficiently large instantaneous current passes through, the ac contactor cannot necessarily cope with such a situation.

Disclosure of Invention

The invention aims to provide a motor power supply system, which can reduce the cost of the motor power supply system, can also cope with the condition of large current and can solve the problem of instantaneous large current.

In order to solve the technical problem, the invention provides a motor power supply system, which comprises a frequency converter 11, an accumulator on-off device 30 and an accumulator 23;

the frequency converter 11 is composed of an alternating current-direct current-alternating current circuit and is used for supplying power to the motor 12 and driving the motor 12 to operate;

the inlet end of the frequency converter 11 is used for connecting an external network alternating current power supply, and the outlet end is connected with the motor 12;

the accumulator on-off device 30 comprises an STO circuit 301, a driving module 302 and a bidirectional direct current converter 303;

the STO circuit 301 has a charging input terminal STO1 connected to the dc side positive terminal of the inverter 11, a discharging input terminal STO2 connected to the negative terminal of the electric storage device 23 and the negative terminal of the bidirectional dc converter 303, a discharging output terminal PWR _ OUT _2 connected to the dc side positive terminal of the inverter 11, and a charging output terminal PWR _ OUT _1 connected to the charging side input positive terminal of the bidirectional dc converter 303; the output end of the working power supply is used for providing working voltage VCC for the driving module 302;

the bidirectional direct current converter 303 adopts a bridge circuit, and the output of the energy storage side of the bidirectional direct current converter is positively connected with the positive end of the accumulator 23;

the bidirectional direct current converter 303 is provided with a fault sampling signal output end;

the fault sampling signal output end outputs a fault sampling signal FB to the driving module 302;

each PWM signal output end of the driving module 302 is used for outputting a PWM control signal to the control end of each bridge arm power switching tube of the bidirectional dc converter 303, and the diagnosis signal output end thereof outputs a diagnosis signal DIAG to the control end of the STO circuit 301;

the driving module 302, when it works, each PWM signal output end normally outputs a PWM control signal, if the fault sampling signal FB is not consistent with the set reference signal, the diagnostic signal DIAG output by its diagnostic signal output end is in a first state; if the fault sampling signal FB is consistent with the set reference signal, the diagnosis signal DIAG output by the diagnosis signal output end is in a second state;

when the diagnostic signal output terminal DIAG is in the second state, the STO circuit 301 has a working power supply output terminal of 0 voltage, so as to power off the driving module 302, disconnect the charging input terminal STO1 from the charging output terminal PWR _ OUT _1, and disconnect the discharging input terminal STO2 from the discharging output terminal PWR _ OUT _ 2; when the diagnostic signal output terminal DIAG is in the first state, the operating power output terminal outputs the operating voltage of the driving module 302, so that the driving module 302 is powered on to operate normally, the charging input terminal STO1 is connected to the charging output terminal PWR _ OUT _1, and the discharging input terminal STO2 is connected to the discharging output terminal PWR _ OUT _ 2.

Preferably, the reference signal is set according to a fault sampling signal when the bidirectional dc converter 303 normally operates without a fault.

Preferably, the first state is a high level, and the second state is a low level; or the first state is low and the second state is high.

Preferably, the accumulator 23 is a super capacitor.

Preferably, the motor 12 is a traction motor for driving the elevator car to move up and down.

Preferably, the motor power supply system further comprises a main contactor 10;

the main contactor 10 is arranged between an external network alternating current power supply and a wire inlet end of the frequency converter 11 and controls the on-off of a power supply loop of the external network alternating current power supply to the motor 12.

Preferably, the frequency converter 11 comprises a rectifier 111 and an inverter 112;

the input end of the rectifier 111 is connected with an external network alternating current power supply, and outputs direct current voltage to the input end of the inverter 112;

the inverter 112 inverts the dc voltage at its input to an ac voltage to power the motor 12.

Preferably, the bidirectional dc converter 303 includes two power switches T1, T2, two diodes D1, D2, and a sampling resistor R;

the power switch tube comprises a control end, a first end and a second end, and the conduction or the cut-off between the first end and the second end is controlled by a PWM signal applied to the control end;

the second end of the first power switch tube T1 and the first end of the second power switch tube T2 are both connected to the first positive output node POUT 1;

the positive terminal of the first diode D1 and the negative terminal of the second diode D2 are also connected to the second positive output node POUT 2;

the first end of the first power switch tube T1 and the negative end of the first diode D1 are connected to the charging output terminal PWR _ OUT _1 of the STO circuit 301;

the second end of the second power switch tube T2 is connected with a negative output node NOUT through a sampling resistor R;

the positive terminal of the second diode D2 is connected to the negative output node NOUT;

