TDPV1000E0C1-KIT

TDPV1000E0C1 Application Note: TDPV1000E0C1 Single-Phase Inverter Evaluation Board 1. Introduction The TDPV1000E0C1 inverter kit from Transphorm provides an easy way to evaluate the performance advantages of GaN power transistors in various inverter applications, such as solar and UPS. The kit provides the main features of a single-phase inverter in a proven, functional configuration, operating at or above 100kHz. At the core of the inverter are four GaN transistors configured as a full bridge. These are tightly coupled to gate-drive circuits on a board which also includes flexible microcontroller options and convenient communication connection to a PC. The switch-mode power signals are filtered to provide a pure sinusoidal output. Fig. 1. Single-Phase Inverter Evaluation Board December 16, 2014 jc TDPV1000E0C1 The control portion of the circuit is designed around the popular C2000TM* family of microcontrollers from Texas Instruments. information directly from TI. Source code is available along with related support In addition to this general resource, however, Transphorm provides original firmware which comes loaded in flash on the microcontroller. The source code, configured as a complete project, is also provided on the USB memory stick which comes with the kit. This project is a convenient starting point for further developments. The microcontroller itself resides on a small, removable control card, supplied by TI, so that different C2000 devices may be used if desired. The schematic for the TDPV1000E0C1 circuit board is provided on the USB memory stick. *C2000™ is a trademark of Texas Instruments Incorporated. Kit Contents The kit comprises  A TDPV1000E0C1 single-phase inverter assembly  A Texas Instruments F28035 controlCARD  A 12V power supply with universal AC adaptors  Related media (documentation and software) on a USB memory stick  Cable for, high-voltage DC input December 16, 2014 jc TDPV1000E0C1 Warning While this kit provides the main features of an inverter, it is not intended to be a finished product. Our hope is that this will be a tool which allows you to quickly explore ideas which can be incorporated in your own inverter design. Along with this explanation go a few warnings which should be kept in mind: To keep the design simple and to provide ready access to signals of interest, high-voltages are present on exposed nodes. It is up to you to provide adequate safeguards against accidental contact, or use by unqualified personnel, in accordance with your own lab standards. There is no short-circuit or over-current protection provided at the output. Current-sense devices are connected to the AC outputs, and may be used for over-current protection, but it should not be assumed that the firmware, as delivered, includes such a feature. 2. TDPV1000E0C1 Input/output Specifications: • Input: 0-400Vdc: • Output: Vdc / 2 Vrms at 50/60Hz*, up to 1000VA; • PWM Frequency: 100kHz to 200 kHz** • Auxiliary Supply (Vgg): 12Vdc. * The output frequency may be changed in the software. As delivered it is 60Hz. ** The switching frequency may be changed in the software. As delivered it is 100kHz. 3. Circuit Description Overview Refer to Figure 2 for a block diagram of the inverter circuit. A detailed schematic is also provided in pdf format on the USB stick which comes with the kit. December 16, 2014 jc TDPV1000E0C1 The TDPV1000E0I inverter is a simple full-bridge inverter. Two GaN half bridges are driven with pulse-width modulated command signals to create the sinusoidally varying output. The output filter largely removes the switching frequency, leaving the 50/60Hz fundamental sinusoid. The high-frequency (100kHz+) PWM signals are generated by the TI microcontroller and connected directly to high-speed, high-voltage gate drivers. A connection for external communication to the microcontroller is provided by an isolated USB interface. Except for the high-voltage supply for the power stage, all required voltages for the control circuitry are derived from one 12V input. Fig .2. Circuit block diagram The inverter takes advantage of diode-free operation*, in which the freewheeling current is carried by the GaN HEMTs themselves, without the need of additional freewheeling diodes. *US patent 7,965,126 B2 December 16, 2014 jc TDPV1000E0C1 For minimum conduction loss, the gates of the transistors are enhanced while they carry the freewheeling current. The high and low-side Vgs waveforms are therefore pairs of non- overlapping pulses, as illustrated in Figure 3. Figure 3: non-overlapping gate-drive pulse. A is a deadtime set