Hello, everyone. I'm [INAUDIBLE]. I am systems engineer in motorized team at Texas Instruments. Today I am going to demonstrate how safety functions can be integrated in variable speed drives.

All the safety functions should satisfy the requirements defined in part 5-2 of the IEC standard 61800 for variable speed drive systems.

This is the complete setup of the demonstration. The motor in this picture has an electromagnetic break inside it. It's free to rotate as long as 24 volts is supplied to the coil of the brake. When the 24 volt supply is disconnected from the brake, it gets held, thereby stopping the motor from making any further rotation.

Now, let's have a look at the function of each GI design one by one. The three phase induction motor is connected to TIDA 1420, which is a basic isolated, compact, three phase power stage.

The power inverter has six switches that are controlled to generate three phase AC output from the DC bus. This reference design uses UCC 53XX basic isolated gauge drivers intended to drive motors for various industrial applications.

The key benefits of this design are low pin count gate driver, which enables compact solution and increased flexibility of gate driver placement. Availability of driver with source/ sink currents up to 10 amperes eliminates the use of external current buffers.

Availability of pin to pin compatible family of gate drivers with source/ sink rating from 0.5 amps to 10 amperes. UVLO detection with reference to emitter provides robust protection of IGBT against operation in linear region.

Miller clamp version enables the use of unipolar power supply to drive IGBTs, simplifying the IGBT gate drive power supply requirements.

TIDA 1420 uses four isolated bipolar supply rails. Three for the three topside gate drivers with 100 milliamps output current each. And one for the three bottom side gate drivers with 300 milliamps output current capacity.

The power supply for driving the gate drivers is taken from another TI design, TIDA 199. This reference design uses a flyback topology, and is intended to operate from an unregulated 24 volts DC input.

This reference design is implemented with LM 5160, a wide input constant on time, synchronous buck regulating.

The key benefits of this design are primary side regulation, which eliminates the need for feedback circuitry, and simplifies the design. Tight load cross regulation, with peak efficiency of 82% at balanced full load. High switching frequency, which reduces the transformer size.

TIDA 1599 is a redundant dual channel reference design for safe toggle in variable speed drives. IEC 61800-5-2 defines STO or safe toggle as a function that prevents torque producing power from supplying the motor.

This design accomplishes a steel functionality where enabling or disabling the power to the isolated gate driver IC to the load switches on VCC1 and VCC2. The TPS 27S 100 is a high side switch capable of powering gate drive power supply, and drives with a rating up to megawatts of power. The high accuracy current monitoring feature of TPS 27S 100 enables intelligent control of the load.

The key benefits of this design are, it's a single fault tolerant system. Plus minus 60 volts input tolerance with the reverse polarity protection helps ensure that steel pins are projected in case of faults, with negligible reverse current.

The use of load switch eliminates discrete FET, which helps in system integration and optimization. Controlled rise time reduces inrush current, and quick output discharge controls the fall time of the device.

The external holding brake of the motor is powered through TIDA 1600. The holding brake is latched when the power supply is cutoff, and released when the voltage is applied to the coil. This setup is accomplished by enabling and disabling the smart electronic load switches that supply power to the coil.

This design uses TPS 27S 100 as a high slide smart switch, and the ULN 2003 as a low side switch. The TPS 27S 100 enables the design to detect open circuit and short circuit conditions at the break output, enhancing the safety of the system.

Output voltage from the brake coil is reduced through the PWM on the low side switch, thus, reducing the power consumption while the brake is energized. The key benefits of this design are, it's a single fault tolerant system. It enhances system reliability by avoiding electromechanical relays. It reduces power dissipation in the holding brake by 20% to 40%. The use of load switch eliminates discrete FET and helps its system integration and optimization.

The induction motor control is achieved by PWF control. PWF signals generated from the MCU control the six IGBT switches. In case of an emergency, as soon as the push button is pressed, the STO signal activates. When the STO signal goes low, TIDA 1599 stops supplying 24 volts to the input of the power supply design.

The gate driver turns off. And the motor goes down to zero. At the same time, a control signal hold brake is signaled by the microcontroller. This control signal disconnects the 24 volt supply to the electromagnetic brake of the motor. And the brake is held.

Let's have a look at the demonstration. This is TIDA 1420, which is a three phase power stage. The inverter section is composed of a six pack IGBT module, which is below the board. It uses shunt based precision current sensing done with AMC1306. Each IGBT of the module is driven by a basic isolated gate driver, UCC5390.

The primary side of the gate driver takes 3.3 volts as input. This [INAUDIBLE] side of the gate driver uses bipolar 15 minus eight volt supply rails. These rails are generated by TIDA 199, or DC to DC, which uses flyback converter LM5160 to generate 2.3 volt per IGBT.

It is powered from 24 volts input, and provides four isolated rails of 15 and minus 8 volts. The 24 volts input to the power supply is controlled by the SGO signal through TIDA 1599. The SGO signal, in this case, is modeled using an emergency shutdown button.

The smart switch TPS27S100 disables the gate driver power supply whenever the SGO is triggered. There is also [INAUDIBLE] channel to disable the primary supply of the gate driver.

A motor with indicated electromagnetic brake is connected to the three phase inverter bridge. The 24 volt supply to the brake coil disengages the break, which enables the shaft to rotate freely. This 24 volts input to the brake is controlled by TIDA 1600, which implements save brake control function. The brake control and feedback signals are isolated from MCU through digital isolator ISO7142.

Channel one is a 24 volts SGO signal. Channel two is used to power up TIDA 1599. Channel three supplies 5 volts to the primary side of the gate drivers on TIDA 1420.

Channel one and two of this power supply powers up TIDA 1600. Let's turn on the DC bus voltage. And here I generate the PWM signals. You can see the motor has started to run.

Now, let's have a look at the waveforms. The blue waveform is the motor phase current. The yellow waveform is a gate drive power supply. It's a secondary power supply between 0 and minus 8 volts.

The green waveform is a brake control signal. It's 3.3 volts. I'll change the scale here. I'll press single. Maybe go back the same scale. And now I press the emergency button.

Let's have a look on the waveforms. The gate supply for minus 8 volts, it became, again, 0 volts. The motor current, it stopped. And after a significant amount of time, this is the brake control signal. So it get activated. It's an active low signal. And our motor gate's latched.

This was all about the demonstration. For more information, you can visit TI.com. Thank you.