the positive end of the accumulator 23 is connected with the second positive output node POUT2 and the first positive output node POUT1, and the negative end is connected with the negative output node NOUT;

the fault sampling signal output end is connected with the second end of the second power switch tube T2;

the driving module 302 outputs a high-side PWM signal HB _ EN connected to the control terminal of the first power switch transistor T1, and outputs a low-side PWM signal LB _ EN connected to the control terminal of the second power switch transistor T2;

when the level of the low-side PWM signal LB _ EN of the driving module 302 is consistent with the level of the fault sampling signal FB, the diagnostic signal output terminal DIAG of the driving module is in a first state; when the level of the low-side PWM signal LB _ EN does not coincide with the level of the fault sampling signal FB, the diagnostic signal output terminal DIAG thereof is in the second state.

Preferably, the bidirectional dc converter 303 further includes a built-in inductor L;

the built-in inductor L is connected between the second positive output node POUT2 and the first positive output node POUT 1.

Preferably, a freewheeling built-in diode is respectively connected between the first end and the second end of each of the two power switching tubes.

Preferably, the first power switch tube T1 and the second power switch tube T2 are thyristors, IGBTs or field effect transistors.

According to the motor power supply system, the STO (safe interruption torque) circuit 301 is used for controlling the on-off of the current of the accumulator 23 at the energy storage end and the motor side, a direct current contactor with high price and large volume is not needed, the cost of the STO (safe interruption torque) circuit 301 is low, and the cost of the motor power supply system is reduced; moreover, the situation that the alternating current contactor cannot deal with large current when the scheme of adding the buffer capacitor to the alternating current contactor is used can be avoided, and the problem of instantaneous large current can be solved.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the present invention are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic diagram of a conventional elevator control apparatus;

FIG. 2 is an overall schematic of the motor power supply system of the present invention;

FIG. 3 is a schematic view of an accumulator on-off device 30 according to an embodiment of the present invention;

FIG. 4 is a schematic view of a modal 1 current loop when an embodiment of the present invention is used to charge an accumulator;

FIG. 5 is a schematic view of a mode 2 current loop for charging an accumulator in an embodiment of the present invention;

FIG. 6 is a schematic view of a modal 1 current loop when an accumulator discharges in an embodiment of a motor power supply system of the present invention;

fig. 7 is a schematic view of a mode 2 current loop when an accumulator discharges in an embodiment of the motor power supply system of the present invention.

The reference numerals in the figures are illustrated as follows:

10 a main contactor; 11 a frequency converter; a 111 rectifier; 112 an inverter; 12 a motor; 23 an accumulator; 30 an accumulator on-off device; 301STO circuit; 302 a drive module; 303 a bidirectional dc converter; t1 first power switch tube; t2 second power switch tube; d1 first diode; d2 second diode; r sampling resistance; l is provided with an inductor inside.

Detailed Description

The technical solutions in the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

As shown in fig. 1, the motor power supply system includes a frequency converter 11, an accumulator on-off device 30 and an accumulator 23;

the frequency converter 11 is composed of an alternating current-direct current-alternating current circuit and is used for supplying power to the motor 12 and driving the motor 12 to operate;

the inlet end of the frequency converter 11 is used for connecting an external network alternating current power supply, and the outlet end is connected with the motor 12;

the accumulator on-off device 30 includes an STO (safe interruption torque) circuit 301, a drive module 302, and a bidirectional direct current converter (DC-DC) 303;

the STO circuit 301 has a charging input terminal STO1 connected to the dc side positive terminal of the inverter 11, a discharging input terminal STO2 connected to the negative terminal of the electric storage device 23 and the negative terminal of the bidirectional dc converter 303, a discharging output terminal PWR _ OUT _2 connected to the dc side positive terminal of the inverter 11, and a charging output terminal PWR _ OUT _1 connected to the charging side input positive terminal of the bidirectional dc converter 303; the working power supply output terminal is used for providing a working voltage VCC (e.g., 12V, 4.5V) for the driving module 302;

the bidirectional direct current converter 303 adopts a bridge circuit, and the output of the energy storage side of the bidirectional direct current converter is positively connected with the positive end of the accumulator 23;

the bidirectional direct current converter 303 is provided with a fault sampling signal output end;

the fault sampling signal output end outputs a fault sampling signal FB to the driving module 302;

each PWM (pulse width modulation) signal output end of the driving module 302 is used for outputting a PWM control signal to the control end of each bridge arm power switching tube of the bidirectional dc converter 303, and the diagnosis signal output end thereof outputs a diagnosis signal DIAG to the control end of the STO circuit 301;

the driving module 302, when it works, each PWM signal output end normally outputs a PWM control signal, if the fault sampling signal FB is not consistent with the set reference signal, the diagnostic signal DIAG output by its diagnostic signal output end is in a first state; if the fault sampling signal FB is consistent with the set reference signal, the diagnosis signal DIAG output by the diagnosis signal output end is in a second state;