in the firmware Gate Drivers High-voltage integrated drivers supply the gate-drive signals for the high and low-side power transistors. These are 600V high-and-low-side drivers (Silicon Labs Si8230 family), specifically chosen for high-speed operation without automatic deadtime insertion. The deadtime between turn-off of one transistor in a half bridge and turn-on of its mate is set in the firmware. Output Filter A simple LCL filter on the output (L3, L4, C37, and C54-57) attenuates the switching frequency, producing a clean sinusoidal waveform for output connections at terminals J4 and J5. The filter inductors and capacitors used on the demo board were chosen to provide an optimal combination of benefits: low loss, good attenuation of the switching frequency, and small size. Consult the schematic and/or bill of materials to verify values, but in general the cutoff frequency will be around 5-10kHz, to accommodate 100kHz switching. The inductors have powder cores with relatively low permeability (60-90) and soft saturation characteristics. The inductors and/or capacitors can be changed to evaluate different filter designs. Current sensing Hall sensors U8 and U10 provide linear current feedback to the microcontroller. These signals could be used to control output power flow, and/or to protect against short circuits. The firmware provided with the kit, however, does not actually make use of this feedback. Note that these are placed at an intermediate point of the output filter Refer to the bill of materials to confirm the sensor part numbers, but typical would be the Allegro ACS712-20A sensor, which December 16, 2014 jc TDPV1000E0C1 has a ±20A range (100mV/A). These parts are pin compatible with ±5A and ±30A versions of the ACS712, should higher or lower ranges be desired. Note also that resistor dividers scale the 5V outputs for the 3V range of the A/D. Communication Communication between the microcontroller and a computer is accomplished with a standard USB cable. The isolated USB interface enables simultaneous operation of two physical ports to the microcontroller: a JTAG port for debug and loading of firmware, and a UART for communication with a host application. Control Card The microcontroller resides on a removable card, which inserts in a DIM100 socket on the inverter PCB. The socket can accept many of the C2000TM series controlCARDs from Texas Instruments. The TMDSCNCD28035 Piccolo controlCARD supplied with the kit provides capability to experiment with a wide variety of modulation and control algorithms. It comes loaded with firmware to allow immediate (out-of-the-box) operation. Should the user wish to use an alternate microcontroller family, an appropriate control card can be designed to insert into the DIM100 socket. Heat Sink The two TO-220 GaN transistors of each half bridge are mounted to a common heat sink. The heat sink is adequate for 1000W operation without forced air flow. Even higher efficiency at high power may be achieved by minimizing the temperature rise. This may be accomplished with forced airflow. Alternately the heat sinks could be replaced with larger or more effective ones. Connections Power for the AC output is derived from the HV DC input. This will typically be a DC power supply with output voltage up to 400Vdc. A 22uF, low ESR, film capacitor is provided as a bypass capacitor for the HV supply, along with several lower valued ceramic capacitors in December 16, 2014 jc TDPV1000E0C1 parallel. This is not intended to provide significant energy storage. It is assumed that the power supply or preceding DC-DC stage contains adequate output capacitance. The control, communication, and gate-drive circuits are all powered from a single 12V input (Vgg). The wall-plug adaptor provided generates the appropriate voltage (typically 12V) and power level. Note that only the USB port is isolated; all other signals on the board are referenced to the negative terminals of the high and low voltage supplies, which are tied together on the PCB. The heat sinks are also connected to the negative terminal of the supplies. Connection sequence Refer to figure 5. Insert the microcontroller card in the DIM100 connector before applying any power to the board. To use the preloaded firmware, verify that jumper JP1 is removed. This releases the JTAG port and allows the microcontroller to boot from flash. For communication with a host over the JTAG port, JP1 should be installed. With the supply turned off, connect the high-voltage power supply to the +/- inputs (J2 and J3). If a load is to be used, connect it to the output terminals (J4 and J5). Insert the Vgg (12V) plug into jack J1. LED1 should illuminate, indicating power is applied to the 5V and 3.3V regulators. Depending on the specific control card used, one or more LEDs on the control card will also illuminate, indicating power is applied. A flashing LED indicates the firmware is executing. To use the pre-loaded firmware no computer connection is required. If a computer connection is required for code modification, connect the USB cable from the computer to the USB connector (CN3). LED2 should illuminate, indicating isolated +5V power is applied over the USB cable. Turn on the high voltage power. The high-voltage supply may be switched on instantly or raised gradually. December 16, 2014 jc TDPV1000E0C1 Figure 5: Connections Test Figure 6 shows typical waveforms. The negative terminal of the high-voltage supply is a convenient reference for oscilloscope measurements, provided there are not multiple connections to earth ground. Typical efficiency results are shown in Figure 7. These data points correspond to efficiency measurements made in still air with 20 minutes dwell at each power level. Input power from the 350Vdc source and output power to a resistive load were measured with a Yokogawa WT1800 power analyzer. December 16, 2014 jc TDPV1000E0C1 99.00 45 98.75 40 98.50 35 98.25 30 98.00 25 97.75 20 97.50 15 97.25 10 97.00 5 96.75 0 1400 0 200 400 600 800 1000 1200 Output Power (W) Figure 7. Typical Efficiency 350Vdc input, 240Vac output December 16, 2014 jc Loss (W) Efficiency (%) Figure 6. Typical Waveforms TDPV1000E0C1 Bill of Materials Qt y 2 Value Device Parts Manf Manf P/N 529802B02500G HS1, HS2 529802B02500G CSTCR X1 Aavid Thermalloy Murata 1 2 CSTCR6M00G53 Z-R0 ES1J CSTCR6M00G53Z-R0 DIODE-DO-214AC D1, D2 Fairchild ES1J 4 120Ohm FB0603 FB1, FB2, FB3, FB4 TDK MMZ1608Q121B 4 7691 KEYSTONE_7691 J2, J3, J4, J5 Keystone 7691 2 SML-211UTT86 LEDCHIP-LED0805 LED1, LED2 Rohm SML-211UTT86 2 320uH MAGINC_TVH49164A L3, L4 CWS 1 961102-6404-AR PINHD-1X2 JP1 3M Mag-Inc 77083 core; 63 turns AWG18 961102-6404-AR 1 PJ-002AH-SMT PJ-002AH J1 CUI Inc PJ-002AH-SMT 1 USBSHIELD CN2 Mill-Max 897-43-004-90-000000 2 897-43-004-90000000 .1u C-EUC1812 C49, C53 Kemet C1812V104KDRACTU 24 .1u C-USC0603 AVX 06033C104JAT2A 5 .1u C-USC0805 C1, C14, C16, C17, C19, C20, C21, C22, C23, C24, C25, C26, C27, C28, C29, C30, C31, C33, C34, C38, C39, C40, C42, C43 C5, C6, C7, C8, C9 AVX 08053C104KAT2A 5 .1u C-USC2225K C10, C54, C55, C56, C57 Vishay VJ2225Y104KXGAT 2 5.76k R-US_R0603 R21, R28 Yageo RC0603JR-070RL 1 0 R-US_R1206 R7 Panasonic ERJ-8GEY0R00V 1 1M R-US_R0603 R14 Rohm MCR03EZPFX1004 2 1k R-US_R0603 R8, R15 Rohm MCR03EZPJ102 1 1k R-US_R0805 R1 Panasonic ERJ-6GEYJ102V 2 1n C-USC0603 C36, C45 AVX 06035C102KAT2A 2 1u C-USC0603 C12, C18 Yageo 1 2.2u C-USC0603 C15 AVX CC0603KRX5R6BB10 5 0603YD225MAT2A 2 2k2 R-US_R0603 R13, R17 Panasonic ERJ-3GEYJ222V 1 2u/630V B32674D6225K C37 Epcos B32674D6225K 6 4.7n C-EUC1206 Kemet C1206C472KDRACTU 2 5.23k R-US_R0603 C46, C47, C48, C50, C51, C52 R19, R26 Panasonic ERJ-3EKF5231V 3 9.09k R-US_R1206 R6, R24, R31 Panasonic ERJ-8ENF9091V 2 10 R-US_R0805 R18, R25 Panasonic ERJ-6GEYJ100V 2 10.2k R-US_R0603 R22, R29 Panasonic ERJ-3EKF1022V 1 10MEG R-US_R1206 R5 Stackpole HVCB1206FKC10M0 2 10k R-US_R0603 R12, R16 Panasonic ERJ-3GEYJ103V December 16, 2014 jc TDPV1000E0C1 4 10u C-EUC0805 C32, C35, C41, C44 Kemet C0805C106M4PACTU 1 10u C-USC1206 C4 AVX 12063D106KAT2A 1 22u C-USC1206 C2 AVX 12103D226KAT2A 2 22u FB0805 L1, L2 Murata LQM21FN220N00L 2 27 R-US_R0603 R10, R11 Vishay CRCW060327R0FKEA 1 93LC46B 93LC46B U6 Microchip 93LC46BT-I/OT 1 100n C-US075-032X103 C13 AVX SA111E104MAR 1 100u PANASONICFPV C3 Panasonic EEE-FPE101XAP 1 348 R-US_R0805 R2 Panasonic ERJ-6ENF3480V 1 470 R-US_R0603 R9 Rohm ESR03EZPF4700 6 560k R-US_R1206 Yageo RC1206FR-07560KL 2 ACS712 ACS712 R3, R4, R20, R23, R27, R30 U8, U10 ACS712ELCTR-20A-T 1 BAW567 BAW567 DA1 Allegro Microsyste ms Diodes Inc 1 DIM100_TICONT CN1 Molex 876301001 1 FT2232D ROLCARD DIM100_TICONTROLC ARD FT2232D U5 FTDI FT2232D-REEL 1 ISO7240 ISO7240 IC1 TI ISO7240CDW 1 ISO7242 ISO7242 IC2 TI ISO7242CDW 1 LVC2G74 LVC2G74 U4 TI SN74LVC2G74DCTR 1 22uF/450V C11 Vishay MKP1848622454P4 1 PTH08080WAH PTH08080WAH U2 TI PTH08080WAH 2 SI8230 SI8230 U7, U9 SI8230BB-B-IS1 2 TPH3006PS TPH_TO220VERT_TRI Q1,Q2,Q3, Q4 2 Q1, Q3 insulator Silicon Laboratorie s Transphor m Bergquist 2 Q2, Q4 insulator 1 TPS73033 TPS73033 1 TPS79533 TPS79533 December 16, 2014 jc P4 MKP1848622454P4 BAW567DW-7-F TPH3006PS SP2000-0.015-00-54 U3 Aavid Thermalloy TI 53-77-9G TPS73033DBVR U1 TI TPS79533DCQR