when the diagnostic signal output terminal DIAG is in the second state, the STO circuit 301 has a working power supply output terminal of 0 voltage, so as to power off the driving module 302, disconnect the charging input terminal STO1 from the charging output terminal PWR _ OUT _1, and disconnect the discharging input terminal STO2 from the discharging output terminal PWR _ OUT _ 2; when the diagnostic signal output terminal DIAG is in the first state, the operating power output terminal outputs the operating voltage of the driving module 302, so that the driving module 302 is powered on to operate normally, the charging input terminal STO1 is connected to the charging output terminal PWR _ OUT _1, and the discharging input terminal STO2 is connected to the discharging output terminal PWR _ OUT _ 2.

Preferably, the reference signal is set according to a fault sampling signal when the bidirectional dc converter 303 normally operates without a fault.

Preferably, the first state is a high level, and the second state is a low level; or the first state is low and the second state is high.

Preferably, the accumulator 23 is a super capacitor.

In the motor power supply system according to the first embodiment, when the bidirectional direct current converter (DC-DC)303 normally operates, the fault sampling signal FB is not consistent with the set reference signal, the diagnostic signal output terminal DIAG of the driving module 302 is in the first state, so that the operating power supply output terminal of the STO circuit 301 provides the driving module 302 with the operating voltage, the driving module 302 is powered on to operate, each PWM signal output terminal thereof outputs a PWM control signal to the control terminal of each bridge arm power switching tube of the bidirectional direct current converter 303, so as to control the on/off of the bidirectional direct current converter (DC-DC)303, and the charging input terminal STO1 is connected to the charging output terminal PWR _ OUT _1, and the discharging input terminal STO2 is connected to the discharging output terminal PWR _ OUT _2, so that the electric storage device 23 can be normally charged or the electric storage device 23 can be normally discharged. When the bidirectional direct current converter (DC-DC)303 fails, the failure sampling signal FB is consistent with the set reference signal, the diagnostic signal output terminal DIAG of the driving module 302 is in the second state, so that the operating power supply output terminal of the STO circuit 301 is at 0 voltage, the driving module 302 is powered off, the bidirectional direct current converter 303 does not operate, the charging input terminal STO1 is disconnected from the charging output terminal PWR _ OUT _1, the discharging input terminal STO2 is disconnected from the discharging output terminal PWR _ OUT _2, and thus the electric storage device 23 cannot be charged or the electric storage device 23 cannot be normally discharged.

In the motor power supply system according to the first embodiment, the STO (safe interruption torque) circuit 301 is used for controlling the on-off of the current between the energy storage end capacitor 23 and the motor side, a high-price and large-volume direct current contactor is not required, the cost of the STO (safe interruption torque) circuit 301 is low, and the cost of the motor power supply system is reduced; moreover, the situation that the alternating current contactor cannot deal with large current when the scheme of adding the buffer capacitor to the alternating current contactor is used can be avoided, and the problem of instantaneous large current can be solved.

Example two

In the motor power supply system according to the first embodiment, the motor 12 is a hoisting motor for driving the elevator car to move up and down.

Preferably, the motor power supply system further comprises a main contactor 10;

the main contactor 10 is arranged between an external network alternating current power supply and a wire inlet end of the frequency converter 11 and controls the on-off of a power supply loop of the external network alternating current power supply to the motor 12.

In the motor power supply system of the second embodiment, when the elevator runs, the external network alternating current power supply is controlled by the main contactor 10 and sent to the main loop of the elevator, and the motor is driven to rotate through the alternating current-direct current-alternating current change of the frequency converter so as to drive the car to move upwards or downwards. When the elevator car is fully loaded and descends, the weight of the car side is greater than that of the counterweight side, and at the moment, the motor does not consume power according to the characteristics of the traction type elevator, and is in a power generation state due to energy conversion. This part of the energy will be stored to the super capacitor side through the elevator main circuit. Normally, the electric energy converted by the bidirectional direct current converter (DC-DC)303 is sent to the electric storage device 23. STO (safe interruption torque) circuit 301 is used to control the opening and closing of the power supply circuit when accumulator 23 supplies power to the motor.

EXAMPLE III

According to the motor power supply system of the first embodiment, as shown in fig. 3, the frequency converter 11 includes a rectifier 111 and an inverter 112;

the input end of the rectifier 111 is connected with an external network alternating current power supply, and outputs direct current voltage to the input end of the inverter 112;

the inverter 112 inverts the dc voltage at its input to an ac voltage to power the motor 12.

Example four

Based on the motor power supply system of the first embodiment, as shown in fig. 3, the bidirectional dc converter 303 includes two power switching tubes T1, T2, two diodes D1, D2, and a sampling resistor R;

the power switch tube comprises a control end, a first end and a second end, and the conduction or the cut-off between the first end and the second end is controlled by a PWM signal applied to the control end;

the second end of the first power switch tube T1 and the first end of the second power switch tube T2 are both connected to the first positive output node POUT 1;

the positive terminal of the first diode D1 and the negative terminal of the second diode D2 are also connected to the second positive output node POUT 2;

the first end of the first power switch tube T1 and the negative end of the first diode D1 are connected to the charging output terminal PWR _ OUT _1 of the STO circuit 301;

the second end of the second power switch tube T2 is connected with a negative output node NOUT through a sampling resistor R;

the positive terminal of the second diode D2 is connected to the negative output node NOUT;

the positive end of the accumulator 23 is connected with the second positive output node POUT2 and the first positive output node POUT1, and the negative end is connected with the negative output node NOUT;

the fault sampling signal output end is connected with the second end of the second power switch tube T2;

the driving module 302 outputs a high-side PWM signal HB _ EN connected to the control terminal of the first power switch transistor T1, and outputs a low-side PWM signal LB _ EN connected to the control terminal of the second power switch transistor T2;

when the level of the low-side PWM signal LB _ EN of the driving module 302 is consistent with the level of the fault sampling signal FB (waveform change is consistent), the diagnostic signal output terminal DIAG of the driving module is in a first state, and at this time, the second power switch transistor T2 is in an normally-on fault; when the level of the low-side PWM signal LB _ EN does not coincide with the level of the fault sampling signal FB, the diagnostic signal output terminal DIAG thereof is in the second state.

Preferably, the bidirectional dc converter 303 further includes a built-in inductor L;

the built-in inductor L is connected between the second positive output node POUT2 and the first positive output node POUT 1.

Preferably, a freewheeling internal diode is connected between the first terminal and the second terminal of each of the first power switch transistor T1 and the second power switch transistor T2.

Preferably, the first power switch tube T1 and the second power switch tube T2 are thyristors, IGBTs or field effect transistors.

In the motor power supply system of the fourth embodiment, when the electric storage device (super capacitor) 23 is charged, the energy on the dc side of the inverter is transferred to the electric storage device 23. According to the on and off of the first power switch tube T1 of the upper bridge arm, the circuit respectively operates in two modes, mode i is shown in fig. 4: when the first power switch tube T1 of the upper bridge arm is conducted, the energy of the direct current side of the frequency converter is transferred to the super capacitor through the charging output end PWR _ OUT _1 of the STO circuit and the first power switch tube T1 of the upper bridge arm; modality 2 is shown in fig. 5: when the upper arm first power switch T1 is turned off, the energy in the built-in inductor L is transferred to the electric storage device 23 (super capacitor) by conduction of the freewheeling built-in diode of the second power switch T2. When the accumulator (super capacitor) 23 is discharged, the circuit is divided into two modes according to the on and off of the second power switch tube T2, and the mode l is shown in fig. 6: when the second power switch T2 is turned on, the energy of the accumulator (super capacitor) 23 is transferred to the built-in inductor L along with the turn-on of the second power switch T2; modality 2 is shown in fig. 7: when the second power switch T2 is turned off, the energy of the accumulator (super capacitor) 23 and the built-in inductor L is released to the dc side of the inverter through the charging output terminal PWR _ OUT _1 and the discharging output terminal PWR _ OUT _2 of the STO circuit 301, which follow the freewheeling current of the first power switch T1 and the built-in diode.

When the second power switch tube T2 of the lower arm has a fault and cannot be turned off by the low-side PWM signal LB _ EN, that is, when the accumulator (super capacitor) 23 is charged, a current flows from the first power switch tube T1 of the upper arm to the second power switch tube T2 of the lower arm, and at this time, the fault sampling signal FB is abnormal (identical to the waveform change of the low-side PWM signal LB _ EN), a diagnostic signal DIAG in a second state is sent to the control terminal of the STO circuit 301 through the driver 302, and at this time, the STO circuit 301 operates to cut off the charge-discharge circuit. When the accumulator (super capacitor) 23 is charged, the upper and lower bridge arms are simultaneously conducted, so that the electric energy originally flowing through the accumulator (super capacitor) 23 directly flows back to the power grid, and at the moment, the electric energy is not consumed by the regenerative resistor, so that the influence on the motor power supply system is caused. The fourth motor power supply system is implemented, so that the cost of the motor power supply system is reduced, the large current condition can be coped with, and meanwhile, the influence on the motor power supply system due to the normally-on fault of the lower bridge arm switching tube of the half-bridge bidirectional direct current converter 303 can be avoided.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.